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Surface application of manure may increase the risk of phosphorus loss in runoff. Manure application, however, often results in increased soil aggregate stability with reduced runoff and erosion and, therefore, reduced P transport potential. Three field studies were conducted with silt loam or silty clay loam soil in Nebraska to determine how water-stable soil aggregation in the 0- to 25-mm soil depth is affected: (1) by application of raw or composted feedlot manure; (2) by repeated annual manure application; and (3) by the residual effect of composted manure applied five to seven years before sampling. Large macro-aggregates (>2mm) were increased 200% or more by both manure and compost application within 15days after application; the effect persisted for the seven months of study with a greater effect due to compost application. Aggregate stability was similar for incorporation and no incorporation of the applied compost or manure. Bray-P1 in large macro-aggregates was 200% more than for the whole soil sample with manure or compost applied, but Bray-P1 in large macro-aggregates was similar to the whole sample in the control. Annual application of swine slurry for several years resulted in a 20% increase in aggregates >250mm. After four years of no compost following three years of compost application, aggregate size distribution was similar for the compost- compared to the no-compost-applied treatments. Increased macro-aggregate formation and high Bray-P1 in these aggregates may protect against P loss in runoff due to reduced runoff and erosion and protection of P in water-stable large macro-aggregates.
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RESEARCH ARTICLE
The effects of manure application on soil aggregation
C. S. Wortmann ÆC. A. Shapiro
Received: 27 April 2007 / Accepted: 8 August 2007
Springer Science+Business Media B.V. 2007
Abstract Surface application of manure may
increase the risk of phosphorus loss in runoff. Manure
application, however, often results in increased soil
aggregate stability with reduced runoff and erosion
and, therefore, reduced P transport potential. Three
field studies were conducted with silt loam or silty
clay loam soil in Nebraska to determine how water-
stable soil aggregation in the 0- to 25-mm soil depth
is affected: (1) by application of raw or composted
feedlot manure; (2) by repeated annual manure
application; and (3) by the residual effect of
composted manure applied five to seven years before
sampling. Large macro-aggregates ([2 mm) were
increased 200% or more by both manure and compost
application within 15 days after application; the
effect persisted for the seven months of study with
a greater effect due to compost application.
Aggregate stability was similar for incorporation
and no incorporation of the applied compost or
manure. Bray-P1 in large macro-aggregates was
200% more than for the whole soil sample with
manure or compost applied, but Bray-P1 in large
macro-aggregates was similar to the whole sample in
the control. Annual application of swine slurry for
several years resulted in a 20% increase in aggregates
[250 mm. After four years of no compost following
three years of compost application, aggregate size
distribution was similar for the compost- compared to
the no-compost-applied treatments. Increased macro-
aggregate formation and high Bray-P1 in these
aggregates may protect against P loss in runoff due
to reduced runoff and erosion and protection of P in
water-stable large macro-aggregates.
Keywords Aggregate stability Compost
Eutrophication Macro-aggregate
Soil porosity
Abbreviations
Ag[2mm Large soil macro-aggregates
Ag0.25–2mm Small macro-aggregates
Ag0.053–0.25mm Soil micro-aggregates
ARDC Agricultural Research and
Development Center
DAA Days after application of
manure or compost
SOM Soil organic matter
UN-L University of Nebraska-Lincoln
A contribution of the University of Nebraska Agricultural
Research Division, supported in part by funds provided through
the Hatch Act.
C. S. Wortmann (&)
Department of Agronomy and Horticulture, University
of Nebraska-Lincoln, 279 Plant Science, Lincoln,
NE 68583-0915, USA
e-mail: cwortmann2@unl.edu
C. A. Shapiro
Northeast Research and Extension Center—Haskell
Agric. Lab, University of Nebraska-Lincoln,
57905 866 Rd, Concord, NE 68728, USA
e-mail: cshapiro1@unl.edu
123
Nutr Cycl Agroecosyst
DOI 10.1007/s10705-007-9130-6
Introduction
Runoff-P concentration is typically higher with
higher soil P concentration as in fields where much
manure has been applied (Sauer et al. 2000; McDo-
well and Sharpley 2001; Andraski and Bundy 2003;
Daverede et al. 2003; Klatt et al. 2003). Dissolved
and particulate P loss in runoff can be significant,
however, even at agronomically moderate soil test P
levels because a large proportion of soil P is non-
labile (Eghball and Gilley 1999; Eghball et al. 2002;
Wortmann and Walters 2006). Runoff P loss is,
therefore, largely dependent on the rate of erosion
and runoff.
Feedlot manure is commonly applied to the soil
surface with no or shallow incorporation. Runoff P
loss was much less after one year compared with one
day after surface application of beef feedlot manure
(Eghball et al. 2002). Such reductions indicate that
soil aggregation is increased by manure application
within two weeks after application resulting in less
runoff P loss, and that the effect persists for a year or
longer.
Manure application is often credited with improv-
ing soil physical properties with benefits such as
reduced runoff and erosion, and these effects can
persist for several years following manure application
(Gilley and Risse 2000; Wortmann and Walters
2006). Celik et al. (2004) found that after five years
of application of 25 t ha
1
yr
1
of manure or com-
post incorporated by moldboard plowing, the mean
weighted diameter of water-stable aggregates was
65% greater for the 0 to 30 cm depth than where no
manure or compost were applied. Aggregation was
similar with compost and manure. They also
observed reduced bulk density, increased macro-
and micro-porosity, and increased hydraulic conduc-
tivity after application of compost or manure.
Available soil waterholding capacity was increased
by 85 and 56% compared to the control for the 0 to
30 cm depth with compost and manure applied,
respectively. Surface application of manure or com-
post may be most advantageous for improving water
infiltration but it results in very high P concentrations
at the soil surface. Much of this P may be protected
from runoff due to the increased formation of water-
stable soil aggregates associated with an increase in
organic particulates with manure application (Six
et al. 2000). While manure application does not
always result in reduced runoff and erosion (Gilley
and Eghball 1998), the effect is common enough to
be considered as partly offsetting the effect of manure
application on runoff P concentration (Angers 1998;
Six et al. 2000; Whalen and Chang 2002).
Research was conducted to test the hypotheses that
application of raw or composted manure will result in
increased macro-aggregate formation in the surface
25 mm of soil and that the effects can persist for
several years after application. The objectives of this
research were to determine how soil aggregation is
affected: (1) during the months following incorpora-
tion and surface application of raw and composted
feedlot manure; (2) by repeated applications of
feedlot solid manure and swine slurry manure; and
(3) by composted feedlot manure applied five to
seven years before sampling. The distribution of
Bray-P1 and soil organic matter (SOM) in large
macro-aggregates relative to the whole surface soil
sample at 30 days after application was determined.
These objectives were addressed using data from
three field studies.
Materials and methods
Study 1
Experiments were conducted on two soil types at
Havelock Agronomy Farm of the University of
Nebraska-Lincoln (UN-L) on the east edge of Lincoln
NE (40
o
510N, 96
o
360W). The soil types were upland
loess Crete soil (fine, smectitic, mesic Pachic Ar-
giustolls) and alluvial Nodaway soil (fine-silty,
mixed, superactive, mesic Cumulic Hapludolls). Each
site was tilled with a tandem disk before application
of the treatments.
The treatments included three manure treatments
and two tillage treatments in a complete factorial with
four replications in a randomized complete block
design. The manure treatments were: (1) 50 Mg
ha
1
, d. wt., of composted feedlot manure; (2)
50 Mg ha
1
, d. wt., of uncomposted, stockpiled
feedlot manure; and (3) the control with neither
compost nor manure applied. The amount of P
applied with the compost and manure treatments
was 610 and 452 kg ha
1
, respectively. The tillage
treatments were no tillage following application and
incorporation with a garden tiller to about 7.5 cm
Nutr Cycl Agroecosyst
123
depth. The plot size was 4.5 ·4 m. The treatments
were applied on 25 April 2005. The crop was non-
irrigated maize (Zea mays L.) planted on 10 May
2005.
Soil samples composed of six cores of 70-mm
diameter were collected for the 0- to 25-mm depth at
15, 30, 60, 90, 120, and 150 days after application
(DAA). All sampling points were determined at the
start of the research to avoid sampling of soil
disturbed by previous sampling. Wheel tracks formed
during planting were avoided during sampling. Bray-
P1 (Bray and Kurtz 1945) and soil organic matter
content by weight loss on ignition (Nelson and
Sommers 1996) were determined for the complete
soil and the individual aggregate fractions collected
30 days after application.
The percent of soil in water-stable aggregates was
assessed by a wet-sieving method (Cambardella and
Elliott 1994). Field-moist soil was gently crumbled,
air-dried, and passed through an 8-mm sieve. Material
retained on the sieve was discarded, and visible pieces
of crop residues and roots were removed. A 100 g d.
wt. sub-sample of soil was distributed on a 2-mm
sieve of 20-cm diameter and immersed in about 3 cm
of water for 5 min. After immersion, samples were
wet sieved by dipping the sieves into water 50 times
during a 2-min period, done first with the 2-mm sieve,
and then sequentially with 0.250-mm and 0.053-mm
sieves. Material retained in each sieve was washed
separately into a 150-ml beaker and allowed to settle
for about 20 min. Supernatant water was carefully
poured from the beaker and discarded, while water-
stable aggregates were transferred into a pre-weighed
aluminum tin, oven dried at 50C, and weighed.
Classes of water-stable aggregates were large macro-
aggregates ([2.0 mm, Ag[2 mm), small macro-
aggregates (0.250–2.0 mm, Ag0.25–2mm), and
micro-aggregates (0.053–0.250, Ag0.053–0.25mm)
expressed as g 100 g
1
of dry soil. The three
aggregate classes were totaled to give the percent of
soil mass in water-stable aggregates.
Analyses of variance were conducted using Sta-
tistix 8 (Analytical Software, 2003). Means were
compared with the ANOVA-protected LSD (0.05)
method. The analysis of variance was conducted with
manure and tillage treatments as main plot effects,
and with sampling time as a subplot effect in a
split-plot analysis. Differences were considered sig-
nificant at P\0.05.
Study 2
This study was conducted on two soil types at the
UN-L Northeast Research and Extension Center-
Haskell Agricultural Laboratory near Concord NE
(42
o
230N, 96
o
570W). The upland site was on a
sloping hillside with a Moody-Leisy complex silt
loam (fine-loamy, mixed mesic Udic Haplustoll and
fine-loamy, mixed mesic Udic Argiustoll; 6–11%
slope) soil and the bottomland site was on a Maskell
loam (fine-loamy, mixed mesic Cumulic Haplustoll
soil; 2–6% slope). The treatments were: beef feedlot
manure applied at a mean rate of 46 Mg ha
1
yr
1
d.
wt. with incorporation after 24 h; swine slurry
manure broadcast and incorporated after 24 h at
2.7 Mg ha
1
yr
1
dry weight; and no manure
applied. The experimental design was a randomized
complete block with three replications. The manure
was applied each year from 1999 to 2003. Composite
soil samples were collected in the fall of 2003 for the
0- to 25-mm depth. The analysis of aggregate size
distribution was as above. Analyses of variance were
conducted using Statistix 8 (Analytical Software,
2003). Differences were considered significant at
P\0.05.
Study 3
Research was conducted at the UN-L Agriculture
Research and Development Center (ARDC) near
Ithaca NE (41100N, 96280W) to determine the
residual effect of applied compost on soil aggrega-
tion. A total of 200 Mg ha
1
composted feedlot
manure was applied in three applications between
1998 and 2002 (Wortmann and Walters 2006). The
study had three treatments: compost from low P
manure; compost from high P manure; and no
compost. The experimental design was a randomized
complete block with three replications. Composite
soil samples were collected in the fall of 2003 for the
0- to 25-mm depth. The analysis of aggregate size
distribution was as above. Analyses of variance were
Nutr Cycl Agroecosyst
123
conducted using Statistix 8 (Analytical Software,
2003). Differences were considered significant at
P\0.05.
Results
Study 1
The interaction effect of soil type by DAA was
significant for all aggregate size fractions and total
aggregates, as was the DAA main effect (Table 1;
Fig. 1). However, the differences due to soil type
were inconsistent over time. Aggregation was greater
with the alluvial soil on some sampling dates but less
or not different on others compared with the loess
soil. The significant effects of the soil type ·DAA
interaction and DAA on soil aggregation may have
been due to sampling conditions rather than to
treatment effects; soil water content was observed
to be higher for the 120-day sample than at other
sampling times and soil in macro-aggregates was
more, especially for the Crete soil site, for this
sampling date than for other dates.
The DAA ·tillage ·manure and the DAA ·
tillage interactions were not significant for all aggre-
gate size fractions (Table 1). The soil type ·
tillage ·manure interaction was significant for
Ag0.25–2mm and nearly so for Ag0.053–0.25mm
(P= 0.06) but not for Ag[2 mm and total aggregates
(Fig. 2). Ag0.053–0.25mm were reduced while
Ag0.25–2mm were increased with compost and
manure application for both soil types. These effects
were less pronounced with incorporation than with
surface application, especially for the alluvial soil.
The reduction in Ag0.053–0.25mm and increase in
Ag0.25–2mm compared with the control were greater
with manure than with compost with incorporation for
the Crete loess soil and with no incorporation for the
Nodaway alluvial soil.
Total amount of soil in aggregates was not affected
by manure treatments. However, the main effect of
the manure treatments was a greater reduction in
Ag0.053–0.25mm and a greater increase in Ag0.25–
2mm with manure than with compost application as
compared with the control, while Ag[2 mm were
increased more with compost (300%) than with
manure (200%) application (Table 2).
Table 1 ANOVA results
for trials conducted on two
sites at UN-L Havelock
Agronomy Laboratory in
2005
a
NS, *, **, ***: not
significant or significant at
P\0.05, 0.01, and 0.001,
respectively
Source of variation df Soil aggregates, g 100 g
1
soil
[2 mm 0.25–2 mm 0.053–0.25 mm Total
Site (S) 1
Rep/site 6
Tillage (T) 1 NS
a
NS NS NS
Manure (M) 2 *** *** *** NS
T·M 2 NS NS NS NS
T·S 1 NS NS NS NS
M·S 2 NS NS NS NS
T·M·S 2 NS * 0.06 NS
Error a 30
DAA (D) 5 *** *** *** ***
S·D 5 ** *** *** ***
T·D 5 NS NS NS NS
M·D 10 0.07 NS NS NS
T·M·D 10 NS NS 0.06 NS
T·D·S 5 ** *** *** ***
M·D·S10NSNSNS NS
T·M·D·S10NS NS NS NS
Error b/CV 180 62.5 18.6 17.2 6.7
Nutr Cycl Agroecosyst
123
Tillage and interaction effects were not significant
for Bray-P1 at 30 DAA. However, the manure
treatment effects generally were highly significant
(Table 3). Bray-P1 was highest with compost applied
and lowest with the control. However, Bray-P1
concentration in Ag[2 mm was about three times
as high compared with the complete soil sample for
the manure and compost treatments. Although Ag[2
mm accounted for a small fraction of the soil, 13 and
8% of soil Bray-P1 was in Ag[2 mm for compost
and manure applied, respectively, while less than 1%
of Bray-P1 was in Ag[2 mm for the control.
Manure and compost application resulted in a
great increase in Ag[2 mm with high SOM con-
centration at the 0- to 25-mm soil depth. The
concentration of SOM was increased in Ag0.25–
2mm (8%) and in the whole soil (6%) with compost-
and manure-applied compared with the control. Mean
SOM was 87, 31, 28, and 32 g kg
1
for Ag[2 mm,
Ag0.25–2mm, Ag0.053–0.25mm, and the whole soil,
respectively. The relatively high SOM in Ag[2mm
for the control as well as the compost- and manure-
applied treatments indicates the importance of pres-
ence of organic material to the formation of large
macro-aggregates, probably due to consolidation of
micro-aggregates (Six et al. 2000).
Study 2
The treatment by site interaction was not significant.
Aggregate size distribution was affected by manure
application, but the total amount of soil in aggregates
[0.053 mm was not affected (Table 4). Macro-
aggregates were increased while Ag0.053–0.25mm
0
10
20
30
40
50
60
70
80
90
Cr No Cr No Cr No Cr No Cr No Cr No
Site and days since application
g001g,setagerggalioS 1-
> 2 mm
0.25 - 2 mm
0.053 - 0.25 mm
15 30 60 90 120 150
Fig. 1 Variation in soil
aggregation as affected by
the site by days after
application interaction on
upland loess Crete, Cr, and
bottomland alluvial
Nodaway, No, soil at UN-L
Havelock Agronomy
Laboratory in 2005, The
standard errors of the mean
for the site by days after
application interaction were
0.27, 1.33, 1.30, and 1.02
for the [2 mm, 0.25–
2 mm, and 0.053–0.25 mm
water-stable aggregate size
fractions, and the total of
aggregates, respectively
0
10
20
30
40
50
60
70
80
NCM NCM NCM NCM
Soil gagr getaion
,g g001
1-
> 2 mm
0.25 - 2 mm
0.053 - 0.25 mm
Tilled Not tilled Tilled Not tilled
Crete Nodaway
Fig. 2 Mean effect of the soil ·tillage ·manure application
interaction on soil aggregation on two soil types at UN-L
Havelock Agronomy Laboratory in 2005, N, C, and M
designate no compost or manure applied, composted feedlot
manure applied, and stockpiled feedlot manure applied. Crete
and Nodaway soils are upland loess soil and bottomland
alluvial soil, respectively. The standard error of the means for
the soil by tillage by manure application interaction were 0.29,
1.32, 1.27, and 0.90 for the [2 mm, 0.25–2 mm, and 0.053–
0.25 mm water-stable aggregate size fractions, and total
aggregates, respectively
Nutr Cycl Agroecosyst
123
were decreased with manure application, with the
greatest effect due to swine manure application.
Study 3
The residual effect of compost applied five to seven
years before sampling on aggregate size distribution
was not significant (Table 5). The residual effect of
compost application on total soil in aggregates
[0.053 mm was not significant.
Discussion
Generally the effect of manure application was to
increase macro-aggregates relative to Ag0.053–
0.25mm without an effect on the total amount of soil
Table 2 Mean effects of manure application treatments on soil aggregation in trials conducted on two sites at UN-L Havelock
Agronomy Laboratory in 2005
Treatments
a
Aggregate size
[2 mm 0.25–2 mm 0.053–0.25 mm \0.053 mm
g 100 g
1
Manure 2.4 a
b
37.3 a 34.9 c 25.4 a
Compost 3.2 b 34.5 b 36.8 b 25.4 a
Control 0.8 c 33.2 b 39.8 a 26.2 a
a
Tillage and interaction effects were not significant
b
Values with different letters in columns are statistically different (P\0.05)
Table 3 Mean effects of manure treatments for two soil types at 30 days after manure and compost application on Bray-P1 in the 0-
to 2.5-cm soil depth at UN-L Havelock Agronomy Laboratory in 2005
Treatments
a
Aggregate size
[2 mm 0.25–2 mm 0.053–0.25 mm \0.053 mm
Bray-P1, mg kg
1b
Manure 326.9 b
c
110.5 b 82.4 b 28.3 b
Compost 753.9 a 182.8 a 107.5 a 81.4 a
Control 32.4 c 49.9 c 51.7 c 5.3 c
a
Tillage and interaction effects were not significant
b
Bray-P1 in the complete soil sample for the 0- to 2.5-cm depth was 106.1, 208.5, and 42.7 mg kg
1
for the manure, compost and
control treatments, respectively
c
Values with different letters in columns are statistically different (P\0.05)
Table 4 The effect of types of applied manure on water-stable soil aggregate size at Haskell Agricultural Laboratory in 2004
Treatments Aggregate size
[0.25 mm 0.053 to 0.25 mm \0.053 mm
g 100 g
1
Swine manure 42.5 a
A
40.3 b 20.2 a
Beef manure 40.1 ab 45.2 ab 16.3 a
No manure 35.0 b 48.5 a 18.5 a
A
Values with different letters in columns are statistically different (P\0.05)
Nutr Cycl Agroecosyst
123
in aggregates [0.053 mm. These effects were con-
sistent across soil types with the soil by treatment
interaction accounting for little of the total variation
due to treatment effects at the Havelock and Haskell
sites. The results generally agree with the finding of
Sommerfeldt and Chang (1985), that larger aggre-
gates were increased while smaller aggregates were
decreased due to manure application, probably due to
increased consolidation of micro-aggregates into
macro-aggregates (Six et al. 2004).
The manure ·DAA interaction effect was not
significant and the effect of manure or compost
application on aggregation occurred soon after
application with a significant increase in Ag[2mm
at 15 DAA. The greatest increase was for compost
with a 240% increase in Ag[2 mm compared with
no manure or compost applied, and this increase
persisted for the 7-month duration of the Havelock
study. Bray-P1 in Ag[2 mm was much more than in
the rest of the soil sample with compost or manure
applied. Whalen and Chang (2002), however, found
that the increase in soil P with long-term manure
application was greater in the 0.5 to 2.0 mm size than
in larger or smaller dry-sieved aggregate sizes. The
increase in water-stable soil macro-aggregates with
high Bray-P1 within a short time after application of
compost or manure may be important to reducing P
loss in runoff due to increased infiltration, less soil
dispersion due to the impact of rain drops, and
protection of applied P in macro-aggregates.
Composted feedlot manure application resulted
in more Ag[2 mm but less Ag0.25–2mm macro-
aggregates than raw feedlot manure. The effect of
applied compost on soil aggregation was not
significant four years after the last application at
the ARDC site. In a related study, however, runoff
at this site continued to be less with the compost-
applied treatments compared to the no-compost
control until five years after the last application
(Wortmann and Walters 2007). This site was disk
tilled every year; the compost effect on soil
aggregation may have persisted longer with no-till
(Six et al. 1999; Wright and Hons 2005). A much
greater residual effect of applied compost was
reported by Celik et al. (2004).
Conclusion
Manure and compost application results in a signif-
icant increase in water-stable large macro-aggregates
within 15 days after application, probably due in part
to consolidation of smaller aggregates. The newly
formed large macro-aggregates were much higher in
Bray-P1 than the rest of the soil and than in the large
macro-aggregates of soil where compost and manure
were not applied. The macro-aggregation was more
with compost than with raw feedlot manure and
swine slurry manure had a similar effect as solid
feedlot manure. The effect of manure or compost
application persisted through one cropping season but
was not detectable at four years after application in a
cropping system that was tilled annually. While
manure or compost application may increase the risk
of P runoff, the risk is likely to be greatest during the
days after application as the resulting increase in
large water-stable soil macro-aggregates with a high
P concentration should reduce the risk of P runoff.
Studies involving simulated rainfall conducted
shortly after manure application may over-estimate
manure application effects on the risk of P runoff.
Manure application should be avoided at times of
Table 5 The residual effect of composted manure (4 years after application) on soil aggregate properties at the Agricultural
Research and Development Center in 2004
Treatments Aggregate size
[0.25 mm 0.053 to 0.25 mm \0.053 mm
g 100 g
1
High P compost 44.7 37.9 17.4
Low P compost 45.9 35.4 18.7
No compost 41.1 38.5 20.4
Significance NS
a
NS NS
a
NS: differences are not statistically significant at P\0.05
Nutr Cycl Agroecosyst
123
high probability of a runoff event within days of
application.
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... Increases in soil aggregation due to compost application have been reported for a wide range of experimental conditions. These included an incubation time from 3 weeks to 336 days [26][27][28][29], turnover [30,31], a field application rate from 0 to 300 t.ha −1 [29,32,33], and a frequency from a single to annual repeated applications [32,34,35]. Different compost maturity levels were also tested for their effect on soil aggregate stability; high-maturity composts performed better than the less mature ones [16]. ...
... Different types of organic amendments stimulate particular groups of the soil microbial population, having a different susceptibility to decomposition and, therefore, distinguished aggregate dynamics in the soil [16,34]. This concept applies to the same organic material with different maturity degrees [29,31] or distinct C pool fractions [60]. Analyzing the fungal lengths and aggregate stability, ref. [27] reported a good correlation between the two variables in sandy loam and silty loam soils and concluded that fungi activity is less critical for aggregate formation in more clayey soils. ...
... In the Fluvisol (clay loam), aggregate stability decreased with the OPC's fine grain size amendment and increased when amended in the coarse grain size, yet neither treatment was statistically different from the unamended soil. The relation between the grain size of compost incorporated and aggregates stability is poorly addressed in the literature, while some studies indicate that compost inputs increase the macro-aggregates fraction (>200 µm) [31,60,65]. These findings are in line with the better performance of coarse grain size amendments obtained in the present experiment. ...
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Mediterranean agriculture asks for sustainable strategies to prevent actual soil organic matter decline rates. Composting agri-food by-products for application in farmland, besides contributing to a circular economy at regional or local scales, may improve soil resistance to physical degradation. Aggregate stability (AS) is a crucial property for building up such resistance. Olive pomace is an abundant by-product of the olive oil industry that may be valorized through composting. This study aimed to assess the influence on AS of olive-pomace-based composts (OPC) applied to a sandy loam Leptosol and a clay loam Fluvisol. To assess the effects of compost characteristics on AS, three OPCs resulting from different olive pomace proportions in the composting raw material (44, 31, and 25% by volume) were applied to aggregate samples in three doses (10, 20, and 40 t.ha−1, plus control) with fine and coarse grain sizes. Controlled laboratory conditions subjected samples to daily wetting-drying cycles during a 30-day experiment. AS was measured by wet sieving. OPC application significantly increased AS in the Leptosol amended with fine (+15% vs. control) and coarse (+19%) grain-size compost. In well-aggregated Fluvisol, amendment induced a significant increase in AS only in the compost coarse grain size (+12%). The application dose significantly affected AS, with 10 t.ha−1 being the best-performing dose. OPC applications in weakly aggregated soils are seemingly an encouraging soil management practice for improving soil resistance to physical degradation and reducing soil organic matter decline rates in Mediterranean farmland.
... Compost is especially effective in stabilizing aggregates in high-clay soils, where clay particles aid in forming stable micro-and Figure 5. Changes in soil structure in Jevíčko demonstrated by water stable aggregates ratio (WSA) changes in 2 nd and 3 rd year from the compost application (SCA) compared to control soil (CON) Figure 6. Soil structure aggregates under the microscope from the Jevíčko locality; the aggregates in compost-treated soil (SCA) exhibit dark colouration due to the incorporation of organic matter, highlighting the effect of compost on soil aggregation compared to untreated (CON) soil (Bresson et al. 2001;Wortmann & Shapiro 2008). ...
... By the relationship shown, soil bulk density decreases from 1.71 Mg/m 3 by about 0.05 Mg/m 3 for every unit change in soil pH (Figure 2a). By contrast, at and even beyond this stage Figure 3. Regression of percent water-stable aggregates on soil pH for the pulverised and poultry droppings-amended Ukehe soil before (a) and after (b) excluding data for 20 weeks after incubation for soil structure reformation when soil bulk density was higher compared to the shorter time intervals (2-12 weeks). of structure reformation of tillage-pulverised and manureamended soil, SOM-mediated progressive improvements in micro-aggregate stability of the soils are expected to still prevail (Adesodun et al., 2001;Wortmann and Shapiro, 2007), because the excess negative charges induced in these soils usually promote the binding of positively charged Fe and Al oxides (Wuddivira et al., 2009;Igwe et al., 2013a). ...
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Organic inputs to tillage-pulverised soils could, by facilitating soil structure reformation with time, enhance environmental quality. This study examined the aggregate stability responses of three texture-contrasting soils from the derived savannah of southeastern Nigeria to poultry-droppings (PD) manure over time. The soils from Nsukka, Ukehe and Adani with clay contents of 53, 100 and 260 g/kg had antecent organic matter concentrations of 18.77, 29.73 and 16.23 g/kg, respectively, with sandy Nsukka/Ukehe being more stable than loamy Adani. Pulverised soils were amended with PD at rates equivalent to 0, 10, 20, 40 and 70 t/ha, watered and open-incubated under glasshouse conditions. They were augmented to field capacity at three-day intervals and sub-sampled at 2, 4, 8, 12, and 20 weeks after incubation (WAI). Treatment effects were highly soil-dependent. For all three soils, water-stable aggregates, mean-weight diameter (MWD) of aggregates and sand-corrected water-stable aggregates were highest with 70 t/ha at 20 WAI which showed similar MWD of aggregates as 0 t/ha at 20 WAI. Also, 70 and 20 t/ha each at 20 WAI consistently had similar effects (Adani only). Treatment effects on soil bulk density were irregular, with the highest values mostly at 20 WAI across rates. Thus, soil bulk density related inversely with aggregate stability only during 2-12 WAI, owing to their concurrent increases with soil pH beyond 12 WAI. These soil structure indices were not influenced by PD-induced fluctuations in electrical condutivity which always peaked 4 WAI. Heavy and modest PD addition, respectively, to tillage-pulverised sandy and loamy tropical soils promote their re-aggregation after 20 weeks; however, such soils even without manuring could re-structure into aggregates of sizes as though PD-amended over this long interval. Rather than PD-induced salinisation, it is soil pH that influences macro-aggregation up till the 20th week, when soil pH should be ≤ 6.65 to avoid soil densification above 1.71 Mg/m3.
... The soil P is comparatively immobile, and plats can be uptake via diffusion (Misra et al., 1988;Balemi and Negisho, 2012). Adoption of best management practices and judicious application of nutrients generally improves crop productivity, which thus provides added additional crop residue (Wortmann and Shapiro, 2008;Yu et al., 2012). ...
... The analysis of structural properties indicated that in the crop rotation where manure was applied, this did not lead to a significant increase in the proportion of water-stable aggregates (macroaggregates). This finding contradicts our expectations and runs counter to numerous research reports highlighting the positive influence of manure and cropping systems on macroaggregate improvement and stability [79][80][81][82]. One interpretation for the decrease in macroaggregate participation and the rise in microaggregates in treatments with manure is provided by [83]. ...
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Knowledge of long-term phosphorus behavior is essential to improve soil structure, nutrient supply potential, and the sustainability of cropping systems. A 45-year long-term experimental trial was used to observe organic phosphorus fractionation and its effects on soil aggregation and nutrient distribution at three depths (0–20, 20–40, and 40–60 cm) in Vojvodina Province, Serbia, under maize monoculture and maize/barley rotation. Five fertilizing systems were studied, including Control, NPK, NPK + maize remains, NPK + manure, and NPK + manure in rotation. Soil aggregates were fractionated into four size categories (>2000, 2000–250, 250–53, and <53 μm) using a wet sieving method. The samples were analyzed for main indicators, including different forms of phosphorus, total and available (PT and PA), as well as its organic forms (Labile Po, Biomass Po, Mod. Labile Po, Fulvic acid Po, Humic acid Po, and Resistant Po), and other fertility parameters. Significant differences in total and available phosphorus as well as all observed organic phosphorus fractions were evident between treatments with and without organic amendments, particularly in the 0–20 and 20–40 cm soil layers. Moderately labile P forms were dominant across all treatments, while labile forms constituted a smaller proportion. The most notable differences between treatments were observed in the labile and moderately labile forms, as well as in the resistant form of organic phosphorus. Manure application led to increased nutrient content in macroaggregates (>250 μm) compared to microaggregates. Microaggregates (<250 μm) were predominant across all depths, while stable structural aggregates did not show a significant increase after manure application. PCA highlighted significant correlations between soil characteristics, including total and available P, total organic carbon, clay content, and enzyme activity, across different aggregate sizes and organic P fractions. Overall, long-term mineral fertilization combined with organic amendment application induced variations in phosphorus fractions and the content of carbon, nitrogen, and phosphorus associated with aggregates in the first two soil layers, except for aggregate size classes.
... Gilley and Risse (2000) also reported that soil incorporated with manure decreased runoff when compared soil without manure application. It has been observed/verified in many studies that the addition of organic matter inputs from manure application can improve soil structure such as density, porosity, aggregate stability which consequently increases water infiltration; thereby decreasing runoff (Bhattacharyya et al., 2007;Allen and Mallarino, 2008;Mellek et al., 2010;Wortmann and Shapiro, 2008;Zhou et al., 2013;Tomer et al., 2016;Cavalcante et al., 2020). However, the benefits observed from manure additions in these studies were a result of multiple applications over time. ...
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Highlights Surface water runoff was reduced following manure additions. Sediment yield was reduced following manure additions. Nutrient loss was increased following manure additions. Abstract. Soil erosion models are becoming increasingly accurate and now can simulate a variety of surface covers which can lessen erosion by reducing detachment and movement of soil particles. Currently, there is limited data on the effects of animal manure on soil erosion. Most process-based models credit animal manure as crop residue cover. Thus, there is a need for bench studies under laboratory conditions, as well as field studies to determine the effects manure applications have on runoff and sediment loss. Rainfall simulation studies were conducted to evaluate the influence of different animal manures on runoff, sediment yield, and nutrient loss using undisturbed soil monoliths placed in perforated trays. The soil was collected from fields managed under long-term no-till and a conventional till for over 15 years. Poultry litter, solid dairy manure, liquid swine manure, liquid dairy manure applied to the experimental units were compared to a no manure treatment. Generally, sediment yield and runoff amounts were reduced following manure application regardless of source (averaged across all rainfall events and manure rates), with reductions generally occurring with increasing rates of manure. When evaluating each rainfall event separately, runoff increased with increasing rates of manure for the liquid dairy manure only in the initial rainfall simulation events due to surface sealing. However, the effects of surface sealing decreased from the first rainfall simulation event to the third event. Sediment yield tended to be higher in conventional till versus no-till (only evaluated with liquid dairy manure); however, the addition of manure tended to be more effective at reducing sediment loss with conventional till. Dissolved reactive P, NH 4 -N, and NO 3 -N levels in the runoff effluent increased for all of the manure sources with increasing rates of manure. These results suggest that manure applications can reduce soil loss, especially from the conventionally-tilled treatment. Keywords: Manure, Rainfall simulation, Runoff, Soil erosion.
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The land use types and soil management have a significant effect on soil properties. However, their impact on the stratification of soil properties, carbon management index (CMI) and soil degradation index (SDI) is still poorly documented in coastal light soils of south eastern India. Soil samples were collected from six divergent land use types, Sugarcane (SC), Fallow – Tobacco (F-T), Paddy- Maize- Fallow (P-M-F), Eucalyptus + Bamboo (AF), Oil Palm (OP), and Forest (NF). The soil samples were collected at 0-5, 5-15, 15-30, and 30-45 cm soil depths, and contents of total organic carbon (TOC), labile organic carbon (LC), non-labile organic carbon (NLC), total nitrogen (TN), their stocks, stratification ratio (SRs), CMI, and SDI were determined. Results showed that the contents of TOC, LC, NLC, and TN in NF were significantly higher followed by OP, whereas the parameters were lower in F-T followed by P- M- F. The proportion of SOC and N stocks under NF were higher than F-T by 56.6 and 50.3 %, respectively. With NF as a reference, the mean CMI followed the order of OP (78) > AF (60) > SC (59.5) > P-M-F (43.8) > F-T (36.3). The SR values of SOC and TN were highest (1.34 to 2.70) for NF, whereas it was lowest (1.10 to 1.54) in F-T in all soil depths. The highest cumulative SDI of –133.2% was observed in F-T followed by P-M-F (-117%). The CMI, SRs were lower and SDI was higher under F– T and P - M- F indicating poor soil quality and its degradation.
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Calcareous soils crusting and low organic matter (OM) content are key problems restrict their management and productivity. The aim of this study is to assess the role of tillage at different depths along with the compost application for improving some characteristics of the calcareous soil as well as the yield, and its components of the intercropped faba bean with wheat (1:1 ratio). A field experiment was carried out at the Nubaryia Agricultural Experimental Station through the two successive winter seasons (2019/2020) and (2020/2021) in a split-plot design with three replicates. The main factor (F1) was the plough depth treatments: Chisel plough (20 cm depth) and subsoiler (40 cm depth) one time and twice. The sub-factor (F2) was the applied compost (C1= 5.95 and C2= 11.9 tons ha-1). A control without additions was involved. The wheat and fababean were sown in a 1:1 intercropping ratio mixed with the surface layers by hatchat under a surface irrigation system and the recommended agronomic practices were followed. The tillage treatments combined with increasing the rate of the applied compost have increased the total stable aggregates (TSA), the aggregation index and aggregation degree in the surface and subsurface soil layers (0 – 20 cm, 20 – 40 cm) as well as the saturated hydraulic conductivity (Ks) for both seasons. The water stable aggregates (WSA) distribution revealed that the 8-2 cm aggregates are the abundant size especially in the surface soil layers. The 40 cm depth subsoiler twice treatment combined with the compost rate C2 resulted in the maximum OM for both seasons. The relative maximum OM increase (%) compared to the corresponding control was by 32.3 and 26.7% in the 0 – 20 cm soil layer and by 64.9 snd 60.0% in the 20 – 40 cm soil layer. For the compost rate C2, the most significant relative increase in the wheat grains yield (kg ha-1) was by 74.8% with the plowing two times at 40 cm depth, while for the faba bean seeds yield (kg ha-1) it increased by 145.5% with the 20 cm depth plowing. The studied treatments were effective for improving the calcareous soil properties and productivity.
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Continued inputs of fertilizer and manure in excess of crop requirements have led to a build-up of soil phosphorus (P) levels and increased P runoff from agricultural soils. The objectives of this study were to determine the effects of two tillage practices (no-till and chisel plow) and a range of soil P levels on the concentration and loads of dissolved reactive phosphorus (DRP), algal-available phosphorus (AAP), and total phosphorus (TP) losses in runoff, and to evaluate the P loss immediately following tillage in the fall, and after six months, in the spring. Rain simulations were conducted on a Typic Argiudoll under a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation. Elapsed time after tillage (fall vs. spring) was not related to any form of P in runoff. No-till runoff averaged 0.40 mg L⁻¹ and 0.05 kg ha⁻¹ DRP and chisel-plow plots averaged 0.24 mg L⁻¹ and 0.02 kg ha⁻¹ DRP concentration and loads, respectively. The relationship between DRP and Bray P1 extraction values was approximated by a logistic function (S-shaped curve) for no-till plots and by a linear function for tilled plots. No significant differences were observed between tillage systems for TP and AAP in runoff. Bray P1 soil extraction values and sediment concentration in runoff were significantly related to the concentrations and amounts of AAP and TP in runoff. These results suggest that soil Bray P1 extraction values and runoff sediment concentration are two easily measured variables for adequate prediction of P runoff from agricultural fields. Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © 2003. American Society of Agronomy, Crop Science Society of America, Soil Science Society . Published in J. Environ. Qual.32:1436–1444.
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Addition of organic materials of various origins to soil has been one of the most common rehabilitation practices to improve soil physical properties. Mycorrhiza has been known to play a significant role in forming stable soil aggregates. In this study, a 5-year field experiment was conducted to explore the role of mycorrhizal inoculation and organic fertilizers on the alteration of physical properties of a semi-arid Mediterranean soil (Entic Chromoxerert, Arik clay-loam soil). From 1995 to 1999, wheat (Triticum aestivum L.), pepper (Capsicum annuum L.), maize (Zea mays L.) and wheat were sequentially planted with one of five fertilizers: (1) control, (2) inorganic (160–26–83 kg N–P–K ha−1), (3) compost at 25 t ha−1, (4) farm manure at 25 t ha−1 and (5) mycorrhiza-inoculated compost at 10 t ha−1. Soil physical properties were significantly affected by organic fertilizers. For soil depths of 0–15 and 15–30 cm, mean weight diameter (MWD) was highest under the manure treatment while total porosity and saturated hydraulic conductivity were highest under the compost treatment. For a soil depth of 0–15 cm, the compost and manure-treated plots significantly decreased soil bulk density and increased soil organic matter concentration compared with other treatments. Compost and manure treatments increased available water content (AWC) of soils by 86 and 56%, respectively. The effect of inorganic fertilizer treatment on most soil physical properties was insignificant (P>0.05) compared with the control. Mycorrhizal inoculation+compost was more effective in improving soil physical properties than the inorganic treatment. Organic fertilizer sources were shown to have major positive effects on soil physical properties.
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Agricultural management practices that alter the soil organic matter (SOM) content are expected to cause changes in soil stability and aggregation. Animal manure is a source of organic matter (OM) that 1985) and (ii) by adding OM in crop residues, due to has been demonstrated to increase macroaggregate formation and higher crop yields in soils receiving manure,(Jenkinson stability. The objectives of this study were to determine how long term cattle manure applications to a calcareous Haploboroll clay loam and Rayner, 1977; Angers and N’Dayegamiye, 1991). (Lethbridge, AB, Canada) affected aggregate size distribthan unamended soils, and dry-sieved aggregates between 0.47 increase in aggregation, but the effect may be tempo- and 2.0 mm tended to have the highest C, N, and P contents. Water rary; whereas organic materials that decompose slowly aggregate stability was higher in irrigated than dryland soils, but did may,produce,a smaller but longer-lasting improvement not improve with increasing manure application rates. Dispersing in aggregation (Khaleel et al., 1981; Sun et al., 1995). agents in the cattle manure appear to have destabilized the larger Aoyama,et al. (1999) proposed,that animal,manure,ap- soil macroaggregates. plications increase the particulate OM pool and promote macroaggregate formation in the short-term, whereas in the longer-term, manure may be transformed into min- T he application,of animal,manureto agricultural,eral-associated OM that can improve,microaggregate land has been viewed as an excellent way to recycle,stability. nutrients and OM that can support crop production and,Despite the benefits to soil aggregation from applying maintain or improve soil quality. Generally, SOM and animal manure to cultivated soils, long-term manure biological activity increase, and some soil physical prop- applications can contribute to nutrient accumulation, erties improve following manure applications (Haynes
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In the Ozark Highlands of the USA (36-38°N, 91-95°W), annual application of poultry litter to pasture land is a routine waste management practice. The objective of this study was to measure the effect of site characteristics and poultry litter application on runoff and nutrient transport from grazed pasture and forest sites at different landscape positions. Sixteen pairs of 1 x 2 m plots were established on Nixa (loamy- skeletal, siliceous, active, mesic Glossic Fragiudults) and Clarksville (loamy-skeletal, siliceous, semiactive, mesic Typic Paleudults) cherty silt loams. One plot of each pair received 4.5 Mg ha-1 of poultry litter. Rainfall was simulated at 75 mm h-1 for 1 h (25-yr return period storm) one month after litter application. A composite runoff sample was analyzed for dissolved reactive phosphorus (DRP), total phosphorus (TP), ammonia N (NH3- N), nitrate N (NO3-N), total Kjeldahl nitrogen (TKN), and total suspended solids (TSS). Poultry litter-treated plots had consistently higher concentrations of all water quality parameters tested compared to untreated plots. Concentration of DRP in runoff from untreated plots was linearly correlated with three soil P tests (0.35 < r2 < 0.85). Soil P on litter- treated plots had little effect on runoff DRP, which averaged 2.20 mg L-1. High variation in runoff resulted in only NO3-N showing significantly greater losses due to poultry litter treatment at two pasture sites. Results indicate that variation in runoff has a significant effect on nutrient transport from grazed pastures receiving poultry litter.
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A long-term manure study was set up in which cattle feedlot manure was applied annually at four rates to nonirrigated and irrigated land and was incorporated into the soil by plow, rototiller, or cultivator. The soil is a Dark Brown Chernozem (Typic Haploborolls) at the Lethbridge Research Station. The effects of the manure, incorporated by different methods, on the physical properties and organic matter content of the soil were determined. On both nonirrigated and irrigated land, the soil organic matter content of the surface 0 to 15 cm increased with increasing rates of manure application. Spring-time soil temperatures, at 8-cm depth, were coldest where the highest rate of manure had been incorporated.
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The amount of organic matter present in soil and the rate of soil organic matter (SOM) turnover are influenced by agricultural management practices. Because SOM is composed of a series of fractions, management practices will also influence the distribution of organic C and N among SOM pools. Our study examined SOM fractions that are occluded within the aggregate structure. Aggregates were disrupted by sonication and the disrupted soil suspensions were passed through a series of sieves to isolate size fractions. Densiometric separations were carried out on the size fractions, creating size-density fractions. Fine-silt-size particles having a density of 2.07 to 2.22 g/cm3 isolated from inside macroaggregates contained the highest percentage of total soil C and N for all cultivation treatments and, because of its properties, will be referred to as the enriched labile fraction (ELF). As cultivation intensity was reduced, the amount of N in the ELF increased from 110 mg N/kg in the bare fallow treatment to 405 mg N/kg in the no-till treatment. About 5% of the N in the ELF was mineralized during a 28-d laboratory incubation, averaged across treatments. The proportion of N mineralized from the ELF (4.7%) was significantly higher than from intact macroaggregates (2.1%), which suggests this fraction may be protected from decomposition within the aggregate structure. We postulate that the ELF is a byproduct of microbial activity and that it contributes to binding microaggregates into macroaggregates in cultivated grassland soils.
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Tillage generally reduces aggregation and particulate organic matter (POM) content. We hypothesized that reduced C sequestration in conventional tillage (CT) compared with no-tillage (NT) is related to differences in aggregate turnover. Four soils (Haplustoll, Fragiudalf, Hapludalf, and Paleudalf), each with NT, CT, and native vegetation (NV) treatments, were separated into aggregates. Free light fraction (LF) and intraaggregate POM (iPOM) were isolated. At one site we used 13C natural abundance to differentiate crop- and grassland-derived C. Concentrations of coarse iPOM C (250-2000 μm iPOM in macroaggregates), expressed on a per unit aggregate weight (g iPOM C kg-1 aggregate), did not differ between tillage treatments. In contrast, concentrations of fine iPOM C (53-250 μm iPOM in macroaggregates) were less in CT compared to NT macroaggregates. On a whole soil basis, fine iPOM C was on average 51% less in CT than in NT, and accounted for 21% of the total C difference between NT and CT. The concentration of free LF C was not affected by tillage, but was on average 45% less in the cultivated systems than NV. Proportions of crop-derived C in macroaggregates were similar in NT and CT, but were three times greater in microaggregates from NT than microaggregates from CT. We suggest that a faster turnover rate of maroaggregates in CT compared with NT leads to a slower rate of microaggregate formation within macroaggregates and less stabilization of new SOM in free microaggregates under CT.