Partial substitution of chemical fertilizers with manure alters soil phosphorus fractions and optimizes vegetable production in alkaline soil

Maintaining phosphorus (P) supply for plants or reducing P mobility is critical to sustainable agricultural production and the environment. However, substituting long-term chemical fertilizer with a fraction of (i.e. partial substitution) manure and its effect on soil P surplus and P fractionation have not been widely studied. An eight-year protected field study with no fertilization (NF), chemical fertilizer substituted with no manure (NS), partial manure (40%, PS), and total manure (100%, TS) combined with multiple P characterization methods were conducted to examine P pools and stability in alkaline soil. NS, PS, and TS have the same input amount of nutrients. It showed that PS treatment lowered the annual P surplus by 6.21% and 11.2% compared with NS and TS, respectively, maintaining optimal P input-output balance and vegetable yields. TS decreased total P-o by 31.9% and stable Ca-associated P by 21.1%, while increased labile organic P, compared with NS. The labile P in PS was at a moderate level compared with NS and TS treatments, which not only maintained the soil labile P pools but also reduced P leaching risk. Therefore, partial substitution of chemical fertilizer with manure leads to an optimal level of nutrients for vegetable production.

Automated summary

This study examines the effect of substituting chemical fertilizer with manure on soil phosphorus surplus and fractionation. The results show that partial substitution of manure can reduce phosphorus surplus, maintain optimal phosphorus input-output balance, and increase vegetable yields.