不同底墒条件下补灌对冬小麦耗水特性、产量和水分利用效率的影响

我国黄淮平原水资源紧缺,而且年际间降水量及其时间分布存在较大差异,探明不同底墒条件下补充灌溉对冬小麦产量和水分利用效率的调节效应及其生理基础,可为该地区冬小麦节水高产栽培提供理论和技术支持。2013—2014和2014—2015年冬小麦生长季,在播种期0~100 cm土层土壤贮水量分别为201.5(A)、266.3(B)和317.0mm(C)3种底墒条件下,各设置4个补灌水处理,包括不灌水、拔节期+开花期补灌、越冬期+拔节期+开花期补灌、播种期+拔节期+开花期补灌,研究不同处理冬小麦耗水特性、旗叶光合、干物质积累与分配、产量及水分利用效率的差异。结果表明,冬小麦生育期总耗水量和土壤水消耗量均随播种期底墒的提高而增加。在底墒A和B条件下,冬小麦主要消耗降水和灌溉水。提高播种期补灌水平或于越冬期补灌,冬小麦在底墒A条件下对土壤水的消耗量显著增加,在底墒B条件下对土壤水的消耗量显著减少。在底墒C条件下,冬小麦耗水以土壤水为主,其次为降水,再次为灌溉水;播种期或越冬期补灌显著增加生育期总耗水量,对土壤水消耗量则无显著影响。于播种期、拔节期和开花期补灌,冬小麦在底墒A条件下可获得较高的籽粒产量,但水分利用效率较低;在底墒B条件下籽粒产量和水分利用效率均较高;在底墒C条件下,仅于拔节期和开花期补灌即可获得高产和高水分利用效率,播种期和越冬期无需补灌。综上所述,播前底墒是实施冬小麦合理补灌的重要依据。

Effects of Supplemental Irrigation on Water Consumption Characteristics,Grain Yield and Water Use Efficiency in Winter Wheat under Different Soil Moisture Conditions at Seeding Stage

Water shortage and unbalanced precipitation distribution are major problems threatening agricultural sustainability, especially winter wheat production, in the Huang-Huai Plain of China and water-saving cultivation with limited irrigation is a promising technique in this area. It is important to understand the regulation effect and physiological basis of supplemental irrigation on grain yield and water use efficiency (WUE) of winter wheat under different soil moisture conditions at seeding stage. In the 2013–2014 and 2014–2015 winter wheat growing seasons, we designed three soil (0–100 cm) moisture conditions at seeding stage (201.5 mm for A, 266.3 mm for B, and 317.0 mm for C) by supplemental irrigation and four irrigation treatments under each soil moisture condition (no-irrigation; irrigated twice at jointing and anthesis stages; irrigated thrice at over-wintering, jointing and anthesis stages; and irrigated thrice at seeding, jointing and anthesis stages). The water consumption characteristics, photosynthesis of flag leaves, dry matter accumulation and distribution, grain yield and WUE of winter wheat were investigated. The soil water consumption and the total water consumption during wheat growth increased when more soil water was available at seeding stage. Wheat mainly consumed precipitation and irrigation water under condition A and B. Supplemental irrigation at seeding or over-wintering stage resulted in significant increase of soil water consumption under condition A, but decrease of soil water consumption under condition B. Under condition C, wheat mainly consumed soil water, followed by precipitation and irrigation water. In this situation, supplemental irrigation at seeding and over-wintering stages resulted in significant increase of total water consumption but no significant effect on soil water consumption. Our results showed high yield but low WUE under condition A and high yield and high WUE under condition B, when watering at seeding, jointing and anthesis stages. Under condition C, high yield and high WUE were obtained only when watering at jointing and anthesis stages, whereas, supplemental irrigations at seeding and over-wintering stages were unnecessary. We conclude that available soil water at seeding stage is the basis and important to reasonable supplemental irrigation during wheat growth.