Study On Improvement Of Saline-Alkalized Abandoned Farmland In Jiuquan Bian Wan Farm

Ganxin inland saline area is the largest saline-alkali area in China,including Gansu Hexi Corridor and most of Xinjiang.Because of the serious salinization,agricultural production is difficult to carry out,and the ecological environment continues to deteriorate,which seriously affects the happiness of the local people.For this reason,this paper selected Bianwan Farm in Jiuquan City,a typical saline-alkali area,to analyze the characteristics of soil salinization,and then to carry out experimental research on soil improvement,in order to provide feasible reference and guidance for the reclamation of saline-alkali abandoned farmland and the improvement of saline-alkali land in Ganxin inland saline-alkali area.Based on the detailed field investigation in the study area,the sample plots and sampling points were scientifically determined,and then the typical soils of Bianwan Farm in Jiuquan were collected.The depth of soil sampling in the profile was 0-100 cm（0¹0 cm,10²0 cm,20³0 cm,30⁵0 cm,50⁸0 80¹00 cm）and the depth of soil sampling in the plough layer of No.7 sample plots was 0³0 cm.And pot experiment.In the improved experiment,the desulphurization gypsum with different gradients（0 kg/hm²,11250 kg/hm²,22500 kg/hm²,33750 kg/hm²,45000 kg/hm²）and the desulphurization gypsum and furfural residue with different gradients were applied separately.Based on the improved experiment,pot experiment was carried out.The formula was 33750 kg/hm² desulphurization gypsum+7500kg/hm²+Furfural residues with different gradients.By measuring the salinization index before and after the improvement and the germination and growth of seeds,the best mixed improvement scheme of saline-alkali abandoned farmland is obtained,which provides scientific basis and practical guidance for the reclamation of saline-alkali abandoned farmland in Jiuquan Bianwan Farm.The main results of this paper are as follows（1）The soil saline-alkali characteristic indicators Ca²⁺,Na⁺,Mg²⁺,K⁺,Cl^-,SO₄^2-,CO₃^2-,HCO₃^-,alkalinity,total alkalinity,sodium adsorption and salinity of different sample plots in the study area showed a trend of surface accumulation,and the general trend decreased gradually with the increase of soil depth.The salinization index of No.7 sample plot was the heaviest.The salinization index of plough layer soil was significantly higher than that of below 30 cm.The salinity of plough layer soil was 35.20%,which was heavily alkaline soil with a salinity of 27.2（g/kg）.The average soil salinization trend of Bianwan farm decreased from the surface（0¹0 cm,10²0 cm,20³0 cm,30⁵0 cm,50⁸0 cm,80¹00 cm）,which accorded with the distribution law of soil salinization in arid area.（2）The average content of soil organic matter in the cultivated layer is 12.733g/kg.According to the Classification Standard of Soil Organic Matter in the Second National Soil Census,the content of soil organic matter in the study area belongs to the fourth level（on the low side）.Therefore,nutrients need to be supplemented when Jiuquan saline-alkali abandoned farmland is improved and reclaimed.（3）When the principal component analysis was carried out on the soil of Bianwan farm in Jiuquan,it was found that the salinization of soil was affected by the degree of salinization,the degree of salinization and the structure of soil.（4）In the soil salinization improvement experiment of No.7 sample plot of Bianwan Farm,Jiuquan City,the optimum application amount of desulfurization gypsum is 33750kg/hm²,but the improvement effect is not as good as that of mixed application of desulfurization gypsum and furfural residue.Through the determination of soil salinization indexes of different improved treatments,it is concluded that the application amount of desulfurization gypsum is 33750 kg/hm²+the application amount of fural residue is 22500kg/hm².The effect of soil salinization is the most remarkable.（5）In the saline-alkaline soil improvement experiment of No.7 sample plot of Bianwan Farm in Jiuquan,according to the germination and growth status of pot experiment seeds,the best treatment was（33750kg/hm² desulfurization gypsum+22500 kg/hm² furfural residue+chicken manure 7500kg/hm²）pot experiment.Because the salinization degree of No.7sample plot is the most serious,in other different sample plots,the corresponding amount of mixed application can be reduced appropriately.