Legume Species Alter the Effect of Biochar Application on Microbial Diversity and Functions in the Mixed Cropping System—Based on a Pot Experiment

Abstract

Biochar application to legume-based mixed cropping systems may enhance soil microbial diversity and nitrogen (N)-cycling function. This study was conducted to elucidate the effect of biochar application on soil microbial diversity and N-cycling function with a particular focus on legume species. Therefore, we performed a pot experiment consisting of three legume species intercropped with maize: cowpea, velvet bean, and common bean. In addition, one of three fertilizers was applied to each crop: biochar made of chicken manure (CM), a chemical fertilizer, or no fertilizer. Amplicon sequencing for the prokaryotic community and functional prediction with Tax4Fun2 were conducted. Under the CM, Simpson’s diversity index was higher in soils with common beans than those in other legume treatments. On the other hand, N-cycling genes for ammonia oxidation and nitrite reductase (NO-forming) were more abundant in velvet bean/maize treatment, and this is possibly due to the increased abundance of Thaumarchaeota (6.7%), Chloroflexi (12%), and Planctomycetes (11%). Cowpea/maize treatment had the lowest prokaryotes abundances among legume treatments. Our results suggest that the choice of legume species is important for soil microbial diversity and N-cycling functions in CM applied mixed cropping systems.

Integrated Crop Management in Sustainable Agriculture

“…The ICM combines several eco-friendly practices to sustain agricultural production. These practices include seed priming [1], the application of organic and inorganic amendments [2][3][4], the use of plant growth promoting bacteria [1], the application of macro-and micronutrients [2,4], biofortification, the use of biopesticides [5], the use of high-yielding genotypes [6], alternative cropping systems [7][8][9], the conservation of natural enemies [10], etc. The use of these management measures improves soil health and crop yield.…”

“…Furthermore, legume species significantly altered soil microorganisms and nitrogen cycling. Common beans (Phaseolus vulgaris L.) grown with chicken dung biochar resulted in a diversified prokaryotic community compared to other legume species [8].…”