Comparison of salt distribution and accumulation characteristics of oasis farmland ecosystem under different irrigation modes in arid region
In order to compare the long-term effects of different irrigation modes and irrigation quota on the salt distribution of oasis farmland ecosystems in arid areas,soil profile excavation and sampling were carried out on flooding irrigated wheat fields,forest lands,drip irrigated cotton fields,alfalfa fields,non-irrigated primitive deserts and abandoned lands in April 2023.At the same time,the soil salt distribution was studied by using the"soil drilling method"at 0-100 cm soil with the interval of 20 cm.The results showed that compared with the average salt content of the primitive desert and the five-year abandoned soil(15.82 g∙kg-1 and 2.83 g∙kg-1),long-term drip irrigation and flooding irrigation significantly reduced the soil salt,and the average salt content of flood irrigation forest and wheat field was 1.17 g∙kg-1 and 1.13 g∙kg-1,respectively.The average salt accumulation in drip irrigated cotton field and alfalfa field was 1.33 g∙kg-1 and 0.92 g∙kg-1,respectively.When the irrigation amount of forest land and cotton land keep the same(4 500 m3∙hm-2)in the long term,the salt accumulation of drip irrigation cotton field is higher than that of forest land,and it mainly distributed in 0～60 cm soil layer;When the long-term irrigation amount of alfalfa field and wheat field was the same(6 000 m3∙hm-2),the soil salt content in the wheat land was slightly higher than that in the alfalfa land,but there was no significant difference.Without considering irrigation method,soil salt content and distribution were obviously related to irrigation quota and the vegetation type,and the order of salt accumulation was alfalfa field<wheat field<forest land<cotton field.Consequently,in the oasis farmland ecosystem with about 7 m deep groundwater table,long-term drip irrigation and flood irrigation both accelerate the leaching of soil salt,and the irrigation quota of 4 500 m3∙hm-2 per year create a non-salinization environment in the 0-100 cm soil profile.When the irrigation amount was the same,the irrigation mode was no longer the main factor affecting the soil salt content,and the salt distribution of 0-60 cm soil mainly depended on vegetation type.When the irrigation mode was the same,the salt distribution in 0-100 cm soil profile was no longer controlled by the irrigation mode,but more depended on the irrigation quota.High irrigation quota promoted salt leaching.
drip irrigationflooding irrigationirrigation quotaagricultural ecosystemland use typesalt movement
万方数据
维普
