Effects of Straw Incorporation and Biochar Amendment on Olsen-P and Phosphorus Fraction in Soil

【Objective】 The low mobility of phosphorus in soil is a main factor limiting its bioavailability. In this paper. The efficacy of straw incorporation and biochar amendment in improving Olsen-P and changing P fraction is soil was studied. 【Method】 The study was based on incubation experiment. Soil taken from a rice field was used in experiments under two soil water contents to mimic paddy field and dried land, respectively. For each soil water treatment, there were four soil amendments: a high (BC2) and a low (BC1) biochar amendment, a high (SC2) and a low (SC1) straw incorporation. The control is without soil amendment (CK). The Hedley phosphorus speciation method was used to classify P fraction in each treatment, and the Olsen-P content and other soil physicochemical properties were measured using standard methods. 【Result】 Depending on its application rate, biochar amendment increased Olsen-P content in the dried soil and the paddy soil by 1.78 to 1.46 mg/kg and 12.04~22.42 mg/kg, respectively. Straw incorpo