Effect of Adaptable Green Manure Plants on Sorghum Yields and Soil Fertility in Eastern Amhara Region of Ethiopia

Abstract

A study was conducted in Eastern Amhara Region of Ethiopia to evaluate effects of intercropping sorghum with Tephrosia vogelii, Tithonia diversifolia and Leucenea palida on sorghum yield and soil fertility. The results showed that intercropping Tephrosia v. and Leucenea p. with sorghum didn’t have significant (p > 0.05) negative effect on sorghum yields. However, sorghum-Tithonia d. intercropping significantly (p < 0.05) harmed sorghum yields. The results of sorghum yields in the subsequent two experimental years, after ploughing under the above ground biomass of the green manures, revealed that plots which received Tephrosia v. and Tithonia d without inorganic fertilizers gave significantly (p < 0.05) similar yields with application of 100% of the recommended NP fertilizers. However, due to its poor growth and lowest biomass, Leucenea p. didn’t effect a significant yield difference over the control. At the end of the experiment, 8.1 and 7.3% residual deposition of soil organic carbon was recorded on the plots under Tephrosia v. and Tithonia d., respectively. Thus, it is possible to recommend sorghum-Tephrosia v. intercropping and green manuring. While, due to its weed effect, Tithonia d. is not recommended for intercropping; it is rather recommended to transfer its biomass through cut and carry system.

Key words: intercropping, green manure, biomass transfer, inorganic fertilizer