基于相对生长率的大豆旱灾系统敏感性定量评估研究

针对大豆旱灾系统敏感性定量评估的复杂性与重要性,依托新马桥农水综合试验站开展大豆防雨棚盆栽受旱胁迫专项试验,分析了大豆不同生育期受旱胁迫对根(冠)干物质积累及根冠比的影响,运用作物生长解析法构建了基于相对生长率(RGR)的大豆旱灾系统敏感性函数,实现对大豆旱灾系统敏感性的定量评估。结果表明:大豆苗期受旱胁迫会出现相对生长率较大幅度的降低,但随着受旱胁迫度的增大对大豆生长和干物质积累的抑制作用增强不明显,且受旱胁迫会激发自身适应受旱胁迫的机制而可能对后期生长发育有利,宜根据时机控制该生育期水分供给,保证苗全即可;大豆分枝期旱灾系统敏感性较强,但该生育期内轻度受旱胁迫对大豆生长发育影响不明显,宜保证该生育期水分供给高于轻度受旱胁迫(土壤含水率田间持水含水率的55%),以保障大豆株壮、枝多;大豆花荚期是水分和养分需求最大的时期,该生育期旱灾系统较敏感,特别是重度受旱胁迫时系统敏感性最大,宜充分保证该生育期的水分供给(土壤含水率田间持水含水率的75%),以保障大豆花多、荚多、粒多;大豆鼓粒成熟期由于营养生长基本停止、干物质积累几乎停滞,导致基于总干物质相对生长率旱灾系统敏感性最小,但该期是产量形成的关键期,宜保证该生育期尤其鼓粒期的水分供给(土壤含水率田间持水含水率的75%),以保障完熟期粒多、粒重。

Quantitative Evaluation of Soybean Drought System Sensitivity based on Relative Growth Rate

In allusion to the complexity and importance of quantitative evaluation for soybean drought system sensitivity,relying on agricultural water comprehensive test station of Xinmaqiao to carry out special soybean potted drought stress tests with anti canopy.Analysis of drought stress of soybean at different growth stages on dry matter accumulation of root and shoot and root-shoot ratio.The sensitivity function of soybean drought system based on relative growth rate (RGR) was constructed by crop growth analysis method.And then to achieve a quantitative assessment of the sensitivity of soybean drought system.The results indicate that soybean seedlings under drought stress will be a relatively large growth rate of the reduction.But with the increase of drought stress,the inhibition of soybean growth and dry matter accumulation was not obvious.And drought stress can stimulate itself to adapt to the mechanism of drought stress beneficial to the late growth and development.Appropriate control of water supply at seedling stage to ensure that all seedlings.Soybean drought system is more sensitive in branching period.But the growth period of mild drought stress on soybean growth effect is not obvious.It is necessary to ensure that the water supply during branching period is higher than the mild drought stress,then the soil moisture can content more than 55％ of field capacity moisture content to protect soybeans thrive.Soybean flowering-poding period requires the most in water and nutrient,the drought system sensitivity of this growth period is also relatively large,especially when serious drought stress system sensitivity is the largest.It is necessary to fully guarantee the water supply during flowering-poding period that the soil moisture content more than 75％ field capacity moisture content.Because the vegetative growth and the accumulation of dry matter are almost stagnant in soybean mature period,the drought system sensitivity is minimal that base on the relative growth rate of total dry matter.But soybean mature period is the critical period of soybean yield formation,it is necessary to fully guarantee the water supply during soybean mature period that the soil moisture content more than 75％ of field capacity moisture content.