Impact of land management on soil quality in Migina catchment at Kansi Sector, Gisagara District

Abstract

Rwandan economy and livelihood are depending on the agriculture. Environment/ natural resources which are currently under stress could negatively affect the agriculture production. In order to contribute to their protection and to have a sustainable agricultural production for food security and soil conservation, this research was carried out in order to determine the Impact of land management on soil quality. This study has been conducted at Akaboti cell, Kansi Sector, Gisagara District of the Southern Province, exactly as one part of Migina Catchment watershed, where there is different agricultural activities. Soil samples have been collected under six different selected land management practices including: Radical terrace, Forestry, Agroforestry, Trenches, Soil Amendment and control where there is no management of land. Three composite soil samples were taken on each land management practice by considering Upper, Middle and the Bottom part of the hill where each land management practice is located. The following physic-chemical soil tests were done in Laboratory: soil reaction (pH), Organic Carbon, Nitrogen, Phosphorus, Exchangeable Basis (Calcium, Sodium, Magnesium, Potassium,), exchangeable acidity, Soil texture, Moisture Content, Bulk Density, and Electrical Conductivity. The laboratory results show that the soil texture was dominated by a Sand Loam class, the soil bulk density varies 0.96 to 1.44 g/cm3in general, the soil porosity ranges from 50.2 to 52.08 % in terraced land; 47.2 to 58.16% in trenches; 53.8 to 63.87% in agroforestry; 53.08 to 53.8 % in forestry; 56.39 to 58.9 % in amended soil and 45.9 to 51.84% in the control (undisturbed land). The soil pH measured in water ranges from 4.73 to 5.14 for radical terraces land, from 5.79 to 5.29 for trenches; 6.29 to 5.79 for agroforestry land, 4.93 to 4.49 for forested land, 5.11to 6.34 for amended soil, 4.69 to 527 for control. The electrical conductivity is low in treatments ranging from 0.076 to 0.390%, The values of mineral Nitrogen measured in treatments were higher compared to control. Ammonium values range from 2.55 to 7.24 mg/Kg while Nitrate values range from 4.36 to 28 mg/kg. Available P values were high in treatments compared to control. The values of available P range from 8.55 to 17.10 ppm. The values of exchangeable bases were slightly high in treatments compared to control. Those values were generally low. Generally the agroforestry land showed high nutrients values compared to the control and other treatments. From the results of this study, it is clear that the land management practices have generally a positive impact on soil properties. Farmers are advised to adopt those practices especially agroforestry