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首页> 外文期刊>Agriculture, Ecosystems & Environment: An International Journal for Scientific Research on the Relationship of Agriculture and Food Production to the Biosphere >Assessment of soil nutrient depletion and its spatial variability on smallholders' mixed farming systems in Ethiopia using partial versus full nutrient balances.
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Assessment of soil nutrient depletion and its spatial variability on smallholders' mixed farming systems in Ethiopia using partial versus full nutrient balances.

机译：利用部分养分平衡与全部养分平衡评估埃塞俄比亚小农户混合农作系统的土壤养分消耗及其空间变异性。

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摘要

Soil fertility depletion in smallholder farms is one of the fundamental biophysical causes for declining per capita food production in Ethiopia. In the present study, we assess soil nutrient depletion and its spatial variability for Ethiopia and its regional states, using nutrient balances as a tool. Data on crop production, fertilizer use and land management practices were collected from the Agricultural sample survey, which was carried out by the Central Statistics Authority (CSA) for the production year 1999/2000. We used a Geographic Information System (GIS) to process, and analyze spatially referenced information like soil properties, precipitation and land use types. We calculated nutrient balances for N, P and K from five nutrient fluxes entering and five nutrient fluxes leaving cultivated lands of smallholders. Some of the fluxes (e.g. leaching, denitrification and wet deposition) were estimated using transfer functions. Erosion was estimated by universal soil loss equation (USLE) and landscape process modelling at multi-dimensions and scales (LAPSUS). At the national level, full nutrient balance results indicate a depletion rate of 122 kg N ha-1 yr-1, 13 kg P ha-1 yr-1 and 82 kg K ha-1 yr-1. Soil nutrient stocks in all regional states were decreasing with the exception of areas under permanent and vegetable crops. In the analysis, soil erosion was the major cause for nutrients depletion, but this flux shows significant variability between different estimates and was highly uncertain. We calculated that the contribution of erosion to N losses was 70%, while its contribution to P and K losses were 80% and 63%, respectively. Nutrient losses under permanent and vegetable cropping were caused mainly by residues removal, harvested products and leaching, while losses under cereals and other annuals were dominated by erosion.
机译：小农农场的土壤肥力枯竭是埃塞俄比亚人均粮食产量下降的根本生物物理原因之一。在本研究中，我们使用养分平衡作为一种工具评估埃塞俄比亚及其区域州的土壤养分消耗及其空间变异性。中央统计局（CSA）在1999/2000年生产年度从农业样本调查中收集了有关作物生产，肥料使用和土地管理做法的数据。我们使用了地理信息系统（GIS）来处理和分析空间参考信息，例如土壤特性，降水和土地利用类型。我们从进入小农户耕地的五种养分通量和五种养分通量得出了氮，磷和钾的养分平衡。使用传递函数估算了某些通量（例如，浸出，反硝化和湿沉降）。侵蚀是通过通用土壤流失方程（USLE）和景观过程建模的多维和规模（LAPSUS）估算的。在国家一级，完全的养分平衡结果表明，枯竭速率为122 kg N ha-1 yr-1、13 kg P ha-1 yr-1和82 kg K ha-1 yr-1。除永久性作物和蔬菜作物外，所有区域州的土壤养分储量都在减少。在分析中，土壤侵蚀是造成养分消耗的主要原因，但是这种通量显示出不同估计之间的显着差异，并且高度不确定。我们计算出侵蚀对氮损失的贡献为70％，而对磷和钾损失的贡献分别为80％和63％。永久性和蔬菜作物的养分流失主要是由于去除残留物，收获的产品和浸出造成的，而谷物和其他年度作物的养分流失主要是侵蚀。

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