西北旱地冬小麦秸秆带状覆盖土壤水热效应及增产机制

In order to resolve the contradictions between water conservation and decreasing temperature with the use of traditional straw covering, bundled straw covering technique had been innovated by college of agronomy, Gansu agricultural university, which was designed by partial mulching as＂planting area with no cover, covering area with no planting＂. Based on years of field-plot experiments and farm-scale demonstrations, it has clearly shown that wheat grain yield can be increased significantly (44.4%) with the use of bundled straw covering technique compared to no cover, at the same time, the bundled straw covering technique looks also promising in potato crops which showed higher by 13.1% than that of black plastic film mulching in increasing tuber-yield. The field experiments will be designed by different straw covering amount and covering strip width, temporal and spatial changes of soil water and temperature was consecutively measured at different soil layers and growth stages, and measuring growth indexes, physiology indexes, yield components and so on. The correlations between them and soil water utilization, soil temperature also will be deeply discussed, which can explain the effects of the soil water, soil temperature and mechanism of increasing yield of winter wheat with bundled straw covering. The results of the project will provide technical support for sustainable increase of production of dry land, building high effect circulation agriculture and the ensuring of foodstuff security in China

秸秆带状覆盖技术是由甘肃农业大学农学院研发的旱地覆盖保墒栽培新技术，即采用“种的地方不覆盖、覆盖的地方不种”局部覆盖思路，旨在解决传统秸秆覆盖保墒与降温的矛盾限制。试验证明，该技术在旱地冬小麦和马铃薯上较不覆盖有显著的增产作用。其中，在小麦上较无覆盖露地栽培平均增产44.4%；在马铃薯上，较目前甘肃省主推的黑色地膜覆盖技术平均增产13.1%。本研究采用大田试验，设置了不同覆盖带幅和覆盖量处理。连续监测不同土层、不同生育时期土壤温度和水分的时空动态变化，同时测定作物生长指标、生理及产量结构要素等指标，最终探讨土壤水温变化与作物生长、生理及产量形成的关系，揭示秸秆带状覆盖的增产机制。项目成果可作为旱地可持续增产和建立高效循环农业、保障我国粮食安全提供技术支撑。

经2015-2019年不同降水年型对秸秆带状覆盖与无覆盖、全地面地膜覆盖的比较研究，明确了秸秆带状覆盖增产和高效用水的水分生理基础和增产机制。研究表明，秸秆带状覆盖可以显著改善土壤供水能力，增产改变了耗水结构，提高了蒸腾耗水比例。与无覆盖相比，秸秆带状覆盖明显提高全生育期0-2m土壤贮水量，但降低了耕层的土壤温度。但随着生育时期和土层的不同，秸秆带状覆盖较无覆盖具有增墒和降墒、增温和降温的双重作用，总体来讲，增墒作用大于降墒作用，降温作用大于增温作用，增墒和增温效应主要出现在生育前期，而降墒和降温效应主要出现在生育后期的高温季节，降墒主要由后期较大的蒸腾性生产耗水引起。前期增温有利于安全越冬和促进前期营养生长，后期降温可以减少土壤蒸散强度和奢侈耗水，有利于高产形成。通过不同覆盖模式的比较，确定出高产高效用水带状覆盖模式为：覆盖带50 cm、种植带35 cm，每带种3行，适宜覆盖量为9000kg/hm2，播种期较无覆盖提前7d左右。增加单位面积库容（总籽粒数），尤其是稳定提高有效穗数，协调花前花后干物质对籽粒的贡献率，通过水温互调耦合实现前控后促是秸秆带状覆盖高产形成和高效用水的主要机制。