紫花苜蓿根系主要功能性状对分根区交替灌溉的响应

Response of the Main Functional Traits of Alfalfa Roots to Alternate Partial Root-Zone Irrigation

分根区交替灌溉是一种具有节水潜力的灌溉方式,为了揭示紫花苜蓿(Medicago sativa L.)根系对分根区交替灌溉的响应,在甘肃武威绿洲农业高效用水国家野外科学观测研究站设置3种占田间持水量(Field capacity,FC)不同比例的灌水梯度(T1:80%~100%FC,T2:60%~80%FC,T3:40%~60%FC)去开展分根区交替灌溉与不分根区灌溉的对比试验。结果表明:分根区交替灌溉在80%~100%FC灌水量时,根颈直径小于不分根区灌溉,60%~80%FC和40%~60%FC灌水量时,根颈直径大于不分根区灌溉。分根区交替灌溉的根系分支多于不分根区灌溉,但根平均直径小于不分根区灌溉。两种灌溉方式下紫花苜蓿地上部和地下部的生物量均随着灌水量梯度的下降而下降。同一灌水梯度下,不分根区灌溉的地下和地上生物量均高于分根区交替灌溉。上述结果说明紫花苜蓿采用分根区交替灌溉方式对根系生长发育具有重要影响。

Alternate partial root-zone irrigation is a water-saving potential irrigation approach.In order to reveal the response of alfalfa(Medicago sativa L.)roots to the alternate partial root-zone irrigation,a comparative experiment between the alternate partial root-zone irrigation and the entire root-zone irrigation was carried out in National Field Scientific Observation and Research Station on Efficient Water Use in Oasis Agriculture in Wuwei of Gansu Province,along with the three irrigation water gradients:T1(180%~100%field capacity(FC)),T2(60%~80%FC),T3(40%~60%FC).The results showed that when 80%~100%FC irrigation was used by the alternate partial root-zone irrigation approach,the root neck diameter of alfalfa was smaller than that under the entire root-zone irrigation;and when 60%~80%FC and 40%~60%FC irrigation were used,the root neck diameter of alfalfa under the alternate partial root-zone irrigation was larger than that under root-zone irrigation.The number of root branches of alfalfa under the alternate partial root-zone irrigation were more than that under the entire root-zone irrigation,but the average root diameter of alfalfa was smaller than that under the entire root-zone irrigation.The aboveground and belowground biomass of alfalfa decreased with the decrease of irrigation gradients under the both two irrigation approaches.Under the same irrigation gradient,the belowground and aboveground biomass under the entire root-zone irrigation were higher than those under the alternate partial root-zone irrigation.The overall outcome of this study showed that the alternate partial root-zone irrigation approach had an important influence on the root growth and development of alfalfa.