不同降水年型水分运筹对冬小麦产量及其构成的影响

Effect of water management on yield and its components of winter wheat in different precipitation years

为明确不同降水条件下实现小麦产量及构成提高的灌水策略,以冀麦585为试验材料,于2010—2017年小麦季设置W0 (雨养)、W1 (拔节)、W2 (拔节、开花)、W3 (拔节、开花、灌浆)和W4 (越冬、拔节、开花、灌浆) 5种灌水处理,分析了不同降水年型下降水、灌水与小麦产量及构成的关系。结果表明:(1)不灌水条件下多数年份的小麦产量在6400~6800kghm^(–2),穗数与产量显著正相关(r=0.860*);增加灌水,产量、穗粒数和千粒重增加,但每增1水增产率显著下降(由13.8%下降到1.7%)。(2)生育期总降水量及阶段降水量与产量无明显相关关系,总降水量对千粒重的影响高于其他因素;W0和W1条件下,总降水量对穗粒数的影响>穗数,增加灌水后反之,而该条件下穗粒数与拔节前降水呈显著正相关且W0下与2月1日至拔节前降水的相关性>播种到拔节前,但随灌水增加其相关性降低;除W4灌水与穗粒数和千粒重相关性>降水且相关显著以外,W1~W3条件下其相关性降水>灌水,这表明灌水缓解降水不足对穗粒数的影响。(3)前多后少年型(拔节前后降水88.2 mm+29 mm)穗粒数和千粒重最高,且3水产量最高,但与2水无差异;相对均衡年型(拔节前后降水<60mm,30~80mm)的小麦产量及构成总体偏低但相对稳定,灌水后穗粒数和千粒重增加,但影响相对较小,2~3水产量差异显著(后期降水<36mm)(增产率为10.5%和22.9%);前少后多年型(拔节前后降水<25 mm, 40~90 mm)增加灌水最高穗粒数增加1.5~7.1粒,多水处理下千粒重差异较小, 4月无有效降雨时灌溉3水较2水产量显著增加13.4%。因此,本区域小麦拔节前降水量低于60mm时(尤其低于25mm)灌溉拔节水对穗粒数增加作用明显;相对均衡年型拔节后降水低于36mm、前少后多年型4月份无明显有效降水年度灌溉3水,其他年度灌水2次可实现有限灌水下的产量最大化。

To clarify the irrigation strategy for improving yield and its components,the relationship among precipitation,irrigation,yield,and its components was systemically studied under different rainfall conditions.In this experiment,Jimai 585 used as the experimental materials,and five irrigation treatments including W0(rain fed),W1(jointing),W2(jointing,flowering),W3(jointing,flowering,filling),and W4(overwintering,jointing,flowering,filling)in the wheat season were set up from 2010 to 2017.The results were as follows:(1)wheat grain yield varied from 6400 to 6800 kg hm^(–2) under different irrigation treatment in most rainfall years,and spike numbers was positively correlated with grain yield(r=0.860*),the grain yield,grain numbers per spike,and thousand grain weight increased with the increase of irrigation amount,however,the yield increase rate decreased with each additional water(from 13.8%to 1.7%).(2)There was no obvious correlation between the total precipitation and stage precipitation and grain yield,but the impact of total precipitation on the thousand grain weight was higher than the other factors.Under the conditions of W0 and W1,the effect of total precipitation on the numbers per spike was greater than spike numbers,and vice versa after increasing irrigation.At the same time,the grain numbers per spike was significantly positively correlated with the precipitation before jointing,and the correlation between the grain numbers per spike and the precipitation from February 1 to jointing under W0 was greater than that from sowing to jointing,but it decreased with the increase of irrigation amount.With the exception of the correlation between W4 irrigation and grain numbers per spike and thousand grain weight was higher than that of precipitation,the correlation between two factors and precipitation was higher under W1–W3 conditions,which indicating that irrigation alleviate the adverse effect of insufficient precipitation on grain number per spike.(3)The number of grains per spike and thousand grain weight were the highest in a rainfall year characterized with more precipitation at early growth stages and less precipitation at later growth stages(precipitation before and after jointing 88.2 mm+29 mm),and the highest yield was observed under 3 irrigation times,and there was no significant difference between 3 irrigation times and 2 irrigation times.In years characterized balanced rainfall(precipitation before and after jointing<60 mm,30–80 mm),lower and relatively stable yield and its component appeared,and the grain numbers per spike and thousand grain weight increased slightly after irrigation,but the difference in grain yield between 2 and 3 irrigation times was significant(yield increase rate:10.5%and 22.9%)(the rainfall after jointing<36 mm).In year characterized with less precipitation at early growth stages and more precipitation at later growth stages in(precipitation before and after jointing<25 mm,40 to 90 mm),the maximum grain number per spike increased by 1.5 to 7.1 grains when irrigation increased,and the grain yield of irrigation 3 times was 13.4%higher than that of irrigation 2 times when inadequate effective rainfall happened in April.In conclusion,when the precipitation before jointing was less than 60 mm(especially less than 25 mm),irrigation at jointing had an obvious effect on the increase of grain number per spike,3 times irrigation promoted grain yield when the precipitation after jointing is less than 36 mm in a relatively balanced rainfall year type and no sufficient effective rainfall in April in years characterized with less precipitation at early stages and more precipitation at late stages,and irrigation 2 times was suggested to achieve the maximum grain yield in other rainfall years.