Substituting chemical P fertilizer with organic manure: effects on double-rice yield, phosphorus use efficiency and balance in subtropical China

Yanhong Lu,Yulin Liao,Qidong Zhu,Yajie Gao,Jun Nie

doi:10.1038/s41598-021-87851-2

Abstract

Organic manure is an ideal alternative fertilizer to provide phosphorus (P) but is not fully recycled in subtropical China. In order to identify if it can replace chemical P fertilizer, a 35-year field trail in a paddy soil under double-rice cropping system was conducted to assess the effects of substituting chemical P fertilizer with pig manure (NKM) on rice yield, phosphorus use efficiency (PUE) and P balance. The N, P and K input under NKM was 1.2, 0.8 and 1.2 times of the combined chemical fertilizer treatment (NPK), respectively. The NKM treatment reached the same level of grain yield with NPK after 20 years’ application, and showed significantly 4.0% decreased double-rice grain yield compared with NPK over the 35 years. The NKM treatment reduced the crop P uptake leading to decreased PUE compared with NPK. Long-term P budget showed that NKM may result in higher potential of P loss than NPK. Thus, substituting chemical P fertilizer with organic manure under this rate of nutrient input slightly sacrificed the crop yield and may increase the P loss. Considering the benefits of soil fertility, adjusting the substitution rate with a more balanced NPK input might be alternative in subtropical China.

Highlights

Organic manure is an ideal alternative fertilizer to provide phosphorus (P) but is not fully recycled in subtropical China
In the intensive double-rice cropping system in subtropical China, Xu et al.[13] observed a higher yield and nutrient absorption by half chemical fertilizers combined with half swine manure application relative to full chemical fertilizers application according to a 6-years study; while fully substitution of mineral P fertilizer with cattle manure resulted in a slightly higher but insignificant mean yield compared with mineral P fertilizer application based on a 25-year experiment reported by Bi et al.[14]
The NPK treatment showed significantly (p < 0.05) higher annual mean grain yield of both the early and late rice compared with the NKM treatment

Summary

Introduction

Organic manure is an ideal alternative fertilizer to provide phosphorus (P) but is not fully recycled in subtropical China. In the intensive double-rice cropping system in subtropical China, Xu et al.[13] observed a higher yield and nutrient absorption by half chemical fertilizers combined with half swine manure application relative to full chemical fertilizers application according to a 6-years study; while fully substitution of mineral P fertilizer with cattle manure resulted in a slightly higher but insignificant mean yield compared with mineral P fertilizer application based on a 25-year experiment reported by Bi et al.[14]. CK NK NPK NKM Treatments the information about long-term manure effect on crop P uptake and P use efficiency in paddy fields in Subtropical China was still limited, and the estimation of manure contribution at an equivalent level of nutrient input is lack[15]. We hypothesized that long-term organic manure addition in replace of inorganic P fertilizer could enhance P use efficiency and increase the P loss in the double-rice paddy field

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