Soil organic carbon dynamics, functions and management in West African agro-ecosystems
Soil organic carbon dynamics, functions and management in West African agro-ecosystems
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DOI：
10.1016/j.agsy.2005.08.011
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发表时间：
2007-04-01
影响因子：
6.6
通讯作者：
Kimetu, Joseph
中科院分区：
文献类型：
--
作者：
Bationo, Andre;Kihara, Job;Kimetu, Joseph
土壤肥力耗竭被认为是西非粮食安全的最重要制约因素。非洲一半以上的人口是农村人口，直接依赖当地种植的作物。此外，28%的人口长期处于饥饿状态，超过一半的人每天的生活费不到1美元，这是由于土壤肥力的描述。土壤有机碳既是养分的源又是养分的汇，在维持土壤肥力方面起着至关重要的作用。在西非农业生态系统的大部分地区（森林区除外），土壤有机碳含量本来就低，这是由于作物和自然植被的茎和根生长缓慢，土壤温度高和动物特别是白蚁活动导致有机物质周转速度快，以及土壤粘土含量低。以高岭石为主要粘粒类型的土壤，其阳离子交换量往往低于1cmol kg（-1），这在很大程度上取决于土壤有机碳。对于该地区的桑迪土壤，年平均损失可能高达4.7%，而对于桑迪壤土，损失较低，平均为2%。为了维持快速增长的人口的粮食生产，必须施用矿物肥料和有效回收作物残茬和粪肥等有机添加物，特别是在主要依靠含油有机残茬维持土壤肥力的小农耕作制度中。有必要在农场一级增加作物生物量，未来的研究应侧重于提高养分利用效率，以增加作物生物量。研究还应侧重于如何减轻社会经济制约因素，以增加种植系统中的豆类成分。这将为牲畜生产更高质量的饲料，并增加农场一级的生物量。本文综述了在改善西非土壤有机碳状况方面的各种策略和经验教训。(C)2006爱思唯尔有限公司版权所有。
Soil fertility depletion has been described as the single most important constraint to food security in West Africa. Over half of the African population is rural and directly dependent oil locally grown crops. Further, 28% of the Population is chronically hungry and over half of people are living oil less than US$ 1 per day as a result of soil fertility depiction. Soil organic carbon (SOC) is simultaneously a source and sink for nutrients and plays a vital role in soil fertility maintenance. In most parts of West Africa agro-ecosystems (except the forest zone), the soils are inherently low in SOC. The low SOC content is due to the low shoot and root growth of crops and natural vegetation, the rapid turnover rates of organic material as a result of high soil temperatures and fauna activity particularly termites and the low soil clay content. With kaolinite as the main clay type, the cation exchange capacity of the soils in this region, often less that 1 cmol kg(-1), depends heavily oil the SOC. There is a rapid decline of SOC levels with continuous cultivation. For the sandy soil in this region, average annual losses may be as high as 4.7% whereas with sandy loam soils, losses are lower, with an average of 2%. To maintain food production for a rapidly growing population, application of mineral fertilizers and the effective recycling of organic amendments such as crop residues and manures are essential especially in the smallholder farming systems that rely predominantly oil organic residues to maintain soil fertility. There is need to increase crop biomass at farm level and future research should focus on improvement of nutrient use efficiency in order to increase crop biomass. Research should also focus Oil ways of alleviating socio-economic constraints in order to increase the legume component in the cropping systems. This will produce higher quality fodder for the livestock and also increase biomass at farm-level. This paper reviews various strategies and lessons learnt in improving soil organic carbon status in West Africa soils. (C) 2006 Elsevier Ltd. All rights reserved.