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首页> 外文会议>STI/PUB/1285; Consultants Meeting on Management Practices for Improving Sustainable Crop Production in Tropical Acid Soils; 19990501-03; Vienna(AT) >IMPROVING SUSTAINABLE INTENSIFICATION OF CEREAL-GRAIN LEGUME CROPPING SYSTEMS IN THE SAVANNAHS OF WEST AFRICA: QUANTIFYING RESIDUAL EFFECTS OF LEGUMES ON MAIZE, ENHANCING P MOBILIZATION BY LEGUMES AND STUDYING LONG-TERM SOIL ORGANIC MATTER (SOM) DYNAMICS
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IMPROVING SUSTAINABLE INTENSIFICATION OF CEREAL-GRAIN LEGUME CROPPING SYSTEMS IN THE SAVANNAHS OF WEST AFRICA: QUANTIFYING RESIDUAL EFFECTS OF LEGUMES ON MAIZE, ENHANCING P MOBILIZATION BY LEGUMES AND STUDYING LONG-TERM SOIL ORGANIC MATTER (SOM) DYNAMICS

机译：改善西部非洲大草原上谷物-谷物豆科作物系统的可持续强化：量化豆粕对玉米的残留效应，增强豆类对磷的迁移并研究长期土壤有机物（微生物）

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Improved cereal-grain-legume systems, allowing farmers to use their land productively on a continuous basis, are being rapidly developed and adopted by small-scale farmers in the West African Moist Savannah. This paper summarizes work on several issues related to the improvement of productivity and sustainability of these intensified systems. A first study looked at the sustainability of several legume-maize cropping systems in a 5-year field trial at Sekou, Benin. Fairly low maize yields were found in continuous maize cropping systems (maize/maize), poor response to N fertilizer beyond 45 kg N ha~(-1), and no evidence that P and K were limiting crop yield. Over the last 5 years of the trial, maize/Mucuna relay cropping gave consistently a 2000 kg ha"1 yield increase relative to maize/maize cropping, and most of this yield gain was preserved even when Mucuna residues were removed from the plots when planting the next year's maize crop. Some yield gain, although far less than with maize/Mucuna, was observed in the maize/pigeon pea system. The maize/cowpea system offered no maize yield gain over maize/maize cropping. In a second study, enhanced isotopic methods to determine the plant available P allowed us to test the hypothesis that certain legume accessions can mobilize sparingly-available P. In one out of the 3 West-African Moist Savanna soils studied, we found that cowpea could access sparingly soluble soil P that is unavailable to maize. This mobilization of P was only observed when P deficiency occurred. These results confirm the P efficiency of some legume genotypes, which may lead to benefits of improved P availability by the incorporation of legumes in rotation systems. A third study, involving a 16-year continuous-cropping field experiment in lbadan, Nigeria, provided information on long-term changes in soil organic matter carbon (SOC) contents in savannah soils with sandy top soil. In the control treatments with continuous maize and cowpea cropping without trees, SOC levels dropped from the initial 15.4 Mg C ha~(-1) to 7.3-8.0 Mg C ha~(-1) in 16 years (SOC content in 1700 Mg ha~(-1) equivalent soil mass). In the two continuously cropped alley cropping systems (Leucaena and Senna), the SOC levels dropped to levels between 10.7 andrn13.2 Mg C ha~(-1). The ~(13)C natural abundance technique yielded useful information to test the ROTHC-rn26.3 SOC model in sub-humid tropical conditions under a complex pattern of cropping systems.
机译：西非潮湿大草原的小规模农民正在迅速开发和采用改良的谷类-豆类系统，使农民能够持续有效地使用土地。本文总结了与提高精简系统的生产率和可持续性有关的几个问题的工作。在贝宁Sekou进行的为期5年的田间试验中，第一项研究考察了几种豆科玉米种植系统的可持续性。在连续玉米种植系统（玉米/玉米）中发现玉米单产相当低，超过45 kg N ha〜（-1）对氮肥的响应较差，没有证据表明磷和钾会限制作物单产。在试验的最后5年中，相对于玉米/玉米种植，玉米/ Mucuna中继种植始终使单产增加2000 kg ha-1，即使在种植时从地块上除去了Mucuna残留物，大部分产量仍得以保留第二年的研究显示，虽然玉米/鸽子豌豆系统的增产幅度远小于玉米/ M豆系统，但玉米/ co豆系统却没有提供玉米增产的优势。确定植物可用磷的增强同位素方法，使我们能够检验某些豆科植物种质可以动员少量利用的P的假设。在研究的3种西非湿性稀树草原土壤中，我们发现cow豆可以利用少量可溶性土壤P仅在磷缺乏时才观察到磷的这种动员，这些结果证实了某些豆类基因型的磷效率，这可能导致公司提高磷的利用率。旋转系统中豆类的配种。第三项研究涉及在尼日利亚的拉巴丹进行的为期16年的连续作物田间试验，该研究提供了沙质顶层沙质土壤中土壤有机质碳（SOC）含量长期变化的信息。在没有玉米的玉米和cow豆连作的对照处理中，SOC水平从16年的最初15.4 Mg C ha〜（-1）降至7.3-8.0 Mg C ha〜（-1）（SOC含量为1700 Mg ha 〜（-1）当量土壤质量）。在两个连续种植的胡同种植系统（Leucaena和Senna）中，SOC含量下降到10.7至13.2 Mg C ha〜（-1）之间。 〜（13）C自然丰度技术提供了有用的信息，可用于在复杂种植模式下的亚湿热带条件下测试ROTHC-rn26.3 SOC模型。

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