BIBLIOGRAPHY PASIWEN, AIZA T. APRIL...
BIBLIOGRAPHY
PASIWEN, AIZA T. APRIL 2010. Effect of Different Mulch Materials on the Growth
and Yield of Lettuce. Benguet State University, La Trinidad, Benguet.
Adviser: Percival B. Alipit, PhD.
ABSTRACT
The study was conducted to evaluate the growth and yield of lettuce as affected by
different mulching materials in April to May.
Results showed that although earlier head formation was observed with the use of
transparent polyethylene plastic and bigger sized heads were developed using black polyethylene
plastic, higher marketable yield at 6.60 t/ha and higher return on investment at 60.06% were
obtained without mulching. Lesser insect and disease incidence were also observed in
unmulched plants.
TABLE OF CONTENTS
Page
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
RESULT AND DISCUSSION
Days to Head Initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Days from Transplanting to Harvest . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Percentage Heading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Polar Circumference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Equatorial Circumference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Average Head Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Marketable Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Non – marketable Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Total Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Computed Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Slug (Deroceras reticulatum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Bacterial Soft rot (Erwinia carotovora) . . . . . . . . . . . . . . . . . . . . . . . . .
18
Cost and Return Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Other Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
INTRODUCTION
Lettuce (Lactuca sativa L.) is a temperate, annual or biennial plant of the daisy
family Asteraceae. It is the most often grown as a leaf vegetable. In many countries, it is
typically eaten cold and raw in salads, hamburgers, tacos and many other dishes. In some
places, including China, lettuce is typically eaten cooked and use of the stem is as
important as use of the leaf. Both the English name and the Latin name of the genus are
ultimately derived from lac, the Latin word for milk referring to the plants milky juice.
Mild in flavors, it has been described over the centuries as a cooling counterbalance to
other ingredients in a salad.
The earliest depiction of lettuce is in the carvings at the temple of Senuscret I at
Karnak, where he offers milk to the God Min, to whom the lettuces was sacred. Later,
Ancient Greek physicians believed lettuce could act as a sleeping inducing agent. The
Romans cultivated it and eventually made its way to France cultivated of the Popal Court
at Avignon Christopher Columbus introduced lettuce to the new world.
There are six commonly recognized groups of lettuce which are classified by head
formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf
shape and color, as well as extended field life, within each of these cultivars groups,
butter head, also called Boston or Bibb, forms loose head; it has a buttery texture. Butter
head cultivars are most popular in Europe, Chinese lettuce types generally have long,
sword shaped, non – head – forming leaves, with a bitter and robust flavors unlike
western types, appropriate for use in stir – fried dishes and stews, Crisphead, also called
Iceberg, which form tight, dense heads that resembles cabbage. They are generally the
mildest of the lettuces, valued for more for their crunchy texture than for flavors.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
2
Cultivars of iceberg lettuce are the most familiar lettuce in the USA. The name iceberg
comes from the way the lettuce was transported in the US starting in the 1920’s on train –
wagons covered in crushed ice, making them look like icebergs, loose leaf, with tender,
delicate and mildly flavored leaves. This group comprises oak leaf and lollorossa lettuces,
Romine lettuce, also called Cos, grows in a long head of sturdy leaves with a firm rib
down the center. Unlike most lettuces, it is tolerant to heat, the Summer Crisp called
Batavian, forms moderately dense heads with a crunchy texture; this type is intermediate
between iceberg and loose leaf types.
Lettuce is a cool – season vegetable and develops best quality under cool, moist
conditions. Lettuce seedling will tolerate a light frost. Temperature between 45°F and
65°F are ideal. Such conditions usually planted in the spring as soon as the ground can be
worked. Butter head and romaine can be grown from either seeds or transplants, due to its
long growing season; crisp head lettuce is grown from transplants. Transplants may be
purchased or started indoors about six weeks before the preferred planting time by .
Mulching is the technique of placing of protective materials on top of the soil.
Mulch comes in two basic forms; organic and non – organic. Mulching also minimizes
weeds growth and also prevents soil splattering during heavy rains. Mulching is also
necessary to the plants to minimize the loss of soil moisture. To some extent, mulching
reduces the temperature of the soil, Grigson (1978).
In the market the prices of commercial mulching materials are high but even
though farmers are still buying and using the products due to this many advantages. What
is not known also is the degree of effectiveness of mulching materials, thus the study
was conducted.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
3
The objective of the study was to determine the effect of the different mulching
materials on the growth and yield of lettuce and to identify the mulching material
appropriate for lettuce production.
This study was conducted at the Horticulture Experiment Area, Benguet State
University, La Trinidad, Benguet from April – May 2009.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
4
REVIEW OF LITERATURE
Description of the Crop
Lettuce plants has a short stem initially (a rosette growth habit), but when it
blooms the stem lengthens and branches, and it produces many flower heads that look
like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is
harvested before it bolts. Lettuce is used as a food plants by the larvae of some
Lepidoptera. The largest lettuce head, of the Salad Bowl cultivar weighted 11 kg (25 lbs)
grown by Colin Bowcock of Willawston, England in 1974.
All lettuce types should be harvested at full size but young and tender. Over
mature lettuce is bitter and woody. Leaf lettuce is harvested by removing individual outer
leaves so that the center leaves can continue to grow. Butter head or romaine types can be
harvested by removing the outer leaves, digging up the whole plants or cutting the plants
about an inch above the soil surface. A second harvested is often possible this way. Crisp
head lettuce is picked when the center is firm, The Columbia Electronic Encyclopedia
(2004).
Nutritional Value
Some lettuce (especially iceberg) has been specifically bred to remove the
bitterness from their leaves. These lettuces have high water content with very little
nutrient value. The more bitter lettuce and the ones with pigments leaves contain
antioxidants.
Lettuce is a fat free, low calorie food. It is a valuable source of Vitamin A and
folic acid. Lactucarium or lettuce opium is a mild opiate like substance that is obtained in
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
5
all types of lettuce. Both the Romans and Egyptians took advantage of this properly
eating lettuce at the end of a meal to induce sleep.
Useful amounts of several nutrients including Vitamin A and C; and minerals
calcium and iron. The nutrient contents are highest in the darker green outer leaves. Low
calories, each heads contains 65 to 70 kilocalories, Grigson (1978).
Soil and Climatic Adaptation
Lettuce can be grown under a wide range of soils, loose, fertile ,sandy loam soils,
well supplied with organic matter are best. The soil should be well drained, moist, but not
soggy. Heavy soils can be modified with well rotted manure, compost or by growing a
cover crops, like most other garden vegetables, lettuce prefers a slight acidic pH of 6.0 to
6.5.
Head lettuce grows best at 15 to 18 °C. germination takes place at a maximum of
5 °C, has an optimum range of 16 to 20 °C, and an optimum germination temperature of
20 °C (depending on the cultivars and type of lettuce). At soil temperatures over 27 °C
germination is poor, Rubatzky and Yamaguchi (1997).
Commercial Importance of the Crop
Lettuce has become a major player in commercial production and marketing of
salad crops. Total production worldwide does not compare with the major cereals crops,
especially rice, corn and wheat, or with other commodities, such as sugars crops, beans
and potatoes. The key word is contemporary use of lettuce is changed; in use of the
various types, in the development of world markets, in methods of marketing and in
methods of production, Whitaker (1974).
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Mulching
Marr (1993) studied the effect of plastic mulch on vegetable. They have
successfully grown muskmelon, tomatoes, peppers, cucumber, watermelons, and okra
using plastics mulch and have shown significant increase in earliness, yield and fruit
quality.
Ricotta and Masiunas (1991) found that mulch plots covered with black
polyethylene conserve more moisture than the un
mulched plot. Likewise, soil temperature increased and sometimes hastened the growth
of the crop, thus leading earlier fruit development.
Assir et al. (1991) found out that the application of clear plastic mulch with or
without a fertilizer did not significantly increase the yield of lettuce grown in the fall
under green house in the Mediterranean mountains in Lebanon. Yield average from 31 to
38 kg/50 heads. Leaf NO3 – N and total P level were higher in mulched than the un
mulched plants and always above the sufficiency level in all treatments.
The Hort. Sci. Dep., University of Florida (1988) found the benefits of
polyethylene mulch and organic mulch on vegetable and fruit production. Firstly, it
increased the yield. The largest benefits from black polyethylene mulch are the increase
in soil temperature in the bed, which promotes faster crop development and earlier yields.
Secondly, it aided in moisture retention. Mulch reduced evaporation from the bed soil
surface. As a result, a more uniform soil moisture regime is maintained and the frequency
of irrigation is reduced. Irrigation is still mandatory for mulched crops so that the soil
under the mulch doesn’t dry out excessively. Thirdly, it inhibits weed growth. Fourthly, it
reduced fertilizer leaching. Fertilizer placed in the bed under the mulch is less subject to
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
7
leaching by rainfall. As a result, the fertilizer program is more sufficient and the potential
exist for reducing traditional amount of fertilizer. Heavy rainfall that floods the bed can
still result in fertilizer leaching. This fertilizer can be replaced if the growers are using
drip irrigation, or it can be replaced with a liquid fertilizer injection wheel. Fifthly, it
decreased the soil compaction. Mulch acts a barrier to the action of rainfall, which can
cause soil crusting, compaction and erosion. Less compaction soil provides a better
environment for seeding emergence and root growth. Sixthly, it protected the fruits.
Mulch reduced rain splashed soil deposited on fruits. In addition, mulch reduced fruit rot
caused by soil inhibiting organism, because there is a protective barrier between the fruit
and the organism. Second to the last, it aided in fumigation. Mulches increased the
effectiveness of the soil fumigant chemical. It did not cause a barrier but allowed a water
layer to form under the mulch and it is this water layer that slowed down the loss of the
fumigant. Lastly, it aided in managing other pest. Highly reflective mulches assisted in
the pest management strategies for pest and the deceases, especially viruses, they may
carry. Metabolized mulches have been shown to repel thrips and reduced the incidence of
tomato spotted wilt viruses in tomatoes.
In the study on Strawberry culture in Reunion Island, Catella (1987) found out
that using white plastic mulch coved increase the fruit medium weight and decreases
waste percentage. The same researcher observed that Sequoia variety improved fruit
production to a level of three hundred grams per plant followed by Aiko variety.
Nnadi et al. (1984) studied the effect of mulch and nitrogen on maize. They
concluded that maize yield responded significantly due to mulching. The mulch crop was
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
8
taller and more vigorous than the un mulched. They also claimed that mulch provided
better soil moisture, temperature regime and reduced weed competition.
Under South Carolina condition, Robbins and Schalk (1982) discovered that the
black aluminum and white polyethylene mulches increase the yield and early fruiting set
of spring grown tomatoes. Black transparent polyethylene mulches increased the soil
temperature resulting in sweet corn, yield earlier and higher than those from un mulched
soil. It reduced the incidence of aphids borne viruses and deterred such pest as aphids,
thrips, leaf miner on field, ornamentals and vegetable crops.
A reduction of 50% in water losses due to evaporation was realized using clear
polyethylene plastic mulch in soybean field.
Knott and Deanon (1967) pointed out that mulch is used by farmers not for the
purpose of conserving moisture but to primarily control weeds. For green onions, the use
of black polyethylene plastic mulch can be greatly advantageous in controlling weeds.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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MATERIALS AND METHODS
Materials
The materials used in the study were lettuce seeds (Great Lakes XL), watering
can, fertilizers, fungicides, insecticides, chicken manure and different mulching materials.
Methods
Experimental design and treatments. The study was laid out following the
Randomized Complete Block Design (RCBD) with three replications.
The treatments were represented as follows:
Treatments
T1 – no mulch (control)
T2 – black polyethylene mulch
T3 – transparent polyethylene mulch
T4 – dried pine needles (5 cm thick)
T5 – coconut sawdust (5 cm thick)
T6 – dried cogon grass (5 cm thick)
T7 – dried mountain grass (5 cm thick)
Seedling production. The seeds was sown by broadcasting in a well prepared
seedbed before preparing the experiment area. The seedlings were regularly irrigated and
sprayed as needed pesticides to control insect pests and diseases.
Land preparation and fertilizer application. An area of 105 square meters was
thoroughly prepared. The area was divided into 3 blocks with 7 plots per block with a
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
10
dimension of 1mx5m. A handful of chicken manure at about 100g was applied in each
hole spaced at 30cm x 30cm apart and mixed thoroughly with soil ready for planting.
Transplanting. When the seedlings were four weeks old, they were carefully
uprooted and transplanted to their assign plots.
Irrigation. Irrigation was done just after transplanting and every other day until
the plants were established after which irrigation was done at weekly interval.
Care and maintenance. All other recommended practices required in the
production of lettuce like weeding, cultivation, pest control and fertilizer application were
uniformly employed to each treatments plot.
Data to be gathered. The data gathered and subjected to variance analysis and
mean separation test by Duncan’s Multiple Range Test (DMRT) were as follows:
1. Number of days from transplanting to head initiation. This was done by
counting the number of days from transplanting up to 50 % of the plants started to form
heads.
2. Number of days from transplanting to harvest. This was the number of days
from transplanting to the day heads are firm (by hand pressing) and ready for harvest.
3. Polar circumference (cm). This was determined by positioning a tape measure
around the polar section of five sample heads selected at random.
4. Equatorial circumference (cm). This was obtained by positioning a tape
measure around the equator of the same sample heads.
5. Percentage heading. This was computed by using the formula:
Heading Percentage = Number of Heads Harvested x 100
Total Number of Plants/Plot
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
11
6. Average head weight (kg). This was taken using the formula:
Head weight (kg) = Total Head Weight/Plot____
Number of Harvested Heads/Plot
7. Marketable yield (kg/plot). This was the weight of all heads without defects
and can be sold in the market.
8. Non – marketable yield (kg/plot). This was the weight of non – marketeable
heads that are very small ,malformed and damaged.
9. Total yield (kg/plot). This was the total yield of ld (kg/plot). This was the
weight of non – marketable heads that are very small, malformed and damaged.
marketable and non – marketable heads.
10. Computed marketable yield (t/ha). The marketable yield per plot was
converted to yield per hectare by multiplying with 2,000 plot based on the plot dimension
(1m x 5m) used in the study.
11. Cost and return analysis. All expenses incurred in the study were recorded.
The return of investment (ROI) was computed using the formula:
Return on Investment = Gross Sales – Total Expenses x 100
Total Expenses
12. Incidence of insect pests and diseases. Observation was done on the presence
of insect pest and disease identified and rated them using the following scale:
A. Insect
Rating
Description
1
0 – 15% of the plants/plot were infested
2 15 – 30% of the plants/plot were infested
3
30 – 45% of the plants/plot were infested
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
12
4 45 - 60% of the plants/plot were infested
B. Disease
Rating
Description
1
10 – 15% of the plants/plot were infected
2
15 – 30% of the plants/plot were infected
3
30 – 45% of the plants/plot were infected
4
45 – 60% of the plants/plot were infected
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
13
RESULTS AND DISCUSSION
Days to Head Initiation
There were significant differences observed among the different mulch materials
on the days from transplanting to head initiation (Table 1). Results showed that
transparent polyethylene plastic effected the earliest days to transplanting to head
initiation, followed by black polyethylene plastic and dried pine needles.
Days from Transplanting to Harvest
There were no significant differences among the different mulching treatments in
affecting the days from transplanting to harvest ranging from 44 to 46 days.
Percentage Heading
As presented in Table 1, lettuce mulched with black polyethylene plastic had the
highest percentage of heading comparable to those of plants mulched with any of the
materials used but significantly higher than that of plants which were not mulched. The
higher percentage of heading of mulched plants could be attributed to the conservation of
soil moisture and suppression of the growth of weeds.
Polar Circumference
As shown in Table 2, lettuce mulch with black polyethylene plastic and those not
mulched significantly had wider polar circumference of heads.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
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Table 1. Days to head initiation, days from transplanting to harvest, and percentage
heading
TREATMENT
DAYS TO HEAD
DAYS FROM
PERCENTAGE
INITIATION
TRANSPLANTING
HEADING
TO HARVEST
No mulch
37.33a
44.33a
59.42b
Black polyethylene
36.00ab
43.67a
84.06a
plastic
Transparent
35.67b
44.33a
78.26a
polyethylene plastic
Dried pine needles
36.67ab
45.67a
71.74ab
Coconut sawdust
37.33a
45.33a
73.91a
Dried cogon grass
37.33a
45.00a
82.61a
Dried napier grass
37.00a
45.00a
74.64a
Means with same later are not significant different at 5% level by DMRT
Equatorial Circumference
Table 2, shows that significantly wider equatorial circumference of heads was
observed in plants mulched with black polyethylene plastic.
Average Head Weight
In Table 2 there were no significant differences observed on the average head
weight as affected by the different mulch materials used. However, lettuce plants that
were not mulched and those mulched with coconut sawdust had the highest average head
weight.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
15
Table 2. Head size and average head weight
TREATMENT
POLAR
EQUATORIAL
AVERAGE
CIRCUMFERENCE CIRCUMFEREN
HEAD WEIGHT
(cm)
CE (cm)
(kg)
No mulch
15.33a
18.67b
0.25a
Black polyethylene
17.33a
21.33a
0.13a
plastic
Transparent
16.00b
19.33b
0.16a
polyethylene plastic
Dried pine needles
15.00c
19.00b
0.16a
Coconut sawdust
15.00c
18.67b
0.21a
Dried cogon grass
15.67bc
19.33b
0.13a
Dried napier grass
15.33c
18.67b
0.14a
Means with same later are not significant different at 5% level by DMRT
Marketable Yield per Plot
With regards to the marketable yield, there were no significant differences that
were observed. Nevertheless, plants not mulched had the highest marketable yield. This
could attributed to better soil aeration and penetration of water during irrigation in
unmulched plots.
Non-Marketable Yield
Table 3 shows that unmulched lettuce plants had the highest non-marketable
yield, although they had the highest marketable yield.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Total Yield
The total yield as affected by the different mulch materials did not differ
significantly as shown in Table 3. However, plants which were not mulched had the
highest total yield.
Table 3. Yield
YIELD (kg/1x5m plot)
TREATMENT MARKETABLE
NON –
TOTAL
COMPUTED
YIELD
MARKETABLE
YIELD
MARKETABLE
YIELD
YIELD
(t/ha)
No mulch
3.30a
3.98a
7.29a
6.60a
Black
2.50a
1.70b
4.20a
4.99a
polyethylene
plastic
Transparent
3.10a
2.38ab
5.48a
6.20a
polyethylene
plastic
Dried pine
2.74a
2.63ab
5.37a
5.48a
needles
Coconut
2.58a
2.48ab
5.06a
5.15a
sawdust
Dried cogon
2.85a
1.97b
4.81a
5.69a
grass
Dried napier
2.59a
2.07ab
4.66a
5.18a
grass
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
17
Computed Yield
Table 3 shows that the computed yield per hectare followed the same trend as in
the marketable yield where lettuce plants that were not mulched had the highest yield but
not significantly different from the yield of the other treatment plants.
Incidence of slug ( Deroceras reticulatum )
As shown in Table 4, lettuce plants mulched with black polyethylene plastic
significantly had the highest incidence of infestation comparable to plants mulched with
any of the materials. Unmulched plants had the lowest incidence of slugs.
The result may imply that the application of mulch will enhance infestation of
slugs on lettuce plants.
Table 4. Incidence of slug ( Deroceras reticulatum )
TREATMENT
MEAN
No mulch
1.70b
Black polyethylene plastic
2.48a
Transparent polyethylene plastic
2.07ab
Dried pine needles
2.07ab
Coconut sawdust
2.07ab
Dried cogon grass
2.07ab
Dried napier grass
2.07ab
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
18
Bacterial Soft Rot ( Erwinia carotova )
As shown in Table 5, the occurrence of bacterial soft rot was higher in plants
mulched regardless of the materials used as compared to unmulched plants which had
lower disease infection.
Cost and Return Analysis
Table 6, presents the cost and return analysis of producing lettuce as affected by
different mulch materials. The highest return on investment of 60.06% was obtained from
lettuce that were not mulched followed by 35.11% from using dried cogon needles and
29.89% from the use of dried pine needles.
Table 5. Incidence of bacterial soft rot (Erwinia carotova)
TREATMENT
MEAN
No mulch
1.70b
Black polyethylene plastic
2.48a
Transparent polyethylene plastic
2.07ab
Dried pine needles
2.07ab
Coconut sawdust
2.07ab
Dried cogon grass
2.07ab
Dried napier grass
2.07ab
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
19
Table 6. Cost and return analysis
MULCH MATERIALS
ITEM
No
Black
White
Dried
Coconut
Dried
Dried
mulch
plastic
plastic
pine
sawdust
cogon
napier
needles
grass
grass
Yield
9.90
7.50
9.30
8.22
7.74
8.55
7.77
(kg/15m2)
Sales (Php)
346.50
262.50
325.50
287.70
270.90
299.25
271.95
Farm inputs
(Php)
Seedlings
14.29
14.29
14.29
14.29
14.29
14.29
14.29
Chicken
34.29
34.29
34.29
34.29
34.29
34.29
34.29
manure
Urea
5.71
5.71
5.71
5.71
5.71
5.71
5.71
14-14-14
17.71
17.71
17.71
17.71
17.71
17.71
17.71
Lannate
41.43
41.43
41.43
41.43
41.43
41.43
41.43
Anthracol
37.14
37.14
37.14
37.14
37.14
37.14
37.14
Mulch
0.00
35.00
35.00
5.00
10.00
5.00
5.00
Labor
Land
15.00
15.00
15.00
15.00
15.00
15.00
15.00
preparation
Planting
14.29
14.29
14.29
14.29
14.29
14.29
14.29
Weeding
14.30
14.30
14.30
14.30
14.30
14.30
14.30
Irrigation
8.00
8.00
8.00
8.00
8.00
8.00
8.00
Harvesting
14.32
14.32
14.32
14.32
14.32
14.32
14.32
Total
216.48
251.48
251.48
221.48
226.48
221.48
221.48
Expenses
Net profit
130.02
11.02
74.02
66.22
44.42
77.77
50.47
(Php)
ROI (%)
60.06
4.38
29.43
29.89
19.61
35.11
22.79
Rank
1
7
4
3
6
2
5
Note: Selling price during harvest = Php 35.00/kg
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
20
Other Observations
During heavy rains, run-off soil erosion was observed on plots which were not
mulched, exposing few roots of the plants but were covered thereafter.
Many weeds were found growing on unmulched plots and those mulched with
transparent polyethylene plastic.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
21
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine the effect of the different mulching
materials on the growth and yield of lettuce and to identify the mulching material
appropriate for lettuce production. The study was conducted at the Horticulture
Experimental Area, Benguet State University from April-May 2009.
Results of the study show that the earliest to form heads were those mulched with
transparent polyethylene plastic. Higher percentage of heading was obtained with the use
of black polyethylene plastic and with the use of any of the materials but significantly
higher than that of plants which were not mulched. Wider polar and equatorial
circumferences of heads were observed in plants mulched with black polyethylene
plastic.
Although no significant differences were observed among the treatments, the
highest marketable yield at 6.60 t/ha and highest return on investment at 60.06% was
obtained from plants that were not mulched. Lesser incidence of slug and bacterial soft
rot was observed in unmulched plants.
Conclusion
Based from the results, mulching lettuce during the dry season does not enhance
the growth and yield of lettuce.
Recommendation
It is recommended that similar study on mulching lettuce be conducted during the
wet season when there are frequent rains.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
22
LITERATURE CITED
ASSIR, A.L., I.G. RHEIZ and R.V. KROURY. 1991. Response of fall green house cost
Lettuce to clear mulch and nitrogen fertilizer. J. Plant Nutrition Pp.50: 1017-1022
CATELLA, G. 1987. Strawberry Culture in Reunion Island. International Training
Course. Southern Hemisphere close to the topic of Capricorn, Colony of
France.Pp.4.
GRIGSON, J. 1978. The Vegetable Book. London, Penguin. ISBN – 14- 046- 352- 6.
HORT. SCI. DEP. 1988. Florida Cooperative Extension Service, Institute of food and
Agricultural Science, University of Florida.
KNOTT, J.E. and J.R. DEANON. 1967. Vegetable production in South Asia. College of
Agriculture, University of the Philippines, College of Los Banos, Laguna.Pp.310.
MARR. C.W. 1993. Plastic Mulches for Vegetable, Kansas State University Agricultural
Experiment Station and Cooperative Extension Service, Kansas State University.
NNADI, L.; B.T. KANG and E.N.O.I. WUAFOR. 1984. Effect of mulch and nitrogen on
maize Southern Guinea Savanna, Central Nigeria. IITA Annual Report
International Institute of Tropical Agriculture, Oyo Road, Ibadan, Nigeria. Pp.
164 – 165.
RICOTTA, J.A. and J.B. MASIUNAS. 1991. The effect of black mulch and weed
control strategies on herb yield. Department of Horticulture, University of
Illionois. Horticulture Science 26 (5). Pp. 539 – 540.
ROBBINS, L.M. and J.M. SCHALK. 1982. Reflective Mulches Influence Plant
Survival, Production and Insect control in fall Tomatoes. Louisiana State
University Agricultural center, Chase, Los Angeles. Pp. 848
RUBATZKY, V.E. and M. YAMAGUCHI. 1997. World Vegetables: Principles,
Production and Nutritive Values, New York: Chapman and Hall.2nd ed.
The COLUMBIA ELECTRONIC ENCYCLOPEDIA Copyright @ 2004. Licenced from
Columbia University Press.
WHITAKER, T.W. 1974. Lettuce: Evolution of a Weedy Cinderella. Hortscience 9. Pp.
512.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
23
APPENDICES
Appendix Table 1. Number of days from transplanting to head initiation
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
37
38
37
112
37.33
T2
36
37
35
108
36.00
T3
36
36
35
107
35.67
T4
37
36
37
110
36.67
T5
37
37
38
112
37.33
T6
37
38
37
112
37.33
T7
36
38
37
111
37.00
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.524
0.762
1.57
0.2472
Treatment
6
8.476
1.413
2.92*
0.0541
Error
12
5.809
0.485
TOTAL
20
15.809
* - Significant
Coefficient of variation = 1.89%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
24
Appendix Table 2. Number of days from transplanting to harvest
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
44
46
43
133
44.33
T2
44
44
45
133
44.33
T3
44
44
43
131
43.67
T4
45
44
48
137
45.37
T5
46
45
45
136
45.33
T6
45
45
45
135
45.00
T7
45
45
45
135
45.00
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.095
0.048
0.04
0.9633
Treatment
6
8.477
1.413
7.11 ns
0.4102
Error
8
15.238
1.270
TOTAL
20
23.81
ns - Not significant
Coefficient of variation = 2.52%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
25
Appendix Table 3. Percentage heading
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
52.17
60.87
65.22
178.26
59.42
T2
93.48
76.09
82.61
252.18
84.06
T3
71.74
84.78
78.26
234.78
78.26
T4
63.04
80.43
71.74
215.21
71.74
T5
80.43
69.57
71.74
221.74
73.91
T6
82.61
89.13
76.09
247.83
82.61
T7
67.39
82.61
73.91
223.91
74.64
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
81.505
40.753
0.74
0.4998
Treatment
6
1215.909
202.615
3.66*
0.0267
Error
12
665.078
55.423
TOTAL
20
1962.492
* - Significant
Coefficient of variation = 9.93%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
26
Appendix Table 4. Polar circumference (cm)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
15
15
16
46
15.33
T2
17
17
18
52
17.33
T3
16
16
16
48
16.00
T4
15
15
15
45
15.00
T5
15
15
15
45
15.00
T6
16
15
16
47
15.67
T7
15
15
16
46
15.33
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.238
0.619
5.20
0.0236
Treatment
6
12.000
2.000
16.80**
0.0001
Error
12
1.428
0.119
TOTAL
20
14.666
** - Highly significant
Coefficient of variation= 2.20%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
27
Appendix Table 5. Equatorial circumference (cm)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
18
18
20
55
18.33
T2
22
20
22
64
21.33
T3
19
20
19
58
19.33
T4
20
18
19
57
19.00
T5
19
19
18
56
18.67
T6
20
18
20
58
19.33
T7
18
18
20
56
18.67
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
3.714
1.857
2.17
0.1573
Treatment
6
16.286
2.714
3.17*
0.0423
Error
12
10.286
0.857
TOTAL
20
30.286
* - Significant
Coefficient of variation = 4.80%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
28
Appendix Table 6. Average head weight (kg)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
0.35
0.27
0.12
0.74
0.25
T2
0.13
0.17
0.09
0.39
0.13
T3
0.19
0.16
0.12
0.47
0.16
T4
0.21
0.15
0.13
0.49
0.16
T5
0.16
0.17
0.29
0.62
0.21
T6
0.17
0.09
0.13
0.39
0.13
T7
0.17
0.10
0.14
0.41
0.14
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.010
0.005
1.42
0.2806
Treatment
6
0.035
0.006
1.65ns
0.2163
Error
12
0.042
0.003
TOTAL
20
0.087
ns - Not significant
Coefficient of variation = 35.61%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
29
Appendix Table 7. Marketable yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
4.34
3.12
2.45
9.91
3.30
T2
2.25
3.01
2.23
7.49
2.50
T3
2.99
3.33
2.98
9/30
3.10
T4
3.02
2.85
2.35
8.22
2.74
T5
3.23
2.35
2.15
7.73
2.58
T6
3.34
2.45
2.75
8.54
2.85
T7
2.34
2.55
2.88
7.77
2.59
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.988
0.494
2.13
0.1615
Treatment
6
1.604
0.267
1.15ns
0.3913
Error
12
2.784
0.232
TOTAL
20
5.376
ns - Not significant
Coefficient of variation = 17.16%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
30
Appendix Table 8. Non – marketable yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
6.20
4.50
1.25
11.95
3.98
T2
1.50
2.50
1.10
5.10
1.70
T3
3.15
2.75
1.25
7.15
2.38
T4
3.00
2.90
2.00
7.90
2.63
T5
2.55
3.00
1.90
7.45
2.48
T6
2.75
1.15
2.00
5.90
1.97
T7
3.00
1.20
2.01
6.21
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
8.217
4.108
4.25
0.0403
Treatment
6
9.990
1.665
1.72ns
0.1992
Error
12
11.607
0.967
TOTAL
20
29.814
ns - Not significant
Coefficient of variation = 39.98%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
31
Appendix Table 9. Total yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
10.54
7.62
3.70
21.86
7.29
T2
3.75
5.57
3.33
12.59
4.20
T3
6.14
6.08
4.23
16.45
5.48
T4
6.02
5.75
4.35
16.12
5.37
T5
5.78
5.35
4.05
15.18
5.06
T6
6.09
3.60
4.75
14.44
4.81
T7
5.34
3.75
4.89
13.98
4.66
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
14.862
7.431
7.24
0.0086
Treatment
6
6.648
1.108
1.08ns
0.4262
Error
12
12.310
1.026
TOTAL
20
33.82
ns - Not significant
Coefficient of variation = 19.23%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
32
Appendix Table 10. Computed marketable yield (t/ha)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
8.68
6.24
4.90
19 .82
6.60
T2
4.50
6.02
4.46
14.98
4.99
T3
5.98
6.66
5.96
18.60
6.20
T4
6.04
5.70
4.70
16.44
5.48
T5
6.46
4.70
4.30
15.46
5.15
T6
6.68
4.90
5.50
17.08
5.69
T7
4.68
5.10
5.76
15.54
5.18
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
3.954
1.977
2.130
0.162
Treatment
6
6.416
1.069
1.152ns
0.391
Error
12
11.136
0.928
TOTAL
20
21.506
ns - Not significant
Coefficient of variation = 6.62%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
33
Appendix Table 11. Incidence of insect pest (slug)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
1.50
2.55
1.05
5.10
1.70
T2
3.00
2.55
1.90
7.45
2.48
T3
3.00
1.20
2.00
6.20
2.07
T4
2.00
1.20
3.01
6.21
2.07
T5
1.61
1.61
3.00
6.22
2.07
T6
2.55
1.83
1.83
6.21
2.07
T7
2.20
1.00
3.00
6.20
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.437
0.718
1.18
0.3396
Treatment
6
0.922
0.153
0.25 ns
0.9486
Error
8
7.291
0.607
TOTAL
20
9.650
ns - Not significant
Coefficient of variation = 37.55%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
34
Appendix Table 12. Incidence of disease ( bacterial soft rot )
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
1.30
2.50
1.30
5.10
1.70
T2
2.00
4.43
1.00
7.43
2.48
T3
2.20
1.00
3.01
6.21
2.07
T4
2.60
1.83
1.79
6.22
2.07
T5
1.79
3.02
1.40
6.21
2.07
T6
2.00
3.00
1.20
6.20
2.07
T7
3.00
1.25
1.95
6.20
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
2.096
1.048
1.03
0.3850
Treatment
6
0.906
0.151
0.15 ns
0.9857
Error
8
12.157
1.013
TOTAL
20
15.159
ns - Not significant
Coefficient of variation = 48.51%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
PASIWEN, AIZA T. APRIL 2010. Effect of Different Mulch Materials on the Growth
and Yield of Lettuce. Benguet State University, La Trinidad, Benguet.
Adviser: Percival B. Alipit, PhD.
ABSTRACT
The study was conducted to evaluate the growth and yield of lettuce as affected by
different mulching materials in April to May.
Results showed that although earlier head formation was observed with the use of
transparent polyethylene plastic and bigger sized heads were developed using black polyethylene
plastic, higher marketable yield at 6.60 t/ha and higher return on investment at 60.06% were
obtained without mulching. Lesser insect and disease incidence were also observed in
unmulched plants.
TABLE OF CONTENTS
Page
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
RESULT AND DISCUSSION
Days to Head Initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Days from Transplanting to Harvest . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Percentage Heading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Polar Circumference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Equatorial Circumference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Average Head Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Marketable Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Non – marketable Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Total Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Computed Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Slug (Deroceras reticulatum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Bacterial Soft rot (Erwinia carotovora) . . . . . . . . . . . . . . . . . . . . . . . . .
18
Cost and Return Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Other Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
INTRODUCTION
Lettuce (Lactuca sativa L.) is a temperate, annual or biennial plant of the daisy
family Asteraceae. It is the most often grown as a leaf vegetable. In many countries, it is
typically eaten cold and raw in salads, hamburgers, tacos and many other dishes. In some
places, including China, lettuce is typically eaten cooked and use of the stem is as
important as use of the leaf. Both the English name and the Latin name of the genus are
ultimately derived from lac, the Latin word for milk referring to the plants milky juice.
Mild in flavors, it has been described over the centuries as a cooling counterbalance to
other ingredients in a salad.
The earliest depiction of lettuce is in the carvings at the temple of Senuscret I at
Karnak, where he offers milk to the God Min, to whom the lettuces was sacred. Later,
Ancient Greek physicians believed lettuce could act as a sleeping inducing agent. The
Romans cultivated it and eventually made its way to France cultivated of the Popal Court
at Avignon Christopher Columbus introduced lettuce to the new world.
There are six commonly recognized groups of lettuce which are classified by head
formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf
shape and color, as well as extended field life, within each of these cultivars groups,
butter head, also called Boston or Bibb, forms loose head; it has a buttery texture. Butter
head cultivars are most popular in Europe, Chinese lettuce types generally have long,
sword shaped, non – head – forming leaves, with a bitter and robust flavors unlike
western types, appropriate for use in stir – fried dishes and stews, Crisphead, also called
Iceberg, which form tight, dense heads that resembles cabbage. They are generally the
mildest of the lettuces, valued for more for their crunchy texture than for flavors.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
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Cultivars of iceberg lettuce are the most familiar lettuce in the USA. The name iceberg
comes from the way the lettuce was transported in the US starting in the 1920’s on train –
wagons covered in crushed ice, making them look like icebergs, loose leaf, with tender,
delicate and mildly flavored leaves. This group comprises oak leaf and lollorossa lettuces,
Romine lettuce, also called Cos, grows in a long head of sturdy leaves with a firm rib
down the center. Unlike most lettuces, it is tolerant to heat, the Summer Crisp called
Batavian, forms moderately dense heads with a crunchy texture; this type is intermediate
between iceberg and loose leaf types.
Lettuce is a cool – season vegetable and develops best quality under cool, moist
conditions. Lettuce seedling will tolerate a light frost. Temperature between 45°F and
65°F are ideal. Such conditions usually planted in the spring as soon as the ground can be
worked. Butter head and romaine can be grown from either seeds or transplants, due to its
long growing season; crisp head lettuce is grown from transplants. Transplants may be
purchased or started indoors about six weeks before the preferred planting time by .
Mulching is the technique of placing of protective materials on top of the soil.
Mulch comes in two basic forms; organic and non – organic. Mulching also minimizes
weeds growth and also prevents soil splattering during heavy rains. Mulching is also
necessary to the plants to minimize the loss of soil moisture. To some extent, mulching
reduces the temperature of the soil, Grigson (1978).
In the market the prices of commercial mulching materials are high but even
though farmers are still buying and using the products due to this many advantages. What
is not known also is the degree of effectiveness of mulching materials, thus the study
was conducted.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
3
The objective of the study was to determine the effect of the different mulching
materials on the growth and yield of lettuce and to identify the mulching material
appropriate for lettuce production.
This study was conducted at the Horticulture Experiment Area, Benguet State
University, La Trinidad, Benguet from April – May 2009.
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4
REVIEW OF LITERATURE
Description of the Crop
Lettuce plants has a short stem initially (a rosette growth habit), but when it
blooms the stem lengthens and branches, and it produces many flower heads that look
like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is
harvested before it bolts. Lettuce is used as a food plants by the larvae of some
Lepidoptera. The largest lettuce head, of the Salad Bowl cultivar weighted 11 kg (25 lbs)
grown by Colin Bowcock of Willawston, England in 1974.
All lettuce types should be harvested at full size but young and tender. Over
mature lettuce is bitter and woody. Leaf lettuce is harvested by removing individual outer
leaves so that the center leaves can continue to grow. Butter head or romaine types can be
harvested by removing the outer leaves, digging up the whole plants or cutting the plants
about an inch above the soil surface. A second harvested is often possible this way. Crisp
head lettuce is picked when the center is firm, The Columbia Electronic Encyclopedia
(2004).
Nutritional Value
Some lettuce (especially iceberg) has been specifically bred to remove the
bitterness from their leaves. These lettuces have high water content with very little
nutrient value. The more bitter lettuce and the ones with pigments leaves contain
antioxidants.
Lettuce is a fat free, low calorie food. It is a valuable source of Vitamin A and
folic acid. Lactucarium or lettuce opium is a mild opiate like substance that is obtained in
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PASIWEN, AIZA T. APRIL 2010
5
all types of lettuce. Both the Romans and Egyptians took advantage of this properly
eating lettuce at the end of a meal to induce sleep.
Useful amounts of several nutrients including Vitamin A and C; and minerals
calcium and iron. The nutrient contents are highest in the darker green outer leaves. Low
calories, each heads contains 65 to 70 kilocalories, Grigson (1978).
Soil and Climatic Adaptation
Lettuce can be grown under a wide range of soils, loose, fertile ,sandy loam soils,
well supplied with organic matter are best. The soil should be well drained, moist, but not
soggy. Heavy soils can be modified with well rotted manure, compost or by growing a
cover crops, like most other garden vegetables, lettuce prefers a slight acidic pH of 6.0 to
6.5.
Head lettuce grows best at 15 to 18 °C. germination takes place at a maximum of
5 °C, has an optimum range of 16 to 20 °C, and an optimum germination temperature of
20 °C (depending on the cultivars and type of lettuce). At soil temperatures over 27 °C
germination is poor, Rubatzky and Yamaguchi (1997).
Commercial Importance of the Crop
Lettuce has become a major player in commercial production and marketing of
salad crops. Total production worldwide does not compare with the major cereals crops,
especially rice, corn and wheat, or with other commodities, such as sugars crops, beans
and potatoes. The key word is contemporary use of lettuce is changed; in use of the
various types, in the development of world markets, in methods of marketing and in
methods of production, Whitaker (1974).
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Mulching
Marr (1993) studied the effect of plastic mulch on vegetable. They have
successfully grown muskmelon, tomatoes, peppers, cucumber, watermelons, and okra
using plastics mulch and have shown significant increase in earliness, yield and fruit
quality.
Ricotta and Masiunas (1991) found that mulch plots covered with black
polyethylene conserve more moisture than the un
mulched plot. Likewise, soil temperature increased and sometimes hastened the growth
of the crop, thus leading earlier fruit development.
Assir et al. (1991) found out that the application of clear plastic mulch with or
without a fertilizer did not significantly increase the yield of lettuce grown in the fall
under green house in the Mediterranean mountains in Lebanon. Yield average from 31 to
38 kg/50 heads. Leaf NO3 – N and total P level were higher in mulched than the un
mulched plants and always above the sufficiency level in all treatments.
The Hort. Sci. Dep., University of Florida (1988) found the benefits of
polyethylene mulch and organic mulch on vegetable and fruit production. Firstly, it
increased the yield. The largest benefits from black polyethylene mulch are the increase
in soil temperature in the bed, which promotes faster crop development and earlier yields.
Secondly, it aided in moisture retention. Mulch reduced evaporation from the bed soil
surface. As a result, a more uniform soil moisture regime is maintained and the frequency
of irrigation is reduced. Irrigation is still mandatory for mulched crops so that the soil
under the mulch doesn’t dry out excessively. Thirdly, it inhibits weed growth. Fourthly, it
reduced fertilizer leaching. Fertilizer placed in the bed under the mulch is less subject to
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
7
leaching by rainfall. As a result, the fertilizer program is more sufficient and the potential
exist for reducing traditional amount of fertilizer. Heavy rainfall that floods the bed can
still result in fertilizer leaching. This fertilizer can be replaced if the growers are using
drip irrigation, or it can be replaced with a liquid fertilizer injection wheel. Fifthly, it
decreased the soil compaction. Mulch acts a barrier to the action of rainfall, which can
cause soil crusting, compaction and erosion. Less compaction soil provides a better
environment for seeding emergence and root growth. Sixthly, it protected the fruits.
Mulch reduced rain splashed soil deposited on fruits. In addition, mulch reduced fruit rot
caused by soil inhibiting organism, because there is a protective barrier between the fruit
and the organism. Second to the last, it aided in fumigation. Mulches increased the
effectiveness of the soil fumigant chemical. It did not cause a barrier but allowed a water
layer to form under the mulch and it is this water layer that slowed down the loss of the
fumigant. Lastly, it aided in managing other pest. Highly reflective mulches assisted in
the pest management strategies for pest and the deceases, especially viruses, they may
carry. Metabolized mulches have been shown to repel thrips and reduced the incidence of
tomato spotted wilt viruses in tomatoes.
In the study on Strawberry culture in Reunion Island, Catella (1987) found out
that using white plastic mulch coved increase the fruit medium weight and decreases
waste percentage. The same researcher observed that Sequoia variety improved fruit
production to a level of three hundred grams per plant followed by Aiko variety.
Nnadi et al. (1984) studied the effect of mulch and nitrogen on maize. They
concluded that maize yield responded significantly due to mulching. The mulch crop was
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8
taller and more vigorous than the un mulched. They also claimed that mulch provided
better soil moisture, temperature regime and reduced weed competition.
Under South Carolina condition, Robbins and Schalk (1982) discovered that the
black aluminum and white polyethylene mulches increase the yield and early fruiting set
of spring grown tomatoes. Black transparent polyethylene mulches increased the soil
temperature resulting in sweet corn, yield earlier and higher than those from un mulched
soil. It reduced the incidence of aphids borne viruses and deterred such pest as aphids,
thrips, leaf miner on field, ornamentals and vegetable crops.
A reduction of 50% in water losses due to evaporation was realized using clear
polyethylene plastic mulch in soybean field.
Knott and Deanon (1967) pointed out that mulch is used by farmers not for the
purpose of conserving moisture but to primarily control weeds. For green onions, the use
of black polyethylene plastic mulch can be greatly advantageous in controlling weeds.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
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MATERIALS AND METHODS
Materials
The materials used in the study were lettuce seeds (Great Lakes XL), watering
can, fertilizers, fungicides, insecticides, chicken manure and different mulching materials.
Methods
Experimental design and treatments. The study was laid out following the
Randomized Complete Block Design (RCBD) with three replications.
The treatments were represented as follows:
Treatments
T1 – no mulch (control)
T2 – black polyethylene mulch
T3 – transparent polyethylene mulch
T4 – dried pine needles (5 cm thick)
T5 – coconut sawdust (5 cm thick)
T6 – dried cogon grass (5 cm thick)
T7 – dried mountain grass (5 cm thick)
Seedling production. The seeds was sown by broadcasting in a well prepared
seedbed before preparing the experiment area. The seedlings were regularly irrigated and
sprayed as needed pesticides to control insect pests and diseases.
Land preparation and fertilizer application. An area of 105 square meters was
thoroughly prepared. The area was divided into 3 blocks with 7 plots per block with a
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
10
dimension of 1mx5m. A handful of chicken manure at about 100g was applied in each
hole spaced at 30cm x 30cm apart and mixed thoroughly with soil ready for planting.
Transplanting. When the seedlings were four weeks old, they were carefully
uprooted and transplanted to their assign plots.
Irrigation. Irrigation was done just after transplanting and every other day until
the plants were established after which irrigation was done at weekly interval.
Care and maintenance. All other recommended practices required in the
production of lettuce like weeding, cultivation, pest control and fertilizer application were
uniformly employed to each treatments plot.
Data to be gathered. The data gathered and subjected to variance analysis and
mean separation test by Duncan’s Multiple Range Test (DMRT) were as follows:
1. Number of days from transplanting to head initiation. This was done by
counting the number of days from transplanting up to 50 % of the plants started to form
heads.
2. Number of days from transplanting to harvest. This was the number of days
from transplanting to the day heads are firm (by hand pressing) and ready for harvest.
3. Polar circumference (cm). This was determined by positioning a tape measure
around the polar section of five sample heads selected at random.
4. Equatorial circumference (cm). This was obtained by positioning a tape
measure around the equator of the same sample heads.
5. Percentage heading. This was computed by using the formula:
Heading Percentage = Number of Heads Harvested x 100
Total Number of Plants/Plot
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6. Average head weight (kg). This was taken using the formula:
Head weight (kg) = Total Head Weight/Plot____
Number of Harvested Heads/Plot
7. Marketable yield (kg/plot). This was the weight of all heads without defects
and can be sold in the market.
8. Non – marketable yield (kg/plot). This was the weight of non – marketeable
heads that are very small ,malformed and damaged.
9. Total yield (kg/plot). This was the total yield of ld (kg/plot). This was the
weight of non – marketable heads that are very small, malformed and damaged.
marketable and non – marketable heads.
10. Computed marketable yield (t/ha). The marketable yield per plot was
converted to yield per hectare by multiplying with 2,000 plot based on the plot dimension
(1m x 5m) used in the study.
11. Cost and return analysis. All expenses incurred in the study were recorded.
The return of investment (ROI) was computed using the formula:
Return on Investment = Gross Sales – Total Expenses x 100
Total Expenses
12. Incidence of insect pests and diseases. Observation was done on the presence
of insect pest and disease identified and rated them using the following scale:
A. Insect
Rating
Description
1
0 – 15% of the plants/plot were infested
2 15 – 30% of the plants/plot were infested
3
30 – 45% of the plants/plot were infested
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4 45 - 60% of the plants/plot were infested
B. Disease
Rating
Description
1
10 – 15% of the plants/plot were infected
2
15 – 30% of the plants/plot were infected
3
30 – 45% of the plants/plot were infected
4
45 – 60% of the plants/plot were infected
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
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RESULTS AND DISCUSSION
Days to Head Initiation
There were significant differences observed among the different mulch materials
on the days from transplanting to head initiation (Table 1). Results showed that
transparent polyethylene plastic effected the earliest days to transplanting to head
initiation, followed by black polyethylene plastic and dried pine needles.
Days from Transplanting to Harvest
There were no significant differences among the different mulching treatments in
affecting the days from transplanting to harvest ranging from 44 to 46 days.
Percentage Heading
As presented in Table 1, lettuce mulched with black polyethylene plastic had the
highest percentage of heading comparable to those of plants mulched with any of the
materials used but significantly higher than that of plants which were not mulched. The
higher percentage of heading of mulched plants could be attributed to the conservation of
soil moisture and suppression of the growth of weeds.
Polar Circumference
As shown in Table 2, lettuce mulch with black polyethylene plastic and those not
mulched significantly had wider polar circumference of heads.
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Table 1. Days to head initiation, days from transplanting to harvest, and percentage
heading
TREATMENT
DAYS TO HEAD
DAYS FROM
PERCENTAGE
INITIATION
TRANSPLANTING
HEADING
TO HARVEST
No mulch
37.33a
44.33a
59.42b
Black polyethylene
36.00ab
43.67a
84.06a
plastic
Transparent
35.67b
44.33a
78.26a
polyethylene plastic
Dried pine needles
36.67ab
45.67a
71.74ab
Coconut sawdust
37.33a
45.33a
73.91a
Dried cogon grass
37.33a
45.00a
82.61a
Dried napier grass
37.00a
45.00a
74.64a
Means with same later are not significant different at 5% level by DMRT
Equatorial Circumference
Table 2, shows that significantly wider equatorial circumference of heads was
observed in plants mulched with black polyethylene plastic.
Average Head Weight
In Table 2 there were no significant differences observed on the average head
weight as affected by the different mulch materials used. However, lettuce plants that
were not mulched and those mulched with coconut sawdust had the highest average head
weight.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
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Table 2. Head size and average head weight
TREATMENT
POLAR
EQUATORIAL
AVERAGE
CIRCUMFERENCE CIRCUMFEREN
HEAD WEIGHT
(cm)
CE (cm)
(kg)
No mulch
15.33a
18.67b
0.25a
Black polyethylene
17.33a
21.33a
0.13a
plastic
Transparent
16.00b
19.33b
0.16a
polyethylene plastic
Dried pine needles
15.00c
19.00b
0.16a
Coconut sawdust
15.00c
18.67b
0.21a
Dried cogon grass
15.67bc
19.33b
0.13a
Dried napier grass
15.33c
18.67b
0.14a
Means with same later are not significant different at 5% level by DMRT
Marketable Yield per Plot
With regards to the marketable yield, there were no significant differences that
were observed. Nevertheless, plants not mulched had the highest marketable yield. This
could attributed to better soil aeration and penetration of water during irrigation in
unmulched plots.
Non-Marketable Yield
Table 3 shows that unmulched lettuce plants had the highest non-marketable
yield, although they had the highest marketable yield.
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Total Yield
The total yield as affected by the different mulch materials did not differ
significantly as shown in Table 3. However, plants which were not mulched had the
highest total yield.
Table 3. Yield
YIELD (kg/1x5m plot)
TREATMENT MARKETABLE
NON –
TOTAL
COMPUTED
YIELD
MARKETABLE
YIELD
MARKETABLE
YIELD
YIELD
(t/ha)
No mulch
3.30a
3.98a
7.29a
6.60a
Black
2.50a
1.70b
4.20a
4.99a
polyethylene
plastic
Transparent
3.10a
2.38ab
5.48a
6.20a
polyethylene
plastic
Dried pine
2.74a
2.63ab
5.37a
5.48a
needles
Coconut
2.58a
2.48ab
5.06a
5.15a
sawdust
Dried cogon
2.85a
1.97b
4.81a
5.69a
grass
Dried napier
2.59a
2.07ab
4.66a
5.18a
grass
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Computed Yield
Table 3 shows that the computed yield per hectare followed the same trend as in
the marketable yield where lettuce plants that were not mulched had the highest yield but
not significantly different from the yield of the other treatment plants.
Incidence of slug ( Deroceras reticulatum )
As shown in Table 4, lettuce plants mulched with black polyethylene plastic
significantly had the highest incidence of infestation comparable to plants mulched with
any of the materials. Unmulched plants had the lowest incidence of slugs.
The result may imply that the application of mulch will enhance infestation of
slugs on lettuce plants.
Table 4. Incidence of slug ( Deroceras reticulatum )
TREATMENT
MEAN
No mulch
1.70b
Black polyethylene plastic
2.48a
Transparent polyethylene plastic
2.07ab
Dried pine needles
2.07ab
Coconut sawdust
2.07ab
Dried cogon grass
2.07ab
Dried napier grass
2.07ab
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Bacterial Soft Rot ( Erwinia carotova )
As shown in Table 5, the occurrence of bacterial soft rot was higher in plants
mulched regardless of the materials used as compared to unmulched plants which had
lower disease infection.
Cost and Return Analysis
Table 6, presents the cost and return analysis of producing lettuce as affected by
different mulch materials. The highest return on investment of 60.06% was obtained from
lettuce that were not mulched followed by 35.11% from using dried cogon needles and
29.89% from the use of dried pine needles.
Table 5. Incidence of bacterial soft rot (Erwinia carotova)
TREATMENT
MEAN
No mulch
1.70b
Black polyethylene plastic
2.48a
Transparent polyethylene plastic
2.07ab
Dried pine needles
2.07ab
Coconut sawdust
2.07ab
Dried cogon grass
2.07ab
Dried napier grass
2.07ab
Means with same later are not significant different at 5% level by DMRT
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Table 6. Cost and return analysis
MULCH MATERIALS
ITEM
No
Black
White
Dried
Coconut
Dried
Dried
mulch
plastic
plastic
pine
sawdust
cogon
napier
needles
grass
grass
Yield
9.90
7.50
9.30
8.22
7.74
8.55
7.77
(kg/15m2)
Sales (Php)
346.50
262.50
325.50
287.70
270.90
299.25
271.95
Farm inputs
(Php)
Seedlings
14.29
14.29
14.29
14.29
14.29
14.29
14.29
Chicken
34.29
34.29
34.29
34.29
34.29
34.29
34.29
manure
Urea
5.71
5.71
5.71
5.71
5.71
5.71
5.71
14-14-14
17.71
17.71
17.71
17.71
17.71
17.71
17.71
Lannate
41.43
41.43
41.43
41.43
41.43
41.43
41.43
Anthracol
37.14
37.14
37.14
37.14
37.14
37.14
37.14
Mulch
0.00
35.00
35.00
5.00
10.00
5.00
5.00
Labor
Land
15.00
15.00
15.00
15.00
15.00
15.00
15.00
preparation
Planting
14.29
14.29
14.29
14.29
14.29
14.29
14.29
Weeding
14.30
14.30
14.30
14.30
14.30
14.30
14.30
Irrigation
8.00
8.00
8.00
8.00
8.00
8.00
8.00
Harvesting
14.32
14.32
14.32
14.32
14.32
14.32
14.32
Total
216.48
251.48
251.48
221.48
226.48
221.48
221.48
Expenses
Net profit
130.02
11.02
74.02
66.22
44.42
77.77
50.47
(Php)
ROI (%)
60.06
4.38
29.43
29.89
19.61
35.11
22.79
Rank
1
7
4
3
6
2
5
Note: Selling price during harvest = Php 35.00/kg
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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Other Observations
During heavy rains, run-off soil erosion was observed on plots which were not
mulched, exposing few roots of the plants but were covered thereafter.
Many weeds were found growing on unmulched plots and those mulched with
transparent polyethylene plastic.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine the effect of the different mulching
materials on the growth and yield of lettuce and to identify the mulching material
appropriate for lettuce production. The study was conducted at the Horticulture
Experimental Area, Benguet State University from April-May 2009.
Results of the study show that the earliest to form heads were those mulched with
transparent polyethylene plastic. Higher percentage of heading was obtained with the use
of black polyethylene plastic and with the use of any of the materials but significantly
higher than that of plants which were not mulched. Wider polar and equatorial
circumferences of heads were observed in plants mulched with black polyethylene
plastic.
Although no significant differences were observed among the treatments, the
highest marketable yield at 6.60 t/ha and highest return on investment at 60.06% was
obtained from plants that were not mulched. Lesser incidence of slug and bacterial soft
rot was observed in unmulched plants.
Conclusion
Based from the results, mulching lettuce during the dry season does not enhance
the growth and yield of lettuce.
Recommendation
It is recommended that similar study on mulching lettuce be conducted during the
wet season when there are frequent rains.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
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CATELLA, G. 1987. Strawberry Culture in Reunion Island. International Training
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France.Pp.4.
GRIGSON, J. 1978. The Vegetable Book. London, Penguin. ISBN – 14- 046- 352- 6.
HORT. SCI. DEP. 1988. Florida Cooperative Extension Service, Institute of food and
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KNOTT, J.E. and J.R. DEANON. 1967. Vegetable production in South Asia. College of
Agriculture, University of the Philippines, College of Los Banos, Laguna.Pp.310.
MARR. C.W. 1993. Plastic Mulches for Vegetable, Kansas State University Agricultural
Experiment Station and Cooperative Extension Service, Kansas State University.
NNADI, L.; B.T. KANG and E.N.O.I. WUAFOR. 1984. Effect of mulch and nitrogen on
maize Southern Guinea Savanna, Central Nigeria. IITA Annual Report
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164 – 165.
RICOTTA, J.A. and J.B. MASIUNAS. 1991. The effect of black mulch and weed
control strategies on herb yield. Department of Horticulture, University of
Illionois. Horticulture Science 26 (5). Pp. 539 – 540.
ROBBINS, L.M. and J.M. SCHALK. 1982. Reflective Mulches Influence Plant
Survival, Production and Insect control in fall Tomatoes. Louisiana State
University Agricultural center, Chase, Los Angeles. Pp. 848
RUBATZKY, V.E. and M. YAMAGUCHI. 1997. World Vegetables: Principles,
Production and Nutritive Values, New York: Chapman and Hall.2nd ed.
The COLUMBIA ELECTRONIC ENCYCLOPEDIA Copyright @ 2004. Licenced from
Columbia University Press.
WHITAKER, T.W. 1974. Lettuce: Evolution of a Weedy Cinderella. Hortscience 9. Pp.
512.
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
23
APPENDICES
Appendix Table 1. Number of days from transplanting to head initiation
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
37
38
37
112
37.33
T2
36
37
35
108
36.00
T3
36
36
35
107
35.67
T4
37
36
37
110
36.67
T5
37
37
38
112
37.33
T6
37
38
37
112
37.33
T7
36
38
37
111
37.00
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.524
0.762
1.57
0.2472
Treatment
6
8.476
1.413
2.92*
0.0541
Error
12
5.809
0.485
TOTAL
20
15.809
* - Significant
Coefficient of variation = 1.89%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
24
Appendix Table 2. Number of days from transplanting to harvest
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
44
46
43
133
44.33
T2
44
44
45
133
44.33
T3
44
44
43
131
43.67
T4
45
44
48
137
45.37
T5
46
45
45
136
45.33
T6
45
45
45
135
45.00
T7
45
45
45
135
45.00
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.095
0.048
0.04
0.9633
Treatment
6
8.477
1.413
7.11 ns
0.4102
Error
8
15.238
1.270
TOTAL
20
23.81
ns - Not significant
Coefficient of variation = 2.52%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
25
Appendix Table 3. Percentage heading
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
52.17
60.87
65.22
178.26
59.42
T2
93.48
76.09
82.61
252.18
84.06
T3
71.74
84.78
78.26
234.78
78.26
T4
63.04
80.43
71.74
215.21
71.74
T5
80.43
69.57
71.74
221.74
73.91
T6
82.61
89.13
76.09
247.83
82.61
T7
67.39
82.61
73.91
223.91
74.64
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
81.505
40.753
0.74
0.4998
Treatment
6
1215.909
202.615
3.66*
0.0267
Error
12
665.078
55.423
TOTAL
20
1962.492
* - Significant
Coefficient of variation = 9.93%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
26
Appendix Table 4. Polar circumference (cm)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
15
15
16
46
15.33
T2
17
17
18
52
17.33
T3
16
16
16
48
16.00
T4
15
15
15
45
15.00
T5
15
15
15
45
15.00
T6
16
15
16
47
15.67
T7
15
15
16
46
15.33
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.238
0.619
5.20
0.0236
Treatment
6
12.000
2.000
16.80**
0.0001
Error
12
1.428
0.119
TOTAL
20
14.666
** - Highly significant
Coefficient of variation= 2.20%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
27
Appendix Table 5. Equatorial circumference (cm)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
18
18
20
55
18.33
T2
22
20
22
64
21.33
T3
19
20
19
58
19.33
T4
20
18
19
57
19.00
T5
19
19
18
56
18.67
T6
20
18
20
58
19.33
T7
18
18
20
56
18.67
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
3.714
1.857
2.17
0.1573
Treatment
6
16.286
2.714
3.17*
0.0423
Error
12
10.286
0.857
TOTAL
20
30.286
* - Significant
Coefficient of variation = 4.80%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
28
Appendix Table 6. Average head weight (kg)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
0.35
0.27
0.12
0.74
0.25
T2
0.13
0.17
0.09
0.39
0.13
T3
0.19
0.16
0.12
0.47
0.16
T4
0.21
0.15
0.13
0.49
0.16
T5
0.16
0.17
0.29
0.62
0.21
T6
0.17
0.09
0.13
0.39
0.13
T7
0.17
0.10
0.14
0.41
0.14
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.010
0.005
1.42
0.2806
Treatment
6
0.035
0.006
1.65ns
0.2163
Error
12
0.042
0.003
TOTAL
20
0.087
ns - Not significant
Coefficient of variation = 35.61%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
29
Appendix Table 7. Marketable yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
4.34
3.12
2.45
9.91
3.30
T2
2.25
3.01
2.23
7.49
2.50
T3
2.99
3.33
2.98
9/30
3.10
T4
3.02
2.85
2.35
8.22
2.74
T5
3.23
2.35
2.15
7.73
2.58
T6
3.34
2.45
2.75
8.54
2.85
T7
2.34
2.55
2.88
7.77
2.59
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
0.988
0.494
2.13
0.1615
Treatment
6
1.604
0.267
1.15ns
0.3913
Error
12
2.784
0.232
TOTAL
20
5.376
ns - Not significant
Coefficient of variation = 17.16%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
30
Appendix Table 8. Non – marketable yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
6.20
4.50
1.25
11.95
3.98
T2
1.50
2.50
1.10
5.10
1.70
T3
3.15
2.75
1.25
7.15
2.38
T4
3.00
2.90
2.00
7.90
2.63
T5
2.55
3.00
1.90
7.45
2.48
T6
2.75
1.15
2.00
5.90
1.97
T7
3.00
1.20
2.01
6.21
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
8.217
4.108
4.25
0.0403
Treatment
6
9.990
1.665
1.72ns
0.1992
Error
12
11.607
0.967
TOTAL
20
29.814
ns - Not significant
Coefficient of variation = 39.98%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
31
Appendix Table 9. Total yield (kg/1x5m plot)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
10.54
7.62
3.70
21.86
7.29
T2
3.75
5.57
3.33
12.59
4.20
T3
6.14
6.08
4.23
16.45
5.48
T4
6.02
5.75
4.35
16.12
5.37
T5
5.78
5.35
4.05
15.18
5.06
T6
6.09
3.60
4.75
14.44
4.81
T7
5.34
3.75
4.89
13.98
4.66
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
14.862
7.431
7.24
0.0086
Treatment
6
6.648
1.108
1.08ns
0.4262
Error
12
12.310
1.026
TOTAL
20
33.82
ns - Not significant
Coefficient of variation = 19.23%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
32
Appendix Table 10. Computed marketable yield (t/ha)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
8.68
6.24
4.90
19 .82
6.60
T2
4.50
6.02
4.46
14.98
4.99
T3
5.98
6.66
5.96
18.60
6.20
T4
6.04
5.70
4.70
16.44
5.48
T5
6.46
4.70
4.30
15.46
5.15
T6
6.68
4.90
5.50
17.08
5.69
T7
4.68
5.10
5.76
15.54
5.18
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
3.954
1.977
2.130
0.162
Treatment
6
6.416
1.069
1.152ns
0.391
Error
12
11.136
0.928
TOTAL
20
21.506
ns - Not significant
Coefficient of variation = 6.62%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
33
Appendix Table 11. Incidence of insect pest (slug)
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
1.50
2.55
1.05
5.10
1.70
T2
3.00
2.55
1.90
7.45
2.48
T3
3.00
1.20
2.00
6.20
2.07
T4
2.00
1.20
3.01
6.21
2.07
T5
1.61
1.61
3.00
6.22
2.07
T6
2.55
1.83
1.83
6.21
2.07
T7
2.20
1.00
3.00
6.20
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
1.437
0.718
1.18
0.3396
Treatment
6
0.922
0.153
0.25 ns
0.9486
Error
8
7.291
0.607
TOTAL
20
9.650
ns - Not significant
Coefficient of variation = 37.55%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
34
Appendix Table 12. Incidence of disease ( bacterial soft rot )
TREATMENT
REPLICATIONS
I II III
TOTAL
MEAN
T1
1.30
2.50
1.30
5.10
1.70
T2
2.00
4.43
1.00
7.43
2.48
T3
2.20
1.00
3.01
6.21
2.07
T4
2.60
1.83
1.79
6.22
2.07
T5
1.79
3.02
1.40
6.21
2.07
T6
2.00
3.00
1.20
6.20
2.07
T7
3.00
1.25
1.95
6.20
2.07
Analysis of Variance
Source of
Degrees of
Sum of
Mean of Computed TABULAR F
Variation
Freedom
Square
Square
F
0.05 0.01
Replication
2
2.096
1.048
1.03
0.3850
Treatment
6
0.906
0.151
0.15 ns
0.9857
Error
8
12.157
1.013
TOTAL
20
15.159
ns - Not significant
Coefficient of variation = 48.51%
Effect of Different Mulch Materials on the Growth and Yield of Lettuce.
PASIWEN, AIZA T. APRIL 2010
Document Outline
- Effect of Different Mulch Materials on the Growthand Yield of Lettuce
- BIBLIOGRAPHY
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- RESULTS AND DISCUSSION
- SUMMARY, CONCLUSION AND RECOMMENDATION
- LITERATURE CITED
- APPENDICES