耕作方式对小麦开花后旗叶水势与叶绿素荧光参数日变化和水分利用效率的影响

2007-2009年小麦生长季, 以高产小麦品种济麦22为试验材料, 利用测墒补灌技术确定灌水量, 研究高肥力条件下条旋耕、深松+条旋耕、旋耕、深松+旋耕和翻耕5种耕作方式对土壤含水量、小麦开花至成熟阶段耗水量及其水分来源、旗叶水势和叶绿素荧光参数日变化、籽粒产量和水分利用效率的影响。结果表明, 深松+条旋耕和深松+旋耕处理成熟期60~200 cm各土层的土壤含水量均低于其他处理, 表明深松促进了小麦对深层土壤贮水的吸收。深松+条旋耕处理开花至成熟阶段的土壤贮水消耗量及其占阶段耗水量的比例最高, 其降水量和灌水量占阶段耗水量的比例最低。深松+条旋耕处理在6:00~18:00的旗叶水势、8:00~14:00的旗叶最大光化学效率(F_v/F_m)和实际光化学效率(Φ_PSII)均高于条旋耕处理, 表明深松有利于小麦旗叶在灌浆中后期保持较高的生理活性, 深松+旋耕和旋耕处理间的规律与其一致。深松+条旋耕处理在2个生长季的籽粒产量分别为9 516.48和8 957.92 kg hm⁻², 与深松+旋耕处理无显著差异, 翻耕处理次之, 条旋耕和旋耕处理低于上述处理。深松+条旋耕处理的水分利用效率最高, 深松+旋耕处理次之, 条旋耕和旋耕处理低于翻耕处理。本试验条件下, 深松+条旋耕是兼顾高产节水高效的耕作方式。

Effect of Tillage Mode on Diurnal Variations of Water Potential and Chlorophyll Fluorescence Characteristics of Flag Leaf after Anthesis and Water Use Efficiency in Wheat

Water resource shortage has become the urgent problem limiting wheat(Triticum aestivum L.) production in Yellow-Huaihe-Haihe Rivers Plain of China.A crucial target of wheat production is to develop water-saving agriculture to reduce irrigation water and increase the water use efficiency(WUE).The objective of this study was to understand the effects of tillage practices on soil moisture content,water potential and consumption in plants,diurnal variation of chlorophyll fluorescence characteristic in flag leaf after anthesis,and grain yield in wheat under flexible irrigation conditions.A high-yielding wheat cultivar,Jimai 22,was continuously planted in the same plot across two growing seasons from 2007 to 2009.Five tillage modes were established with flexible irrigation after measuring soil moisture,which were strip rotary tillage(SR),strip rotary tillage after subsoiling(SRS),rotary tillage(R),rotary tillage after subsoiling(RS),and plowing tillage(P).The moisture contents of soil layers within 0-200 cm were measured at sowing,jointing,anthesis,and maturity stages.In the 2008-2009 growing season,the diurnal variation of water potential and chlorophyll fluorescence characteristic in flag leaf were measured at 22 d and 24 d after anthesis.The SRS and RS treatments had the lowest moisture content in different soil layers of 60-200 cm below surface.The result indicated that subsoiling had the effect to promote water absorption of wheat in deep soil layers.From anthesis to maturity,the water consumption of SRS treatment exhibited the highest amount and ratio from soil and the lowest ratio from precipitation and irrigation.Compared with SR treatment,SRS treatment had higher water potential from 6:00 to 18:00 and larger values of Fv/Fm and ΦPSII of flag leaf from 8:00 to 14:00.Clearly,subsoiling was favorable to keep high physiological activity from mid to late filling stage.The positive effect of subsoiling was confirmed by the comparison between RS and R treatments.Among the five tillage treatments,SRS produced the highest grain yield of 9 516.48 kg ha-1 in 2007-2008 growing season and 8 957.92 kg ha-1 in 2008-2009 growing season.The yield level of RS had no significant difference from that of SRS treatment.In contrast,SR and R treatments showed the lowest yields in all treatments.As for WUE,the ranking sequence of treatments was SRS > RS > P > SR or R.Therefore,we recommend SRS as the best tillage practice for high yield and water saving in wheat producing areas with similar ecological conditions to the experiment.