Nutrient Balance in Small Catchments of the Upland Areas of the Gumara River, Northwestern Ethiopia

Abstract Nutrient balance analysis provides essential information concerning the current nutrient status of the soils and used to take appropriate nutrient replenishment practices. Nutrient flows were analyzed in Enqulal watershed of Dera district, Northwestern Ethiopia in the cropping season of 2018. Direct measurement and empirical formulas were used to identifying and measuring major inputs and outputs of NPK from different land uses within the catchments. Four nutrient inputs (Mineral fertilizer, Organic fertilizer, Atmospheric deposition and Nitrogen fixation) and five nutrient outputs (Crop yield, Crop residue, Gaseous lose, Leaching and Soil erosion) leaving the catchment were directly measured to calculate the partial and full nutrient balances. The results indicated that with the exception of phosphorus, teff cropland had negative partial N and K balances. The results also showed that the partial nutrient balances in wheat cropland were observed positive only for nitrogen. The full nutrient balances for the major cropland (wheat and teff) were found to be -20.9 kg , -0.7 kg , -37.87 kg ha-1 yr-1 and -61.4 kg ,+11 kg, and -26.7 kg ha-1 yr-1of N, P and K respectively. Generally, negative N and K full balances were found in this study for all land use/land cover. Therefore, the negative nutrient balances observed in cultivated land and other land uses indicated nutrient depletion which leads to land degradation and reduced agricultural productivity. Finally, analysis of the overall finding on nutrient balance implies that there is a need to enhance nutrient management in order to improve productivity and agricultural sustainability.