Crop rotation and organic matter application restore soil health and productivity of degraded highland crop farms in northwest Ethiopia

Abstract

Potentials of pragmatic crop rotation practices and organic matter applications for restoration of soil health and productivity of degraded highland crop fields were studied for three rotation phases from 2013 to 2015 in northwest Ethiopia. Factorial combinations of five crop rotations (R1+ = bread wheat–clover–potato, R2+ = clover–bread wheat undersowing lupine–potato, R3+ = potato–clover–bread wheat, R4+ = bread wheat undersowing lupine–potato undersowing lupine–bread wheat, and R5+ = lupine–potato undersowing lupine–bread wheat) and four manure application rates [M1 = control/0tha−1 manure, M2 = 2.5 tha−1 sesbania green manure (SGM), M3 = 5 tha−1 fresh cattle manure (FCM), and M4 = 2.5 tha−1 SGM + 5 tha−1 FCM] were laid out in randomized complete block design (RCBD) with four replications. Plus sign (+) with crop rotation indicated that crop residues and green manure of legumes at 50% flowering were incorporated into the soil. The results showed that soil properties and productivity of crops were markedly improved with three-year interventions of crop rotation and manure application. As compared to that of the initial before starting the experiment, soil bulk density, pH, CEC, and contents of organic carbon, total nitrogen, available phosphorous, and exchangeable potassium were improved on average by about 23%, 18%, 67%, 89%, 150%, 89%, and 44%, respectively, with R1+M4 treatment combination in three-year period. Similarly, compared to that of 2013, productivity of bread wheat and potato increased on average by about 446% and 540% in 2015 with R3M4 and R1M4, respectively.

Keywords

• cattle manure
• crop residues
• crop rotation
• green manure
• crop productivity
• soil degradation