Precision biochar and inoculum applications shift bacterial community structure and increase specific nutrient availability and maize yield
Foster, E.J.;Baas, P.;Wallenstein, M.D.;Cotrufo, M.F.. 2020. Applied Soil Ecology 151:103541
Abstract
To increase crop yield under full and limited irrigation, we applied an engineered biochar, P-solubilizing bacterial inoculum, and a combined treatment in a maize field with calcareous soil. The coconut hull biochar banded directly next to the seed at a rate of 0.8 Mg ha-1 increased maize yield by 20% over the control (1.95 Mg ha-1). The results suggest that the biochar increased availability of soil K and S, increasing early leaf nutrient concentration of S and grain accumulation of S, K, and N, potentially reducing nutrient limitation. The bacterial inoculum and combined application of inoculum and biochar had no impact on plant nutrient uptake, but indicator bacterial taxa (ASVs) demonstrated that one of the four added strains potentially persisted in the soil through the first maize reproductive stage (R1). The biochar-induced changes in crop nutrient uptake may relate to the early season changes in the soil bacterial community. With no observed changes in diversity, and only broad comparisons available with previous biochar-soil 16S marker gene analysis, our work is the first of its kind to implement ASVs and present results on the basis of single nucleotide differences to enhance comparability to future studies. This field experiment demonstrates that precision application of engineered biochar can improve availability of specific soil nutrients and maize yield in temperate agriculture.
