Agricultural impact on environment and counter measures in Rwanda

摘要

Rapid intensive agriculture often generates serious environmental concerns including soil erosion, water pollution and greenhouses gases. This paper assesses the impact of agriculture and its practices on environment in Rwanda from 1990 to 2012. Data provided by the World Bank were analyzed with Origin Pro 9 for statistical analysis. Also, a review on physical-chemical parameters and heavy metals of water resources home to or surrounded by cultivated mountains was adopted in this study. The results showed that agricultural records decreased from 1990 to 1994. However, after then, the short season cropland like cereals increased from 7.04 to 17.45%; roots and tubers increased from 13.17 to 21.69% in 1995 and 2012, respectively, whilst permanent cropland remained constant at 10.13%. As Rwandan soil is almost steep slope, this heavily exposes the soil to erosion, fertility loss and landslides as permanent crops to enhance fertility and erosion control are decreasing. Also, fertilizers increased from 2,149 to 27,748 tons, irrigation spaced from 4,000 to 10,000 ha which can be the reasons of rise of agricultural emissions. The reviewed studies estimated high concentration of the total nitrogen, total suspended solids, manganese, lead and iron exceeding the standards of the European Union and World Health Organization. From the above findings, it is suggested to regularly monitor water quality and promote its purification measures, to fertilize and irrigate timely and appropriately, expand areas under agroforestry and permanent crops, promote bench terraces practices for durable soil erosion control and water quality in Rwanda.