| The salinization of farmland soil,in the saline-alkali area of Dengmayinghu Lake in Wuwei City,Gansu Province,is becoming more and more serious.There are 141300 hectares of saline-alkali land,of which 18700 hectares of cultivated land and 122500 hectares of wasteland.In addition,ecological phenomena,such as soil secondary salinization and soil desertification,also aggravated the deterioration of ecological environment in saline-alkali area of Dengmayinghu Lake to a great extent.The local typical treatment model has slow effect and high cost,and there are few reports on the related studies in this area.Although,the purpose of this experiment is to screen the improver suitable for improving the salinization of farmland soil in this area,and to provide some theoretical support for the related research.Phosphogypsum(TP),sulfur(TS),Hekang(TH)and humic acid organic fertilizer(TF)are chemical improvement measures.They are common soil ameliorantss.There are quick and low cost.Yandibao(TY)is an independent research and development product,which makes the research innovative.The study based on the characteristics of soil physical and chemical properties in the study area and combined with chemical improvement of saline-alkali soil,to study the effect of leaching on saline-alkali soil of Dunmayinghu Lake by using five improvers: TP,TS,TH,TY and TF under four additions.By detecting the conductivity,total hardness,total alkalinity and four kinds of water-soluble salt cations of leaching solution,the most suitest addition amount which was selected and applied to the field localization test should should be choosen.The changes of soil index and sunflower growth index were detected and analyzed,and the overall improvement effect of five kinds of improvers was discussed.The results show:1.The indoor soil column leaching test: Combined with the whole effect of leaching saline-alkali soil,all the soil amendments were selected with 2.56g/kg dry soil,0.11g/kg dry soil,2.22g/kg dry soil,2.22g/kg dry soil and 0.44 g/kg dry soil,optimum dosage,specifically:(1)With the increase of leaching times,the conductivity of leaching solution increased and then decreased,and the TP,TH and TF treatment increased significantly when the addition amount were respectively 2.56g/kg dry soil,2.22g/kg dry soil and 0.44 g/kg compared with that of control;(2)With treatments,the accumulations of each cation increased significantly,and when the addition of the five ameliorantss were respectively 2.56g/kg dry soil,0.11g/kg dry soil,2.22g/kg dry soil,2.22g/kg dry soil and 0.44 g/kg dry soil,and the effect of leaching cation was the most significant;(3)As the number of times of leaching increased,the total hardness of leaching solution decreased rapidly and then increased slowly,and the total alkalinity of leaching solution increased significantly when the addition of five ameliorantss were respectively 2.56g/kg dry soil,0.11g/kg dry soil,2.22g/kg dry soil,2.22g/kg dry soil and 0.44g/kg dry soil;(4)With the increase of elution times,the total alkalinity of leaching solution increased and then decreased.The total alkalinity of TP treatment increased with the increasing addition amount,and the total alkalinity of TS,TH,TY and TF treatment decreased with the increasing addition amount.2.The Field Positioning Test:(1)The five amendments can both significantly reduce the soil pH,among which the TS effect is the most significant;(2)TH,TY and TF treatments can both significantly increase the content of soil organic matter,among which the effect of adding TF is the most significant;(3)All five amendments could significantly reduce the total amount of soil salt,among which the TP and TY effects was both the most significant;(4)The five ameliorantss can significantly reduce the water soluble salt ions,the effect of adding TP on reducing cation is the most significant,and adding TY?TF?TH?TS on reducing cation is the most significant;(5)The five amendments can effectively reduce the total alkalinity of soil,among which the TY and TF effects is both the most significant;(6)The five amendments can effectively improve the soil desalination rate,among which the TP and TH effects is both the most significant;(7)TP,TH,TY and TF treatment can both promote the gronomic traits of sunflower,among which the effect of adding TF is the most significant.Conclusion: according to the results of laboratory simulation and field localization experiments,humic acid organic fertilizer was the best improvement effect of these soil ameliorantss on saline-alkali soil,Yandibao and Hekang followed,then phosphogypsum,but the overall improvement effect of sulfur was not ideal. |
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