Soil Fertility Replenishment in Africa: An Investment in Natural Resource Capital
Soil Fertility Replenishment in Africa: An Investment in Natural Resource Capital
复制标题
非洲土壤肥力补充：自然资源资本投资
DOI：
10.2136/sssaspecpub51.c1
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
P. Woomer
中科院分区：
文献类型：
--
作者：
P. Sánchez;K. Shepherd;M. Soule;F. Place;R. Buresh;A. Izac;A. Mokwunye;F. Kwesiga;C. Ndiritu;P. Woomer
小农农场土壤肥力耗竭是非洲人均粮食产量下降的根本生物物理根源，土壤肥力补充应被视为对自然资源资本的投资。在过去30年中，37个非洲国家约2亿公顷耕地平均损失了660 kg N ha-1、75 kg P ha-1和450 kg K ha-1。其后果在农场、流域、国家和全球各级都能感受到。经济学中的资本存量和服务流概念与土壤学中的养分库和养分通量概念之间存在着完全一致的关系。磷素补充策略主要是以肥料为主，辅以生物补充，而氮素补充策略主要是以生物为主，辅以化学补充。非洲有丰富的磷酸盐岩矿床，可以直接使用或作为过磷酸盐来逆转磷的枯竭。分解有机输入产生有助于溶解磷酸盐岩的有机酸。农林业树木和草本豆科绿色肥料在氮素捕获和内部循环中发挥着重要作用。需要土壤保持等配套技术，以使资本结构调整能够运作。需要改进政策，以便以合理的成本和在适当的时间提供适当的肥料;改善基础设施;获得小额信贷;及时进入市场;适应性研究和推广教育。在三个对比鲜明的案例研究中发现，土壤肥力补充在农场一级是有利可图的，但资源贫乏的农民缺乏资本和获得信贷的机会，无法进行初始投资。由谁来为这种资本调整买单的问题所依据的原则是，从一系列行动中受益的人应当承担实施这些行动的费用。将总结非洲各地土壤肥力倡议迄今取得的进展。
Soil fertility depletion in smallholder farms is the fundamental biophysical root cause for declining per-capita food production in Africa, and soil fertility replenishment should be considered as an investment in natural resource capital. An average of 660 kg N ha-1, 75kg P ha-1, and 450 kg K ha-1 has been lost during the last 30 years from about 200 million ha of cultivated land in 37 African countries. The consequences are felt at the farm, watershed, national, and global levels. There is an exact congruence between the concepts of capital stocks and service flows in economics and that of nutrient pools and fluxes in soil science. Phosphorus-replenishment strategies are mainly fertilizerbased with biological supplementation, while N replenishment strategies are mainly biological with chemical supplementation. Africa has ample phosphate rock deposits that could be used directly or as superphosphates to reverse P depletion. Decomposing organic inputs produce organic acids that help solubilize phosphate rocks. Agroforestry trees and herbaceous leguminous green manures play a major role in N capture and internal cycling. Accompanying technologies, such as soil conservation are needed to make recapitalization operational. Policy improvements are needed to provide the appropriate fertilizers at a reasonable cost and at the right time; better infrastructure; access to micro credit; timely access to markets; adaptive research and extension education. Soil fertility replenishment was found to be profitable at the farm level in three contrasting case studies, but resource poor farmers lack the capital and access to credit to make the initial investment. The issue of who should pay for this recapitalization is based on the principle that those who benefit from a course of action should incur the costs of its implementation. Progress to date on soil fertility initiatives throughout Africa will be summarized.