滴灌带铺设模式对成龄枣树根系再分布及产量的影响

Location of Drip Irrigation Tapes Affects Root Redistribution and Yield of Mature Jujube

【目的】探明长期漫灌改滴灌后适宜的滴灌带铺设模式对成龄枣树根系再分布及产量的影响。【方法】以新疆长期漫灌红枣为研究对象,设置3个滴灌带铺设模式,分别为枣树二侧50 cm(T1)、35 cm(T2)和20 cm(T3)处铺设滴灌带,以漫灌为对照(CK),研究漫灌改滴灌对土壤水分分布、枣树根系再分布及产量的影响。【结果】漫灌改滴灌后,土壤湿润区显著收缩,水分集中在根系聚集区;随着滴灌带铺设距离的增大,土壤湿润区由窄深型演变为宽浅型,有利于红枣根系生长。长期漫灌条件下成龄枣树根系空间分布相对均匀,经过连续2 a的滴灌调控,T1、T2、T3处理0~60 cm土层平均根长密度分别比CK增加了32.7%、31.6%和21.4%;水平方向上,T1处理和T2处理距离树干0~75 cm根长密度较CK提高了20.1%和24.5%,T3处理0~50 cm根长密度较CK提高了25.8%,但50~100 cm下降了15.2%;漫灌改滴灌还可显著提高红枣产量和灌溉水分利用效率,滴灌第2年,T1处理和T2处理红枣产量分别达到了9 135 kg/hm^(2)和9 107 kg/hm^(2),分别比CK提高了12.9%和12.5%。【结论】针对新疆长期漫灌红枣改滴灌初期,35 cm或50 cm的滴灌带铺设模式,有利于提高枣树根系的调控和果实产量。

【Background】Flooding irrigation is commonly used to water jujube in Xinjiang.It is not only an inefficient use of the scarce water resources and increases evaporation and leakage,but could also result in soil compaction and secondary soil salinization.Over the past decade,drip irrigation has emerged as an improved alternative to replace flooding irrigation of jujube.【Objective】This paper investigates how locations of drip irrigation tapes impact on root redistributions and yield of mature jujube trees.【Method】We took jujube trees under long-term flooding irrigation as an example and replaced it with drip irrigation.We compared three locations by laying the drip irrigation tapes at 50 cm(T1),35 cm(T2)and 20 cm(T3)away from either side of the tree stem,with continuing flooding irrigation taken as the control(CK).In each treatment,we measured the wetted soil zone,root distribution and ultimate yield of the jujube.【Result】Changing flooding irrigation to drip irrigation narrowed the wet zone significantly,with the majority of the irrigating water constrained to the root zone.With the distance between drip tape and tree stem increasing,the wetted zone changed from narrow-deep shape to wide-shallow shape,benefiting root growth as a result.Long-term flooding irrigation has made root distribute more uniformly,and two years after change to drip irrigation,the root-length density in the top 0~60 cm soil increased by 32.7%(T1),31.6%(T2)and 21.4%(T3),respectively,compared to those in CK.Horizontally,T1 and T2 increased root-length density in 0~75 cm soil and T3 increased root-length density in 0~50 cm soil by 20.1%,24.5%and 25.8%,respectively,compared to CK.Drip irrigation improved yield,with T1 and T2 increasing the yield by 12.9%and 12.5%,at 9135 kg/hm2 and 9107 kg/hm2 respectively,compared to CK.【Conclusion】Replacing flooding irrigation with drip irrigation not only reduces irrigation amount and increases water use efficiency,but also inhibits vegetative growth and increases the ultimate yield.For jujube production in Xinjiang,laying the drip tapes 30~50 cm from either side of the tree stem is optimal for regulating root growth and improving jujube yield.