Study On Effects Of Subsurface Pipe Drainage And Planting Sorghum Crops To Repair Saline Alkali Soil

The problem of soil salinization seriously restricts the agricultural and economic and social development in southern Xinjiang.In this study,the secondary saline-alkali abandoned farmland of the Fourteenth Division 224 Regiment of the South Xinjiang Corps was used as the object.Different tube spacing of 30 m,40 m,50 m,and 60 m were laid,and the buried depth was 2 m.After washing and draining the salt,sweet sorghum and Sudan grass were planted at four different subduct distances respectively.The effect of subsoil draining at different intervals and planting sorghum crops to repair saline-alkali soil and the effect of salt segregant removal were studied.The main results of the test are as follows:1.With the increase in the number of soil salinity in subsurface drainage and leaching,the soil salinity gradually decreases,and the distribution of soil salinity profile changes from the initial apparent superposition to a vertical distribution that is more uniform up and down and has a lower salinity.The performance of the treatment of the four different dark tube spacings is consistent.2.The effect of drainage and desalination of the hidden pipe is remarkable.The desalination effect gradually deteriorates with increasing soil depth.After the first flood irrigation,the average salt content of the 0²0 cm soil layer decreased from26.92 g/kg to 11.03 g/kg,the desalination rate was 58.13%;the 0¹00 cm soil layer12.53 g/kg decreased to 8.26 g/kg,the desalination rate 34.1%;the 0¹80 cm soil layer 9.25 g/kg dropped to 7.02 g/kg desalination rate 24.1%.After the crop is harvested,the average salt content of the 0-20 cm soil layer drops to 0.89 g/kg,and the desalination rate is 96.7%;the 0-100 cm soil layer drops to 3.15 g/kg,and the desalination rate is 74.9%;the 0-180 cm soil layer drops To 3.62 g/kg,the desalination rate is 74.9%.3.The effect of desalination of different subduct distances is 60 m>30 m>50m>40 m.There are differences in the desalination effect of different crops.According to the analysis of the distance between different subsurface pipes,after the first flood irrigation at the intervals of 30 m,40 m,50 m and 60 m,the desalination rates of the0-20 cm soil layer were 66.7%,37.22%,57.4%,71.44%;The desalination rates of0¹00 cm soil layer were 48.3%,13.2%,22.6%and 44.3%respectively;the desalination rates of 0¹80 cm soil layer were 26.7%,12.8%,6.7%and 32%.The desalination rates of 0-20 cm soil layer after harvesting of Sudan grass are 95.4%,96.7%,87.4%and 92.6%;the desalination rates of 0-100 cm soil layer are 80.8%,74.9%,81.8%and 83.9%;0-180 cm The desalination rates were 64.8%,60.7%,70.6%,and 72.7%.After the sweet sorghum is harvested,the 0²0 cm soil layer has a desalination rate of 87.9%,78.3%,84.9%,91.9%;the 0¹00 cm soil layer has a desalination rate of 75.8%,46.9%,65.4%,79.4%;The desalination rates of 0¹80 cm soil layer were 60.4%,32.8%,42.2%and 63.7%,respectively.In summary,from an economic point of view,it is appropriate to use a 60 m dark pipe spacing.Different salt separators have different dissolution effects,Cl^->Na⁺+K⁺>Ca²⁺+Mg²+>SO₄²-,the average extraction rate of 0-20 cm is 94.0%?92.2%?82.2%?82.7%,and the average of 0-180 cm soil layer The removal rates were 68.2%?59.5%?55.8%,and 47.5%,respectively.