Effect of fertilization on farmland phosphorus loss via surface runoff in China: A meta-analysis

Abstract

Fertilization inevitably induces phosphorus (P) loss via runoff from farmland causing aquatic eutrophication. A current challenge is estimating farmland P loss induced by fertilization under different conditions of soil hydroclimate, field managements and soil properties. Thus, we synthesized 1636 observations from 69 studies in China to analyze how multiple factors influence P loss in surface runoff from upland and paddy fields. The results showed that P fertilization increases P loss in surface runoff from farmland, and that P loss is lower from upland than paddy fields. The amount of P fertilization (P2O5 in fertilizer) had significantly positive correlations with the effect size of P loss in upland and paddy fields. The rise of P application rate (times of fertilization during study period) significantly decreased P loss in upland fields, but increased P loss in paddy fields. The expansion of crop acreage decreased P loss in upland fields compared to paddy fields. P loss from upland fields is more sensitive to temperature and precipitation than paddy fields, although the responses of P loss differed among fertilizers, crops and soil types. The value of soil pH was significantly positive correlated with P loss in upland and paddy fields. Overall, our study examined the effects of P fertilization on P loss in surface runoff from farmland and estimated the potential variations of P loss under various conditions from the perspective of increasing air temperature and precipitation, providing reference data for field management activities to reduce P output from upland and paddy fields.