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为了研究不同滴灌措施对极端干旱区防护林土壤盐分的淋洗作用,以沙枣(Elaeagnus angustifolia)防护林作为研究对象,对塔里木河下游喀拉米吉绿洲沙枣防护林开展了灌溉与不灌溉、不同滴头距离、不同滴灌年限处理的试验。结果表明:①不灌溉林地土壤盐分含量与流动沙丘相似,流动沙丘土壤盐分分布的空间异质性大于不灌溉林地。滴灌林地土壤含盐量低于不灌溉林地。②1.5m滴头距离处理与其他处理相比压盐碱效果显著(P<0.01)。1.5m与3m滴头距离处理在50cm土体中含盐量差异达极显著水平(P<0.01),前者比流动沙丘低30.5%～32.7%、后者比流动沙丘高17.1%～13.3%。与3m滴头距离处理相比,1.5m滴头距离处理产生水盐运移的“互作”影响,盐峰下移。③滴灌后的第1、2、3年,林地的土壤盐分分别下降至30cm、50cm和70cm以下,基本对沙枣根系生长没有影响。随着滴灌次数增加,根系生物量逐渐增大,根系附近土壤盐分逐渐减少。滴灌能使防护林的根系分布上移,大部分在10～65cm土层内,土层越深,林木的根系越少。④灌水季节末期,不同林龄的防护林在120cm土体的含盐量表现为:1a林>2a林>6a林,说明滴灌对林龄大的防护林淋洗效果更为明显;非灌溉季节里,防护林的林龄越大,其土壤盐分表聚现象越明显。
In order to study the leaching action of different drip irrigation measures on soil salinity of shelterbelt in extreme arid region, Elaeagnus angustifolia shelterbelt was taken as the research object. Irrigation and non-irrigation were carried out on the shelled shelled sand shellac of Elaeagnus angustifolia in the lower reaches of the Tarim River. Distance, different drip irrigation years of treatment test. The results showed that: (1) The soil salinity in the non-irrigated forest was similar to that in the moving dune. The spatial heterogeneity of soil salinity in the mobile dune was greater than that in the non-irrigated forest. The soil salt content of drip irrigation forest is lower than that of non-irrigation forest. ②1.5m dripper distance treatment compared with other treatments salinization effect was significant (P <0.01). The difference of salt content in 50cm soil between 1.5m and 3m drip distance reached extremely significant level (P <0.01). The former was 30.5% ~ 32.7% lower than that of flowing dune while the latter was 17.1% ~ 13.3% higher than that of flowing dune. Compared with the 3m drip distance treatment, 1.5m dripper distance treatment resulted in the interaction of water and salt “interaction ”, the salt peak down. ③ The soil salinity in the first, second and third years after drip irrigation decreased to below 30cm, 50cm and 70cm, respectively. With the increase of drip irrigation frequency, the biomass of root system increased gradually, and the soil salinity gradually decreased near the root system. Drip irrigation can make the root distribution of shelterbelt up, mostly in 10 ~ 65cm soil layer, the deeper the soil layer, the less forest root system. At the end of the irrigation season, the salt content of shelterbelts with different ages in the 120 cm soil layer was: 1a> 2a> 6a forest, indicating that drip irrigation was more effective for the older shelterbelts. In non-irrigation season, The larger the stand age of shelterbelts, the more obvious the phenomenon of soil salinity.