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1.
Soil organic carbon fractions after 16-years of applications of fertilizers and organic manure in a Typic Rhodalfs in semi-arid tropics 总被引:5,自引:0,他引:5
K. Banger G. S. Toor A. Biswas S. S. Sidhu K. Sudhir 《Nutrient Cycling in Agroecosystems》2010,86(3):391-399
Agricultural soils can act as a potential sink of the increased carbon dioxide in the atmosphere if managed properly by application
of organic manures and balanced fertilizers. However, the rate of carbon (C) sequestration in soils is low in warm climates
and thus the short term changes in soil organic carbon (SOC) contents are almost negligible. Therefore, the knowledge about
other C fractions that are more sensitive or responsive and indicative of the early changes in SOC can help to determine the
effect of the management practices on soil C sequestration. The objective of this study was to determine the soil C sequestration
after 16-years of applications of chemical fertilizers and farmyard manure (FYM) to rice (Oryza sativa)—cowpea (Vigna unguiculata) rotation system in a sandy loam soil (Typic Rhodalfs). The treatments were—(1) one control (no fertilizer or FYM); (2) three chemical fertilizer treatments [100 kg N ha−1 (N), 100 kg N ha−1 + 50 kg P2O5 ha−1 (NP), 100 kg N ha−1 + 50 kg P2O5 ha−1 + 50 kg K2O ha−1 (NPK)]; (3) one integrated treatment [(50 kg N ha−1 + 25 kg P2O5 ha−1 + 25 K2O ha−1) + (50 kg N ha−1 from FYM)]; and (4) one organic treatment at10 Mg ha−1 FYM. Compared to the control treatment, the increase in SOC was 36, 33, and 19% greater in organic, integrated, and NPK treatments.
The 16-years application of fertilizers and/or FYM resulted in much greater changes in water soluble C (WSC), microbial biomass
C (MBC), light fraction of C (LFC), and particulate organic matter (POM) than SOC. Of the SOC, the proportion of POM was highest
(24–35%), which was followed by LFC (12–14%), MBC (4.6–6.6%), and WSC (0.6–0.8%). The application of fertilizers and/or FYM
increased the mean weight diameter of soil aggregates; thus provided physical protection to SOC from decomposition. Our results
suggests that the application of fertilizers and/or FYM helps to sequester C in the soil and that the labile fractions of
C can be used as indicators to determine the amount of C sequestered as a result of different management practices. 相似文献
2.
A long term field experiment was conducted for 8 years during 1994–2001 to evaluate the effect of N, P, K and Zn fertilizer
use alone and in combination with gypsum, farmyard manure (FYM) and pressmud on changes in soil properties and yields of rice
and wheat under continuous use of sodic irrigation water (residual sodium carbonate (RSC) 8.5 meq l−1, and sodium adsorption ratio (SAR) 8.8 (m mol/l)1/2 at Bhaini Majra experimental farm of Central Soil Salinity Research Institute, Karnal, India. Continuous use of fertilizer
N alone (120 kg ha−1) or in combination with P and K significantly improved rice and wheat yields over control (no fertilizer). Phosphorus applied
at the rate of 26 kg P ha−1 each to rice and wheat significantly improved the yields and led to a considerable build up in available soil P. When N alone
was applied, available soil P and K declined from the initial level of 14.8 and 275 kg ha−1 to 8.5 and 250 kg ha−1 respectively. Potassium applied at a rate of 42 kg K ha−1 to both crops had no effect on yields. Response of rice to Zinc application occurred since 1997 when DTPA extractable Zn
declined to 1.48 kg ha−1 from the initial level of 1.99 kg ha−1. Farmyard manure 10 Mg ha−1, gypsum 5 Mg ha−1 and pressmud 10 Mg ha−1 along with NPK fertilizer use significantly enhanced yields over NPK treatment alone. Continuous cropping with sodic water
and inorganic fertilizer use for 8 years slightly decreased the soil pHe and SAR from the initial value of 8.6 and 29.0 to 8.50 and 18.7 respectively. However, treatments involving the use of gypsum,
FYM and pressmud significantly decreased the soil pH and SAR over inorganic fertilizer treatments and control. Nitrogen, phosphorus
and zinc uptake were far less than additions made by fertilizer. The actual soil N balance was much lower than the expected
balance thereby indicating large losses of N from the soil. There was a negative potassium balance due to greater removal
by the crops when compared to K additions. The results suggest that either gypsum or FYM/pressmud along with recommended dose
of fertilizers must be used to sustain the productivity of rice – wheat system in areas having sodic ground water for irrigation. 相似文献
3.
In degraded soils, establishment of soil-improving legumes can be problematic and requires investment of labour and other
resources. We investigated various aspects of managing herbaceous legumes in farmers’ fields in Bukoba District, Tanzania.
Biomass and N accumulation by Crotalaria grahamiana was 1.1 Mg ha−1 and 34 kg N ha−1 when established without farmyard manure (FYM) and 3.0 Mg ha−1 and 95 kg N ha−1 when established with 2 Mg FYM ha−1, and incorporation of the biomass gave an increment of 700 kg ha−1 of grain in the subsequent maize crop. Maize grain yield at different application rates of Tephrosia candida residues ranged from 1.4 to 3.3 Mg ha−1 and from 2.0 to 2.8 Mg ha−1 in the high and low rainfall zone, respectively. Application of tephrosia biomass at a rate of 2 Mg ha−1 had no significant effect on maize yield whereas rates of 4, 6 and 8 Mg ha−1 gave comparable yields. Apparent N recovery efficiencies at all rates of tephrosia residues were maximally 27 and 13% for
the high and low rainfall zones, respectively. Mulching with Mucuna pruriens suppressed weeds by 49 and 68% and increased maize yield by 57 and 103% compared with the weedy fallow in the respective
zones. Incorporated residues had a weaker effect on suppressing weeds and poor labour productivity (2 l and 36 kg grain person-day−1) compared with mulched residues (32 and 52 kg grain person-day−1) in the high and low rainfall zone, respectively. These results indicate that if well managed, legume residues have the potential
to increase yields of subsequent maize crops on degraded soils. 相似文献
4.
Smallholder farmer management impacts on particulate and labile carbon fractions of granitic sandy soils in Zimbabwe 总被引:1,自引:0,他引:1
Crop production in maize-based smallholder farming systems of Southern Africa is hampered by lack of options for efficiently
managing limited and different quality organic nutrient resources. This study examined impacts of farmers’ short- and long-term
organic resource allocation patterns on sizes and quality of soil organic matter (SOM) fractions. Farmers’ most- (rich) and
least- (poor) productive fields were studied for two seasons under low (450–650 mm yr−1) to high (>750 mm yr−1) rainfall areas in Zimbabwe, on Lixisols with ∼6% clay and 88% sand. Rich fields received 0.5–14 Mg C ha−1 compared with <4 Mg C ha−1 for poor fields, and the differences were reflected in soil particulate organic matter (POM) fractions. Organic inputs were
consistent with resource endowments, with well-endowed farmers applying at least five times the amounts used by resource-constrained
farmers. Rich fields had 100% more macro-POM (250–2,000 μm diameter) and three times more meso-POM (53–250 μm) than poor fields.
Application of high quality (>25 mg N kg−1) materials increased labile C (KMnO4 oxidizable) in top 60 cm of soil profile, with 1.6 Mg C ha−1 of Crotalaria juncea yielding labile C amounts similar to 6 Mg C ha−1 of manure. Labile C was significantly related to mineralizable N in POM fractions, and apparently to maize yields (P < 0.01). Farmers’ preferential allocation of nutrient resources to already productive fields helps to maintain critical levels
of labile SOM necessary to sustain high maize yields. 相似文献
5.
Mingsheng Fan Shihua Lu Rongfeng Jiang Xuejun Liu Xiangzhong Zeng Keith W. T. Goulding Fusuo Zhang 《Nutrient Cycling in Agroecosystems》2007,79(3):255-265
A field experiment and farm survey were conducted to test nitrogen (N) inputs, 15N-labelled fertilizer balance and mineral N dynamics of a rice–wheat rotation in southwest China. Total N input in one rice–wheat
cycle averaged about 448 kg N ha−1, of which inorganic fertilizer accounted for 63% of the total. The effects of good N management strategies on N cycling were
clear: an optimized N treatment with a 27% reduction in total N fertilizer input over the rotation decreased apparent N loss
by 52% and increased production (sum of grain yield of rice and wheat) compared with farmers’ traditional practice. In the
15N-labelled fertilizer experiment, an optimized N treatment led to significantly lower 15N losses than farmers’ traditional practice; N loss mainly occurred in the rice growing season, which accounted for 82% and
67% of the total loss from the rotation in farmers’ fields and the optimized N treatment, respectively. After the wheat harvest,
accumulated soil mineral N ranged from 42 to 115 kg ha−1 in farmers’ fields, of which the extractable soil NO3
−–N accounted for 63%. However, flooding soil for rice production significantly reduced accumulated mineral N after the wheat
harvest: in the 15N experiment, farmers’ practice led to considerable accumulation of mineral N after the wheat harvest (125 kg ha−1), of which 69% was subsequently lost after 13 days of flooding. Results from this study indicate the importance of N management
in the wheat-growing season, which affects N dynamics and N losses significantly in the following rice season. Integrated
N management should be adopted for rice–wheat rotations in order to achieve a better N recovery efficiency and lower N loss. 相似文献
6.
T. M. Aye M. J. Hedley P. Loganathan R. D. B. Lefroy N. S. Bolan 《Nutrient Cycling in Agroecosystems》2009,83(2):111-123
Phosphorus (P) deficiency is a major constraint for crop production in many parts of the world including Myanmar and field
research into management of P fertilizers and P responsiveness of crops on infertile soils has been limited. The purpose of
this study is to determine maize yield response to different forms of P fertilizers on an acidic (pH 4.9) P deficient (Olsen-P
8 mg kg−1) Yellow Earth (Acrisol) in Southern Shan State, Myanmar and to establish relationships between soil Olsen-P test values (0.5 M
sodium bicarbonate extracted P) and maize yield. Field experiments were conducted during two cropping seasons. There were
15 treatments in total: P was applied at seven rates of a soluble P fertilizer as Triple superphosphate (TSP) (0–120 kg P ha−1) to establish a P response curve; one rate of a partially soluble P fertilizer (Chinese partially acidulated phosphate rock,
CPAPR) and two organic P fertilizers (farmyard manure (FYM) and Tithonia diversifolia) at 20 kg P ha−1; combination of TSP and CPAPR at 20 kg P ha−1 with FYM and Tithonia at 20 kg P ha−1; an additional treatment (TSP 20 kg P ha−1 plus 2.5 t ha−1 dolomite) for assessing the liming effect of a local dolomite. In Year 1, applications of TSP at 40–60 kg P ha−1 produced near maximum grain yields, whereas in Year 2 this could be achieved with a reapplication of 20–30 kg P ha−1 on top of the residual value of the Year 1 application. In both years, CPAPR, TSP and Tithonia at 20 kg P ha−1 significantly increased maize grain yield, but FYM failed to increase grain yield. In Year 1, CPAPR and TSP effects on grain
yield were higher than that of Tithonia but in Year 2 the effects were same for all these three treatments. In both years
the combination of FYM (20 kg P ha−1) with TSP (20 kg P ha−1) produced significantly higher grain yield than TSP at 20 kg P ha−1 whereas 40 kg P ha−1 of TSP application did not significantly increase grain yield over the TSP application at 20 kg P ha−1. Similar results were obtained when half the P applied as CPAPR was substituted with P from Tithonia and FMP during the first
year. The combined data from the two years experiment suggests that 90% of maximum maize grain yields can be obtained by raising
the Olsen-P to 30–35 mg P ha−1 soil at the silking stage of growth. Olsen-P for the treatments at silking in Year 1 was: Control < FYM, Tithonia < TSP,
CPAPR and in Year 2 was: Control < FYM < Tithonia < TSP, CPAPR. The results showed that for a long-term approach, repeated
annual applications of Tithonia can be considered as a potential P source for improving soil P status in P deficient Yellow
Earths. 相似文献
7.
Soil nitrate-N levels required for high yield maize production in the North China Plain 总被引:4,自引:0,他引:4
Zhenling Cui Fusuo Zhang Yuxin Miao Qinping Sun Fei Li Xinping Chen Junliang Li Youliang Ye Zhiping Yang Qiang Zhang Chunsheng Liu 《Nutrient Cycling in Agroecosystems》2008,82(2):187-196
High profile nitrate-nitrogen (N) accumulation has caused a series of problems, including low N use efficiency and environmental
contamination in intensive agricultural systems. The key objective of this study was to evaluate summer maize (Zea mays L.) yield and N uptake response to soil nitrate-N accumulation, and determine soil nitrate-N levels to meet N demand of high
yield maize production in the North China Plain (NCP). A total of 1,883 farmers’ fields were investigated and data from 458
no-N plots were analyzed in eight key maize production regions of the NCP from 2000 to 2005. High nitrate-N accumulation (≥172 kg N ha−1) was observed in the top (0–90 cm) and deep (90–180 cm) soil layer with farmers’ N practice during maize growing season.
Across all 458 no-N plots, maize grain yield and N uptake response to initial soil nitrate-N content could be simulated by
a linear plus plateau model, and calculated minimal pre-planting soil nitrate-N content for maximum grain yield and N uptake
was 180 and 186 kg N ha−1, respectively, under no-N application conditions. Economically optimum N rate (EONR) decreased linearly with increasing pre-planting
soil nitrate-N content (r
2 = 0.894), and 1 kg soil nitrate-N ha−1 was equivalent to 1.23 kg fertilizer-N ha−1 for maize production. Residual soil nitrate-N content after maize harvest increased exponentially with increasing N fertilizer
rate (P < 0.001), and average residual soil nitrate-N content at the EONR was 87 kg N ha−1 with a range from 66 to 118 kg N ha−1. We conclude that soil nitrate-N content in the top 90 cm of the soil profile should be maintained within the range of 87–180 kg N ha−1 for high yield maize production. The upper limit of these levels would be reduce if N fertilizer was applied during maize
growing season. 相似文献
8.
Mitigating greenhouse gas and nitrogen loss with improved fertilizer management in rice: quantification and economic assessment 总被引:1,自引:0,他引:1
H. Pathak 《Nutrient Cycling in Agroecosystems》2010,87(3):443-454
Several technologies have been developed to improve the recovery efficiency of N (REN) but their impacts on greenhouse gas (GHG) emission, N loss and economic implication are rarely analysed. A decision support
system (DSS) has been developed to quantify inputs, outputs and balance of N in soil; GHG emission and REN with the prominent N management technologies in rice. This DSS, named InfoNitro (Information on Nitrogen Management Technologies
in Rice), integrated analytical and expert knowledge with databases on bio-physical, agronomic and socio-economical features
to establish input–output relationships related to N management in rice. Sixteen technologies, which differed in terms of
water regime, method of N application, forms of N and tools of fertilizer recommendation were analysed for their REN, N losses, GHG emission and economic return in Haryana, a rice growing region in India. In the current farmers’ practice,
REN was 32.7%, which increased up to 40.8% with various technologies except in mid-season drainage and alternate flooding technologies
where it decreased up to 29.3%. Loss of N through leaching, volatilization and denitrification in the farmers’ practice (67.5 kg N ha−1) decreased up to 40.5 kg N ha−1 except in mid-season drainage and alternate flooding technologies where it increased. The technologies also reduced global
warming potential (GWP) by 1 to 9%. However, the technologies except no tillage, mid-season drying and alternate flooding
reduced the net income of the farmers. When the environmental cost (cost of N loss and GWP) was included net income with various
technologies was either at par or more than the farmers’ practice. The marginal abatement cost of N loss was Rs. 8 to 134 kg−1 N and for GWP was Rs. 766 to 4854 Mg−1 CO2 eq. Resource conserving technology was the most cost effective strategy to reduce N loss and GHG emission whereas integrated
N management cost high for mitigating GHG emission. 相似文献
9.
Understanding the effects of long-term use of fertilizers on soil carbon and nitrogen pools and their activities is essential
for sustaining soil productivity. Our objectives were to quantify long-term changes in soil organic carbon (SOC), soil microbial
biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) and mineralizable C in maize–wheat cropping sequence in fertilized
and unfertilized plots (control, N, NP, NPK, and NPK + FYM). Continuous application of fertilizers increased SOC over its
initial content. Active fractions of SOC, i.e., water-soluble carbon, hydrolysable carbohydrates, SMBC, SMBN and dehydrogenase
activity, improved significantly with an application of NPK and NPK + FYM. A general increase in carbon mineralization with
time period was observed throughout the experiment and was maximum in 100% NPK + FYM treated plots. The estimated annual C
input value in NPK + FYM treatment was 1.05 MgC ha−1 year−1. The overall net change in organic carbon was maximum in treatment receiving FYM along with inorganic fertilizers. Therefore,
these results suggest that the integrated use of NPK and FYM is an important nutrient management option for sustaining maize–wheat
cropping system. 相似文献
10.
E. N. Masvaya J. Nyamangara R. W. Nyawasha S. Zingore R. J. Delve K. E. Giller 《Nutrient Cycling in Agroecosystems》2010,88(1):111-120
Variability of soil fertility within, and across farms, poses a major challenge for increasing crop productivity in smallholder
systems of sub-Saharan Africa. This study assessed the effect of farmers’ resource endowment and nutrient management strategies
on variability in soil fertility and plant nutrient uptake between different fields in Gokwe South (ave. rainfall ~650 mm year−1; 16.3 persons km−2) and Murewa (ave. rainfall ~850 mm year−1; 44.1 persons km−2) districts, Zimbabwe. In Murewa, resource-endowed farmers applied manure (>3.5 t ha−1 year−1) on fields closest to their homesteads (homefields) and none to fields further away (outfields). In Gokwe the manure was
not targeted to any particular field, and farmers quickly abandoned outfields and opened up new fields further way from the
homestead once fertility had declined, but homefields were continually cultivated. Soil available P was higher in homefields
(8–13 mg kg−1) of resource-endowed farmers than on outfields and all fields on resource constrained farms (2–6 mg kg−1) in Murewa. Soil fertility decreased with increasing distance from the homestead in Murewa while the reverse trend occurred
in Gokwe South, indicating the impact of different soil fertility management strategies on spatial soil fertility gradients.
In both districts, maize showed deficiency of N and P, implying that these were the most limiting nutrients. It was concluded
that besides farmers’ access to resources, the direction of soil fertility gradients also depends on agro-ecological conditions
which influence resource management strategies. 相似文献
11.
Ranjan Bhattacharyya S. C. Pandey S. Chandra S. Kundu Supradip Saha B. L. Mina A. K. Srivastva H. S. Gupta 《Nutrient Cycling in Agroecosystems》2010,86(2):255-268
To date, the sustainability of wheat (Triticum
aestivum)–soybean (Glycine
max) cropping systems has not been well assessed, especially under Indian Himalayas. Research was conducted in 1995–1996 to 2004
at Hawalbagh, India to study the effects of fertilization on yield sustainability of irrigated wheat–soybean system and on
selected soil properties. The mean wheat yield under NPK + FYM (farmyard manure) treated plots was ~27% higher than NPK (2.4 Mg ha−1). The residual effect of NPK + FYM caused ~14% increase in soybean yield over NPK (2.18 Mg ha−1). Sustainable yield index values of wheat and the wheat–soybean system were greater with annual fertilizer N or NPK plots
10 Mg ha−1 FYM than NPK alone. However, benefit:cost ratio of fertilization, agronomic efficiency and partial factor productivity of
applied nutrients were higher with NPK + FYM than NPK, if FYM nutrients were not considered. Soils under NPK + FYM contained
higher soil organic C (SOC), total soil N, total P and Olsen-P by ~10, 42, 52 and 71%, respectively, in the 0–30 cm soil layers,
compared with NPK. Non-exchangeable K decreased with time under all treatments except NPK. Total SOC in the 0–30 cm soil layer
increased in all fertilized plots. Application of NPK + FYM also improved selected soil physical properties over NPK. The
NPK + FYM application had better soil productivity than NPK but was not as economical as NPK if farmers had to purchase manure. 相似文献
12.
Field studies on the substitution of N and P fertilizers with farm yard manure (FYM) and their effect on the fertility status of a loamy sand soil in rice—wheat rotation are reported. The treatments consisted of application of 12 t FYM ha–1 in combination with graded levels of N and P. Application of fertilizer N, FYM and their different combinations increased the rice yield significantly. There was no significant response to P application. The magnitude of response to the application of 12 t FYM and its combined use with each of 40 kg and 80 kg N ha–1 was 0.7, 2.2 and 3.9 t ha–1 respectively. Application of 120 kg N ha–1 alone increased the yield by 3.9 t ha–1, and was comparable to rice yield obtained with 80 kg N and 12 t FYM ha–1. This indicated that 12 t FYM ha–1 could be substituted for 40 kg N as inorganic fertilizer in rice. In addition FYM gave residual effects equivalent to 30 kg N and 13.1 kg P ha–1 in the succeeding wheat. The effect of single or combined use of inorganic fertilizers and FYM was significantly reflected in the build up of available N, P, K and organic carbon contents of the soil. The relationship for predicting rice yield and nutrients uptake were also computed and are discussed. 相似文献
13.
Farmyard manure (FYM) applied to rice-growing soils can substitute for industrial fertilizers, but little is known about the influence of FYM on the effectiveness and optimal management for industrial N fertilizers. A field experiment was conducted in northern Vietnam on a degraded soil in the spring season (February to June) and summer season (July to November) to determine the effect of FYM on optimal timing for the first application of urea. The experimental design was a randomized complete block with two rates of basal incorporated FYM (0 or 6 Mg ha–1) in factorial combination with two timings of the first application of 30 kg urea-N ha–1 (basal incorporated before transplanting or delayed until 14 to 16 d after transplanting). The FYM was formed by composting pig manure with rice straw for 3 months. Basal incorporation of FYM, containing 23 kg N ha–1, increased rice grain yield in both seasons. The yield increase cannot be attributed to reduced ammonia loss of applied urea-N, because FYM did not reduce partial pressure of ammonia (pNH3) following urea application in either season. Basal and delayed applications of urea were equally effective in the absence of FYM, but when FYM was applied rice yields in both seasons were higher for delayed (mean = 3.2 Mg ha–1) than basal (mean = 2.9 Mg ha–1) application of urea. Results suggest that recommendations for urea timing in irrigated lowland rice should consider whether farmers apply FYM. 相似文献
14.
Soil organic matter (SOM), besides influencing carbon (C) transfer between soils and atmosphere, impacts soil functional ability
and its response to environmental and anthropogenic influences. We studied the impact of continuous application of rice straw
and farmyard manure (FYM) either alone or in conjunction with inorganic fertilizers on aggregate stability and distribution
of C and nitrogen (N) in different aggregate fractions after 7 years of rice–wheat cropping on a sandy loam soil. Macroaggregates
(>0.25 mm) constituted 32.5–54.5% of total water stable aggregates (WSA) and were linearly related (R
2 = 0.69) to soil organic carbon content. The addition of rice straw and FYM significantly (P < 0.05) improved the formation of macroaggregates with a concomitant decrease in the proportion of microaggregates at all
the three sampling depths (0–5, 5–10 and 10–15 cm). Macroaggregates had higher C and N density as compared to microaggregates.
Application of rice straw and FYM improved C and N density in different aggregate sizes and the improvement was greatest in
plots that received both rice straw and FYM each year. Application of FYM along with inorganic fertilizer resulted in a net
C sequestration of 0.44 t ha−1 in the plough layer after 7 years of rice–wheat cropping. Carbon sequestration was greater (1.53 t ha−1) when both rice straw and FYM along with inorganic fertilizers were applied annually. It is concluded that addition of rice
straw and FYM in rice–wheat system improves soil aggregation and enhances C and N sequestration in macroaggregates. This will
help in sustainable rice–wheat productivity in the region. 相似文献
15.
Fritz Oben Tabi Jan Diels Ayo O. Ogunkunle Emmanuel N. O. Iwuafor Bernard Vanlauwe N. Sanginga 《Nutrient Cycling in Agroecosystems》2008,80(2):161-172
Potential N (SN) and P (SP) supplies, N and P utilization efficiencies and fertilizer recovery rates for the northern Guinea
Savanna (NGS) agro-ecological zone of Nigeria were derived from data collected on farmers’ fields, and used as input in the
QUantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model. The potential N supply ranged from 7 to 56 kg N ha−1, with a mean of 25 kg N ha−1, while SP ranged from 2 to 12 kg P ha−1 with a mean of 5 kg P ha−1. Both SN (CV = 42%) and SP (CV = 57%) were highly variable between farmers’ fields. Deriving potential nutrient supply from
‘a’ values gives lower estimates. The empirical equation in QUEFTS that estimates SN (
) sufficiently predicted the SN of soils in the NGS (RMSE = 8.0 kg N ha−1 index of agreement (IOA) = 0.81). The SP equation () predicted moderately potential P supply (RMSE = 6.80 kg P ha−1, IOA = 0.54). When N or P is maximally accumulated in the plant (i.e., least efficiently utilized), the utilization efficiency
was 21 kg grain kg−1 N taken up and 97 kg grain kg−1 P taken up. When these nutrients were maximally diluted in the plant (i.e., most efficiently utilized), the utilization efficiency
was 70 kg grain kg−1 N taken up and 600 kg grain kg−1 P taken up. The range in N recovery fraction (NRF) of N fertilizer applied was from 0.30 to 0.57, with a mean of 0.39, while
the P recovery fraction (PRF) ranged from 0.10 to 0.66 with a mean of 0.24. Although SP was moderately predicted, when QUEFTS
model input parameters were adjusted for the NGS, the model sufficiently (IOA = 0.83, RMSE = 607 kg DM ha−1) estimated maize grain yield in the NGS of Nigeria. The original QUEFTS model however, gave better predictions of maize grain
yield as reflected by the lower RMSE (IOA = 0.84, RMSE = 549 kg DM ha−1). Consequently, QUEFTS is a simple and efficient tool for making yield predictions in the NGS of northern Nigeria. 相似文献
16.
Yadvinder-Singh Bijay-Singh Jagdish K. Ladha Jaswinder S. Bains Rajeev K. Gupta Jagmohan-Singh V. Balasubramanian 《Nutrient Cycling in Agroecosystems》2007,78(2):167-176
Nitrogen use efficiency (NUE) in rice is low due to the inefficient management of fertilizer N by farmers. We evaluated a
leaf color chart (LCC) as a simple tool for improving the time and rate of N fertilizer use in farmers’ fields for 4 years
(2000–2003) in irrigated rice in northwestern India. Application of N fertilizer whenever leaf greenness was less than shade
4 on the LCC (the critical LCC value) produced rice grain yields on a par with blanket recommendation of applying 120 kg N ha−1 in three equal splits in different years, but it resulted in an average saving of 26% fertilizer N across villages and seasons.
In most situations, there was no significant advantage of applying 20 kg N ha−1 as basal N at transplanting on grain yield and NUE of rice compared with no basal N. Use efficiencies of fertilizer N were
higher when N was applied using LCC with a critical value of 4 than the recommended practice of applying 120 kg N ha−1 in three equal split doses on all sites and in all years. The LCC with a critical value of 4 for real-time N management can
be efficiently used to increase NUE in all types of inbred rice cultivars presently popular with the farmers of the Indian
Punjab. The LCC is a cheap and easy-to-use tool that allows real-time N management by farmers on a large area leading to improved
fertilizer N use efficiency, and reduced risks associated with fertilizer N application. 相似文献
17.
Nitrogen fixation (N2) by leguminous crops is a relatively low-cost alternative to N fertilizers for smallholder farmers in Africa. Nitrogen fixation in pea (Pisum sativum L. cv. Markos) as affected by phosphorus (P) fertilization (0, 30 kg P ha−1) and inoculation (uninoculated and inoculated) in the semiarid conditions of Northern Ethiopia was studied using the 15N isotope dilution method and locally adapted barley (Hordeum vulgare L. cv. Bureguda) as reference crop. The effect of pea fixed nitrogen (N2) on yield of the subsequent wheat crop (Triticum aestivum L.) was also assessed. Phosphorus and inoculation significantly influenced nodulation at the late flowering stage and also significantly increased P and N concentrations in shoots, and P concentration in roots, while P and N concentrations in nodules were not affected. Biomass, pods m−2 and grain yield responded positively to P and inoculation, while seeds pod−1 and seed weights were not significantly affected by these treatments. Phosphorus and inoculation enhanced the percentage of N derived from the atmosphere in the whole plant ranging from 53 to 70%, corresponding to the total amount of N2 fixed varying from 55 to 141 kg N ha−1. Soil N balance after pea ranged from − 9.2 to 19.3 kg N ha−1 relative to following barley, where barley extracted N on the average of 6.9 and 62.0 kg N ha−1 derived from fertilizer and soil, respectively. Beneficial effects of pea fixed N2 on yield of the following cereal crop were obtained, increasing the average grain and N yields of this crop by 1.06 Mg ha−1 and 33 kg ha−1, respectively, relative to the barley–wheat monocrop rotation. It can be concluded that pea can be grown as an alternative crop to fallow, benefiting farmers economically and increasing the soil fertility. 相似文献
18.
J. Kanmegne E. M. A. Smaling L. Brussaard A. Gansop-Kouomegne A. Boukong 《Nutrient Cycling in Agroecosystems》2006,76(2-3):233-248
The flows and balances of N, P and K were studied in 20 farms in the Campo Ma’an area in Cameroon between March and August
2002 to assess the nutrient dynamics in smallholder farms. Data were collected through farmer interviews, field measurements
and estimates from transfer functions. Nutrient input from mineral (IN1), animal feed (IN2a) and inorganic amendments (IN2b)
was absent. Major outputs were through crop (OUT1a) and animal (OUT1b) products sold. Partial budgets for farmer managed flows
were negative: −65 kg N, −5.5 kg P and −30.8 kg K ha−1 year−1. For inflows not managed by farmers, deep capture (IN6) was the major source: 16.6, 1.4 and 6.6 kg ha−1 year−1 of N, P and K, respectively. Atmospheric deposition (IN3) was estimated at 4.3 kg N, 1.0 kg P and 3.9 kg K ha−1 year−1, and biological nitrogen fixation (IN4) at 6.9 kg N ha−1 year−1. Major losses were leaching (OUT 3a): 26.4 kg N, and 0.88 kg K ha−1 year−1. Gaseous losses from the soil (OUT 4a) were estimated at 6.34 kg N, and human faeces (OUT 6) were estimated at 4 kg N, 0.64 kg P
and 4.8 kg K ha−1 year−1. The highest losses were from burning (OUT 4c), i.e. 47.8 kg N, 1.8 kg P and 14.3 kg K ha−1 year−1. Partial budgets of environmentally controlled flows were negative only for N −4.8 kg N, +2.4 kg P and +9.6 kg K ha−1 year−1. The overall farm budgets were negative, with annual losses of 69 kg N, 3 kg P and 21 kg K ha−1. Only cocoa had a positive nutrient balance: +9.3 kg N, +1.4 kg P and +7.6 kg K ha−1 year−1. Nutrients reaching the household waste (1.9 kg N, 2.8 kg P and 18.8 kg K ha−1 year−1), animal manure (4.9 kg N, 0.4 kg P and 1.6 kg K), and human faeces (4 kg N, 0.64 kg P and 4.8 kg K ha−1 year−1) were not recycled. Five alternative management scenarios were envisaged to improve the nutrient balances. Recycling animal
manure, household waste and human faeces will bring the balance at −62.6 kg N, 0 kg P and +1 kg K ha−1 year−1. If, additionally, burning could be avoided, positive nutrient balances could be expected. 相似文献
19.
Horizontal nutrient flows and balances in irrigated urban gardens of Khartoum, Sudan 总被引:1,自引:1,他引:0
Sahar Babiker Abdalla Martina Predotova Jens Gebauer Andreas Buerkert 《Nutrient Cycling in Agroecosystems》2012,92(2):119-132
The role of urban agriculture (UA) for the supply of fresh vegetables, fruits and meat for local markets is well known. The
periodically flooded Gerif soils on the River Nile banks in the core of Khartoum city harbour vegetable gardens that supply perishable leafy vegetables
with a short life cycle. In an effort to assess their sustainability and possible negative environmental impact we used a
horizontal balance approach to determine the nutrient use efficiency of four intensively cropped UA gardens. Two of the gardens
were located in downstream lowlands (L1 and L2) and the other two belonged to the upstream highlands (H1 and H2). The river
sediments contributed on average 873 kg nitrogen (N), 6.5 kg phosphorus (P), 6.8 kg potassium (K) and 8,317 kg carbon (C)
per hectare in lowland gardens, while only 289, 1.6, 2.5 and 1,938 kg N, P, K and C ha−1 reached the highlands. The farmers’ management in all four gardens resulted in horizontal N and C surpluses of 75–342 kg N ha−1 year−1 and 798–6,412 kg C ha−1 year−1, in contrast to P and K for which negative balances up to −45 kg P ha−1 year−1 and −583 kg K ha−1 year−1 were recorded. While the River Nile floods as important N and C source contribute significantly to soil fertility maintenance,
the negative P and K balances call for a better integration of UA gardening with livestock husbandry and the regular addition
of animal manure in these cropping systems. 相似文献
20.
M. S. Maskina Bijay-Singh Yadvinder-Singh H. S. Baddesha O. P. Meelu 《Nutrient Cycling in Agroecosystems》1988,17(2):153-164
Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha–1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha–1 as urea could increase the grain yield of rice equivalent to 120 kg N ha–1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha–1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha–1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils. 相似文献