Tillage and crop management impacts on soil loss and crop yields in northwestern Ethiopia
Fekremariam Asargew Mihretie, Atsushi Tsunekawa, Nigussie Haregeweyn, Enyew Adgo, Mitsuru Tsubo, Kindiye Ebabu, Tsugiyuki Masunaga, Birhanu Kebede, Derege Tsegaye Meshesha, Wataru Tsuji, Muluken Bayable, Mulatu Liyew Berihun
Abstract
Lack of appropriate agronomic practices is one of the major causes for soil erosion and low yields in teff (Eragrostis tef [Zucc.]) production in Ethiopia. A 3-yr study was conducted at the Aba Gerima watershed in northwestern Ethiopia, to investigate the effects of two tillage practices (reduced tillage [RT] and conventional tillage [CT]), two planting methods (row planting [RP] and broadcast planting [BP]), and two compaction options (with [+T] and without [–T] trampling) on soil loss and teff yields in a split-split plot arrangement. Sediment concentration ranged from 0.01 to 5.37 g L−1 (mean, 0.25 g L−1) in our study. Accordingly, the estimated total (August–October) soil loss ranged from 0.2 to 0.5 t ha–1 (mean, 0.3 t ha–1). The sediment concentration and total soil loss were significantly influenced (P < 0.05) by tillage, planting methods, and trampling only in the third monitoring year. RT reduced soil loss by 19% relative to that of CT, whereas RP resulted in a 13% reduction in soil loss over BP. The −T plots showed a 15% reduction in soil loss as compared to + T plots. Results revealed significant increase in soil total carbon and nitrogen in RT and –T. Less soil loss and greater teff grain yield were obtained in plots with improved agronomic practices (RT and RP) compared to conventional ones (CT and BP). Based on our findings we conclude that the use of RT, RP, and –T practices can effectively minimize soil loss without any crop yield penalty.