温度响应性控释肥对寒地玉米土壤氮素的调控机制研究

Aiming at the problem of uncoordinated maize yields, benefits, carbon (C) sequestration and easy cultivation for maize field in Heilongjiang cold region, and the uncertain mechanism of environmental responsive controlled release fertilizer and greenhouse effect in maize field, taking the maize field in black soil as the research object, temperature-responsive controlled release fertilizer (TR-CRF) as the main treatment, and two types of conmmon fertilizer as control, the nitrogen release characteristics of TR-CRF for maize will be studied with small experimental fields and isotope 15N tracer method under different fertilization conditions. The effect of the changeable water and temperature cultivation on chemical structure, crystallinity, thermostability and micromorphology of TR-CRF coating materials will be analyzed with FTIR, XRD, DSC and SEM. Furthermore, the prediction model of nitrogen release rate will be constructed. We will analyse the effect of three types of fertilizer on maize yield and N2O gas emissions under different fertilization levels with field observation, the static chamber-gas chromatograph method, and isotope 15N and 13C tracer method. We will try to reveal the mechanism of temperature-responsive controlled release fertilizer on greenhouse effect of maize farmland while keeping grain productivity in Heilongjiang. This research would be of great of scientific and practical significance in the respects of improving nitrogen fertilizer use efficiency, fixing carbon and reducing discharge for high yield corn region of Heilongjiang.

针对黑龙江寒地玉米区轻简栽培与产量、效益和减排不协调的问题，以及环境响应性控释肥在田间条件下控释机理及其对温室气体排放状况不明确等问题，本项目拟以寒地黑土玉米为研究对象，以温度响应性控释肥（TR-CRF）为主处理，2种常用肥料为对照，采用田间小区试验结合同位素15N示踪法，研究不同施肥方法下TR-CRF对黑土玉米的供氮特征；采用室内变温、控湿条件下的培养试验，结合红外光谱仪、X射线衍射仪、热重分析仪和扫描电镜方法，研究不同土壤水、热变化对TR-CRF外层包膜化学结构、结晶度、热稳定性和微观形态变化，构建氮素释放预测模型；采用田间野外监测、静态箱-气相色谱法结合同位素15N、13C示踪法，研究3种类型肥料不同施肥方法对黑土玉米产量及其对N2O气体排放量的影响，阐明保持较高产量基础上的温度响应性控释肥减排的互作机制和环境效应，对黑龙江优质高产玉米区高效施肥与固碳减排具有重要的科学和现实意义。

施用控释肥对作物有增产和减排效果，但对于黑龙江寒地黑土的特殊环境，环境响应性控释肥在玉米田间条件下控释机理尚不明确。本研究以寒地黑土玉米为研究对象，采用田间小区试验与室内变温培养试验，结合红外光谱仪、X射线衍射仪和扫描电镜等技术，研究不同施肥方法对温度响应性控释肥（TR-CRF）的供氮特征，并综合考虑土壤水热变化对TR-CRF外包膜材料变化与氮素释放的影响。主要研究结果表明：在寒地黑土玉米周期内，不同施肥处理的氮肥利用率在不同生育期表现不同，但是在成熟期表现为随着氮肥施用量的增加而降低的变化趋势，常规氮肥处理的氮肥利用率为32.45％，而商业用控释肥和TR-CRF处理分别达到67.10%和71.30％，同时商业控释肥释放规律呈抛物型，TR-CRF呈S型，整个释放期略显延长，随着时间的延长氮素积累量呈增加趋势。TR-CRF的施用可显著提高寒地黑土玉米产量，显著提高氮肥利用率。通过分析各个指标间相互作用与影响，建立了TR-CRF对寒地黑土氮素释放预测模型，对环境响应性控释肥的开发应用以及秸秆资源利用具有重要的意义。