干旱区枸杞水分亏缺综合诊断及其精量补充灌溉研究

Water is migrates constantly in soil, plant, atmosphere continuum(SPAC), but water deficit indicator for crop is aim at only for one or two parts of SPAC now, so ,lack of a comprehensive index system. Moreover, it is needs to research how to make comprehensive analysis and judgment in the decision-making of irrigation on crop by soil, weather composite system. Ningxia is the origin of Lycium barbarum L, planting area is 47 000hm2, the yields accounted for 60% in all over the China and export volume 90%. Ningxia is locates in arid area, the climate is very drought and irrigation capacity of farmland per unit takes up 1/27 of country ration. Water resources are extremely scarce. The study is takes Ningxia as a target area and Lycium barbarum L which grows in the field with drip irrigation as the research object. Based on the SPAC, obtained the data of soil water, crop physiological and meteorological factors according by field observation and laboratory analysis. Then, analyses the relationship among the indexes of Lycium barbarum L. Constructing fuzzy evaluation model for water deficit indicator of Lycium barbarum L, meanwhile, validated it in field. Applied the model to control precisely supplemental irrigation, then, determined the corresponding supplemental irrigation index of Lycium barbarum L. The research will provide new ideas and targets for comprehensive water deficit indicator and precision irrigation decision-making. The achievements will be applied widely for Lycium barbarum L irrition in arid area.

水分在土壤、植物、大气连续体中不断迁移，但目前对于作物的水分亏缺诊断多只针对其中1-2两个环节，缺乏多指标的综合，而如何在灌溉决策中对作物、土壤、气象复合系统做出综合性的分析和判断也亟待研究。宁夏是枸杞的原产地，种植面积达70万亩，产量占全国60%，出口量90%。当地气候干旱，亩均水资源量仅为全国1/27，水资源极为匮乏。本课题以宁夏为靶区，以大田滴灌枸杞为研究对象，基于SPAC系统，以田间定位观测结合室内试验获取不同水分处理下，土壤水分、作物生理及气象要素等水分亏缺诊断指标数据，分析各指标间的关系；探讨关键指标对枸杞水分亏缺的敏感性；构建多指标模糊评判枸杞水分亏缺综合诊断模型并进行田间验证；应用该模型预报并精量控制枸杞的补充灌溉，确定其相应灌溉指标。课题研究将为作物水分亏缺综合诊断及其精量灌溉决策提供新的思路和靶点并具有巨大的应用前景。

水分在土壤、植物、大气连续体中不断迁移，但目前对作物的水分亏缺诊断多只针对其中1-2两个环节，缺乏多指标的综合，而如何在灌溉决策中对其做出综合性的分析和判断亟待研究。宁夏是枸杞原产地，种植面积达85万亩，产量占全国60%，出口量90%，而当地气候干旱，水资源极为匮乏。课题以宁夏大田滴灌枸杞为对象，基于SPAC系统，以田间定位观测试验获取不同水分处理下土壤水分、生理生长指标及气象参数等水分亏缺诊断指标数据，分析其不同时间尺度变化规律、互相关关系及其对蒸腾耗水的响应特征，通过构建枸杞多指标综合耗水模型，进行枸杞水分亏缺的诊断，应用耗水模型模拟预报进行枸杞精量控制灌溉，确定其灌溉指标。结果表明：距树干水平40cm处的20-50cm主根系土层是干旱区枸杞土壤水分变化敏感区；夜间液流量仅为日累计量6.68-8.15%；午间出现的液流骤减现象是干旱区植物减少水分损耗的保护机制；5-11月全生育期日均耗水1102.7g/d ，6-8月占全生育期耗水的58.12%，日均耗水强度1388.3g/d。蒸腾耗水（S）随着基径（r）增大而增大，满足S=1.1377r-2.1052（R2=0.821）；与冠幅（A）满足S=0.9053A+0.5416（R2=0.680）；与太阳辐射（Rs）、温度（Ta）及饱和水汽压差（VPD）符合多元回归模型 S=0.005Rs+0.066Ta+0.318VPD-0.533（R2=0.695）；与参考作物腾发量（ET0）满足S =0.4515ET0-0.8229（R2=0.641）。建立耗水量与各诊断参量拟合模型S4-10月=1.378r+0.017θ+0.004Rs+0.028T+0.34VPD-4.579（R2=0.693），模型检验误差-5.80%—2.52%。基于模型模拟及产量品质指标综合认为，平水年型（P=50%），枸杞滴灌灌溉定额250m3/亩，灌水次数14次，其中萌芽期灌水1次，营养生长期2次，盛花期、盛果期各4次，秋季生长期3次。项目将土壤-植物-大气作为一个整体，探讨了土壤水和枸杞生长的关系、并考虑了大气环境影响，综合分析了枸杞耗水过程、变化规律、影响因素及其响应特征，构建了蒸腾耗水与土壤含水率、生长生理指标及气象参数的多指标综合模拟模型，为枸杞适时、适量的科学合理灌灌溉提供依据，也丰富了干旱区作物水分亏缺诊断及精量灌溉决策研究的内容。