Vol.3, No.5, 678-696 (2012) Agricultural Sciences
http://dx.doi.org/10.4236/as.2012.35083
Short-term influence of anaerobically-digested and
conventional swine manure, and N fertilizer on
organic C and N, and available nutrients in two
contrasting soils
Sukhdev S. Malhi1*, R. L. Lemke2, M. Stumborg3, F. Selles4
1Agriculture and Agri-Food Canada, Melfort, Canada; *Corresponding Author:
2Agriculture and Agri-Food Canada, Saskatoon, Canada
3Agriculture and Agri-Food Canada, Swift Current, Canada
4Agriculture and Agri-Food Canada, Brandon, Canada
Received 3 June 2012; revised 3 July 2012; accepted 23 July 2012
ABSTRACT
A three-year (2006-2008) field experiment was
conducted at Swift Current and Star City in
Saskatchewan to determine the short-term in-
fluence of land-applied anaerobically digested
swine manure (ADSM), conventionally treated
swine manure (CTSM) and N fertilizer on total
organic C (TOC), total organic N (TON), light
fraction organic C (LFOC), light fraction organic
N (LFON) and pH in the 0 - 7.5 and 7.5 - 15 cm
soil layers, and ammonium-N, nitrate-N, ex-
tractable P, exchangeable K and sulphate-S in
the 0 - 15, 15 - 30, 30 - 60, 60 - 90 and 90 - 120 cm
soil layers. Treatments included spring and au-
tumn applications of CTSM and ADSM at a 1x
rate (10,000 and 7150 L·ha−1, respectively) ap-
plied each year, a 3x rate (30,000 and 21,450
L·ha−1, respectively) applied once at the begin-
ning of the experiment, plus a treatment receiv-
ing commercial fertilizer (UAN at 60 kg·N·ha−1·yr−1)
and a zero-N control. There was no effect of
swine manure rate, type and application time on
soil pH. Mass of TOC and TON in the 15 cm soil
layer increased significantly with swine manure
application compared to the control, mainly at
the Swift Current site, with greater increases
from 3x rate than 1x rate (by 2.21 Mg·C·ha−1 and
0.167 Mg·N·ha−1). Compared to the control, mass
of LFOC and LFON in the 15 cm soil layer in-
creased with swine manure application at both
sites, with greater increases from 3x rate than 1x
rate (by 287 kg·C·ha−1 and 26 kg·N·ha−1 at Star
City, and by 194 kg·C·ha−1 and 19 kg·N·ha−1 at
Swift Current). Mass of TOC and TON in soil
layer was tended to be greater with ADSM than
CTSM, but mass of LFOC and LFON in soil was
greater with CTSM than ADSM. Mass of TOC,
TON, LFOC and LFON in soil also increased with
annual N fertilizer application compared to the
control (by 3.2 Mg·C·ha−1 for TOC, 0.195 Mg·N·ha−1
for TON, 708 kg·C·ha−1 for LFOC and 45 kg·N·ha−1
for LFON). In conclusion, our findings suggest
that the quantity and quality of organic C and N
in soil can be affected by swine manure rate and
type, and N fertilization even after three years,
most likely by influencing inputs of C and N
through crop residue, and improve soil quality.
Keywords: Anaerobic Digestion; Available N; P, K
and S; Organic C and N; Soil; Swine Manure
1. INTRODUCTION
Of the approximately 30 million hogs marketed in
Canada, nearly one-half of that industry is located in the
Canadian prairie region, and approximately 90% of in-
tensive livestock operations (ILOs) store manure in liq-
uid form in a holding tank or lagoon until it can be
land-applied. Land application of liquid swine manure
(LSM) is an effective source of nutrients for crop pro-
duction [1-3]. Economically feasible, environmentally
friendly, and socially acceptable management of LSM
from ILOs is a key element for the future viability of this
industry. In LSM, there is usually less than 2% solid ma-
terial [4] and most of the nutrients are in plant-available
inorganic form. Thus, LSM can potentially increase soil
organic C (SOC) mainly by supplying nutrients to crops
[5,6] and increasing above and below ground plant bio-
mass thereby adding organic matter to the soil. In the
Prairie Provinces of Canada, previous research has

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 679
documented the agronomic benefits of LSM application
on enhancing crop yields [1]. Increased soil fertility is an
important benefit of LSM application that substantially
increases the concentration of N, P, K and micronutrients
in soil [1,3].
Anaerobic digestion is a promising technology that
may reduce greenhouse gas (GHG, CH4 and N2O) emis-
sions by utilizing the biogas produced during digestion to
displace fossil fuels and by reducing emissions during
lagoon storage. The effects of land-applied anaerobically
digested swine manure (ADSM) versus conventionally
treated swine manure (CTSM) or N fertilizer on crop
yields and GHG emissions in the Canadian prairies are
presented in our previous report [7]. However, the re-
search information on the impact of ADSM versus
CTSM or N fertilizer on soil biochemical and chemical
properties is lacking in the Canadian prairies, especially
in the Parkland region. The objective of this study was to
compare relative effects of land-applied ADSM, CTSM,
or N fertilizer on quantity and quality of soil organic C
and N (TOC, TON, LFOC and LFON), and some soil
chemical properties (pH, ammonium-N, nitrate-N, ex-
tractable P, exchangeable K and sulphate-S).
2. MATERIALS AND METHODS
A field experiment was conducted over three years
from 2006 to 2008 at two field sites in Saskatchewan
[Star City (Dark Gray Luvisol soil) and Swift Current
(Brown Chernozem soil)], having contrasting soil and
climatic conditions. Precipitation in the growing season
(May, June, July and August) at the two sites from 2006
to 2008, and long-term (30-year) average of precipitation
in May to August at the nearest Environment Canada
Meteorological Station (AAFC Melfort and AAFC Swift
Current) are presented in Table 1. Precipitation in the
2006 growing season was slightly below average at both
sites. In 2007, the growing season precipitation was
much below long-term average at Swift Current (with
particularly limited precipitation in July), but was slight-
ly above average at Star City. In 2008, the growing sea-
son precipitation was much higher than average (espe-
cially in June) at Swift Current, but much below average
(especially in May during seeding) at Star City. Treat-
ments included autumn and spring applications of CTSM
and ADSM at a 1x rate (10,000 and 7150 L·ha−1 respec-
tively) applied each year, and a 3x rate (30,000 and
21,450 L·ha−1 respectively) applied once at the beginning
of the study. A treatment receiving commercial fertilizer
urea-ammonium nitrate (UAN) solution and a check (no
N) were also included. Eleven treatments (Table 2) were
arranged in a randomized complete block design with
four replications. Liquid swine manures were applied by
the Prairie Agricultural Machinery Institute (PAMI) us-
ing a customized applicator, which injected the material
to 10 cm. All plots were seeded to barley (Hordeum vul-
gare L.) in each of the three years, and harvested for seed
and straw yield, and total N uptake. In the autumn of
2008, soil in each plot was sampled to 0 - 7.5, 7.5 - 15
and 15 - 20 cm depths for TOC, TON, LFOC, LFON and
pH, and to 0 - 15, 15 - 30, 30 - 60 and 60 - 90 cm depths
for ammonium-N, nitrate-N, extractable P, exchangeable
K and sulphate-S.
For TOC, TON, LFOC, LFON and pH, soil cores at 10
locations in each plot were collected using a 2.4 cm di-
ameter coring tube. Bulk density of soil was determined
by the core method using soil weight and core volume
[8]. The soil samples were air dried at room temperature
after removing coarse roots and easily detectable crop
Table 1. Monthly cumulative precipitation in the growing season during 2006, 2007 and 2008 at Star City and Swift Current, Sas-
katchewan.
Precipitation (mm)
Location/Year
May June July August Total
Star City
2006 63 73 39 46 221
2007 71 119 47 40 277
2008 6 32 117 22 177
30-year mean 46 66 76 57 245
Swift Current
2006 35 96 31 21 183
2007 26 48 10 19 103
2008 27 152 64 69 312
30-year mean 50 66 52 40 208

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Table 2. List of treatments and the corresponding total amount of N applied and input of C from crop residue returned and land-ap-
plied liquid swine manure (LSM) during a three-year (2006-2008) field study at Star City and Swift Current, Saskatchewan.
Time of
application
Product
appliedz
Application rate of LSM
or N fertilizer
Total amount of N
applied in 3 years
(kg·N·ha−1)
Input of C from crop residue
plus LSM in 3 years at Star
City (kg·C·ha−1)
Input of C from crop residue
plus LSM in 3 years at Swift
Current (kg·C·ha−1)
Control No manure or N fert 0 4037 3710
Autumn ADSM-3x 21,450 L·ha−1 214 6665 5753
ADSM-1x 7150 L·ha−1 205 6446 4719
CTSM-3x 30,000 L·ha−1 403 7603 5919
CTSM-1x 10,000 L·ha−1 360 8765 4872
Spring ADSM-3x 21,450 L·ha−1 257 6745 5270
ADSM-1x 7150 L·ha−1 255 7601 4444
CTSM-3x 30,000 L·ha−1 343 7405 5701
CTSM-1x 10,000 L·ha−1 326 7906 5210
UAN 60 kg·N·ha−1 180 6158 5278
zADSM = anaerobically digested swine manure, CTSM = conventionally treated swine manure, UAN = urea ammonium nitrate (liquid), 3x = once in 3 years,
1x = annual application.
residues, and ground to pass a 2-mm sieve. Sub-samples
were pulverized in a vibrating-ball mill (Retsch, Type
MM2, Brinkman Instruments Co., Toronto, Ontario) for
determination of TOC, TON, LFOC and LFON in soil.
Soil samples used for organic C and N analyses were
tested for the presence of inorganic C (carbonates) using
dilute HCl, and none was detected in any soil sample.
Therefore, C in soil associated with each fraction was
considered to be of organic origin. Total organic C in soil
was measured by Dumas combustion using a Carlo Erba
instrument (Model NA 1500, Carlo Erba Strumentazione,
Italy), and Technicon Industrial Systems [9] method was
used to determine TON in the soil. Light fraction organic
matter (LFOM) was separated using a NaI solution of 1.7
Mg·m−3 specific gravity, as described by Janzen et al. [10]
and modified by Izaurralde et al. [11]. The C and N in
LFOM (LFOC, LFON) were measured by Dumas com-
bustion.
Soil samples (ground to pass a 2-mm sieve) taken for
organic C and N from the 0 - 15 cm layer were also
monitored for pH in 0.01 M CaCl2 solution with a pH
meter. For other chemical properties, soil cores (using a 4
cm diameter coring tube) were collected at 4 locations in
each plot from the 0 - 15, 15 - 30, 30 - 60, 60 - 90 and 90
- 120 cm layers. The bulk density of each depth was cal-
culated using soil weight and core volume [8]. The soil
samples were air dried at room temperature, ground to
pass a 2-mm sieve, and analyzed for ammonium-N [12]
and nitrate-N [13] by extracting soil in a 1:5 soil: 2M
KCl solution; extractable P [9] by extracting soil in
Kelowna extract, exchangeable K [14] and sulphate-S
[15].
The data on each parameter were subjected to analysis
of variance (ANOVA) using GLM procedure in SAS [16].
For each ANOVA, the least significant difference at P ≤
0.05 (LSD0.05) was used to determine significant differ-
ences between treatment means, and standard error of the
mean (SEM) and significance are also reported.
3. RESULTS
3.1. Soil Biochemical Properties
At Star City, there was no significant beneficial effect
of swine manure or UAN fertilizer application on TOC
and TON mass in soil compared to the zero-N control
treatment (Ta bl e 3 ). At Swift Current, mass of TOC and
TON in soil increased with application of swine manure
at 3x rate compared to control in the 0 - 7.5 and also in
the total 0 - 15 cm depth, with the greatest increase from
3x rate of ADSM applied in spring (Table 4). On average,
TOC and TON in soil was greater with 3x rate (once in 3
years) than 1x rate (annual application) of swine manure,
and greater with ADSM than CTSM in some cases.
At Star City, mass of LFOC and LFON in soil in-
creased with increasing rate of swine manure and also
with UAN application compared to the zero-N control
treatment in the 0 - 7.5 cm layer (Ta bl e 5). On average,
mass of LFOC and LFON was greater with the 3x rate
(once in 3 years) than the 1x rate (annual application) of
swine manure in the 0 - 7.5 cm soil layer, but there was
little or no effect of timing and type of swine manure
application on these parameters. At Swift Current, there
was a significant effect of swine manure and N fertilizer
treatments on mass of LFOC and LFON in the 0 - 7.5 cm

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 681
Table 3. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on mass of total organic C (TOC) and total
organic N (TON) in soil in autumn 2008 at Star City, Saskatchewan, Canada (Gray Luvisol soil).
TOC mass (Mg·C·ha−1) in soil layers (cm) TON mass (Mg·N·ha−1) in soil layers (cm)
Treatments
0 - 7.5 7.5 - 15 0 - 15 0 - 7.5 7.5 - 15 0 - 15
Control 22.27 16.58 38.85 2.024 1.519 3.543
ADSM-3x Autumn 22.57 17.73 40.31 2.037 1.636 3.673
ADSM-1x Autumn 22.26 15.52 37.78 1.999 1.476 3.474
CTSM-3x Autumn 21.86 17.49 39.34 2.082 1.751 3.833
CTSM-1x Autumn 21.31 16.21 37.52 1.926 1.463 3.388
ADSM-3x Spring 22.52 15.99 38.51 2.106 1.588 3.694
ADSM-1x Spring 22.54 17.94 40.48 2.045 1.723 3.768
CTSM-3x Spring 21.96 16.43 38.39 2.001 1.556 3.557
CTSM-1x Spring 21.55 17.90 39.45 1.924 1.673 3.597
UAN Spring 23.64 19.13 42.76 2.106 1.774 3.880
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 0.733ns 1.249ns 1.620ns 0.0731ns 0.1116ns 0.1505ns
Manure rate
1x 21.91 16.89 38.80 1.973 1.584 3.557
3x 22.23 16.91 39.14 2.057 1.633 3.690
LSD0.05 ns ns ns 0.112 ns ns
SEM (Probability) 0.359ns 0.653ns 0.837ns 0.0385• 0.0592ns 0.0816ns
Manure type
ADSM 22.47 16.80 39.27 2.047 1.606 3.653
CTSM 21.67 17.01 38.68 1.983 1.611 3.594
LSD0.05 1.04 ns ns ns ns ns
SEM (Probability) 0.359• 0.653ns 0.837ns 0.0385ns 0.0592 ns 0.0816ns
Manure application time
Autumn 22.00 16.74 38.74 2.011 1.581 3.592
Spring 22.14 17.07 39.21 2.019 1.635 3.654
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 0.359ns 0.653ns 0.837ns 0.0385ns 0.0592ns 0.0816ns
• and ns refer to significant treatment effects in ANOVA at P ≤ 0.10 and not significant, respectively.
soil layer (Table 6). On average, mass of LFOC and
LFON in soil was greater with the 3x rate (once in 3
years) than the 1x rate (annual application) of swine
manure, but there was little effect of timing and type of
swine manure application on these parameters.
At both sites, the correlation coefficients among the
TOC, TON, LFOC and LFON fractions in soil were
strong, and were highly significant between TOC and
TON, and between LFOC and LFON (Table 7). At Swift
Current, the correlation between TOC and LFOC or
LFON was significant at P = 0.12 or 0.15. The correla-
tion coefficients between crop residue C input over 3
growing seasons (Table 1) and TOC, TON, LFOC or
LFON were not significant in any case at Star City, but

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Table 4. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on mass of total organic C (TOC) and total
organic N (TON) in soil in autumn 2008 at Swift Current, Saskatchewan, Canada (Dark Brown Chernozem soil).
TOC mass (Mg·C·ha−1) in soil layers (cm) TON mass (Mg·N·ha−1) in soil layers (cm)
Treatments
0 - 7.5 7.5 - 15 0 - 15 0 - 7.5 7.5 - 15 0 - 15
Control 19.50 15.60 35.10 1.948 1.723 3.671
ADSM-3x Autumn 21.59 16.69 38.28 2.096 1.760 3.856
ADSM-1x Autumn 20.50 17.57 38.07 2.065 1.814 3.879
CTSM-3x Autumn 22.02 15.88 37.90 2.126 1.711 3.837
CTSM-1x Autumn 20.50 16.17 36.67 2.062 1.714 3.776
ADSM-3x Spring 23.31 17.52 40.83 2.347 1.853 4.200
ADSM-1x Spring 20.41 16.17 36.58 2.016 1.694 3.710
CTSM-3x Spring 22.08 16.69 38.77 2.121 1.726 3.847
CTSM-1x Spring 20.67 14.97 35.64 2.084 1.623 3.707
UAN Spring 20.68 16.90 37.58 2.023 1.701 3.724
LSD0.05 2.14 ns 3.48 0.178 ns 0.290
SEM (Probability) 0.736* 0.845ns 1.201• 0.0613* 0.0682ns 0.0999*
Manure rate
1x 20.52 16.22 36.74 2.057 1.711 3.768
3x 22.25 16.70 38.95 2.172 1.762 3.935
LSD0.05 1.14 ns 1.87 0.107 ns 0.167
SEM (Probability) 0.392** 0.439ns 0.644* 0.0366* 0.0343ns 0.0575*
Manure type
ADSM 21.45 16.99 38.44 2.131 1.780 3.911
CTSM 21.32 15.93 37.25 2.098 1.693 3.792
LSD0.05 ns 1.28 ns ns 0.100 0.167
SEM (Probability) 0.392ns 0.439• 0.644ns 0.0366ns 0.0343• 0.0575•
Manure application time
Autumn 21.15 16.58 37.73 2.087 1.750 3.837
Spring 21.62 16.34 37.96 2.142 1.724 3.866
LSD0.05 ns ns ns ns ns 0.167
SEM (Probability) 0.392ns 0.439ns 0.644ns 0.0366ns 0.0343ns 0.0575ns
•, *, **and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05, P ≤ 0.01 and not significant, respectively.
was significant for LFOC and LFON at Swift Current.
For linear regressions between crop residue C input and
TOC, TON, LFOC or LFON, the R2 values were not sig-
nificant in any case at Star City, but highly significant for
LFOC and LFON at Swift Current (Table 8).
3.2. Soil Chemical Properties and
Distribution of Available N, P, K and S
in the Soil Profile
There was no significant effect of swine manure (fre-
quency, type and application time) or N fertilizer appli-
cation after three years on soil pH in the 0 - 15 cm layer
at either site (data not shown). The soil pH ranged from
6.4 to 6.7 at Star City and from 5.8 to 6.5 at Swift Cur-
rent among different treatments. There was also no effect
of swine manure or N fertilizer treatments on ammo-
nium-N and exchangeable K in soil at both sites, and
sulphate-S in soil at Swift Current (data not shown). The
amount of nitrate-N increased with the 3x rate of swine
manure application in the 30 - 60, 60 - 90 and 90 - 120
cm soil layers at Star City (Table 9), and in all soil layers

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 683
Table 5. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on mass of light fraction organic C (LFOC) and
light fraction organic N (LFON) in soil in autumn 2008 at Star City, Saskatchewan, Canada (Gray Luvisol soil).
LFOC mass (Mg·C·ha−1) in soil layers (cm) LFON mass (Mg·N·ha−1) in soil layers (cm)
Treatments
0 - 7.5 7.5 - 15 0 - 7.5 7.5 - 15 0 - 7.5 7.5 - 15
Control 1931 649 2580 135 35 170
ADSM-3x Autumn 2263 603 2866 158 33 191
ADSM-1x Autumn 2116 749 2865 143 40 183
CTSM-3x Autumn 2286 1004 3290 154 52 206
CTSM-1x Autumn 2306 762 3068 149 41 190
ADSM-3x Spring 2333 817 3150 160 47 207
ADSM-1x Spring 2034 673 2707 134 36 170
CTSM-3x Spring 2277 957 3234 161 55 216
CTSM-1x Spring 1878 875 2753 127 48 175
UAN Spring 2203 952 3155 150 55 205
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 206.8ns 122.1ns 241.7ns 13.3ns 7.2ns 14.6ns
Manure rate
1x 2083 765 2848 138 41 179
3x 2290 845 3135 158 47 205
LSD0.05 296 ns 346 19 ns 21
SEM (Probability) 101.5ns 55.0ns 118.7• 6.5* 3.1ns 7.1*
Manure type
ADSM 2187 710 2897 149 39 188
CTSM 2187 900 3087 148 49 197
LSD0.05 ns 160 ns ns 9 ns
SEM (Probability) 101.5ns 55.0* 118.7ns 6.5ns 3.1* 7.1ns
Manure application time
Autumn 2242 780 3022 151 41 192
Spring 2131 830 2961 145 47 192
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 101.5ns 55.0ns 118.7ns 6.5ns 3.1ns 7.1ns
•, * and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05 and not significant, respectively.
up to the 120 cm depth at Swift Current (Tabl e 10 ). Ap-
plication of UAN fertilizer had a significant effect on
nitrate-N in soil at Swift Current, but no effect on soil
nitrate-N at Star City. The increase in nitrate-N due to
swine manure in the 120 cm soil profile was greater with
CTSM than ADSM, and also greater with autumn appli-
cation than spring application at Star City site. However,
the opposite was true at Swift Current. The amounts of
extractable P in soil tended to increase in a few cases
with swine manure application in the 0 - 15 and 15 - 30
cm layers at Star City (Ta bl e 11) and in the 0 - 15, 15 -
30 or 30 - 60 cm layers at Swift Current (Table 12). Ap-
plication of UAN fertilizer had no significant effect on
extractable P in soil at either site. On average, extractable
P in soil tended to be greater with CTSM than ADSM at
Swift Current, but there was no effect of swine manure

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696
684
Table 6. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on mass of light fraction organic C (LFOC) and
light fraction organic N (LFON) in soil in autumn 2008 at Swift Current, Saskatchewan, Canada (Dark Brown Chernozem soil).
LFOC mass (Mg·C·ha−1) in soil layers (cm) LFON mass (Mg·N·ha−1) in soil layers (cm)
Treatments
0 - 7.5 7.5 - 15 0 - 7.5 7.5 - 15 0 - 7.5 7.5 - 15
Control 1808 635 2443 123 36 159
ADSM-3x Autumn 2726 806 3532 186 46 231
ADSM-1x Autumn 2360 936 3296 159 53 212
CTSM-3x Autumn 2935 905 3740 201 47 249
CTSM-1x Autumn 2570 884 3454 172 51 223
ADSM-3x Spring 2783 712 3496 190 39 229
ADSM-1x Spring 2272 774 3046 151 43 193
CTSM-3x Spring 2677 777 3454 182 44 225
CTSM-1x Spring 2825 814 3640 189 45 234
UAN Spring 2397 886 3284 163 51 214
LSD0.05 679 ns ns 48 ns ns
SEM (Probability) 233.8• 94.8ns 294.9ns 16.5• 5.5ns 19.8ns
Manure rate
1x 2507 852 3359 167 48 215
3x 2780 775 3555 190 44 234
LSD0.05 348 ns ns 25 ns ns
SEM (Probability) 119.4• 45.4ns 146.3ns 8.4• 2.7ns 9.9ns
Manure type
ADSM 2535 807 3342 171 45 216
CTSM 2752 820 3572 186 47 233
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 119.4ns 45.4ns 146.3ns 8.4ns 2.7ns 9.9ns
Manure application time
Autumn 2648 857 3505 179 49 228
Spring 2639 769 3408 178 43 221
LSD0.05 ns ns ns ns 8 ns
SEM (Probability) 119.4ns 45.4ns 146.3ns 8.4ns 2.7• 9.9ns
• and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05, P ≤ 0.01, P ≤ 0.001 and not significant, respectively.
type, rate or application time on extractable P in soil at
Star City. At Star City, the amount of sulphate-S in soil
increased (but not significantly) with swine manure ap-
plication mainly in the 30 - 60, 60 - 90 and 90 - 120 cm
layers (Tables 13). Application of UAN fertilizer had no
significant effect on sulphate-S in soil at Star City, and in
fact sulphate-S in the surface 0 - 15 cm soil layer tended
to decrease compared to the zero-N control treatment. On
average, sulphate-S in soil was greater with ADSM than
CTSM, considerably greater with autumn application
than spring application, and slightly greater with 1x rate
than 3x rate of swine manure. There was no effect of any
amendment treatment on sulphate-S in soil at Swift Cur-
rent, and exchangeable K in soil at both sites (data not

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 685
Ta ble 7. Relationships among organic C or N fractions (TOC, TON, LFOC, LFON) in the 0 - 15 cm soil, or between crop residue
and/or swine manure C input from 2006 to 2008 growing seasons and organic C or N stored in the 0 - 15 cm soil sampled in autumn
2008 at Star City (Gray Luvisol) and Swift Current (Dark Brown Chernozem), Saskatchewan, Canada.
Correlation coefficients (r)
Soil Parameter
TOC TON LFOC LFON
Relationships among soil organic C or N fractions
Star City TOC 0.820** −0.004ns 0.041ns
TON 0.279ns 0.276ns
LFOC 0.950***
LFON
Swift Current TOC 0.913*** 0.492• 0.527•
TON 0.406ns 0.436ns
LFOC 0.994***
LFON
Relationships between crop residue and/or swine manure C input and soil organic C or N fractions
Star City −0.196ns −0.083ns 0.413ns 0.226ns
Swift Current 0.587• 0.386ns 0.891*** 0.921***
•, **, *** and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.01, P ≤ 0.001 and not significant, respectively.
Table 8. Linear regressions for relationships between crop residue and swine manure C input from 2006 to 2008 growing seasons and
organic C or N (TOC, TON, LFOC, LFON) stored in the 0 - 15 cm soil sampled in autumn 2008 at Star City (Gray Luvisol) and
Swift Current (Dark Brown Chernozem), Saskatchewan, Canada.
Soil Crop parameter (X) Soil C or N parameter (Y) zLinear regression (Y = a + bX) R2
Star City Crop residue C input TOC Y = 40.97 – 0.0002X 0.038ns
TON Y = 3.721 – 0.00001X 0.009ns
LFOC Y = 2420 + 0.079X 0.170ns
LFON Y = 170.5 + 0.003X 0.052ns
Swift Current Crop residue C input TOC Y = 30.21 + 0.001X 0.345ns
TON Y = 3.378 + 0.00009X 0.149ns
LFOC Y = 848.9 + 0.489X 0.794**
LFON Y = 41.41 + 0.035X 0.847**
zY = Soil organic C or N fraction (TOC and TON as Mg C or N·ha−1; and LFOC, LFON as kg C or N·ha−1; a = Intercept on Y, origin of the line; b = Regression
coefficient of Y on X, slope of line; X = Crop residue and/or swine manure C input (Mg·ha−1); ** and ns refer to significant treatment effects in ANOVA at P ≤
0.01 and not significant, respectively.
shown).
3.3. Amounts of N Uptake in Crop, Nitrate-N
in Soil, N Balance Sheets, and Recovery
of Applied N
The N balance over the 2006 to 2008 period for the 10
treatments included the amount of nitrate-N recovered in
the 0 - 90 cm soil in autumn 2008 and in seed yield
(which was removed from the land/field), and N applied
as UAN or swine manure, plus N added in seed at seed-
ing over 3 years, and the estimated amount of N balance
and unaccounted N (Tables 14 and 15). At Star City, the
estimated amounts of nitrate-N recovered in soil in au-
tumn 2008 plus N recovered (removed) in seed in 3 years
in various treatments ranged from 139 to 357 kg·N·ha−1.
The corresponding values of N applied as UAN fertilizer
or manure plus N added in seed at seeding in 3 years
ranged from 7 to 410 kg·N·ha−1. The amounts of N that

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686
Table 9. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on the amount of residual nitrate-N in soil in
autumn 2008 at Star City (Gray Luvisol), Saskatchewan, Canada.
Amount of nitrate-N (kg·N·ha−1) in soil layers (cm)
Treatments
0 - 15 15 - 30 30 - 60 60 - 90 90 - 120 0 - 120
Control 6.7 1.2 2.4 4.2 6.2 20.7
ADSM-3x Autumn 5.2 1.4 6.6 14.1 16.6 43.9
ADSM-1x Autumn 5.4 1.7 3.6 7.9 8.2 26.8
CTSM-3x Autumn 5.6 2.0 8.5 37.1 33.8 87.0
CTSM-1x Autumn 3.8 1.5 3.9 7.3 9.0 25.5
ADSM-3x Spring 7.2 1.6 4.8 11.8 13.2 38.6
ADSM-1x Spring 4.9 0.8 1.9 4.5 6.3 18.4
CTSM-3x Spring 5.8 1.3 7.5 25.8 21.2 61.6
CTSM-1x Spring 3.9 1.0 3.6 7.1 8.1 23.7
UAN Spring 4.8 1.1 4.3 7.3 8.3 25.8
LSD0.05 ns 0.7 3.9 10.6 7.3 18.8
SEM (Probability) 0.88ns 0.23* 1.35* 3.67*** 2.52*** 6.49***
Manure rate
1x 4.5 1.2 3.2 6.7 7.9 23.5
3x 5.9 1.6 6.9 22.2 21.2 57.8
LSD0.05 1.3 0.4 2.0 6.8 4.7 12.1
SEM (Probability) 0.43* 0.13• 0.69** 2.34*** 1.63*** 4.16***
Manure type
ADSM 5.7 1.4 4.2 9.6 11.1 32.0
CTSM 4.8 1.4 5.9 19.3 18.0 49.4
LSD0.05 1.3 ns 2.0 6.8 4.7 12.1
SEM (Probability) 0.43• 0.13 ns 0.69• 2.34** 1.63** 4.16**
Manure application time
Autumn 5.0 1.6 5.6 16.6 16.9 45.7
Spring 5.4 1.2 4.5 12.3 12.2 35.6
LSD0.05 ns 0.4 ns 6.8 4.7 12.1
SEM (Probability) 0.43ns 0.13* 0.69ns 2.34 ns 1.63* 4.16•
•, *, **, *** and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05, P ≤ 0.01, P ≤ 0.001 and not significant, respectively.
could not be accounted for ranged from −132 to 57
kg·N·ha−1. The amounts of unaccounted N from N ap-
plied/added ranged from 91 to 192 kg·N·ha−1. At Swift
Current, the estimated amounts of nitrate-N recovered in
soil in autumn 2008 plus N recovered (removed) in seed
in 3 years in various treatments ranged from 170 to 399
kg·N·ha−1. The corresponding values of N applied as
UAN fertilizer or manure plus N added in seed at seed-
ing in 3 years ranged from 7 to 410 kg·N·ha−1. The
amounts of N that could not be accounted for ranged
from −163 to 101 kg·N·ha−1. The amounts of unac-
counted N from N applied/added ranged from 35 to 207
kg·N·ha−1. The percent recovery of applied N over 3
years ranged from 37.7% to 50.0% in seed and from 50.7%
to 65.0% in seed + straw at Star City, and from 0.3% to
7.0% in seed and from 27.5 to 54.7 in seed + straw at

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 687
Table 10. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on the amount of residual nitrate-N in soil in
autumn 2008 at Swift Current (Dark Brown Chernozem), Saskatchewan, Canada.
Amount of nitrate-N (kg·N·ha−1) in soil layers (cm)
Treatments
0 - 15 15 - 30 30 - 60 60 - 90 90 - 120 0 - 120
Control 5.9 2.0 2.9 12.8 37.5 61.1
ADSM-3x Autumn 10.3 7.8 29.9 85.9 46.6 180.5
ADSM-1x Autumn 14.8 9.8 53.6 43.1 43.0 164.3
CTSM-3x Autumn 11.4 6.6 63.8 79.1 30.0 190.9
CTSM-1x Autumn 13.8 13.7 121.7 61.4 41.1 251.7
ADSM-3x Spring 12.5 8.5 45.8 122.1 83.5 272.4
ADSM-1x Spring 11.8 10.1 50.1 41.6 22.8 136.4
CTSM-3x Spring 13.5 5.7 69.2 89.5 46.0 223.9
CTSM-1x Spring 17.8 16.7 53.9 48.0 43.2 179.6
UAN Spring 10.0 7.1 22.5 68.0 63.8 171.4
LSD0.05 5.7 7.4 56.1 45.5 31.2 91.4
SEM (Probability) 1.98* 2.56* 19.33* 15.69** 10.77* 31.51**
Manure rate
1x 14.6 12.6 69.8 48.5 37.5 183.0
3x 11.9 7.1 52.2 94.1 51.5 216.8
LSD0.05 3.0 4.1 ns 24.2 18.0 ns
SEM (Probability) 1.03• 1.41* 11.02 ns 8.30*** 6.19• 18.69 ns
Manure type
ADSM 12.3 9.0 44.9 73.2 49.0 188.4
CTSM 14.1 10.7 77.2 69.5 40.1 211.6
LSD0.05 ns ns 32.1 ns ns ns
SEM (Probability) 1.03ns 1.41 ns 11.02* 8.30 ns 6.19 ns 18.69 ns
Manure application time
Autumn 12.6 9.4 67.3 67.4 40.2 196.9
Spring 13.9 10.2 54.8 75.3 48.9 203.1
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 1.03 ns 1.41 ns 11.02 ns 8.30 ns 6.19 ns 18.69 ns
•, *, **, *** and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05, P ≤ 0.01, P ≤ 0.001 and not significant, respectively.
Swift Current in the various swine manure or N fertilizer
treatments (Tabl es 1 4 and 15). The recovery of applied
N in seed or seed + straw for swine manure was usually
greater in the 3x than the 1x rate and also greater with
the ADSM than the CTSM treatments.
4. DISCUSSION
Research has shown potential for improvement in or-
ganic C and/or N storage in soil and/or increase in soil
fertility level from the application of LSM [1,5,6] and N
fertilization [17-19]. Previous research has also sug-
gested that long-term application of LSM can increase N,
P, S and K fertility of soil, due to the return of these nu-
trients in manure and in crop residue to soil over years
[1]. Similarly, in our study, applications of LSM and N
fertilizer increased organic C and N, and amounts of

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696
688
Ta b l e 11. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on the amount of residual extractable P in soil
in autumn 2008 at Star City (Gray Luvisol), Saskatchewan, Canada.
Amount of extractable P (kg·N·ha−1) in soil layers (cm)
Treatments
0 - 15 15 - 30 30 - 60 60 - 90 90 - 120 0 - 120
Control 21.4 8.6 12.6 6.0 4.5 53.1
ADSM-3x Autumn 22.0 11.5 7.1 5.7 4.3 50.6
ADSM-1x Autumn 21.7 10.5 9.1 3.9 3.3 48.5
CTSM-3x Autumn 18.4 8.6 10.9 3.3 3.6 44.8
CTSM-1x Autumn 27.2 11.9 7.4 4.7 5.0 56.2
ADSM-3x Spring 18.4 9.1 10.3 5.5 4.2 47.5
ADSM-1x Spring 34.2 16.8 8.7 4.8 4.1 68.6
CTSM-3x Spring 39.3 11.2 12.7 6.4 4.2 73.8
CTSM-1x Spring 24.0 9.8 10.8 5.0 7.5 57.1
UAN Spring 21.8 10.0 9.4 4.8 5.2 51.2
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 5.88ns 2.29 ns 3.42 ns 1.06 ns 1.43 ns 8.28 ns
Manure rate
1x 26.8 12.3 9.0 4.6 5.0 57.5
3x 24.5 10.1 10.3 5.2 4.1 54.2
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 3.24ns 1.21ns 1.73ns 0.53ns 0.76ns 4.39ns
Manure type
ADSM 24.1 12.0 8.8 5.0 4.0 53.9
CTSM 27.2 10.4 10.5 4.9 5.1 58.1
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 3.24ns 1.21ns 1.73ns 0.53ns 0.76ns 4.39ns
Manure application time
Autumn 22.3 10.6 8.6 4.4 4.1 50.0
Spring 29.0 11.7 10.6 5.4 5.0 61.7
LSD0.05 ns ns ns ns ns 12.8
SEM (Probability) 3.24ns 1.21ns 1.73ns 0.53ns 0.76ns 4.39•
• and ns refer to significant treatment effects in ANOVA at P ≤ 0.10 and not significant, respectively.
plant-available N, P or S in soil in many cases, depend-
ing on soil type/site. The following sections discuss the
short-term effects of LSM and N fertilization on soil
biochemical and chemical properties.
4.1. Soil Biochemical Properties
Earlier research has shown positive effects of swine
manure or N fertilizer application on crop yield, and soil
organic matter and fertility [1,5,6]. Similarly, we found
increase in TOC and TON from swine manure applica-
tion due to its dual effect by directly contributing to or-
ganic C and N, plus additional indirect contribution of C
from increased crop residue (roots, stubble, straw, chaff/
fallen leaves) returned to the land/soil, as evidenced by
greatest increase in straw yield in this treatment [7]. In-
organic fertilizers supply specific nutrients, but do not

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 689
Table 12. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on the amount of residual extractable P in soil
in autumn 2008 at Swift Current (Dark Brown Chernozem), Saskatchewan, Canada.
Amount of extractable P (kg·P·ha−1) in soil layers (cm)
Treatments
0 - 15 15 - 30 30 - 60 60 - 90 90 - 120 0 - 120
Control 53.0 8.4 7.7 7.3 13.4 89.7
ADSM-3x Autumn 55.0 9.1 8.7 8.2 13.9 94.9
ADSM-1x Autumn 51.6 8.4 11.0 8.0 19.6 98.6
CTSM-3x Autumn 48.4 8.1 6.9 7.3 25.9 96.6
CTSM-1x Autumn 56.8 10.6 7.1 9.1 24.7 108.3
ADSM-3x Spring 48.1 11.0 11.6 5.4 16.6 92.7
ADSM-1x Spring 52.4 8.4 8.5 4.6 16.7 90.6
CTSM-3x Spring 66.6 13.7 8.1 6.1 15.7 110.2
CTSM-1x Spring 59.6 8.6 7.2 6.2 18.4 100.0
UAN Spring 54.3 10.4 9.1 5.3 14.6 93.7
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 7.25ns 2.01 ns 1.68 ns 1.80 ns 3.33 ns 8.64 ns
Manure rate
1x 55.1 9.0 8.5 7.0 19.8 99.4
3x 54.5 10.5 8.8 6.8 18.0 98.6
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 3.71ns 1.02ns 0.83ns 0.87ns 1.77ns 4.06ns
Manure type
ADSM 51.8 9.2 10.0 6.5 16.7 94.2
CTSM 57.9 10.3 7.4 7.2 21.2 104.0
LSD0.05 ns ns 2.4 ns 5.2 11.8
SEM (Probability) 3.71ns 1.02ns 0.83* 0.87ns 1.77• 4.06•
Manure application time
Autumn 53.0 9.1 8.4 8.2 21.0 99.7
Spring 56.7 10.5 8.9 5.6 16.8 98.5
LSD0.05 ns ns ns 2.5 5.2 ns
SEM (Probability) 3.71ns 1.02ns 0.83ns 0.87* 1.77• 4.06ns
•, * and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05 and not significant, respectively.
contribute directly to soil organic matter, and thus may
result in much less contribution to soil organic C and N.
However, in our study, there was relatively greater stor-
age of organic C and N from N fertilizer application than
swine manure, at least at Star City site. The smaller stor-
age of TOC or TON from swine manure or UAN fertil-
izer applications at Star City than Swift Current was
probably due to the differences in soil type (Gray Luvisol
loam soil at Star City versus Brown Chernozem silt loam
at Swift Current) and climatic conditions (relatively
moister soils at Star City than Swift Current) at the two
sites, resulting in greater turn over of organic matter at
Star City compared to Swift Current.
In our study, the changes in LFOC and LFON due to
LSM application and N fertilization were more pro-
nounced than TOC and TON in both soils. For example,

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696
690
Table 13. Effect of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and
urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 on the amount of residual sulphate-S in soil in
autumn 2008 at Star City (Gray Luvisol), Saskatchewan, Canada.
Amount of sulphate-S (kg·S·ha−1) in soil layers (cm)
Treatments
0 - 15 15 - 30 30 - 60 60 - 90 90 - 120 0 - 120
Control 27.9 8.8 12.7 11.2 13.8 74.4
ADSM-3x Autumn 23.3 9.7 20.5 44.5 45.1 143.1
ADSM-1x Autumn 27.8 10.4 13.2 19.0 30.1 100.5
CTSM-3x Autumn 18.9 10.1 13.4 10.7 9.9 63.0
CTSM-1x Autumn 22.7 11.1 16.5 38.2 42.6 131.1
ADSM-3x Spring 30.2 10.1 11.6 12.1 11.2 75.2
ADSM-1x Spring 25.8 9.1 10.4 9.5 8.8 63.6
CTSM-3x Spring 18.1 9.8 13.2 9.5 8.6 59.4
CTSM-1x Spring 17.0 8.1 12.7 13.9 22.2 73.9
UAN Spring 18.6 10.3 12.0 12.4 13.7 67.0
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 6.48ns 0.99ns 4.24ns 12.68ns 11.77ns 28.29ns
Manure rate
1x 23.3 9.7 13.2 20.1 25.9 92.2
3x 22.7 9.9 14.7 19.2 18.8 85.3
LSD0.05 ns ns ns ns ns ns
SEM (Probability) 3.15ns 0.51ns 2.23ns 7.04ns 6.62ns 15.42ns
Manure type
ADSM 26.8 9.8 13.9 21.3 23.8 95.6
CTSM 19.2 9.8 13.9 18.1 20.9 81.9
LSD0.05 9.2 ns ns ns ns ns
SEM (Probability) 3.15• 0.51ns 2.23ns 7.04ns 6.62ns 15.42ns
Manure application time
Autumn 23.2 10.3 15.9 28.1 31.9 109.4
Spring 22.8 9.3 12.0 11.2 12.8 68.1
LSD0.05 ns ns ns 20.5 19.3 44.9
SEM (Probability) 3.15ns 0.51ns 2.23ns 7.04• 6.62* 15.42•
•, * and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05 and not significant, respectively.
in the 0 - 15 cm soil layer after 3 years, and compared to
the zero-N control treatment, the manure and N fertilizer
treatments, respectively, increased TOC by 10.1% and
3.2%, TON by 9.5% and 2.3%, LFOC by 22.3% and
16.0% and LFON by 20.6% and 12.9% at Star City. The
corresponding increases at Swift Current were 7.1% and
7.8% for TOC, 1.4% and 4.9% for TON, 34.4% and
41.5% for LFOC and 34.6% and 41.5% for LFON, re-
spectively. Other researchers have also observed greater
responses of LFOC and LFON to N fertilization and
other management practices than TOC and TON [18-20].
Our findings confirm that the changes in LFOC and
LFON can be considered good indicators of changes of
organic C and N in soil as a result of manure addition or
appropriate fertilization. This also suggests that monitor-
ing the changes in LFON and LFOC in the surface soil

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 691
Table 14. Balance sheets of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure
(CTSM) and urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 at Star City (Gray Luvisol), Sas-
katchewan, Canada.
Treatments
Fall application Spring application
Parameters
Control UAN
spring ADSM-3x ADSM-1xCTSM-3xCTSM-1xADSM-3x ADSM-1x CTSM-3xCTSM-1x
Nitrate-N recovered in soil (0 - 90 cm)
after 3 years in fall 2008 (kg·N·ha−1) 21 26 44 27 87 26 39 18 62 24
N recovered in seed in 3 years kg·N·ha−1) 118 199 225 204 270 284 235 242 253 262
N recovered in soil after 3 years + N
recovered in seed in 3 years (kg·N·ha−1) 139 225 269 231 357 310 274 260 315 286
Total N applied in UAN or in SM in 3
years (kg·N·ha−1) 0 180 214 205 403 360 257 255 343 326
Organic N added in seed in 3 years
(kg·N·ha−1) 7 7 7 7 7 7 7 7 7 7
Total N added in UAN + SM + seed in 3
years (kg·N·ha−1) 7 187 221 212 410 367 264 262 350 333
N balance (N applied in UAN/SM/seed –
N recovered in seed) (kg·N·ha−1) −111 −12 −4 8 140 83 29 20 97 71
Unaccounted N (N applied in
UAN/SM/seed – N recovered in soil +
seed) (kg·N·ha−1)
−132 −38 −48 −19 53 57 −10 2 35 47
N recovered in seed in 3 years from
applied N (kg·N·ha−1) 81 107 86 152 166 117 124 135 144
N recovered in soil after years + seed in
3 years from applied N (kg·N·ha−1) 86 130 92 218 171 134 121 176 147
N balance (N applied in UAN/SM/seed –
N recovered in seed from applied N)
(kg·N·ha−1)
106 114 126 258 201 147 138 215 189
Unaccounted N (N applied in
UAN/SM/seed – N recovered in soil +
seed from applied N) (kg·N·ha−1)
101 91 120 192 196 130 141 174 186
Recovery of applied N in seed over
3 years (%) 45.0 50.0 42.0 37.7 46.1 45.5 48.6 39.4 44.2
N recovered in seed + straw in 3 years
(kg·N·ha−1) 159 264 298 263 365 371 313 311 346 341
Recovery of applied N in seed + straw
over 3 years (%) 58.3 65.0 50.7 51.1 58.9 59.9 59.6 54.5 55.8
could be a good strategy to determine the potential for N
supplying power, and improvement in soil quality/health.
The trends of higher organic C and N in light organic
fractions than total organic fractions in the manure and N
fertilizer treatments were most likely associated with
greater inputs of C and N to soil through manure, and
also straw, chaff [17] and roots [21,22].
The relative greater increases in C or N for LFOC or
LFON than TOC or TON in our study are in agreement
with other research, where light organic fraction was also
more responsive to management practices than total or-
ganic fraction [18-20]. Unlike TOC and TON, there was
a greater build-up of light fraction organic C or N at
Swift Current than at Star City, in spite of greater input
of C from crop residues plus LSM in 3 years at Star City
than Swift Current. We do not have any real explanation
for this unusual trend for the greater build-up of light
organic fraction under relatively warmer temperature
conditions at Swift Current than Star City, but this may
be possibly due to relatively drier conditions which may
have resulted in relatively slower decomposition of
freshly added crop residues at swift Current than Star
City.
Earlier long-term research studies have shown strong
and highly significant correlations among TOC, TON,
LFOC and LFON fractions in soil due to management
practices [18-20]. However, in our study, the strong posi-
tive correlations were found only between TOC and TON,

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696
692
Table 15. Balance sheets of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure
(CTSM) and urea-ammonium-nitrate (UAN) solution fertilizer over three years from 2006 to 2008 at Swift Current (Dark Brown
Chernozem), Saskatchewan, Canada.
Treatments
Fall application Spring application
Parameters
Control UAN
spring ADSM-3x ADSM-1xCTSM-3xCTSM-1xADSM-3x ADSM-1x CTSM-3xCTSM-1x
Nitrate-N recovered in soil (0 - 90 cm)
after 3 years in autumn 2008 (kg·N·ha−1)61 171 181 164 191 252 272 136 224 180
N recovered in seed in 3 years (kg·N·ha−1) 109 110 123 114 118 110 127 112 132 116
N recovered in soil after 3 years + N
recovered in seed in 3 years kg·N·ha−1) 170 281 304 278 309 362 399 248 356 296
Total N applied in UAN or in SM in 3
years (kg·N·ha−1) 0 180 214 205 403 360 257 255 343 326
Organic N added in seed in 3 years
(kg·N·ha−1) 7 7 7 7 7 7 7 7 7 7
Total N added in UAN + SM + seed in 3
years (kg·N·ha−1) 7 187 221 212 410 367 264 262 350 333
N balance (N applied in UAN/SM/seed –
N recovered in seed) (kg·N·ha−1) −102 77 98 98 292 257 137 150 218 217
Unaccounted N (N applied in
UAN/SM/seed – N recovered in soil +
seed) (kg·N·ha−1)
−163 −94 −83 −66 101 5 −135 14 −6 37
N recovered in seed in 3 years from
applied N kg·N·ha−1) 1 14 5 9 1 18 3 23 7
N recovered in soil after years + seed in 3
years from applied N (kg·N·ha−1) 111 134 108 139 192 229 78 186 126
N balance (N applied in UAN/SM/
seed – N recovered in seed from applied
N) (kg·N·ha−1)
186 207 207 401 366 249 259 327 326
Unaccounted N (N applied in
UAN/SM/seed – N recovered in soil +
seed from applied N) (kg·N·ha−1)
76 87 104 271 175 35 184 164 207
Recovery of applied N in seed over 3
years (%) 0.6 6.5 2.4 2.2 0.3 7.0 1.2 6.7 2.1
N recovered in seed + straw in 3 years
(kg·N·ha−1) 162 242 279 240 297 261 290 233 299 259
Recovery of applied N in seed + straw
over 3 years (%) 44.4 54.7 38.0 35.5 27.5 49.8 27.8 39.9 29.8
and between LFOC and LFON in both soils. Previous
long-term studies have shown positive relationships be-
tween the input of increased amounts of manure and/or
crop residue C or N and TOC, TON, LFOC or LFON,
especially in the labile/light organic fractions [18-20,
23,24]. However, in our study after 3 years, the signifi-
cant linear regressions between the amounts of C or N
input and mass of organic C or N in the 0 - 15 cm soil
layer in various organic fractions were found only for
LFOC and LFON and only at Swift Current. This lack of
significant relationships between C or N input and mass
of organic C or N stored in soil was probably due to short
duration of our study.
4.2. Soil Chemical Properties and
Distribution of Available N, P, K and S
in the Soil Profile
Slow acidification of soil from N fertilization has been
earlier reported after long-term annual applications of
moderate rates of N fertilizer to annual crops in North
America [25-27]. However, in our study, there was no
effect of manure or N fertilization on soil pH, and this
was probably due to the shorter duration of our present
study. In a study in Quebec, Canada, Ndayegamiye and
Cote [5] also found no effect of pig slurry application on
soil pH even after 10 annual applications.
There was no build-up of residual ammonium-N in

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696 693
soil after three annual applications of swine manure or N
fertilizer, no doubt due to the rapid nitrification of any
ammonium-N released during mineralization of organic
matter. The amount of residual nitrate-N in soil increased
with increasing rate of swine manure in the 30 - 60, 60 -
90 and 90 - 120 cm layers in the 0 - 120 cm soil profile,
particularly at Swift Current. This suggests potential risk
of nitrate leaching below the root zone, even within the
short duration of our study (only three years), as other
long-term studies in China have shown a great potential
of underground water contamination with nitrate-N from
annual applications of farmyard manure (FYM) at rela-
tively high rates [28-30]. Our findings also suggest the
need for deep soil sampling, as soils in our study were
sampled only to the 120 cm depth. In our study at Star
City, there was a significant increase in nitrate-N in the
soil profile with 3x LSM rate while there was only little
increase in residual nitrate-N in the 0 - 120 cm soil pro-
file due to fertilizer N application. The rate of fertilizer-N
applied in our study was below the rate needed for opti-
mum yield in this soil-climatic region [31], and the
amount of N removed in the grain closely matched the
amount of fertilizer-N added. This would have mini-
mized the amount of surplus N available for leaching or
other losses. However, a portion of the applied N may
have been immobilized into the soil organic N pool, es-
pecially when straw was retained [20]. It is also possible
that a portion of the residual soil nitrate-N may have
been lost as gaseous N over the winter and especially in
early spring after snow melting [32,33]. It is unlikely that
much of the applied N at Star City leached below the 120
cm depth, as evidenced by little residual nitrate-N recov-
ered in the 30 - 60, 60 - 90 and 90 - 120 cm soil layers in
autumn 2008 sampling
At Swift Current, the amounts of fertilizer and manure
N applied exceeded the amounts of N removed in the
grain, and based on the moderate amounts of residual
nitrate-N recovered in the 30 - 60, 60 - 90 and 90 - 120
cm soil layers in autumn 2008 at Swift Current it may
well that a portion of the applied N had leached below
the 120 cm depth, particularly at the high rate of manure.
Previous research in Saskatchewan where soil samples
were taken to 240 cm depth after 12 growing seasons,
Malhi et al. [34] observed large amounts of residual ni-
trate-N accumulation in the 210 - 240 cm layer for treat-
ments where N applications had exceeded N removals. It
should be noted that at Swift Current, crops were drought
stressed during grain filling during both 2006 and 2007
and final grain yields were greatly depressed, while in
2008 the study suffered severe hail damage prior to grain
filling. Minimal grain N uptake at Swift Current in all
three years no doubt influenced the amount of nitrate N
accumulating in the soil profile. Regardless, the results
also emphasizes the need for deep soil sampling (maybe
up to 3 or 4 m depth) in future research in order to make
valid conclusions related to nitrate leaching losses in the
soil profile.
Earlier research in China has shown substantial in-
crease in extractable P and total P in soil with long-term
annual applications of FYM [35]. In our study, there was
a tendency towards increased extractable P in the surface
0 - 5 cm soil with swine manure in some treatments even
after three annual applications, probably due to fairly
high concentration of P in swine manure. The increase of
extractable P with swine manure only in the 0 - 15 cm
soil layer suggests that P is relatively immobile, but the
slow build-up of P in the surface soil, especially after
repeated applications to increase crop production, may
subsequently increase the potential risk of contamination
of surface waters with P from surface run-off of water
after snow melt in early spring and/or after heavy rainfall
events which often occur in this region during summer.
Sulphate-S in soil tended to increase with swine ma-
nure at Star City. This suggests that swine manure either
contained sulphate-S or possibly increased sulphate-S
through mineralization of organic matter. Sulphate-S
increased with increasing rate of swine manure. It is pos-
sible that a portion of the sulphate-S may have leached
below the 120 cm depth, as evidenced by large amounts
of sulphate-S in the 30 - 60, 60 - 90 and 90 - 120 cm lay-
ers, although no soil samples were obtained below 120
cm to verify this in our study. This suggests the need for
future soil sampling to greater depths in order to make
valid conclusions related to sulphate-S leaching. Earlier
research in Saskatchewan has suggested that long-term
application of LSM can increase K fertility of soil, due to
the return of these nutrients in manure and in crop resi-
due to soil over years [1]. However, in our present study,
there was no increase in extractable K in soil from LSM
or UAN application over three years at both sites.
4.3. Amounts of N Uptake in Crop, Nitrate-N
in Soil, N Balance Sheets, and Recovery
of Applied N
The amounts of unaccounted N increased with appli-
cation of swine manure or N fertilizer compared to
zero-N control. This unaccounted N reflects a portion of
the applied N which did not become available to the crop,
and may have been lost from the soil mineral N pool
and/or from the soil-plant system. At Star City, it is
unlikely that a portion of the applied N was leached
down below 120 cm soil depth, because there was little
nitrate-N recovered in the deeper soil layers in autumn
2008. At Swift Current, it is possible that a portion of the
applied N may have leached down below 120 cm soil
depth, because there were large amounts of nitrate-N
recovered in the 30 - 60, 60 - 90 and 90 - 120 cm soil

S. S. Malhi et al. / Agricultural Sciences 3 (2012) 678-696
694
layers in autumn 2008 in many cases for swine manure
and UAN treatments. Other researchers have reported an
increase in the concentration of residual nitrate-N in the
soil profile at high N fertilizer rates [36-39], and any soil
nitrate-N below the effective root zone of crops is sus-
ceptible to leaching, The loss of nitrate-N through leach-
ing can result in N contamination of groundwater, and
thus represents a potential risk to groundwater quality
and soil health [40]. Our N balance results suggest that a
portion of the applied N in the N treatments may have
been immobilized in soil organic N, as evidenced by
higher amount of soil organic N, especially in LFON
even after 3 years in autumn 2008 (Ta b l e s 3 - 6 ). At Star
City, the amount of applied N recovered in LFON in soil
ranged from −155 to 290 kg·N·ha−1 in various swine
manure and UAN treatments. The corresponding values
for the amounts of applied N recovered in total organic N
in soil at Swift Current ranged from 36 to 529 kg·N·ha−1.
In addition, it is possible that a portion of the applied N
may have been lost from the soil-plant system through
denitrification (e.g., nitrous oxide and other N gases) due
to wet surface soil conditions which temporarily exist in
the present study area in most years in early spring after
snow melt, or after occasional heavy rainfalls during
summer and/or autumn [32,33,41]. It is also possible that
a small portion of the applied N may have leached below
the 120 cm soil depth profile, as suggested by Malhi et al.
[34] who found large amounts of nitrate-N accumulation
in the 120 to 240 cm soil profile in a long-term study in
Saskatchewan with high input of N fertilizer and low
crop intensity. This suggests the need for deep soil sam-
pling below the 120 cm depth in future in our present
long-term experiments.
Overall, the amount of residual soil nitrate-N recov-
ered in the 0 - 120 cm soil profile was relatively small in
the Gray Luvisol soil at Star City. This indicates low ac-
cumulation of nitrate-N in the soil profile. However,
large amounts of unaccounted N from applied N suggest
a great potential for gaseous N loss, especially in early
spring after snow thawing when the surface soil is very
wet (conducive to denitrification), and N immobilization,
and possibility of some nitrate-N leaching below the 120
cm depth soil profile in the Brown Chernozem soil at
Swift Current. However, as noted previously, grain N
uptake was limited due to environmental conditions
which no doubt influenced the amount of nitrate N ac-
cumulating in the soil profile. There were large amounts
of N balance and unaccounted N in the zero-N treatments
and also in the swine manure or N fertilizer treatments,
especially at Swift Current. The implication of these
large negative values for N balance and unaccounted N
in the zero-N treatments is that large amounts of N be-
came available to the crops in the growing seasons
through mineralization of soil organic matter. However,
the large negative values for N balance and unaccounted
N in the N fertilizer treatments at Swift Current suggest
that the soil at this site may be gaining some N by wet/
dry deposition through precipitation (rain/snow) and po-
ssibly by non-symbiotic N fixation. The Swift Current
site is not close to any large city or industry, we don’t
know if soil at this site gained any N deposited through
dry (snow) and wet (rainfall) precipitation. This supports
the need for future research to obtain information on the
contribution of N from rain/snow and non-symbiotic N
fixation, or other outside sources, in order to optimize the
use and accounting of N resources, and their effects on
greenhouse gas (GHG) emissions to the atmosphere.
The percent recovery of applied N over 3 years ranged
from 37.7% to 50.0% in seed and from 50.7% to 65.0%
in seed + straw at Star City, and from 0.3% to 7.0% in
seed and from 27.5 to 54.7 in seed + straw at Swift Cur-
rent in various swine manure or N fertilizer treatments
(Tables 13 and 14). The recovery of applied N in seed or
seed + straw for swine manure was usually greater in the
3x rate than the 1x rate and also greater with the ADSM
than the CTSM treatments. The greater recovery of ap-
plied N from swine manure in seed or seed + straw with
the 3x rate than the 1x rate was possibly due to greater
mineralization of any organic N because of much longer
time of contact with soil microorganisms. The poor re-
covery of applied N in LSM or UAN fertilizer at Swift
Current was most likely due to lack of crop response to
these amendments, thus low input of organic C or N
from crop residue which probably is the main/major
source of C or N input to soil.
5. CONCLUSION
Our findings suggest that the quantity and quality of
organic C and N in soil can be affected by swine manure
rate and type, and N fertilization, most likely influencing
inputs of C and N through crop residue, and improve soil
quality.
6. ACKNOWLEDGEMENTS
We are grateful to Environmental Technologies Assessment for Ag-
riculture (ETAA) program for funding, Prairie Agricultural Machinery
Institute (PAMI) for excellent collaboration, Cudworth Pork Investors
Group Ltd. and Clear-Green Environmental Inc. for providing access to
raw and digested material, and D. Leach, D. Hahn and D. James for
technical help.
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