ABSTRACT

Conversion of native pasturelands to cultivated land led to a decline in soil fertility resulting in low agricultural productivity. This study attempted to investigate the magnitude and rate of pastureland to cultivated land conversion and the associated impact on selected soil properties. The study was conducted in three villages of Ofla district, northern Ethiopia. Land-use conversion that happened between 1973 and 2015 was investigated using satellite images supplemented by field observation and key informant interview. Cultivated lands with different history of cultivation period (2, 10, 20, 30 and 42 years) since conversion were identified. A total of 54 soil samples were collected from cultivated and pasture lands for soil physico-chemical analysis. Results showed that pastureland conversion to cultivated land increased at a medium rate of 17 ha year⁻¹ and by 46% over the last 42 years. Over the same period, soil organic carbon, total nitrogen, available phosphorous, available potassium and electrical conductivity declined by 65%, 59%, 57%, 70% and 74%, respectively. The continued steady decline in soil quality with increasing period of cultivation shows that the current management practices are not sustainable and calls for urgent solution to reverse the negative scenario.

摘要

原生牧场转为耕地导致土壤肥力下降，导致农业生产力低下。本研究试图调查牧场向耕地转化的规模和速率以及对选定土壤特性的相关影响。该研究在埃塞俄比亚北部奥弗拉区的三个村庄进行。1973 年至 2015 年间发生的土地利用转变采用卫星图像进行调查，并辅以实地观察和关键知情人访谈。确定了自转换以来具有不同耕作历史（2、10、20、30 和 42 年）的耕地。从耕地和牧场共采集土壤样品54份，进行土壤理化分析。^-1，在过去 42 年中增长了 46%。同期，土壤有机碳、全氮、速效磷、速效钾和电导率分别下降了65%、59%、57%、70%和74%。随着耕作时间的延长，土壤质量持续稳步下降，这表明目前的管理做法是不可持续的，需要紧急解决方案来扭转负面情况。