滴灌水肥一体化策略对植烟土壤N2O排放的影响及其机理研究

Fertigation is an inevitable trend in the development of agriculture, however, research on N2O emission from the fertigation farmland was rarely been reported. In addition, only one fertigation method was used in the current studies of N2O emission from the fertilgation farmland, which would probably cover up the potential of N2O reduction in fertilgation farmland by the fertilgation strategy optimization. This item is intended to: on the one hand, promote the utilization of nutrition in the soil, which will reduce the substrate for nitrification and denitrification, on the other hand, control the soil moisture of the crop root layer out of the appropriate range for nitrification and denitrification. Visibly, the aim of this item is to discuss the effects and mechanism of drip fertigation strategy on N2O emission from tobacco soil. The study of this item could not only supply the datas for calculation of the farmland source of atmospheric N2O, but also provide theoretical and technical reference to the N2O emission reduction in the fertigation farmland.

水肥一体化技术是现代化农业发展的必然趋势，而有关水肥一体化条件下农田土壤N2O排放研究鲜见报道。此外，在目前有限的有关水肥一体化条件下农田土壤N2O排放的研究中，大多仅采用一种既定的水肥一体化方式，这就掩盖了水肥一体化技术可以通过策略优化，进一步减缓农田N2O排放的潜力。本项目拟通过肥料统筹和控水调墒，一方面促进作物对养分的吸收利用，减少硝化反硝化底物供应，另一方面，精准调控作物根层土壤含水量，规避导致N2O大量排放的土壤水分环境。以此来探索通过水肥一体化策略调整，进一步减缓土壤N2O排放的作用机理及其可行性。通过本项目研究，不仅可为水肥一体化技术迅速发展背景下的农田系统N2O排放源贡献率计算提供数据保障，而且可为减缓水肥一体化条件下农田N2O排放提供理论与技术支撑。

水肥一体化技术是现代化农业发展的必然趋势，探索通过水肥一体化策略优化和水分调控减缓农田土壤N2O排放的可行性，对于推进农田生态系统节肥减排具有重要的科学意义。在烤烟栽培过程中，分别采用不同肥料统筹方式和滴灌施肥次数进行养分管理，采用静态箱法观测土壤N2O排放。结果表明，与常规统筹和均匀统筹相比，滴灌施肥优化统筹可以分别降低烤烟生育期土壤矿质氮含量13.2%～24.8%（p<0.05）和4.0%～8.4%，减少烟田N2O排放17.8%～41.0%（p<0.05）和8.2%～37.1%（p<0.05），且不影响烟叶产量。与施肥期一次滴灌施肥和二次滴灌施肥相比，施肥期三次滴灌施肥可使施肥后3d内的土壤含水量降低0.0%～35.2%，减少烟田N2O排放25.5%～45.1%（p<0.05）和13.6%～21.1%（p<0.05），且不影响烟叶产量。可见，通过滴灌水肥一体化肥料统筹优化，可以促进作物对养分的吸收利用，从而减少硝化反硝化底物供应；通过滴灌水肥一体化滴灌次数调控，能够降低施肥期土壤含水量，从而规避导致N2O大量产生的土壤水分环境；上述两项措施均可以实现滴灌水肥一体化农田N2O排放的降低，为农田N2O减排和养分高效管理提供了科学参考。