Application and residual effects of poultry litter biochar on cropping system yields

Abstract

Animal manures such as poultry litter supply plant‐available phosphorus (P), but P loss can occur following manure application to crops, particularly in sandy soils. The transformation of poultry litter biochar (PLB) reduces P losses upon application to crops while providing essential plant nutrients. Our objectives were to evaluate: (1) the effects of PLB on crop yields when applied at the same total P rate as inorganic P fertilizer and (2) the residual effect of previous‐year PLB and inorganic P fertilization on crop yield at two locations with different soil types (Entisols and Spodosols). Inorganic P, PLB, and no‐P treatments were allocated to six replicates of a randomized complete block design at each location. The cropping system was sequential plantings of rye, corn, and sorghum each year for 2 years. The residual effect of P application was quantified in Year 2 when first‐year PLB and inorganic P plots were subdivided, with half receiving no additional P and half receiving the same P application as the previous year. After each crop was harvested, crop yield, nitrogen (N) and P levels in plant tissue, and the soil phosphorus storage capacity were determined. PLB supported either similar or significantly greater cumulative biomass yields compared with inorganic P fertilization at the two locations. The effect of residual PLB on yield varied with the location and crop, highlighting the importance of soil type and management practices in optimizing the benefits of this amendment.