关键生育期补灌对陕北旱作区大豆产量与水分生产力的影响

Effects of supplemental irrigation at key growth stages on soybean yield and water productivity in arid area of northern Shaanxi

为探究关键生育期补灌对陕北旱作区大豆生长、产量与水分生产力的影响,开展为期两年的田间试验,设置6个处理:分枝期补灌至田间持水量(θ_(f))的80%(BI_(80))、分枝期补灌至100%θ_(f)(BI_(100))、开花期补灌至100%θ_(f)(FI_(100))、分枝期补灌至80%θ_(f)+开花期补灌至100%θ_(f)(BI_(80)+FI_(100))、分枝期补灌至100%θ_(f)+开花期补灌至100%θ_(f)(BI_(100)+FI_(100))和出苗后雨养(CK),探究分枝期和开花期补灌对大豆株高、叶面积指数(LAI)、土壤储水量(SWS)、蒸散量及其生育期分配、干物质积累与转运、产量(SY)、水分生产力(W_(p))和灌溉水利用效率(IWUE)的影响。结果表明:与雨养处理相比,BI_(80)+FI_(100)可以获得适宜的株高和LAI,并同步提高花前、花后干物质积累与转运量,其中SY显著提高28.03%~38.71%(P<0.05),W_(p)显著提高3.80%~13.51%。分枝期将补灌上限从80%θ_(f)增至100%θ_(f),可引起LAI冗长,加速土壤水分消耗,造成花后SWS和蒸散量下降,降低了花后干物质积累与转运量,与BI_(100)+FI_(100)相比,BI_(80)+FI_(100)的SY无显著差异,且其W_(p)较BI_(100)+FI_(100)提高1.23%~9.33%,IWUE显著提高37.69%~60.20%(P<0.05),灌水量较BI_(100)+FI_(100)减少18.54%~20.21%。在BI_(80)+FI_(100)处理下,LAI介于6.66~7.48,ET a/ET b稳定在0.85~1.04,花后干物质贡献率稳定在80.78%~81.07%,均处于适宜范围,实现了当季最高SY、W_(p)和IWUE。综上所述,BI_(80)+FI_(100)处理可以平衡营养生长与生殖生长的水分供需矛盾,为大豆提供一个更稳定和高效的生产环境,推荐在陕北旱作农业区采用该补灌制度。

To investigate the effects of supplementary irrigation during critical growth stages on the growth,yield,and water productivity of soybeans in the dryland farming areas of northern Shaanxi,a two-year field experiment was conducted with six treatments:irrigation to 80%of field capacity(θ_(f))at branching stage(BI_(80)),irrigation to 100%θ_(f) at branching stage(BI_(100)),irrigation to 100%θ_(f) at flowering stage(FI_(100)),irrigation to 80%θ_(f) at branching stage followed by irrigation to 100%θ_(f) at flowering stage(BI_(80)+FI_(100)),irrigation to 100%θ_(f) at branching stage followed by irrigation to 100%θ_(f) at flowering stage(BI_(100)+FI_(100)),and rainfed control(CK).The effects of branching and flowering stage irrigation on soybean plant height,leaf area index(LAI),soil water storage(SWS),evapotranspiration,biomass accumulation and translocation,yield(SY),water productivity(W_(p)),and irrigation water use efficiency(IWUE)were examined.The results showed that compared to the rainfed control,BI_(80)+FI_(100) treatment resulted in appropriate plant height and LAI,along with increased pre-flowering and post-flowering biomass translocation.SY was significantly increased by 28.03%to 38.71%compared to CK(P<0.05),and W_(p) was increased by 3.80%to 13.51%compared to CK.Increasing the upper limit of irrigation from 80%θ_(f) to 100%θ_(f) at branching stage led to prolonged LAI,accelerated soil water consumption,decreased post-flowering SWS and evapotranspiration,and reduced post-flowering biomass accumulation and translocation.Compared to BI_(100)+FI_(100),there was no significant difference in SY for BI_(80)+FI_(100).However,W_(p) increased by 1.23%to 9.33%,and IWUE significantly improved by 37.69%to 60.20%(P<0.05),with irrigation water reduced by 18.54%to 20.21%compared to BI_(100)+FI_(100).Under the BI_(80)+FI_(100) treatment,LAI ranged from 6.66 to 7.48,ET a/ET b stabilized between 0.85 and 1.04,and the post-flowering biomass contribution rate remained steady at 80.78%to 81.07%.These values were within suitable ranges,resulting in the highest SY,W_(p),and IWUE of the season.The BI_(80)+FI_(100) treatment effectively balanced water supply and demand for both the nutritional and reproductive growth of soybeans,creating a more stable and efficient production environment.This approach is recommended for adoption in dryland farming areas of northern Shaanxi.