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Northeast Agricultural University (2018)

Monitoring Study on Wind Erosion in Hailun of the Typical Mollisols Farmland in Northeast China

杨润城;

Titre : Monitoring Study on Wind Erosion in Hailun of the Typical Mollisols Farmland in Northeast China

Auteur : 杨润城;

Grade : Master’s Theses 2018

Université : Northeast Agricultural University

Résumé
The Mollisols area is one of the most serious soil erosion serious regions in China.Besides water erosion,wind erosion is a serious problem and causes a threat on regional food production in Northeast China.Soil wind erosion is the process of soil denudation,separation and transportation by the influence of wind erosion.It is one of the most critical environment problems in arid and semiarid areas.Current researches of wind erosion are mainly conducted in Shaanxi,Inner Mongolia,Gansu and other provinces which are the arid and semi-arid areas in China.Thus there is less studies of wind erosion in the Northeast China.Sand sampler is an important device to monitor the wind erosion,while most sand samplers are used for the monitoring of sandy land.In this study,the general used abroad sand sample,Big Spring Number Eight(BSNE),was developed and applied to the monitoring of wind erosion in the Mollisols farmland.The purpose of this study is focused on the quantitative research of the characteristics and laws of the wind erosion in the farmland of the Mollisols farmland.The results are as follows :(1)The BSNE sand sample did not available for monitoring the wind erosion in Mollisols farmland.The monitoring results of farmland displayed that BSNE sand sample just collected0.13-0.44 g soil particles in the farmland of conventional tillage and no-tillage during the observation period in 2016,which was not enough for the next analysis of wind erosion.This results indicated the large pore screen structure of BSNE sand sampler was not suitable for the monitoring of wind erosion in Mollisols farmland,which major particles were silt(<0.002 mm)and clay(0.002-0.5 mm)particles.(2)The HT sand sample(developed BSNE sand sample)can efficient collect and retain the small soil particles in Mollisols farmland.There was a developed interior structure in HT sand sample.The structure of big diameter screen flapper was changed to the structure of converse shutter flapper,which could increase the capacity of collecting and retaining of small size soil particle.The result indicated HT sand sample could decrease the loss rate of all sizes soil particle under different wind speeds.The loss rate was decreasing more apparent with the increasing of wind speed.Especially when the wind speed reached 20 m s-1,the loss rate of less than 0.075 mm size soil particles decreased from 88.6%to 1.4%and the loss rate of large size soil particles was close to 0.Thus HT sand sample was more suitable for the monitoring of wind erosion in Mollisols farmland.(3)The characteristics and laws of the wind erosion were quantified in the Mollisols farmland.There were 90.9%and 75%strong winds(wind speeds greater than 17 m·s-1),which means the major occurrence period,happened in April and May in 2016 and 2017.During this period in 2017,the results showed the value of different height(0.2,0.5,1.0,1.5 and 2.0 m)of soil saltation per unit area were 4.76,6.93,1.63,1.38 and1.09 kg·m-2,respectively,while the value of soil deposition per unit area on 2 m height and the surface soil creep per unit area were 0.12 and 19.18kg·m-22 in the conventional tillage farmland,respectively.These results indicated that the wind erosion was major based on soil creep,and partially based on soil saltation and deposition in Mollisols farmland in Northeast China.Compared with the conventional tillage farmland,the no-tillage farmland increased 11.71%of soil water content,and decreased 13.11%,40%and39.41%of soil saltation,deposition and creep by the cover of crop residue,respectively.This results indicated the cover of crop residue could effectively reduce the movement of soil particles in surface and prevent wind erosion.

Mots clés : Wind Erosion; Black Soil Farmland; Sand cllector;

Présentation (CNKI)

Page publiée le 26 mai 2019