Maintaining soil structure and sustaining soil fertility is thought to play an important role in the continuous cultivation of crops, but the fertility of land is exhausted by long-term different fertilization modes.
A sixteen years field experiment made by researchers in the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) has proved that long-term fertilization affects the distribution of carbon (C), nitrogen (N) and phosphorus (P) in water-stable aggregates in paddy soil.
The researchers found that application of organic materials resulted in increase of mean weight diameter of water-stable aggregate (WSA). Meanwhile, total C, N and P were prone to concentrate in the large WSA because of the addition of organic materials. But compared with full dose of chemical fertilizers, economical fertilization model (less chemical fertilizers combined with organic materials) maintained the soil fertility, indicating that green manure and half straw returning could replace about 1/3 of chemical fertilizers.
"However, if soil was amended only with chemical fertilizers, some of its characteristics, such as total C and N contents, were not significantly different from those of the unfertilized (CK).”said WANG Wei, the main researcher of this experiment in ISA.
Funded by the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-423) and the National Basic Research Program of China(2005CB121106), the results of the research have been published on AGRICULTURAL SCIENCES IN CHINA in December, 2011.(DOI: 10.1016/S1671-2927(11)60194-6)