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1.
Multiple benefits of manure: The key to maintenance of soil fertility and restoration of depleted sandy soils on African smallholder farms 总被引:1,自引:0,他引:1
Shamie Zingore Robert J. Delve Justice Nyamangara Ken E. Giller 《Nutrient Cycling in Agroecosystems》2008,80(3):267-282
Manure is a key nutrient resource on smallholder farms in the tropics, especially on poorly buffered sandy soils, due to its
multiple benefits for soil fertility. Farmers preferentially apply manure to fields closest to homesteads (homefields), which
are more fertile than fields further away (outfields). A three-year experiment was established on homefields and outfields
on sandy and clayey soils to assess the effects of mineral nitrogen (N) fertilizer application in combination with manure
or mineral phosphorus (P) on maize yields and soil chemical properties. Significant maize responses to application of N and
manure were observed on all fields except the depleted sandy outfield. Large amounts of manure (17 t ha−1 year−1) were required to significantly increase soil organic carbon (SOC), pH, available P, and base saturation, and restore productivity
of the depleted sandy outfield. Sole N as ammonium nitrate (100 kg N ha−1) or in combination with single superphosphate led to acidification of the sandy soils, with a decrease of up to 0.8 pH units
after three seasons. In a greenhouse experiment, N and calcium (Ca) were identified as deficient in the sandy homefield, while
N, P, Ca, and zinc (Zn) were deficient or low on the sandy outfield. The deficiencies of Ca and Zn were alleviated by the
addition of manure. This study highlights the essential role of manure in sustaining and replenishing soil fertility on smallholder
farms through its multiple effects, although it should be used in combination with N mineral fertilizers due to its low capacity
to supply N. 相似文献
2.
Different fields within a farm have been observed to have different soil fertility status and this may affect the response
of a maize crop to applied N, P, and K fertiliser. A limiting nutrient trial was carried out at six farms each, in three districts
of Western Kenya. In each of the farms, the following treatments were laid out in three fields with different soil fertility
status at different distances from the homestead (close, mid-distance, remote fields): no inputs, application of NPK, NP,
NK, or PK fertiliser (urea, triple super phosphate, KCl) to maize. Total soil N decreased at all sites with distance to the
homestead (from 1.30 to 1.06 g kg−1), as did Olsen-P (from 10.5 to 2.3 mg kg−1). Grain yields in the no-input control plots reflected this decrease in soil fertility status with distance to the homestead
(from 2.59 to 1.59 t ha−1). In the NPK treatments, however, this difference between field types disappeared (from 3.43 to 3.98 t ha−1), indicating that N and P are the major limiting nutrients in the target areas. Response to applied N was related to the
soil total N content in Aludeka and Shinyalu, but not in Emuhaia, probably related to the high use of partially decomposed
organic inputs with limited N availability. Consequently, response to applied N decreased with distance to the homestead in
Aludeka (from 0.95 kg kg−1 relative yield to 0.55 kg kg−1) and Shinyalu (from 0.76 kg kg−1 to 0.47 kg kg−1), but not in Emuhaia (from 0.75 kg kg−1 to 0.68 kg kg−1). Response to applied P was related to the soil Olsen-P content at all sites. While for farms with a relatively high Olsen-P
gradient, response to applied P decreased with distance to the homestead (from 0.99 kg kg−1 to 0.68 kg kg−1), large variability in Olsen-P gradients across field types among farms within a specific site often masked clear differences
in response to P between field types for a specific site. Clear scope for field-specific fertiliser recommendations exists,
provided these are based on local soil knowledge and diagnosis. Scenario analysis, using farm-scale modelling tools, could
assist in determining optimum allocation strategies of scarcely available fertiliser for maximum fertiliser use efficiency. 相似文献
3.
Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies 总被引:4,自引:0,他引:4
Xiaobin Wang Dianxiong Cai Willem B. Hoogmoed Udo D. Perdok Oene Oenema 《Nutrient Cycling in Agroecosystems》2007,79(1):1-16
The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and
nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented
here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus
(P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects
on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland
Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12
treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use
efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS).
There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations
in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha−1 to 10,000 kg ha−1 and treatment mean yields from 4,500 kg ha−1 to 7,000 kg ha−1. Balanced combination of stover (3,000–6,000 kg), manure (1,500–6,000 kg) and N fertilizer (105 kg) gave the highest yield.
Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery
efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced
combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure
in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications
of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N
use efficiency. 相似文献
4.
Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: II nutrient balances and soil fertility 总被引:1,自引:0,他引:1
Xiaobin Wang Willem B. Hoogmoed Dianxiong Cai Udo D. Perdok Oene Oenema 《Nutrient Cycling in Agroecosystems》2007,79(1):17-34
A long-term experiment was carried out in the dryland of northern China to assess the effects of applications of maize stover,
cattle manure and NP (1:0.44) fertilizer on partial nitrogen (N), phosphorus (P) and potassium (K) balances, extractable soil
N (SEN), P and K, and soil organic matter (SOM) in a spring maize cropping system, under reduced tillage conditions. The experiment
was set-up according to an incomplete, optimal design, with three factors at five levels and 12 treatments, including a control
with two replications. Statistical analyses using multiple regression models showed that the partial N, P and K balances were
strongly influenced by annual variations in the amounts of soil water at seeding (SWS) and growing season rainfall (GSR).
Most treatments had positive P but negative N and K balances. Cumulative P and K balances were reflected in extractable soil
P (P-Olsen) and K (exchangeable K), but the weak relationships indicated that the sorption of P and buffering of K were strong.
Cumulative balances of effective organic carbon (C) were weakly related to soil organic C (SOC) content after 12 years. Negative
C balances were related to decreases in SOC, but positive C balances were not translated into increases in SOC. The analysis
of nutrient balances and soil fertility indices revealed that nutrient inputs in most treatments were far from balanced. It
is concluded that the concepts of ‘ideal soil fertility level’ and ‘response nutrient management’ provide practical guidelines
for improving nutrient management under the variable rainfall conditions of dry land areas in northern China. 相似文献
5.
A. C. Franke G. Laberge B. D. Oyewole S. Schulz 《Nutrient Cycling in Agroecosystems》2008,82(2):117-135
Legume–maize rotation and maize nitrogen (N)-response trials were carried out simultaneously from 1998 to 2004 in two distinct
agro-ecological environments of West Africa: the humid derived savannah (Ibadan) and the drier northern Guinea savannah (Zaria).
In the N-response trial, maize was grown annually receiving urea N at 0, 30, 60, 90 and 120 kg N ha−1. In Ibadan, maize production increased with N fertilization, but mean annual grain yield declined over the course of the
trial. In Zaria, no response to N treatments was observed initially, and an increase in the phosphorus (P) and sulphur (S)
fertilizer application rate was required to increase yield across treatments and obtain a response to N applications, stressing
the importance of non-N fertilizers in the savannah. In the rotation trial, a 2-year natural fallow–maize rotation was compared
with maize rotated with different legume types: green manure, forage, dual-purpose, and grain legumes. The cultivation of
some legume types resulted in a greater annual maize production relative to the fallow–maize combination and corresponding
treatments in the N-response trial, while there was no gain in maize yield with other legume types. Large differences in the
residual effects from legumes and fallow were also observed between sites, indicting a need for site-specific land management
recommendations. In Ibadan, cultivation of maize after the forage legume (Stylosanthes guianensis) achieved the highest yield. The natural fallow–maize rotation had improved soil characteristics (Bray-I P, exchangeable
potassium, calcium and magnesium) at the end of the trial relative to legume–maize rotations, and natural fallow resulted
in higher maize yields than the green manure legume (Pueraria phaseoloides). In Zaria, maize following dual-purpose soybean achieved the highest mean yield. At both sites, variation in aboveground
N and P dynamics of the legume and fallow vegetation could only partly explain the different residual effects on maize. 相似文献
6.
B. Fofana M. C. S. Wopereis A. Bationo H. Breman A. Mando 《Nutrient Cycling in Agroecosystems》2008,81(1):25-36
Field experiments were designed to investigate the effectiveness of integrated soil fertility management (ISFM), comparing
fertilizer use efficiency and its impact on millet, cultivated close to the homestead (“infields”) and away from the homestead
(“outfields”). Millet yields and response to N (0, 30, and 60 kg ha−1) and P (0, 15, and 30 kg ha−1) were determined on nine infields and nine outfields over a period of 3 years (from 1999 to 2001) in the southern Sahel of
Niger. Rainfall was 650, 470, and 370 mm during the three successive years, interaction between decreasing rainfall and millet
yield performance was also analyzed. While soil organic carbon (1.5 g kg−1 on outfields and 1.6 g kg−1 on infields) and pH-H2O (4.8 on outfields and 5.1 on infields) were comparable, total-N, plant available P (measured as P-Olsen and P-Bray), and
exchangeable Ca, K, and Mg levels were higher on infields as compared to outfields. Without fertilizer, average grain yield
(GY) and stover yield obtained on infields were three times as high as on outfields. GY across years and fertilizer treatments
was higher on infields as compared to outfields (P < 0.001). Average yield was 800 kg ha−1 on outfields and 1,360 kg ha−1 on infields (P < 0.001). On outfields, average GY was stagnant over the 3-year experimental period. Despite declining rainfall, millet GY
across all treatments gradually increased over time on infields (P < 0.001). P fertilization alone resulted on both field types to steadily and substantial yield increases while yield response
to N fertilization was only obvious when fertilizer P was applied. With no fertilizer applied, N uptake on infields (19 kg N ha−1) was more than twice as high as on outfields (7 kg ha−1), and P uptake was four times higher on infields (3 kg ha−1) than on outfields (0.8 kg ha−1). Indigenous soil N supply was on average 24 kg N ha−1 on outfields and 46 kg N ha−1 on infields. Average value for indigenous soil P supply was 4 kg P ha−1 on infields and 2 kg ha−1 on outfields. Apparent recovery of fertilizer N applied varied considerably among treatments and ranged from 17 to 23% on
outfields and 34 to 37% on infields (P < 0.001). Average apparent recovery of fertilizer P applied was significantly higher (P < 0.001) on infields (31%) than on outfields (18%) over the 3-year growing period, illustrating ISFM-induced positive effect
on millet nutrient N and P use. Results indicate higher inherent soil fertility, underline ISFM-induced drought tolerance
of soils on infields as compared to outfields, and highlight the crucial role of fertilizer P (especially on outfields) for
millet production. These call for site-specific nutrient management and support, even under low rainfall conditions, the potential
value of fertile infields for efficient and productive external input use and sustainable millet production in West African
Sahel. 相似文献
7.
Tef [Eragrostis tef (Zucc.) Trotte] is a major staple crop in Ethiopia and a large proportion of the imported fertiliser is being applied to tef fields. However, since the 1980s the yield on farmers fields has stagnated. Response of the crop to applied fertiliser is influenced by several factors. We aimed to study the fertiliser N use efficiency (FNUE) of four tef varieties from ammonium sulphate and urea on different soil types with the help of the 15N isotopic dilution technique. Three experiments were conducted under greenhouse and field conditions. On a typic Eutrocrept soil, higher percent N derived from fertiliser (% Ndff) and % FNUE were obtained for all the tested tef varieties when the N source was urea, while percent N derived from soil (% Ndfs) was higher for ammonium sulphate. The mean % FNUE for urea and ammonium sulphate was 49 and 34%, respectively. When the varieties were grown on a Nitosol or a Vertisol and ammonium sulphate was applied, the % Ndff, the total and fertiliser N yield and % FNUE of the tef varieties were higher on a eutric Nitosol compared to the Vertisol. The mean % FNUE was 61.3 for the Nitosol and 27.8 for the Vertisol. In an on farm experiment, relatively higher FNUE (33.3%) was obtained on an Andosol compared to Vertisols (17 and 27%). The tested varieties showed no difference in FNUE. As tef is the most important crop grown on Vertisols in Ethiopia, the low FNUE has a direct negative implication for the livelihood of the farmers and the environment. 相似文献