全膜覆土免耕栽培技术土壤碳氮代谢特征研究

The film covering and no tillage technique nowadays is widely used in Gansu Province but few studies investigate into its mechanism involving in yield increment and environmental effect, particularly in the aspect of carbon nitrogen metabolism which is regarded as an important evaluation factor for soil quality and health. This study carried out on a long term trial (starting in 2012) is to elicit the impact of this technique on the process and outcome of carbon nitrogen metabolism in cultivated soil and then reasonably assess the long term impact on soil quality and environmental effect.In the field,we will in situ measure soil carbon nitrogen fraction and density,temperature,humidity and respiration in pure cultured plot of maize and pea,maize/pea intercropping plot applied with this technique;in the lab we will determine enzymatic activity of nitrate reductase, urease and transferase, soil pH, mineralization rate of organic carbon and nitrogen. The study is also to explore how different modes of the film covering and no tillage technique influen cecarbon nitrogen metabolism of cultivated soil and whatis the driving force,and then to shed light on the interaction between cropping system and soil carbon nitrogen metabolism. By analyzing the relationship among Hydrothermal condition, enzymatic activity,mineralization rate and carbon nitrogen fraction density,the study will clarify the technique’s impact on soil quality and environmental effect.The study results will then give theory support for improvement,development and sustainably utilization of the film covering and no tillage technique.

全膜覆土免耕技术目前在甘肃省大面积推广应用，但对其增产机理及土壤环境效应缺乏深入研究，尤其在作为耕地质量和土壤健康状况主要评价因子的碳氮代谢方面缺乏中探讨分析。为探明全膜覆土免耕技术对耕层土壤碳氮代谢过程和结果的影响，科学评价该技术长期应用的耕地质量和环境效应，本研究在已有定位田间试验（2012-）的基础上，对全膜覆土免耕单作玉米、豌豆/玉米间作、单作豌豆等种植模式的耕层土壤碳氮组分和密度、土壤温度、湿度、土壤呼吸进行观测，并在室内对土壤硝酸还原酶、脲酶和转化酶活性、pH值、有机C和土壤N的矿化速率进行测定，研究全膜覆土免耕栽培模式对耕层土壤碳氮代谢及其驱动因素的影响，阐明作物体系和土壤有机碳氮代谢的相互作用，分析水热条件-酶类活性-矿化速率-碳氮组分密度之间的关系，明确该项技术的耕地质量和土壤环境效应，为该技术的完善、发展和可持续开发利用提供理论支持。

全膜覆土免耕技术目前在甘肃省大面积推广应用，但对其增产机理及土壤环境效应缺乏深入研究，尤其在作为耕地质量和土壤健康状况主要评价因子的碳氮代谢方面缺乏中探讨分析。为探明全膜覆土免耕技术对耕层土壤碳氮代谢过程和结果的影响，科学评价该技术长期应用的耕地质量和环境效应，本研究在已有定位田间试验（2012-）的基础上，对全膜覆土免耕单作玉米、豌豆/玉米间作、单作豌豆等种植模式的耕层土壤碳氮组分和密度、土壤温度、湿度、土壤呼吸进行观测，研究全膜覆土免耕栽培模式对耕层土壤碳氮代谢及其驱动因素的影响，阐明作物体系和土壤有机碳氮代谢的相互作用，分析水热条件-酶类活性-矿化速率-碳氮组分密度之间的关系。研究结论：1、全膜覆土免耕模式改变了土壤水分循环方式，使土壤碳氮的释放和积累平衡被打破，进而影响土壤的碳氮代谢过程和结果。2、全膜覆土免耕改变土壤热传导和通量，进而调节改变土壤的呼吸作用来对碳氮代谢过程及结果产生影响。