[Biochar addition improves soil phosphorus availability: A meta-analysis]. / ç”Ÿç‰©ç‚­æé«˜åœŸå£¤ç£·ç´ æœ‰æ•ˆæ€§çš„æ•´åˆåˆ†æž.

ABSTRACT

Biochar is a potential source for improving soil fertility and crop yield by enhancing phosphorus (P) availability. But the information on quantitative effect of biochar addition on soil P availability is still limited. To address this query, we conducted a meta-analysis with 507 data from 95 eligible literature. The results showed that irrespective of biochar characters (raw material, CN ratio, pyrolysis temperature, application rate), soil characteristics (texture, pH, organic carbon content), and fertilizer application, biochar addition significantly improved soil available P content by 57.6%. Meanwhile, biochar addition promoted P utilization of crops. The response ratios of plant P concentration to biochar addition were generally lower than those of soil available P. The average response ratio of plant P concentration was 30.6%. The biochars, derived from livestock manure, low-temperature pyrolysis, with lower CN ratio, alkaline, or higher application rate, were more effective to improve soil available P content and plant P concentration in sandy and loamy soils. For main enzymes involved in P cycle, biochar addition increased activity of alkaline phosphatase (2.8%) but decreased the acid phosphatase activity (17.8%). Overall, biochar addition positively affects soil available and plant P concentration, but has a minute effect on soil phosphatase. The improvement of soil P availability might mainly be ascribed to a great amount of active P fractions in biochar itself.