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Simulation Study On Soil Water And Salinity Dynamics Of Coastal Salinized Soil Under Mulching And Tilliage

Posted on:2021-03-08Degree:MasterType:Thesis
Country:ChinaCandidate:Z Y ZhongFull Text:PDF
GTID:2370330602962504Subject:Water conservancy project
Abstract/Summary:PDF Full Text Request
With the continuous development of urbanization level in China,the supply of agricultural water and land resources are becoming more and more scarce.It is of great significance for ensuring national food security to develop and utilize the salinized soil as it is an important reserve land resource.Based on this,this study discussed the effects of different mulching and tillage systems on coastal salinized soil.The simulated experiments and potted experiments were carried out with 4 practices(traditional tillage(CK),film mulching(FM),straw burying(SDB)and straw burying combined with plastic mulching(F+S)).The effects of different mulching and tillage systems on saline soil infiltration,evaporation as well as spring maize growth were analyzed,and the dynamics of soil salt and water were discussed.The main findings are as follows:(1)Compared with the traditional tillage,the buried straw layer obviously slowed down the water leakage rate.The infiltration rate significantly reduced after the infiltration water passed through the buried straw layer.The relationship between the cumulative infiltration and the dynamics of wet front over time changed into linear relationship from the power function relationship.The evaporation was restrained under all treatments to varying degrees,the straw interlayer impeded the upward supply of deep soil water,and the inhibition of evaporation was better than film mulching during the later stage of evaporation.(2)During the water Infiltration,buried straw layer improved the water holding capacity of the upper soil.Compared with traditional tillage,the water retention in the upper soil layer was increased by straw layer after irrigation.During the water evaporation,the straw interlayer impeded the upward supply of deep soil water,which improved the water storage capacity of the lower soil layer.The plastic film mulching effectively inhibited the invalid evaporation of soil moisture and improved the water content of the upper soil layer.The upward movement of soil salt was inhibited under each treatment as well as the decrease of soil water evaporation.Compared to the plastic film mulching,straw burying treatment had better salt regulating effect during the later stage of evaporation.The straw burying combined with plastic mulching had the best effect on soil salt regulation.(3)During the potted experiments,the straw burying combined with plastic mulching had the best effect on water storage and soil salt regulation.The water storage of 0?30 cm soil layer under film mulching treatments(FM,F+S)were significantly higher than that under other treatments(CK,SDB)during the whole stage of maize growth.The buried straw layer changed the water status of soil profile.Compared with traditional tillage,the water content of lower soil layer was significantly increased by straw layer.The plastic film mulching showed a good role of salt suppression during the whole growth stage,while the buried straw layer mainly worked at the seedling period of maize growth.(4)The maize growth and yield were promoted under all the mulching and tillage systems,and the straw burying combined with plastic mulching(F+S)showed the best effect during the growth stage of maize.The straw burying combined with plastic mulching(F+S)increased the soil temperature,improved the soil water content as well as the salt environment,and the decomposition of straw during the middle and later stages of maize growth increased the soil fertility,which promoted the crop growth.(5)The mulch and tillage systems were evaluated by the gray multidimensional comprehensive feudatory degree evaluation method,the results showed that that straw burying combined with plastic mulching(F+S)had the best effect on the improvement of coastal saline soil,and can be recommended as a suitable land reclaimation method in this area.
Keywords/Search Tags:Salinized soil, Straw burying, Soil water infiltration, soil salt and water distribution, crop growth
PDF Full Text Request
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