苹果园有机无机肥配施土壤氨化微生物群落构建机制及对有机氮组分的影响

有机无机肥配施是苹果园化肥减施的重要技术。与单施化肥相比，有机无机肥配施苹果园中有机氮矿化分解对作物供氮来说显得尤为重要。而土壤氨化微生物是有机氮分解为作物供氮的主要驱动因子。果园局部集中施肥的特点，常常使土壤微生物群落产生时空变化进而影响有机氮分解。因此，探究氨化微生物群落的时空变化及构建机制是揭示有机无机肥配施下土壤有机氮分解机制的关键，具有重要科学意义。本项目基于苹果园长期定位试验，采用宏基因组测序、液-质联用、气-质联用等技术开展研究：探讨苹果园有机无机肥配施下土壤各类氨化微生物群落的时空变化特征及其构建过程，揭示土壤各类氨化微生物群落时空变化的环境影响机制，阐明各类氨化微生物群落的时空变化与有机氮组分及土壤供氮能力的作用关系。以期为探究苹果园有机无机肥配施土壤有机氮组分的分解机制，挖掘土壤供氮潜力，减施化肥，提高果树氮效率提供科学依据。

Combination of chemical fertilizer and manure is an important technology for decreasing application rate of chemical fertilizer in apple orchard. Compared to chemical fertilizer, the decomposition of soil organic nitrogen in apple orchard with combination of chemical fertilizer and manure is more important for nitrogen supplication. Soil ammonifiers are the main driving factors for organic nitrogen decomposition and nitrogen supplying for crops. The concentrated fertilization in apple orchard would impact soil microbial community spatiotemporally, thereby affect the decomposition of organic nitrogen. Thus, exploring the mechanism of assembly and spatiotemporal changes of ammonifier communities is a key point for revealing the mechanism of organic nitrogen decomposition under chemical fertilizer combined with manure. This project bases a long-term experiment, and uses metagenome, LC-MS and GC-MS technologies. The objectives are: 1) discussing the spatiotemporal changes and assembly process of ammonifier communities under long-term application of chemical fertilizer combined with manure in apple orchard; 2) revealing the environmental impact mechanism of spatiotemporal changes of ammonifier communities in soil; 3) illuminating the relationships between spatiotemporal changes of ammonifier communities and the contents of soil organic nitrogen fractions and nitrogen supply capacity of soil. The results provide a scientific basis for the mechanism of soil organic nitrogen decomposition under application of chemical fertilizer combined with manure in apple orchard, thereby tapping the potential of soil nitrogen supply, reducing the application rate of fertilizer and increasing the nitrogen use efficiency of apple trees through combination of chemical fertilizer and manure.