HUME LIBRA1ycUL"U'-L c- VnIVERSITY 017FLORIDA
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Dover, Florida AS
' DoverEfEd-RBdgch Rep rt SV-1972-2 December, 1972
EFFECT OF MULCHES ON OKRA, PEPPER AND STRAWBERRIES IN CENTRAL FLORIDA
.F.A.S. Univ. of Florida
""- E. E. Albregts and C. M. Howard
The use of mulches in crop production has been a widespread practice for many
years. Vegetables have been mulched with straw, peat, stones, paper, aluminum foil,
polyethylene, asphalt, and petroleum emulsions. Mulches help control weeds, conserve
moisture and fertilizer, modify the soil temperature, and stabilize the soil
environment; all of which can promote plant growth and yield.
In the Plant City, Florida, area, most soils do not have a spodic horizon
(organic hardpan) to retard the downward movement of water; therefore, irrigation
is by overhead sprinkler rather than by furrow or seep. It is important to keep
adequate moisture available in the soil under the mulch since it is more difficult
to moisten than the unmulched soil. With overhead sprinkler irrigation no
difficulty should be present from fertilizer injury if the fertilizer is properly
placed. On two row beds, part of the fertilizer can be incorporated into the soil
and the remainder banded about 1 to 2 inches deep in the bed center. On one row
beds, the banded fertilizer should be placed to the sides of the bed about 1 to 2
inches below bed top. Placement of fertilizer in the upper portion of the bed
makes it readily available to the plant and yet not subject to the heavy leaching
losses of deeper placement.
In a two year study with mulch on strawberries, yields were similar with black
polyethylene and black or gray PE paper (see Table 1). Either mulch type can be
applied with equal ease if the proper equipment is available. However, paper mulch
i~ slightly more difficult to set strawberry transplants through since paper is
nore rigid than polyethylene.
In a trial with pepper and okra, the use of a full bed PE paper mulch increased
jlant size and yields in comparison to unmulched areas (Tables 2,3, and 4). Strip
rulch i.e., the application of a strip mulch to cover the fertilizer band -
enhanced growth and yields of pepper over that of the unmulched treatment, but had
little effect on okra yields. The soil fertility level remained higher with the
use of mulch, strip or full bed, than with no mulch. Root mass was greater and was
contained in a larger soil volume with the use of a full bed mulch. In addition,
the soil moisture content was more stable under the full bed mulch than with the
strip or no mulch treatments. All of these factors were probably responsible for
the more rapid plant growth and increased yields from the full bed mulched plots.
Although either PE paper or polyethylene mulch should perform equally well in
increasing yields of strawberries, PE paper has the advantage of being disked into
the soil at season's end where it will decompose. Polyethylene must be removed
from the field at the end of the harvest season which requires from 8 to 30 man
hours/acre. Paper mulch is somewhat more expensive than polyethylene consequently
the economics of its use will need to be considered. Initially the cost of black
polyethylene is about $100/acre and PE paper $170/acre, and must be added to the
production expenses. With a selling price of $5/bushel for pepper and okra one will
neid to produce an extra 20 bushel/acre (640 lbs/acre) to pay for the cost of the
polyethylene mulch and 34 bushel/acre (1088 lbs/acre) to pay for the PE paper.
Since the use of mulch lowers some of the production expenses, this will reduce
sor:ewhat the yield increases necessary to defray the cost of the mulch. "lulch
suppresses most weed growth except that between plant beds and around the plant
holes which can usually be controlled with narrow band applications of herbicides.
In addition, nutsedge (Cyperus sp.) cannot penetrate PE paper mulch as it does
black polyethylene giving a further measure of its control. Fertilizer is
conserved with mulch since leaching from the root zone is curtailed (Table 4).
'lulch will reduce the total amount of fertilizer needed and the number of fertilizer
applications required (only one with mulch). Consequently, mulch will lower
herbicide and labor costs for weed control and fertilizer and fertilizer
application expenses. These cost savings can be deducted from the initial cost of
In summary, black polyethylene or PE paper should serve equally well as a mulch
for strawberries while pepper and okra have responded well to PE coated paper
mulches. In comparison to a bare soil pepper and okra will emerge earlier, grow
faster, and produce higher yields when grown under full bed mulch. To a lesser
degree, pepper growth and yields will be enhanced with strip mulch. Although the
cost of mulch needs to be added to the production expenses, their use will lower
costs for weed control, fertilizer, and fertilizer application. The prices of the
PE paper and black polyethylene mulches need to be considered in selection of mulch
type. However, unlike black polyethylene, PE paper will suppressnnatsedge-andd-'oes
not need to be removed from the field at season's end.
Table 1. Effects of paper and polyethylene (PE) mulches on marketable strawberry
yields and soluble salts in solution extracts.
Marketable yield Soluble salts
Mulch type Fungicide (Ibs/acre) (ppm)7
-nd placement level 1971 1972 1972
lack paper (PE down) 1x 15470 abw 18380 a 460 a
(Double PE) M 12850 b 21190 a 374 a
(PE down) II 19210 a 605 a
(Double PE) H 14650 ab 19790 a 535 a
G-ray paper (PE down) H 18720 a 530 a
(Double PE) 16005 a
Black PE 15470 ab 20030 a 579 a
expresseded on basis of soil solution at field capacity in plant beds. Samples
taken at end of harvest season.
-il = medium, H = high
M .ans in any column followed by different letters are significantly different
at: the 5% level of probability.
Table 2. Effect of mulch and fertility on relative plant size of okra for three
trials and pepper for two seasons.
Spring 1971 Fall 1971 Spring 1972
Treatment Early Mid-season Early Mid-season Early M"id-season
'one 2.8 cXy 7.9 b 6.1 b 7.5 b 8.6 ab 9.4 ab
String 6.5 b 9.1 a 7.8 ab 6.8 b 7.4 b 8.6 b
Full Bed 9.0 a 9.9 a 9.9 a 10.0 a 9.6 a 10.0 a
Ione 4.5 c 5.1 b 6.0 c 8.3 b
f:rip 8.0 b 7.0 ab 7.3 b 8.5 ab
lull Bed 9.5 a 8.6 a 9.4 a 9.5 a
meanss in any column within a treatment followed by different
icantly different at the 5% level of probability.
letters are signif-
Y\ll. plant size are relative within a date and within a vegetable with the largest
plant rated at 10. A pepper plant rated as 4.5 would be one-half the size of one
rated as 9.
Table 3. Pepper and okra marketable yield,
influenced by the mulches.
number fruit per plant, and average fruit weight as
Marketable yield lbs/acre No./plant Avg. wt. (g)
Treatment S-1971 F-1971 S-1972 S-1971 F-1971 S-1972 S-1971 F-1971 S-1972
None 3798xb 7023 b 5101 b 1.5 b 2.4 b 1.8 b 8.8 a 10.3 a 9.8 a
Strip 6321 b 6544 b 3384 c 2.5 b 2.3 b 1.2 c 8.7 a 10.0 a 10.0 a
Full 'ed 12034 a 16630 a 6352 a 4.2 a 3.3 a 2.2 a 9.8 a 11.1 a 11.1 a
None 7278 c 7118 c 2.40 b 1.93 c 63.4 b 76.2 b
Strip 16344 b 14461 b 4.75 a 3.58 b 72.1 a 83.5 ab
Full Bed 21259 a 21643 a 5.95 a 5.19 a 74.6 a 87.1 a
xieans in any column within a treatment followed by different letters are significantly different at
the 5% level of probability.
Table 4. Effect of treatment on soil NO3 and K in soil solutions
1971 1972 1971 1971
Treatment N03 K NO K NO3 K NO, K
"ppm in.soil. solution at field capacity. Soil samples taken at 5 places across the bed during the harvest season.
YSoil data for fall 1971 only.
z''ans in any cblumn-wi'thin a-treatment'" followed' b different' etters' are significantly 'ifflereYt atIthc .
5% level of probability.
The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
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site maintained by the Florida
Cooperative Extension Service.
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