甘肃省冬小麦水分盈亏指数的改进及其应用

冬小麦是甘肃省主要粮食作物,水分是限制该省旱作冬小麦生产最主要的因素,降水时空分布不均造成冬小麦干旱常年发生,因此准确监测甘肃省冬小麦干旱及定量评估灾害损失可为决策部门制定农业防灾减灾措施及保障区域粮食安全提供科学依据。利用甘肃省1981—2014年3个农业气象观测站土壤水分和冬小麦生育状况观测资料,38个冬小麦种植县气象资料、产量资料及干旱灾情资料,考虑冬小麦休闲期土壤储水及生育期水分盈亏量修订了作物水分盈亏指数,修订后作物水分盈亏指数与土壤储水、冬小麦产量要素和产量损失相关性较高,能客观、准确、定量地反映干旱对甘肃冬小麦产量的影响;利用水分盈亏指数分别建立冬小麦产量要素和产量损失评估模型。结果表明:产量要素评估模型均通过0.01水平显著性检验,产量损失评估模型大部分通过0.05水平显著性检验。产量要素评估模型回代结果与冬小麦产量要素实测值间均通过0.01水平的F检验;产量损失评估模型验证结果表明,68.4%种植县通过0.05水平F检验,基本能准确评估全省大部分地方干旱对冬小麦产量造成的损失。修订后作物水分盈亏指数能客观反映甘肃省冬小麦干旱,建立的评估模型能准确评估干旱对冬小麦造成的损失,具有一定的应用价值。

Improvement and applicability of winter wheat water budget index in Gansu Province

Winter wheat is a major grain crop in Gansu Province, where precipitation is the most limiting factor for winter wheat production. The uneven space-time distribution of precipitation results in perennial winter wheat drought in Gansu Province. It is therefore practically important to accurately monitor drought and quantitatively evaluate disaster losses of winter wheat in Gansu Province. This can provide the needed scientific basis for decision-making departments to formulate agricultural disaster prevention and mitigation measures towards regional food security. In this study, we collected data on soil water content and winter wheat growth conditions in three agronomic observatory stations. Data were also collected on meteorological conditions, yield and drought disaster in 38 winter wheat growing counties for the period 1981-2014. Based on soil water storage during fallow period and on water budget for winter wheat development stage, crop water budget index was revised. There was a high correlation among crop water budget index and soil water storage, yield factors and losses. Therefore, it objectively, accurately and quantitatively reflected the impact of drought on winter wheat yield in Gansu Province. A yield-factor assessment model and a yield-loss assessment model were developed in the study based on the revised water budget index. The results showed that while the yield-factor assessment model passed 0.01 test of significance, and much of the yield-loss assessment model passed 0.05 test of significance. The assed and measured values of winter wheat yield factors passed F-test (P<0.01). The validation results of the yield loss assessment model showed that 68.4% of wheat growing counties passed F-test (P<0.05), which more accurately assessed the loss due to drought in Gansu Province. The revised crop water budget index objectively reflected the drought of winter wheat in Gansu Province and the established assessment model accurately estimated the loss due to drought, which provided a reliable reference for application.