Short-term effects of tillage practices on soil properties under Tef [Eragrostis tef (Zucc. Trotter)] crop in northern Ethiopia

Abstract

Tef crop shares the largest area of production in Ethiopia. However, its productivity is lower than 0.7tonha−1 which is mainly related to low soil fertility and moisture. An experiment was conducted using tef on Chromic Cambisols for two rainy cropping seasons (2008–2009) in northern Ethiopia. The objective was to assess the short-term effects of tillage frequencies on selected soil properties under continuous tef cropping system. The layout of the experiment was randomized complete block design using three tillage treatments, namely, conventional plowing (T1), four times plowing (T2), and reduced plowing (T3). A statistically significant (P≤0.05) effect of tillage treatments on soil moisture (SM) was determined during the experimental periods. SM was higher in T2 in both years followed by T3 in 2009. Soil physical properties (bulk density, BD; total porosity, TP; soil structural stability index, SSI) and soil nutrients (total nitrogen, TN; organic carbon, OC; cation exchange capacity, CEC; potassium, K) were significantly deteriorated by the application of T1 for consecutive two-years. The Paired-Samples T-Test showed significant improvements in these soil parameters due to T2 and T3 in 2009 as compared to the corresponded values in 2008. For example, there were significant increments in SM (11%), TP (18%), SSI (12%), TN (1.2 times), phosphorous (5%), OC (13%), and CEC (15%); but significantly decreased in OC: TN (48%) and BD (4%). Generally, despite the non-significant differences between the effects of T2 and T3, higher TP, SSI, OC, CEC; and lower BD were observed by T3 in 2009. Based on such short-term results of T3 it is possible to forecast its significant long-term effects on soil properties. Thus, for sustainable use of soil systems in the long-term due attention should be given to practice T3 as soil and water management practice in the study area conditions.