Short-Term Interactive Effects of Biochar, Green Manure, and Inorganic Fertilizer on Soil Properties and Agronomic Characteristics of Maize

Abstract

The application of biochar with inorganic fertilizers is shown to improve crop productivity. However, resource-poor farmers may be constrained in their ability to meet the fertilizer requirements. In this short-term greenhouse research, we investigated whether combining biochar and green manure sources of Tithonia diversifolia and Vicia faba could be a viable soil management option for smallholder agroecosystems. Generally, the application of the green manures either singly or mixed with biochar showed similar effects on soil properties. However, in contrast to mixed biochar and fertilizer treatments, soil microbial biomass C, mineral N, available P, and pH were generally higher in soils that received mixed green manure and biochar applications. The results also showed a positive but comparable synergistic effect of applying green manure or fertilizers with biochar. It was inferred that the combined applications of biochar and V. faba or T. diversifolia increased maize grain yield by 35 and 25 %, respectively, compared with sole V. faba and T. diversifolia applications. Relative to sole fertilizer application, there was a 27 % increase in maize grain yield when fertilizer was combined with biochar. The increased biological yield of maize in mixed than single treatments was attributed to the increased N use efficiency of maize plants that received mixed application of biochar and green manures or inorganic fertilizer. The results established that in places where inorganic fertilizers are limited, green manures could be applied with biochar for improved soil fertility and crop productivity.