旱地冬小麦根域集水种植水分调控机制及抗旱增产原理

The drought and water shortage are key constraints on crop production in arid areas in recent years. The result showed that root zone catchment planting in farmland can effectively alleviate the situation of crop water shortage in arid area of north China. In this study, we used the open-close shelter and self-made simulated precipitation device, combining artificial simulation with field experiment, to obtain different precipitation and precipitation conditions during the growth period of winter wheat. Based on the scientific distinction between "furrow and ridge ratio" and "collection and planting ratio" , the main research showed as follows: 1) Dynamic change characteristics of soil moisture under catchment planting in root zone and complementary law of "furrow water" and "ridge water"; 2) Effects of root zone catchment planting on soil nutrient availability, spatial distribution and utilization efficiency in field; 3) Effects of root zone catchment planting on crop population structure, dry matter accumulation, economic yield and its components; 4) The interaction of different furrow and ridge structure and precipitation on the effects of water and fertilizer use, collection and planting ratio and crop yield in field. The purpose of the experiment was to study the water regulation mechanism of catchment planting in dryland crop, to reveal the rule of soil moisture compensation in ridge and furrow, and to clarify the yield increase principles of winter wheat under root zone catchment planting and the relationship between drought yield increase effect of catchment planting under furrow and ridge structure and collection and planting ratio, and the rainfall amount during crop growing periods. The research could provide theoretical and technical foundation for perfecting root zone catchment planting pattern.

干旱缺水是旱区作物生产水平的关键限制因素。多年的旱农研究结果表明，农田根域集水种植可有效缓解我国北方旱区作物缺水状况。本研究采用开闭式遮雨大棚及自制模拟降水装置，在冬小麦生育期内，获得不同降水量和降水条件，通过人工模拟结合大田试验，在科学区分“沟垄比”和“集种比”的基础之上，进行以下主要研究：(1)根域集水种植田间土壤水分动态变化特征及“沟水”、“垄水”互补规律；(2)根域集水种植对田间土壤养分有效性、空间分布及利用效率的影响；(3)根域集水种植对作物群体结构、干物质积累、经济产量及构成要素的影响；(4)不同沟垄结构和降水量对田间水肥利用、集种比及作物产量影响的交互作用。目的在于探明旱地作物集水种植田间水分调控机制，揭示垄沟土壤水分补偿规律，阐明冬小麦根域集水种植增产原理及不同沟垄结构和集种比下，集水种植抗旱增产效果与作物生育期降水量间的关系，为该技术模式的优化完善提供理论基础和实践依据。

2019年1月至2022年12月项目实施期间，项目组严格按照预期计划，针对几种较优沟垄结构根域集水种植模式，利用开闭式遮雨大棚以及自主设计的模拟降雨装置，在冬小麦生育期内获取不同降雨量，探索根域集水种植田间土壤水分动态变化特征及“沟水”、“垄水”互补规律，明确根域集水种植对田间土壤养分有效性、空间分布及利用效率的影响等。模拟实验结合大田试验，以限量补灌补充模拟实验降水量控制，进一步研究了根域集水和沟垄比对土壤水热条件的影响，探索了根域集水和沟垄比对氨挥发和温室气体排放的影响。结果表明：（1）根域集水种植田间，覆膜垄的集水效率与降雨强度有关，在雨强为30mm/h～40mm/h时，覆膜垄的集水效率较高，可达到90%以上；（2）在冬小麦生育期，随着时间的推移和累积降雨量的增加，根域集水种植垄下土壤水分逐渐增加，在230mm、285mm、340mm、390mm和440mm 5 个降雨量水平，随着雨量递增，沟中种植区土壤水分含量提高幅度增大，垄下土壤水分含量增加速度也加大；（3） 在冬小麦全生育期230mm、285mm、340mm、390mm和440mm雨量下，根域集水种植耕层土壤速效养分含量明显增加，并且其增幅大小随雨量不同而异；（3） 在年降雨量较少的情况下，各集水处理显著增加冬小麦穗数并增加穗粒数和千粒重，从而使小麦产量显著高于平作。而在年降雨量较高的情况下，实际种植面积减少对作物群体生长的负效应强于集水对作物生长的正效应，导致集水种植较平作种植的产量有所下降。（4）不同降水年型下，根域集水改善了冬小麦-夏玉米的生长状况；（5）在集水种植模式下，改变垄沟比对氨挥发和温室气体排放的影响无显著差异，但均以沟宽40cm和沟宽80cm高于沟宽60cm；（6）在半湿润易旱区，干旱年份根域集水种植与补灌75 mm相结合相对来说能够缓解干旱胁迫、提高冬小麦-夏玉米产量、资源利用效率、净利润和温室气体排放；但在平水年和丰水年，当垄宽为40 cm，沟宽为80 cm时产量效益、生态效益和环境效益相对较好。