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Ningxia University (2018)

Effects of Rainfall and Gravel-soil Covered on Soil Water Evaporation in Gavel-mulched Land of Ningxia Central Arid Region


Titre : Effects of Rainfall and Gravel-soil Covered on Soil Water Evaporation in Gavel-mulched Land of Ningxia Central Arid Region

Auteur : 刘学智;

Grade : Master’s Theses 2018

Université : Ningxia University

The paper carried out investigations and data collection on the practical problems of water shortage,strong evaporation,and low utilization efficiency of water resources in the central arid region of Ningxia,and reviewed a large number of domestic and foreign relevant literatures to suppress local climate change and sand cover to inhibit soil moisture evaporation and soil moisture.The research results of transport laws and other systems were systematically summarized and analyzed.In order to reduce the evaporation of soil moisture,a sand mixture test with different amounts of precipitation and different proportions was designed to monitor and analyze the effects of precipitation,sand mixture mixture,and their combinations on the soil moisture evaporation process.Through data collection,experimental research and analysis,the following conclusions were obtained under the specific conditions of this experiment :(1)From 1960 to 2016,the average temperature,sunshine duration,and average wind speed in the Xiangshan area of Ningxia showed an increasing trend,with an increase of 0.41℃,33.Ih,and 0.09m/s per decade respectively ;Humidity and evaporation showed a downward trend,dropping by 0.22℃,3.85mm,1.69%,and 33.1mm,respectively,every 10 years.Poor day,precipitation,sunshine duration,average wind speed,and relative humidity have a greater impact on evaporation in the Xiangshan area.(2)The evaporation of soil moisture is greatly affected by rainfall.Under the same proportion of sand and soil mixture,the greater the rainfall,the greater the daily evaporation intensity and the accumulated evaporation of soil in the same period.After the rainfall,the evaporation intensity of soil moisture gradually decreased with the extension of time,and the accumulated evaporation and time of soil moisture showed an exponential function.(3)The amount of rainfall control is constant,and the daily evaporation intensity of soil moisture decreases with the increase of the sand content of the cover.The effect of full sand coverage on evaporation is best,and it is more conducive to precipitation accumulation and evaporation inhibition.The cumulative soil evaporation and time after rainfall showed an exponential function ;(4)Under the same mixed proportion of sand and soil,the evaporation duration of a soil moisture rainfall increases with the increase of rainfall,and the smaller the rainfall,the greater the change,the relationship between the evaporation duration of a rainfall and rainfall can be used.5 times polynomial description ;the relationship between the time and size of a single rainfall evaporation with different proportions of sand mixed under the same rainfall is:full sand>40%>80%>60%>20%>bare soil,full sand is more favorable for water conservation and evaporation Inhibition,the relationship between evaporation duration of a rainfall and sand ratio can be described by polynomial of degree 2 ;(5)The effect of sand mixture mixture and rainfall combination on the evaporation intensity of soil moisture and the evaporation duration of a rainfall can be expressed by the polynomial of degree 5.R2 reaches 0.983 and 0.980,respectively,and the goodness of model fitting is high.And each item and the whole have reached a significant level.The study has important academic and practical value for understanding the evaporation of soil moisture in the sand-pressed areas of the central arid region of Ningxia,the suppression of soil water evaporationunder the climate and environmental changes,the establishment of a reasonable water conservation system,and the improvement of water use efficiency.In the central Ningxia region,continuous development of pressure sand areas,and the realization of efficient use of water resources and ecological restoration provide data support

Mots clés : Gavel-mulched land; Evaporation intensity; Cumulative evaporation; Evaporation duration; Gravel-soil;

Présentation (CNKI)

Page publiée le 17 mai 2019