MAPPING THE SPATIAL VARIABILITY OF SOIL ACIDITY AND EVALUATION OF PHYSICO-CHEMICAL SOIL PROPERTIES:- IN CASE OF DEWOSHE SUB-WATERSHED, GUMMER DISTRICT, GURAGE ZONE , ETHIOPI

Abstract

Mapping the spatial variability of soil acidity and evaluation of physico-chemical soil properties on the study area is important to design appropriate soil fertility management practices. Mapping the spatial variability is a key operation as it provides knowledge about soil acidity and how it can be used sustainably. The study was conducted at the Dewoshe sub-watershed Gummer district, Guraghe Zone, SNNPR, Ethiopia. Twenty-eight soil samples were collected from two crop types with seven replication at two soil depths (0–20 and 20–40 cm), respectively. The evaluation of physico-chemical soil properties were analyzed using the ANOVA GLM procedure of SAS software, and mapping the spatial variability of soil acidity were analyzed using Arc GIS 10.4. Furthermore, the study has investigated that various physico-chemical soil properties were profoundly influenced due to crop types and soil depths. Soil BD, total porosity, and exchangeable acidity, TN, OM, and C: N, available P, exchangeable Mg, CEC, and exchangeable acidity were significantly af ected due to Enset and cereal crops, soil depths, and their interaction between crop types and soil depths. In contrast, sand, silt, and clay fraction and change of pH exhibited no statistically significant variation within the crop and their interaction between crop types and soil depths. But there was a variation of sand and clay on soil depths. Exchangeable (K, Na, and H) were only varied in crop types. The change of pH, exchangeable Al, and Ca were varied within crop types, soil depths, and their interaction between crop types and soil depths and only within crop types and soil depths, respectively. The highest and the lowest values of some physico-chemical soil properties of sand, clay, BD, total porosity, pH-H2O, pH-KC, OM, TN, available P, and CEC were (38.9, 34.4 ), (23.07, 19.4), (1.35, 1.07), (59.7, 49), (6.27, 4.84), (5.67, 4.1), (4.58, 0.79), (0.26, 0.07), and (28.6, 15.6) within cop types, and soil depths respectively. Cereal crop fields as compared to the Enset crop fields were suf ered from soil degradation and decline in soil fertility on the spatial points of beginning at strong to steep slope mapping parts with the same soil depths. But both in the study area, in general, pointed out that these changes are not in favour of the ecosystem and caused deterioration in the quality of soil resources which in turn led to a decline in agricultural crop productivity. This calls for urgent measures to be taken that encompass a mix of technological and policy options. Further research and development interventions into the dynamics and impact of crop land-use change on ecosystems and their components at various scales (from small sub-watersheds to region and country) are required if conservation and agricultural development goals for this sub-watershed in particular and the country in general, are to be met on a sustainable basis. And again, mapping the spatial variability of soil acidic problems by OK is needed to clearly show the specific locations of the study areas, where attention is required with respect to sustainable management of crop nutrients.