Effects Of Application Of Organic-Inorganic Mixed Fertilizers On Growth And Nitrogen Nuitrition In A Rotation Of Wheat-Rice

Field experiments of wheat and rice in rotation were carried out to study effects of application of organic-inorganic mixed fertilizers on growth, yields, nitrogen (N) use efficiency, soil mineral N, soil microbial biomass N and microbial diversity. Rapeseed cake compost (RCC), pig manure compost (PMC) and Chinese medicine residue compost (CMC) were separately mixed with chemical fertilizers (CF) (10-3-2, OM>20% for ratio 1 and 12-4-4, OM> 15% for ratio 2). The results obtained were as follows:1. Yield of wheat obtained by RCC2 (5872 kg-hm"2) was significantly higher than CF (4560 kg·hm"2); The yield of RCC (5220 kg-hm-2) was increased by 713 kg-hm"2 and 1017 kg-hm-2 when compared with PMC and CMC, respectively. The yields of ratio 2 treatment of organic-inorganic mixed fertilizers were increased by 3.0-29.0% when compared with ratio 1 treatment. Rice yields of organic-inorganic mixed fertilizers (7415-9449 kg-hm-2) were increased by 4.9-32.2% when compared with CF. In addition, the yield of rice of CMC was highest of all three different material composts. The yields of rice of ratio 1 treatment were higher than ratio 2 treatment.2. In wheat experiment, there was no significant difference between CF (32.7%) and organic-inorganic mixed fertilizers (33.2%) in terms of nitrogen recovery efficiency (NRE). NRE of RCC (39.6%) was increased by 9.4% and 9.7% when compared with those of PMC and CMC respectively and NRE of ratio 2 treatment (32.2-44.6%) were increased by 4.0%-10.0% compared with ratio 1 treatment. In rice experiment, compared to CF, NRE of organic-inorganic mixed fertilizers (36.3-51.4%) were increased by 7.5-20.4%. NRE of CMC (43.6%) was higher than the other two composts (RCC, PMC), and NRE of ratio 1 treatment (37.4-51.4%) were also higher than ratio 2 treatment.3. Regardless of the experiments of wheat and rice, soil mineral N supply of organic-inorganic mixed fertilizers were increased in the middle and later growth stage of crops, compared to CF. Soil mineral N of RCC in wheat experiment and that of CMC in rice experiment were higher than other treatments. Thus, the application of organic-inorganic mixed fertilizers could maintain better synchronization of soil mineral N to supply with the requirement by crops.4. The soil microbial biomass N in CF was significantly lower than organic-inorganic mixed fertilizers during the whole rice growth stage except of booting. The soil microbial biomass N of the treatment supplied with CMC was increased by 1.1 mg-kg-1 and 4.4 mg-kg-1 compared with those of RCC and PMC respectively, and ratio 1 treatment were increased by 6.8-23.2 mg-kg-1 compared with ration 2 treatment.5. Analysis of soil microbial diversity of rice experiment with DGGE indicated that application of organic-inorganic fertilizers could improve soil bacterial communities, while the application of CF had little effect on them.It was concluded that the application of organic-inorganic mixed fertilizers could improve the soil N supplying characteristics and synchronize the soil nitrogen supplying process with the requirement by wheat and rice. Same or higher yields of wheat and rice could be obtained in the application of organic-inorganic mixed fertilizers compared to CF application alone. Therefore, the organic-inorganic mixed fertilizers will have a promising future in the development of sustainable crop production.