Examining the effects and safeties of urban trash input for combatingdesertification in Sahel, West Africa

在开发西非萨赫勒地区的土地恢复方法时，豪萨人将垃圾撒在土壤上以提高土壤生产力的耕作方法带来了希望。当田地退化时，豪萨人将牲畜粪便以及家庭垃圾，有时是城市垃圾撒在他们的土地上。有机质能改善土壤质量。笔者在三年多的时间里，利用不同数量的城市垃圾进行了实地试验，量化了垃圾抛撒的土壤改良效果，同时也增加了土壤中白蚁的活性。根据植物生长观察，城市垃圾的临界量至少为20kg/m2，地面厚度约为2cm。结果表明，豪萨人的做法能够使草地再生，防止土壤侵蚀和沉积层暴露。经过两年的垃圾输入，植物生长开始恶化。为了维持利用城市垃圾恢复的植物生产力，需要持续的垃圾输入来补偿植物移除和侵蚀造成的营养消耗。

In developing land rehabilitation methods in Sahel of West Africa, the Hausa farming practice of scattering refuse over the soil for improving soil productivity holds promise. When the fields become degraded, the Hausa scatter livestock manure as well as household refuse and sometimes urban refuse over their land. The organic matter improves the soil quality. The author carried out an in situ experiment, using multiple plots scattered with varying amounts of urban refuse over three years, to quantify the soil improvement effect of the refuse scattering practice, which increased termite activity in the soil as well. According to the plant growth observation, the critical amount of urban refuse was at least 20kg/m2, approximately 2 cm thick on the ground. The results revealed that the Hausa practice was able to regenerate grassland and to prevent soil erosion and exposure of the sedimentary layer. After two years from refuse input, the plant growth began to deteriorate. In order to maintain plant productivity recovered using urban refuse, it is necessary for continuous input of refuse to compensate for nutrition depletion from the plant remove and erosion.