American Journal of Plant Sciences, 2011, 2, 675-682
doi:10.4236/ajps.2011.25081 Published Online November 2011 (http://www.SciRP.org/journal/ajps)
675
Covering Tree Line with Black Poly Ethylene
Sheets for Composting Fresh Animal Manures
Reduces Weeds and Improves Tree Growth in
Newly Established Orchards
Barakat Abu Irmaileh1, Azmi Abu Rayyan2, Fahmi Shatat2
1Department of Plant Protection, Faculty of Agriculture, University of Jordan, Amman, Jordan; 2Department of Horticulture and
Crop Science, Faculty of Agriculture, University of Jordan, Amman, Jordan.
Received July 23rd, 2011; revised August 25th, 2011; accepted October 9th, 2011.
ABSTRACT
Three field experiments were carried out over two growing seasons to evaluate the response of weeds and the volume of
fruit trees; peach, pear and olive to composting of manures at 10 kg·m–2. Planting holes were prepared early January.
Animal manures from different sources; broiler, cow, layer and sheep were mixed in the top 20-cm of the soil surface
over a 40-cm band X 2.5m row per treatment in the planting row then either non covered or covered with black poly-
ethylene (BPE) sheets for six weeks or for the period from January to October. Trees were then planted late February.
The same treatments were repeated in November of the next year. Weeds were significantly reduced and fruit trees were
significantly larger in the treatments with manures in the BPE-covered treatments as compared to the non-covered
treatment. Perennials; Cynodon dactylon (L.) Pers. and Cardaria draba L. in addition to Convolvulus arvensis L. and
Sorghum halepense (L.) Pers. tolerated the composting process. Most annual weeds did not appear in composted ma-
nure subplots. Main annual weeds included; Amaranthus blitoides S. Wats. A. garacilis Desf. Sinapis arvensis L.
Chenpodium album L. in addition to some weeds species belonging to Leguminosae and Caryphyllaceae.
Keywords: Orga ni c F ar mi n g , Crop Tolerance, Sustainable Agriculture, Environmental Safety
1. Introduction
The use of composted organic matter, which contains
essential nutrients for plants, reduces chemical use, thus
reducing fertilizer imports and or their manufacture. Ani-
mal manure supp lies all major nutrients (N, P, K, Ca, Mg,
S), necessary for plant growth, as well as micronutrients
(trace elements), hence it acts as a mixed fertilizer. The
chemical composition of fresh manures varies according
to the animal source and th e type of feed and location. In
general, the percentages of N, P2O5, K2O, Ca, Mg, or-
ganic matter, and moisture in cow, sheep and poultry
manures are: 0.5%, 0.5%, 0.3%, 0.1%, 0.3%, 16.7%, 81.3%;
0.9%, 0.5%, 0.8 %, 0.2%, 0.3%, 30.7%, 64.8%, and 0.9% ,
0.5%, 0.8 % , 0.4%, 0.2%, 30.7%, 64. 8% ; respectivel y [1].
In addition, a small fraction of the added organic mate-
rial is transformed into humus or stable organic matter.
Humus contributes to soil fertility by retaining plant nu-
trients through adsorption. It also acts as binding material
in the soil, thus improv ing soil structure. It is respon sible
for making clay less susceptible to compaction, silt less
susceptible to erosion, and it increases water holding
capacity and cation exchange capacity of soil [2,3]. It
was always looked upon manure favorably because of its
fertilizing value since ancient times. However, raw ma-
nure generally releases nitrogen compounds and ammo-
nia which may burn plant roots, young plants and inter-
fere with seed germination. Application of fresh manures
attracts large amount of plant pests and houseflies as
manure is a favorable medium for the multiplication and
propagation of various microorganisms and insects, in-
cluding houseflies (Musca domestica L.) [4,5]. Surface
application of manure, particularly liquid manure, may
cause substantial losses of NH3 by volatilization [2,3].
Most of the emitted NH3 is deposited near the emission
source which lowers soil pH and may lead to mobiliza-
tion of aluminum ions, which disturbs the nutrient uptake

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 676 and Improves Tree Growth in Newly Established Orchards
by plants and enhances sensitivity to stress factors like
drought and fungi. Besides its acidifying effect, NH3
deposition accounts for a considerable N load to the en-
vironment, causing eutrophication problems and N en-
richment of the soils in nature reserves, causing undesir-
able changes in species composition and biodiversity [2].
Most of the odor comes from the anaerobic decomposi-
tion of manure due to the production of hydrogen sul-
phide and ammonia among other compounds. Thus, dis-
posal of manures, without any further composting treat-
ment, is a major environmental pollutant in agro-eco-
systems.
Composting animal manures and recycling them in
cultivated fields has been widely adopted in many coun-
tries [6] as it improves soil physical characteristics, low-
ers C:N ratio, thus reducing competition for nutrients
between plants and microorganisms, and the high tem-
perature produced during composting process reduces
the viability o f soil borne pests and weed seeds [7,8 ] and
lower housefly populations [9]. Composting of manure
can also solve odor problems, recover nutrients and en-
ergy from manure, increase the fertilizer value, and de-
crease the pollution potential to allow safe discharge of
the manure in the environment [10]. Manure manage-
ment practices are strictly regulated and enforced in the
developed countries to minimize pollution problems [10],
but management of surplus manure in the animal produc-
tion sector is far from satisfactory in developing coun-
tries where it is sold at low prices to farmers who spread
raw manure on soil surface at rates ranging from 50 to
100 t·ha–1. Collected raw manure from grazing animal
barnyards (goat and sheep) is normally contaminated
with seeds of various p lant species; as these animals, and
to a lesser extent cattle, are normally allowed to graze
crop remains and weeds after harvest [8 ]. Therefore, raw
manure could increase the weed seed bank in receiving
fields. Weeds are one of the most limiting factors in ag-
ricultural production, as weed infestations can result in
serious yield losses compared to other constraints in crop
productio n [11,12].
Farmers in most developing countries remove weeds
by manual hoeing [13]. In these countries chemical weed
control is typically unaffordable, especially if more than
one herbicide is required and if market economics limit
profits. Nonchemical weed control practices, such as soil
solarization with black polyethylene mulch during the
hottest months of the year, are favored for the control of
weeds and other pests [14]. Recent findings indicated
that pre-plant composting of various organic manures in
the planting rows for six weeks can effectively control
weeds including broomrapes [8,15].
Good weed control is essential for rapid establishment
and vigorous growth of you ng tr ees. Gr owth of fruit tr ees
during the phase of orchard establishment is normally
hampered by the presence of weeds. Weed control in
young orchards is critical. Competition from smooth
pigweed reduced tree growth of newly established trees
by more than 40% [16], and Bermuda grass infestation
can reduce fresh weights of peach trees by 87% after one
year [17].
The objective of this research is to evaluate the impact
of pre- and post-plant composting of different manures
on weed infestation and tree growth in newly established
olive, pear and peach orchards.
2. Materials and Methods
Three field experiments were conducted over two grow-
ing seasons (2009-2011) at the University of Jordan re-
search stations, to study the growth response of three
species of fruit trees; olive (Olea europea) cv. “Grosadi”
(own rooted cuttings), peach (Prunus persica) cv. “Crim-
son Lady”/Montclar and pear (Pyrus communis) cv.
“Cosia”/BA29 rootstock to composting treatments of
four types of fresh manures in the tree line. Each manure
type; cow, sheep, broiler and layer, was incorporated
with the soil six weeks before planting the trees during
January in the first growing season and during the fall
period (November) in the second season. Planting holes
were prepared before manure application in the first
growing season, and manure was also mixed in the soil
of the planting holes. The main treatments were: BPE6-
composting by covering the tree line by black polyethy-
lene (BPE) sheets for only six weeks before planting th en
the cover was removed, BPEC—as in the treatment BPE6,
but BPE cover was retained for the whole growing sea-
son, NO BPE—treatment without BPE cover. Each main
treatment included five sub treatments; cow, sheep, broi-
ler, layer manures and a check (no-manure treatment).
Each manure sub-treatment received a different source of
manure in 40 cm bands, at the rate of 10 kg·m–2. Planting
of fruit trees commenced at late February. Planting dis-
tances were 3 m within the tree lines which were 3 m
apart. Each sub-treatment included three trees in plots of
3 × 9 m2. The area of each main treatment was 45 × 3 m2.
The area of each experiment was 45 × 9 m2. The same
set of treatments was also repeated during the second
season in an open area nearby, in order to verify the ef-
fect of composting on weeds without interference of the
shading effect of the tree canopies on weed growth. All
experiments were drip irrigated to field capacity at
weekly intervals except during the period of rainfall. No
chemical fertilizers were added. Light pruning was car-
ried out late autumn of the first growing season to re-
move the dead branches and suckers. The same treat-

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 677
and Improves Tree Growth in Newly Established Orchards
ments were repeated for the next growing season.
Each of the fruit tree species; olive, peach and pear,
was planted separately to constitute an experiment by
itself. Experiments were conducted at the Agricultural
Research Station in Jubeiha, 32˚N, 35 ˚ longitu de an d 980
m above sea level. It was considered that the incorpo-
rated manure was composted in the soil when it was
moistened under BPE during the covering period. The
uncovered manure-treated soil was considered as a treat-
ment without manure composting.
All experiments were arranged in a split plot design.
The main plots were three composting methods; BPE
cover for 6 weeks (BPE6), BPE cover for the whole
growing season (BPEC) and no BPE cover (NO BPE) in
each of the fruit tree types. Each main plot included five
subplots; four different types of manure in addition to
no-manure as a check. Three trees were planted in each
subplot.
The initial tree volume was visually estimated for each
tree by three researchers on a scale from 1 (for the
smallest-sized tree) to 10 (for the largest-sized tree). Tree
volumes were estimated during the period from mid-
August to mid-October. The estimated tree size at plant-
ing for olive, peach, and pear was 2, 2 and 1; respect-
tively. Weeds were collected from the middle of each
plot during spring and late summer. Weeds were identi-
fied and dried at 70˚C for three days in a drying oven.
Weed dry weights were recorded.
Analysis of variance was conducted with the SAS
program, version 7 for split-plot arrangement, and the
interactive means were separated by least squared means
according to GLM procedure [18]. Means were separated
according to Duncan’s Multiple Range Test at 5% level
of probability.
3. Results and Discussion
3.1. Effect of Main Treatments of Manure
Composting on Weed Control
The grand means of dry weights of weeds collected from
the main treatments with BPE cover for 6 weeks (BPE6),
or with BPE cover for the whole growing season
(BPEC), were significantly lower than in the uncovered
treatment (NO BPE) in all fruit tree types (Table 1).
When the BPE cover was removed after 6 weeks,
weeds that tolerated the treatments under the BPE cover
grew to the end of the season, but their dry weights re-
mained significantly lower compared to those in the
main treatment NO BPE, except in the pear experiment.
This was related to the fact that weed populations in the
pear experiment were mixed with perennial weeds that
tolerated the BPE cover treatment, namely; Cynodon
dactylon (L.) Pers. and Cardaria draba L. in addition to
Convolvulus arvensis L. and Sorghum halepense (L.)
Pers. which appeared sporadically. When BPE cover was
removed after 6 weeks, the treatment-tolerant weeds
grew in the absence of weed interference from the weeds
that did not tolerate the treatments. Most annual weeds
did not appear in composted manure subplots. Main an-
nual weeds included; Amaranthus blitoides S. Wats. A.
garacilis Desf. Sinapis arvensis L. Ch enpodium a lbum L.
in addition to some weeds species belonging to Legumi-
nosae and Caryphyllacea. A second factor that may have
contributed to such result is that pear branching was
mostly upright compared to that in peach and olive
where the tree line was mostly shaded, thus discouraged
weed growth as compared to pear. No weeds were col-
lected from the main treatment BPEC as the BPE cover
was retained on the surface of the planting line for the
whole season.
The impact of different treatments on weed dry weights
varied among experiments, depending on the dominating
weed types in each. The overall impact of composting
manures on weed dry weights was apparent during
summer, especially in peach as weed dry weights in the
check plots (the no-manure subplots) were significantly
lower (Table 2). Weed dry weights in the olive experi-
ment had the same trend, but only weed weights in the
check plots were significantly lower than those that re-
ceived sheep and broiler manures. No significant diffe-
rences appeared in weed dry weights either in pear or in
the open area experiment.
All subplots with manur e had h igh er weed dry weigh ts
within the main treatment without BPE cover, NO BPE,
compared to treatment with BPE cover for six weeks,
BPE6, and with continuous BPE cover, BPEC (Tabl e 3 ).
This was an expected result as manures are organic fer-
tilizers; in addition to the untreated manures are normally
contaminated with weed seeds, depending on the types of
feed lots or the grazing areas [8]. Weeds continued to
grow faster in most of the subplots which received ma-
nure application than the weeds in the no-manure sub-
plots across all experiments. When weed dry weight
measurements were carried out late summer, about 5 - 6
months after PBE removal in the main treatment BPE6,
weed dry weights in the no-manure subplot (check) was
either significantly lower than those in the check sub-
plots of the NO BPE in peach and olive experiments, but
were similar to those in the pear and the open area ex-
periments. The different weed population in the pear
experiment resulted in almost equal dry weights of weed
masses across all subplots compared to those in peach
and olive experiments. Annual weeds that dominated
peach and olive areas were mostly annuals, while the
pear and the open areas were dominated by perennials,

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds
and Improves Tree Growth in Newly Established Orchards
678
Table 1. Grand means of weed dry weights in the main treatments.
Weeds dry weight (g)*
First growing season Second growing season
Peach Pear Olive Open area
Main treatment
Spring Summer Spring Summer Spring Summer Spring Summer
BPE6 5 b 116 b 12 b 407 a 9 b 201 b 11 b 82 b
BPEC 0 c 0 c 0 c 0 b 0 b 0 c 0 c 0 c
NO BPE 102 a 605 a 84 a 446 a 115 a 681 a 39 a 13 0 a
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.
Table 2. Grand means of weed dry weights in various manure treatments.
Weeds dry weight (g)*
First growing season Second growing season
Peach Pear Olive Open area
Manure types
Spring Summer Spring Summer Spring Summer Spring Summer
Sheep 39 ab 284 a 35 a 269 a 27 b 320 ab 15.8 ab 73.6 a
Broiler 33 b 262 a 33 ab 276 a 43 ab 353 a 15.5 ab 46.7 b
Cow 32 b 220 a 34 a 282 a 38 b 233 c 14.9 b 45.4 b
Layer 41 a 300 a 28 b 273 a 38 b 311 ab 15.8 ab 63.5 ab
Check 34 b 134 b 32 ab 322 a 62 a 251 bc 21.7 a 59.6 ab
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.
Table 3. Effect of interactive combination of manure amendment x manure type on mean weed dry weights.
Weeds dry weight (g)*
First growing season Second growing season
Peach Pear Olive Open area
Main treatments Manure
types
Spring Summer Spring Summer Spring Summer Spring Summer
Sheep 110 a b 737 a 95 a 397 ab 73 c 703 b 15 bcd 115 abc
Broiler 92 c 670 ab 78 bc 517 a 120 b 857 a 7 cd 56 cd
Cow 90 c 543 b 92 a 390 ab 105 bc 530 c 9 cd 68 cd
Layer 121 a 783 a 72 c 38 3 ab 105 bc 737 b 8 cd 92 abc
NO BPE
Check 99 bc 291 c 86 ab 543 a 172 a 577 c 17 bcd 79 bc
Sheep 5 d 117 d 10 ef 410 ab 7 d 257 d 33 abc 155 a
Broiler 7 d 117 d 21 d 310 b 8 d 203 d 39 ab 115 abc
Cow 7 d 118 d 10 ef 457 ab 10 d 170 d 36 ab 98 abc
Layer 4 d 117 d 13 de 437 ab 9 d 197 d 4 0 ab 140 ab
BPE6
Check 4 d 110 d 9 ef 423 ab 13 d 177 d 48 a 139 ab
Sheep 0 d 0 d 0 f 0 c 0 d 0 e 0 d 0 d
Broiler 0 d 0 d 0 f 0 c 0 d 0 e 0 d 0 d
Cow 0 d 0 d 0 f 0 c 0 d 0 e 0 d 0 d
Layer 0 d 0 d 0 f 0 c 0 d 0 e 0 d 0 d
BPEC
Check 0 d 0 d 0 f 0 c 0 d 0 e 0 d 0 d
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 679
and Improves Tree Growth in Newly Established Orchards
namely; Cynodon dactylon (L.) Pers. and Cardaria draba
L. in addition to Convolvulus arvensis L. and Sorghum
halepense (L.) Pers. which appeared sporadically in BPE6.
Weeds which were removed at the end of summer
each growing season in the uncovered main treatment,
NO BPE, mainly included Cardaria draba L., Cynodon
dactylon, Chenopodium vulvaria L., C. murale L., Ama-
ranthus blitoides S. Wats., A. retroflexus L., Sonchus
oleraceous L., Malva sylvestris L. The main weeds
which appeared in the main treatment BPE6 were Card-
aria draba L., Cynodon dactylon, while Cynodon dacty-
lon appeared in the holes around the trees in the main
treatment BPEC. Weed species that were effectively
controlled included Chenopodium murale, C. album,
Amaranthus retroflexus, Sonchus oleraceous, Polygonum
aviculare, and Sisymbrium irio.
The impact of composting each type of manure in the
treatment BPE6 on weed dry weights taken three months
after PBE removal during spring time was not significant
compared to the check. However, weed dry weights of
the different sub-treatments in BPE6 were significantly
lower than the corresponding sub-plots in the NO BPE
main treatment. The variations in weed dry weights
among and within each experiment was due to variations
in weed populations dominating each site. Such variation
could not be controlled under normal field weed infesta-
tions. This indicated that the main significant effect of
treatment BPE6 was due to the PBE covering rather than
to the manure composting.
Unlike the obtained results here, it was reported that
composting manure and other organic matter prior to
planting under PBE cover reduced weed population in
vegetables in warmer regions [15] as composting ma-
nures resulted in warming up the soil besides the produc-
tion of volatile compounds wh ich are retained und er BPE
cover in high concentrations, such as ammonia, which
enhanced detrimental effects on weed growth.. Such ef-
fect was not evident in the relatively cooler regions
where this research was carried out. However, weed
seeds can be killed during composting even though lethal
temperatures are not reached [19]. The efficacy of the
composting process for controlling soil borne living pro-
pagules is not necessarily dependent on simply raising
soil temperatures. For instance, imbibed weed seeds have
been reported to be killed faster than non imbibed weed
seeds at typically sub lethal soil temperatures when un-
der mulch [20]. But, some weed species and other soil
borne pest propagules may not be controlled effectively
if BPE cover is applied during the winter months.
3.2. Effect of Main Treatments of Manure
Composting on Tree Volume
Despite the fact that there were no significant negative
impact of manure composting on weed dry weights com-
pared to the no-manure composting in both main treat-
ments; BPE6 and BPEC (Table 2), tr ee grow th w as very
much improved by manure composting process. In addi-
tion to the positive effects of composting [2,3], it en-
hances microbial activity and accelerates rates of de-
composition, leading to a humification effect through
which the unstable organic matter is oxidized and stabi-
lized [21].
The response of tree volume to the main treatments
varied among fruit tree species (Table 4). Tree volumes
were significantly increased within four to five months
of planting in peach and pear in the first growing seasons
in BPE6 and BPEC, and in response to the main treat-
ment BPEC in olives as compared to NO BPE, but were
numerically higher in the BPE6. Greater tree volumes
were due to the BPE cover in addition to the manure
composting effect.
The response of tree volume to different manure
treatments (Table 5) was evident during summer in all
tree species, but significantly larger in peach and olives,
and was numerically smaller in the check subplots.
However, pear branching was more upright and the trees
grew in height rather than in width.
The response to composting each manure type was
much more variable among the tree species, but there
was no clear trend in response to specific manure in any
of the tree species among the main treatments. In general,
subplots where manure was composted produced larger
tree volumes than the check subplots with no-manure
application (Table 6).
In conclusion, covering the tree line at planting with
BPE reduces weeds and improves tree growth, especially
if BPE cover was retained during spring and summer
after planting. Composted fresh animal manures under
BPE cover increased tree growth. If the applied fresh
manures were not composted, the weed growth will be
increased tremendously. The variable response of diffe-
rent tree species to different treatments of manure com-
posting is more likely to be due to the variability of dif-
ferent species nutrient requirements and or growth habit.
Olives, as evergreen species with relatively longer grow-
ing season, may require larger amounts of nutrients and
water compared to peach and pear. It is also due to the
different interference levels from different weed popula-
tions. As not all weeds are sensitive to either BPE cover
with or without manure, certain weeds tolerate this
treatment and continue to grow at faster rates in the ab-
sence of interference of the BPE cover-sensitive weeds.
The positive effects of manure application on the growth
of trees is a common phenomenon, as manures provide
nutrients [22] to the trees and increase the soil aggrega-

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 680 and Improves Tree Growth in Newly Established Orchards
Table 4. Grand means of tree volumes in response to BPE covers.
Tree volume estimates*
Peach Pear Olive
Main treatments
1st season 2nd season 1st season 2nd season 1st season 2nd season
BPE6 7.2 a 8.1 b 5.1 b 5.8 b 6.2 ab 7.7 ab
BPEC 7.9 a 8.8 a 7.0 a 7.9 a 6.8 a 7.8 a
NO BPE 5.0 b 7.1 c 3.9 c 4.4 c 6.0 b 7.1 b
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.
Table 5. Grand means of tree volumes in various manure treatments.
Tree volumes estimates*
Peach Pear Olive
Manure types
1st season 2nd season 1st season 2nd season 1st season 2nd sea son
Sheep 6.8 a 8.4 ab 5.1 bc 5.9 a 6.4 a 8.0 a
Broiler 6.9 a 9.0 a 5.6 ab 6.1 a 6.7 a 8.0 a
Cow 6.2 a 8. 0 b 5.2 bc 6.1 a 6.6 a 8.0 a
Layer 7.2 a 8.6 ab 6.0 a 6.4 a 6.5 a 8.0 a
Check 6.4 a 6.2 c 4.8 c 5.8 a 5.5 b 6.4 b
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.
Table 6. Effect of interactive combination of manure amendment X manure type on mean tree volumes.
Mean tree volumes estimates*
Peach Pear Olive Main treatments Manure Types
1st season 2nd season 1st season 2nd season 1st season 2nd season
Sheep 7.2 ab 9.4 a 5.8 cde 6.3 cdef 6.0 ab 7.4 abc
Broiler 7.9 ab 9.2 a 6.1 bcd 6.6 cd e 6.2 ab 8.6 ab
Cow 7.1 ab 7.7 bcde 4.8 def 5.8 defg 6.6 a 8.2 abc
Layer 7.1 ab 8.6 abc 4.4 ef 5.0 fgh 6.3 a 7.7 abc
BPE6
Check 6.6 abc 5.7 f 4.6 ef 5.4 efg 6.0 ab 6.8 cd
Sheep 8.2 ab 8.9 ab 6.0 cd 7.6 bc 7.0 a 8.9 a
Broiler 7.8 ab 9.3 a 6.9 bc 7.4 bc 6.7 a 7.3 abcd
Cow 7.2 ab 9.2 a 7.4 ab 8.1 ab 7.1 a 7.8 abc
Layer 8.5 a 9.7 a 8.7 a 9.2 a 7.3 a 8.6 ab
BPEC
Check 7.7 ab 7.1 cdef 6.0 cd 7.1 bcd 5.9 ab 6.7 cd
Sheep 4. 9 cd 6.9 ef 3.6 e 3.7 h 6.2 ab 7.8 abc
Broiler 4.9 cd 8.4 abcd 3.9 e 4.3 gh 7.2 a 8.0 abc
Cow 4.2 d 7.0 def 3.3 e 4.3 gh 6.1 ab 7.1 bcd
Layer 6.1 bcd 7.6 bcde 4.8 cde 5.1 efgh 5.9 ab 7.2 abcd
NO BPE
Check 4.8 cd 5.8 f 3.8 e 4.8 gh 4.7 b 5.7 d
*Means within columns carrying the same l etter are not significant ly different at 5% level of probab i l ity accor d ing to Duncan’s Multiple Range Test.

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 681
and Improves Tree Growth in Newly Established Orchards
tion, improve soil structure and texture and improve wa-
ter holding capacity [2,3]. However, if fresh manures
were applied to the soil without composting process, the
local environment would suffer from the side effects
such as increasing weed populations and intensifying
competition with the trees for the essential growth re-
sources [13], and incr easing housefly problems [2 3]. Pre-
plant or autumn composting of fresh manures without
being covered with BPE offer a solution as nutrient
source, and alleviate the problem of weeds, houseflies
and other ill effects that application of fresh man ure may
bring about [5].
REFERENCES
[1] A. Clemente, R. Sánchez-Vioque, J. Vioque, J. Bautista
and F. Millán, “Chemical Composition of Extracted Dried
Olive Pomaces Containing Two and Three Phases,” Food
Biotech, Vol. 11, 1997, pp. 273-291.
doi:10.1080/08905439709549936
[2] P. J. Bran djes, J. de Wit, H. G. van der Me er and H. Van
Keulen, “Environmental Impact of Animal Manure
Management,” International Agriculture Centre, Wage-
ningen, 1996.
http://www.fao.org/WAIRDOCS/LEAD/X6113E/x6113e
05.htm#2%20Manure%20management%20and%20effect
s%20of%20manure%20on%20the%20environment
[3] P. L’Hermite, P. Sequi and J. H. Voorburg, “Scientific
Basis for Environmentally Safe and Efficient Manage-
ment of Livestock Farming,” Report of the Scientific
Committee of the European Conference Environment,
Agriculture and Stock Farming in Europe, European
Conference, Mantova, Mantua, 1993.
[4] R. W. Crosskey and R. P. Lane, “House-Flies, Blowflies,
and Their Allies (Calyptrate Diptera),” In: R. P. Lane and
R. W. Crosskey, Eds., Medical Insects and Arachnids,
Chapman and Hall, London, 1993, pp. 403-428.
doi:10.1007/978-94-011-1554-4_11
[5] A. M. Abu-Rayyan, B. E. Abu-Irmaileh and M. M. Ak-
kawi, “Manure Composting Reduces House Fly Popula-
tion,” Journal of Agricultural Safety and Health of
ASABE, Vol. 16, No. 2, 2010, pp. 99-110.
[6] M. A. Ross and C. A. Lembi, “Applied Weed Science,”
2nd Edition, Prentice Hall, New Jersey, 1999, pp. 1-22.
[7] K. H. Linke, M. C. Saxena, J. Sauerborn and H. Masri,
“Effect of Soil Solarization on the Yield of Food Leg-
umes and on Pest Control,” In: J. E. De Vay, J. J. Staple-
ton and C. L. Elmore, Eds., Soil Solarization, Proceed-
ings of the 1st International Conference on Soil Solariza-
tion, Amman, 19-25 February, 1990, FAO Plant Produc-
tion and Protection Paper # 109. Rome, 1991, pp. 139-
154.
[8] B. E. Abu-Irmaileh and A. Abu-Rayyan, “In-Row Pre-
plant Manure Composting Reduces Weed Populations,”
HortScience, Vol. 39, No. 6, 2004, pp. 1456-1460.
[9] S. J. Brown, “Manure Composting: A Solution to Dealing
with Stricter Environmental Regulations,” Sustainable
Farming: Resource Efficient Agricultural Production,
Ste-Anne-de-Bellevue, McGill University, Ecological
Agriculture Projects, Quebec, 1995.
http://www.eap.mcgill.ca/MagRack/SF/Winter%2095%2
0E.htm
[10] E. Hammill and M. Murphy, “Alternate Methods of Ma-
nure Treatment and Utilization,” Guidelines for Man-
agement for Prince Edward Island, P.E.I. Department of
Agriculture and Forestry and P.E.I. Department of Tech-
nology and Environment, Manitoba, 1999.
<http://www.gov.mb.ca/agriculture/livestock/pork/swine/
bah11s01.html
[11] B. E. Abu-Irmaileh and A. S. El Kady, “Some Factors
Affecting Pest Control in Jordan,” Arab Journal of Plant
Protection, Vol. 15, No. 1, 1997, pp. 24-30
[12] S. E. Azrag, “Future Trends in Agricultural Production
within the Arab Countries,” Proceedings in FAO I m p r ove d
Weed Management in the Near East. Proceedings of FAO
Expert Consultation on Improved Weed Management in
the Near East, FAO Plant Production and Protection
Paper #80, Nicosia, 30 October-1 November 1985, pp.
5-15.
[13] R. Parker and B. E. Abu-Irmaileh, “Weed Co ntrol Man ual
for the Jordan Valley,” University of Jordan Publication,
Amman, 1987.
[14] B. E. Abu-Irmaileh and U. A. R. Saghir, “Components of
Successful Weed Management with Special Reference to
Vegetable Growers in the Near East,” FAO Plant Protec-
tion Bulletin, Paper No. 30, 683/B, Vol. 42, No. 4, 1994,
pp. 191-200.
[15] A. M. Abu-Rayyan and B. E. Abu Irmaileh. “Efficiency
of Fermenting Poultry Manure for Weed Control in Or-
ganically Grown Eggplants (Solanum melongena L.),”
Arab Journal of Plant Protection, Vol. 22, No. 1, 2004,
pp. 35-40.
[16] B. A. Majek, P. E. Neary and D. F. Polk, “Smooth Pig-
weed Interference in Newly Planted Peach Trees,” Jour-
nal of Production Agriculture, Vol. 6, No. 2, 1993, pp.
244-246.
[17] S. C. Weller, W. A. Skroch and T. J. Monaco, “Common
Bermuda Grass (Cynodon dactylon) Interference in
Newly Planted Peach (Prunus persica) Trees,” Weed
Science, Vol. 33, 1985, pp. 50-56.
[18] S. A. S. “Statistical Analysis System,” Version 7, Li-
censed to North Carolina State University, Site # 0027-
585007, SAS Institute. Inc., Cary, 1998.
[19] E. Bahman and G. W. Lesoing, “Viability of Weed Seeds
Following Manure Composting,” Tektran, USDA-ARS,
1999.
http://www.nal.usda.gov/ttic/tektran/data/000010/47/0000
104751.html.
[20] L. C. Standifer, P. W. Wils on and R. Porche-Sorbet, “Ef-
fects of Solarization on Soil Weed Seed Population,”
Weed Science, Vol. 32, 1984, pp. 569-573.

Covering Tree Line with Black Poly Ethylene Sheets for Composting Fresh Animal Manures Reduces Weeds 682 and Improves Tree Growth in Newly Established Orchards
[21] C. Elvira, L. Sampedro, E. Benitez and R. Nogales,
“Vermicomposting of Sludges from Paper Mill and Dairy
Industries with Eisenia Andrei,” A Pilot-Scale Study,
Bioresource Technology, Vol. 63, 1998, pp. 205-211.
doi:10.1016/S0960-8524(97)00145-4
[22] F. M. Bradley and B. W. Ellis, “Rodale’s All-New Ency-
clopedia of Organic Gardening. The Indispensable Re-
source for Every Gardener,” Rodale Books, Emmaus,
1993.
[23] N. A. Romiah and H. M. Elmosa, “A Cultural Method for
Controlling the House Fly Musca domestica (Diptera:
Muscidae) and Studying Certain Aspects of Its Biology in
the Jordan Valley,” MSc. Thesis, University of Jordan,
Amman, 1996.