Effects of Poultry Manure and Biochar on Acrisol Soil Properties and Yield of Common Bean. A Short-Term Field Experiment

Common bean is usually cropped under rainfed conditions and in soils with low pH and water retention, in the sub-humid and semiarid regions of Brazil. To improve soil conditions, smallholder farmers commonly use cattle manure. However, manure is available in limited amounts, insufficient to fertilize all cropping areas. Thus, other amendments, such as poultry manure (PM) and biochar (BC), have been proposed to increase soil water retention and pH. We evaluated the effects of BC (10, 20, and 40 t ha−1; BC10, BC20, and BC40, respectively), PM (5 t ha−1; PM), the combination of both amendments (BC10 + PM, BC20 + PM, and BC40 + PM) and an absolute control (Control), with no amendment, on soil physical, chemical, and biological properties, and on common bean water use efficiency (WUE) and yield. The treatments had no effects on total organic carbon, cation exchange capacity, microbial biomass carbon, soil physical properties, and evapotranspiration. Treatment combination BC (10 t ha−1) + PM (5 t ha−1) significantly improved phosphorus concentration, enzymatic activities, WUE, and bean yield in this one-year experiment and it can be a viable management practice for smallholder farmers in the Brazilian sub-humid region. However, further investigations are required to study the long-term field effects of the best performing soil amendments.