The role of grasses used to rehabilitate degraded land on soil properties: the case of kersa district, southwest Ethiopia

Abstract

Land degradation is one of the main problems in Sub-Saharan Africa, threatening the lives of millions of people. It is becoming a major ecological and agricultural problem in Ethiopia. Grasses play vital role to tackle problem of land degradation by giving effective surface cover and increasing slope stability. Considering their effectiveness to control erosion in-situ and siltation of dam’s ex-situ, grass plantation were used as strategy to rehabilitate degraded lands in Bulbul Kebele at Kersa Woreda, Southwest Ethiopia since July 2011 and their suitability and effectiveness was studied. But, the influence of such grass plantation on the physico-chemical properties of the soil was not quantified. Therefore, this study was undertaken to evaluate the potential of vetiver grass, elephant grass and mission grass species on selected soil physico-chemical properties. The experimental design was a split plot design with compost application as main plot and grass treatment as a sub-plot factor with three replications.. Soil samples were collected at the depth of (0-40cm) from plots planted with grass without composted manure, with composted manure and adjacent degraded land without any plantations. The results revealed that the average value of moisture content (MC), total porosity(TP), Soil pH, electrical conductivity (EC), organic matter (OM), total nitrogen (TN), available phosphorus (Av.P), cation exchange capacity (CEC) and exchangeable base recorded under all three grass species without composted manure were higher than that of the average value of degraded land. Similarly, the average value of MC,TP,pH, EC, OM, TN, Av.P, CEC and exchangeable base recorded under grass species treated with composted manure were higher than the average mean value of grass species without composted manure. The highest average mean values of exchangeable Ca2+ (7.17cmol (+)/kg), exchangeable Mg2+ (2.76 cmol (+)/kg) and CEC (17.40 cmol (+)/kg) were observed under the elephant grass grass as compared to the lowest values 5.91, 2.45 and 14.35 cmol (+/kg), respectively, under vetiver grass species without composted manure respectively. In general, degraded land rehabilitation by grass species resulted in significant contribution to improve soil physico chemical properties in the study area. Therefore, degraded land rehabilitation program have to consider grasses as a pioneer species to improve the soil physico-chemical properties.

Land degradation is one of the main problems in Sub-Saharan Africa, threatening the lives of millions of people. It is becoming a major ecological and agricultural problem in Ethiopia. Grasses play vital role to tackle problem of land degradation by giving effective surface cover and increasing slope stability. Considering their effectiveness to control erosion in-situ and siltation of dam’s ex-situ, grass plantation were used as strategy to rehabilitate degraded lands in Bulbul Kebele at Kersa Woreda, Southwest Ethiopia since July 2011 and their suitability and effectiveness was studied. But, the influence of such grass plantation on the physico-chemical properties of the soil was not quantified. Therefore, this study was undertaken to evaluate the potential of vetiver grass, elephant grass and mission grass species on selected soil physico-chemical properties. The experimental design was a split plot design with compost application as main plot and grass treatment as a sub-plot factor with three replications.. Soil samples were collected at the depth of (0-40cm) from plots planted with grass without composted manure, with composted manure and adjacent degraded land without any plantations. The results revealed that the average value of moisture content (MC), total porosity(TP), Soil pH, electrical conductivity (EC), organic matter (OM), total nitrogen (TN), available phosphorus (Av.P), cation exchange capacity (CEC) and exchangeable base recorded under all three grass species without composted manure were higher than that of the average value of degraded land. Similarly, the average value of MC,TP,pH, EC, OM, TN, Av.P, CEC and exchangeable base recorded under grass species treated with composted manure were higher than the average mean value of grass species without composted manure. The highest average mean values of exchangeable Ca2+ (7.17cmol (+)/kg), exchangeable Mg2+ (2.76 cmol (+)/kg) and CEC (17.40 cmol (+)/kg) were observed under the elephant grass grass as compared to the lowest values 5.91, 2.45 and 14.35 cmol (+/kg), respectively, under vetiver grass species without composted manure respectively. In general, degraded land rehabilitation by grass species resulted in significant contribution to improve soil physico chemical properties in the study area. Therefore, degraded land rehabilitation program have to consider grasses as a pioneer species to improve the soil physico-chemical properties