基于15N和13C双标记的黄土高原旱地麦田有机肥替代化肥氮的效应及机理研究

Combined application of manure and chemical fertilizer has become an important method for achieving the zero growth of chemical fertilizer application. Although there have been many studies which focused on the nitrogen (N) transformation in chemical fertilizer, when combined with manure in in Northwest dryland, the relation between dynamic characteristics of manure N mineralization with its crop availability, and the mechanisms of the interactive effects of fertilizer N and manure N on plant growth remained unknown. Using the 15N and 13C double labeled manure as objects, this study investigated the transformation and supply characteristics of manure carbon (C), N in soil, the ratio of manure and inorganic N and their interactive effect ; The effect of soil microbial biomass and community change on manure mineralization, and the recycle of soil residual organic N, etc. through the combination of indoor cultivation and field experiment, and advanced technology, including soil C and N grouping, isotope tracer, spectral analysis, phospholipid fatty acids specra. The objective of this study were: determining the transformation of C and N in manure after being applied into the soil and the interaction mechanism of them under the condition of the combination of manure and chemical fertilizer in dry-land; Exploring the interaction mechanism of N supplied by manure and inorganic N; Clarifying the impact of soil residual organic N on soil environment; Providing a theoretical basis for the sustainable development of Northwest dry-land agriculture through increasing application of manure, decreasing the input of inorganic fertilizer, to improve nutrient use efficiency, and protect the ecology and environment.

有机无机配施作为重要的化肥有机替代技术，已成为实现化肥用量零增长重要途径。目前在西北旱地麦田关于有机无机配施下化肥氮在土壤中转化规律及其供应特征研究较多，而对有机肥氮的矿化动力特征与作物有效性关系、有机肥氮与化肥氮的互作增效机制尚不十分清楚。本项目以15N和13C双标记有机肥为研究对象，通过室内培养和田间微区相结合，采用先进的土壤碳氮分组、同位素示踪、波谱分析、磷脂脂肪酸谱图等技术研究旱地有机无机配施下有机肥中碳、氮在土壤中的转化及其供应特征；有机肥氮替代化肥氮比例及其互作效应；土壤微生物数量及其群落结构变化对有机肥矿化的影响；土壤中残留有机氮再利用等。明确旱地有机无机配施下有机肥中碳、氮转化规律及其互作机制；探明有机肥氮与化肥氮的互作增效机制；搞清残留有机氮的土壤环境效应及调控。以便为通过增施有机肥替代化学氮肥，减少用量，提高效率，保护生态环境，促进西北旱地农业可持续发展提供理论依据。

有机无机配施作为重要的化肥有机替代技术，已成为实现化肥用量零增长重要途径。目前在西北旱地麦田关于有机无机配施下化肥氮在土壤中转化规律及其供应特征研究较多，而对有机肥氮的矿化动力特征与作物有效性关系、有机肥氮与化肥氮的互作增效机制尚不十分清楚。本项目以15N和13C双标记有机肥为研究对象，通过室内培养和田间微区相结合，采用先进的同位素示踪技术研究旱地有机无机配施下有机肥中碳、氮在土壤中的转化及其供应特征；有机肥氮替代化肥氮比例及其互作效应；土壤微生物数量及其群落结构变化对有机肥矿化的影响；土壤中残留有机氮再利用。用98% 15N-硫酸铵和98% 13C-二氧化碳标记玉米得到双标记玉米。用双标记玉米饲喂黄牛，收集牛粪进行堆腐，得到双标记（牛粪）有机肥中15N丰度4.86%、13CPDB -7.75‰。有机肥与不同氮肥配施田间试验，M+N150处理产量较高，且M+N150处理N2O的排放通量和增温潜势低于M+N300处理。有机肥与不同氮肥配施的室内培养试验，中等氮处理的二氧化碳累积排放量较低，有机肥氮的矿化率较高，土壤微生物生物量碳氮较高。大田微区试验，M+N150处理的产量较高，有机肥氮在土壤中的残留量较低，有机肥氮对于小麦地上部的贡献率最高，有机肥氮在植物-土壤系统分配较合理。双标记有机肥的制备方法可以为直接标记有机肥的试验提供依据和详细方法指导；不同配施试验可以为小麦增产和降低环境风险提供合理方案；培养试验和微区试验揭示了有机肥氮的作用机理，可以为有机肥氮肥的配施及后续的研究提供理论指导。