Influence of poultry litter and biochar on soil water dynamics and nutrient leaching from a very fine sandy loam soil

Soil amendments affect various soil properties that influence water and nutrient dynamics in the soil. Thus, appropriate understanding of their influence on some of these soil properties will be helpful to improve water and nutrient use efficiency, while minimizing environmental pollution. In this study, the effect of poultry litter (PL) and pinewood biochar (PBC) on soil water holding capacity (SWHC), plant available water (PAW), unsaturated and saturated water permeability (WP), evaporation, leaching losses of dissolved organic C (DOC), inorganic-N and metals from a very fine sandy loam soil were evaluated. Addition of both PL and PBC significantly increased SWHC, while PAW was increased by PBC and decreased by PL. Amending of soil with PL at 2.5 and 5% w/w increased unsaturated WP rate, while10% PL decreased WP rate. At all three levels PL decreased saturated WP rate of soil by up to 67% compared to control. Pinewood biochar improved unsaturated WP by up to 2.5 times and saturated WP of soil by up to 2.2 times as compared to control. Despite the black color of biochars that increases thermal absorption, PBC treatments had lower evaporation rates than the control. Both PL and PBC extended the drought tolerance of ryegrass compared to control. Soil amended with PL lost appreciable amounts of DOC, inorganic-N and metals. Amending soil with PBC along with PL benefited by significantly minimizing the leaching losses of DOC, NH4+ and heavy metals. Overall, application of PL along with PBC could benefit crop production by improving SWHC, PAW, and drought tolerance while minimizing the non point source pollution compared to PL only application for very fine sandy loam soils.