[Responses of microbial biomass P to the changes of organic C and P in paddy soils under different fertilization systems].
Based on a fifteen years field experiment in double rice-cropping region of subtropical China, the responses of microbial biomass P (MB-P) to organic C and P in red paddy soils under different fertilization systems were investigated. The results indicated that a long-term input of organic carbon sources and the increasing soil organic carbon made soil microbial biomass remain at a high level (MB-C > 800 mg x kg(-1)), being a main reason of the increase of MB-P. Under long-term zero chemical P fertilization, there was a significant decrease in soil total P (P < 0.05), but soil organic P increased by 29.3% on average. The inorganic P forms in deficit were mainly Al-P, Fe-P, Ca-P and O-P, with the lowest content of Al-P (only 0.5 mg x kg(-1) on average). The content of soil MB-P under zero chemical P fertilization was much higher than that of Olsen-P. Correlation analysis showed that there was a significant relationship (P < 0.05) between MB-P and Al-P, from which, it was deduced that the utilization of Al-P, Fe-P, Ca-P and O-P by soil microbes could be the key approach of promoting these P forms transformed into available P. Chemical P fertilization combined with organic nutrient recycling could not only enlarge the soil P pool, but also improve the P availability.
Chen
An-Lei
AL
Key Laboratory of Subtropical Agro-ecology, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China. alchen@isa.ac.cn
Wang
Kai-Rong
KR
Xie
Xiao-Li
XL
Liu
Ying-Xin
YX
D018533:Biomass; D002244:Carbon / Q000032:analysis*; D002681:China; D017753:Ecosystem; D005308:Fertilizers; D009930:Organic Chemicals / Q000032:analysis; D012275:Oryza / Q000254:growth & development*; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D014329:Tropical Climate
D005308:Fertilizers; D009930:Organic Chemicals; D012987:Soil; D010758:Phosphorus; D002244:Carbon