黄土高原旱作麦田深层土壤水利用与小麦产量及产量稳定性的关系

Relationship between water use of subsoil and wheat yield and yield stability in dryland wheat on the Loess Plateau

黄土高原是我国重要旱作农业区,冬小麦是该地区重要的粮食作物之一,如何进一步提高旱作小麦产量并降低由干旱缺水引起的产量波动是该区域未来小麦生产亟待解决的重要问题。由于黄土高原地区冬小麦生育期和降水季节不匹配,土壤水的利用对该区域小麦生产至关重要。基于黄土高原地区以往研究数据,分析表明当前冬小麦产量水平下土壤水利用并不充分;进一步分析表明,1~2 m深层土壤水残留量和产量高度相关,即在冬小麦收获期,当1~2 m深层土壤中有效水残留量为100~130 mm时,冬小麦产量为2640~4920 kg·hm^(-2),而当残留量减少至30~70 mm时,其产量可显著提高至5250~6576 kg·hm^(-2);此外,加强深层土壤水利用亦可显著提高高产概率。统计结果表明,在可用水量为666~766 mm(播前0~2 m土层储水量与生育期降水量之和)条件下,收获时如果1~2 m深层土壤水残留量从270~210 mm降低至150~90 mm时,小麦产量高于4000 kg·hm^(-2)和5000 kg·hm^(-2)的概率可分别从6%提高至92%、1%提高至66%;在可用水量大于766 mm条件下,小麦产量高于5000 kg·hm^(-2)和6000 kg·hm^(-2)的概率可分别从14%提高至99%、1%提高至41%。进一步讨论了如何通过品种和农艺措施的选用来提高小麦对深层土壤水的利用,基于实际研究案例印证了在该区域可通过优化农艺措施增加深层水利用从而提高产量和水分利用效率的可行性。

The Loess Plateau of China is a typical dryland area and winter wheat is one of the major cereal crops on the Loess Plateau.How to further increase wheat yield as well as maintain the yield stability is a crucial issue that needs to be addressed urgently in this region.Wheat production is profoundly affected by the utilization of soil water due to the region’s erratic precipitation and the mismatch between the rainy season and the winter wheat growing season.We collected the data from published studies on the Loess Plateau and found that large amounts of available soil water remain in soil layer at harvest time.We further analyzed the relationship between grain yield of winter wheat and soil water utilization.The results showed that at wheat harvest time,grain yield was 2640~4920 kg·hm^(-2)when the residual subsoil water storage(RSWS)was 100~130 mm,and it was increased to 5250~6576 kg·hm^(-2)when the RSWS was 30~70 mm.Furthermore,the probability of high grain yield was enhanced by increasing the utilization of subsoil water.When the RSWS reduced from(270~210 mm)to(150~90 mm)mm,the probability of yield exceeding 4000 kg·hm^(-2)or 5000 kg·hm^(-2)was increased from 6%to 92%or 1%to 66%,respectively,under 666~766 mm WS(water supply during the growing season and the sum of soil water storage in 0~200 cm and growing season precipitation)condition.The probability of yield exceeding 5000 kg·hm^(-2)or 6000 kg·hm^(-2)was increased from 14%to 99%or 1%to 41%,respectively under>766 mm WS condition.In addition,we discussed how to increasing subsoil water utilization by variety and agronomic practices and exemplified the feasibility of enhancing yield and water use efficiency by increasing subsoil water utilization through the improvement of agronomic practices.