| There are many problems in Hetao irrigation area,such as large area of salinized soil,lack of fresh water resources and rich brackish water resources.It is a great demand for the sustainable development of agricultural planting industry in Inner Mongolia to carry out the experiment and Research on planting Lycium barbarum in shaxue under the condition of micro salt water drip irrigation in the medium and heavy salt alkali land,and to reasonably develop and utilize the local salinized soil and micro salt water resources.In this paper,through two years of field experiment under the condition of micro saline water drip irrigation and sand hole planting,through the contrast experiment of setting the original soil planting and sand hole planting respectively in the middle and heavy saline alkali soil experimental area,the law of soil environment change under different treatments is explored,and the different soil moisture and salt content under the condition of micro saline water drip irrigation and sand hole planting are revealed On this basis,by setting up different irrigation levels of brackish water,we found the appropriate irrigation systems for each treatment.The main conclusions are as follows:(1)Sand holes can expand the water-soil contact surface,increase the infiltration area of irrigation water,further reduce the supply rate of irrigation water,and make it closer to the saturated water conductivity of the soil;Secondly,the sand hole can temporarily store the water which has not been infiltrated,so as to prolong the infiltration time and promote the soil infiltration.Thirdly,the setting of sand burrow also avoids the damage to the surface soil structure caused by the impact of water droplets during irrigation.The results show that under the combined action of "drip irrigation+sand hole",soil infiltration performance is improved significantly.(2)The salt content in the moderately to severely saline-alkali soil mainly accumulates in the surface layer of soil above 30cm,and decreases with the increase of soil depth.The high value of soil salinity in the original soil planting treatment mainly appeared in the soil layer above 30cm,while the high value of EC in the sand hole treatment appeared in the soil range of 0-60cm.The EC value in the sand hole treatment was about 10%lower than that in the original soil planting treatment.At the same time,there was an obvious trend of salt movement towards the sand hole in the horizontal direction.After single irrigation,the average EC value of the primary soil planting treatment in the heavy test area was reduced by about 10%,and the sand hole treatment was reduced by about 25%.The EC value of the original soil planting treatment in the medium test area was reduced by about 7%,and the sand hole treatment was reduced by about 20%.It is believed that the sand caverns in the saline-alkali land begin to collect the salt in the soil and accelerate its movement to the deep soil.(3)Compared with the original soil planting treatment,the nutrient accumulation ratio in the space range was increased by 3%in the severe test area and 5%in the moderate test area.Nutrients will be easier to absorb and utilize after being collected by the burrow,thus reducing the loss of nutrients.(4)On the whole,the growth amount of lycium barbarum crops in the sand hole planting treatment was significantly higher than that in the original soil planting treatment:the plant height growth amount in the sand hole planting treatment in the severe test area was 2.91%higher than that in the original soil planting treatment,and the plant height growth amount in the medium test area was 3.19%higher than that in the original soil planting treatment.The diameter growth amount of sand hole treatment in the severe test area was 4.64%higher than that of the original soil planting treatment,and the diameter growth amount of sand hole treatment in the moderate test area was 0.65%higher than that of the original soil planting treatment.The growth rate of new branches under sand hole planting in the severe test area was 3.57%higher than that under the original soil planting treatment,and the growth rate of new branches under sand hole planting in the moderate test area was 2.82%higher than that under the original soil planting treatment.It is believed that the sand hole can collect water and salt and accelerate the infiltration of water and salt,so the growth performance of lycium barbarum crops treated by sand hole is better than that of the original soil.(5)In terms of the impact of brackish water irrigation on the yield of Lycium barbarum,in 2019,the maximum yield of raw soil planting treatment in the heavy test area was 453.76 kg/hm2,and the maximum yield of sand hole planting treatment in the heavy test area was 946.71 kg/hm2,an increase of 108.6%.Meanwhile,the wet and dry ratio of lycium barbarum fruit also decreased from 3.612 to 3.450.The maximum yield of original soil planting treatment in the medium test area was 1256.82 kg/hm2,and that of sand hole planting treatment in the medium test area was 1526.78 kg/hm2,with an increase of 21.5%.Meanwhile,the wet and dry ratio of lycium barbarum fruit decreased from 3.420 to 3.232.It is concluded that the treatment of sand hole has a good promoting effect on the increase of production of moderate and severe saline-alkali land,and at the same time can reduce the wet and dry ratio of lycium barbarum fruit to a certain extent,so as to further improve the economic benefits.(6)Considering the changes of soil moisture,salt,nutrient and the crop index of Lycium barbarum under different irrigation levels,it is considered that a irrigation level is suitable for the cultivation of the original soil in the heavy test area when using the brackish water for irrigation,i.e.22.5MM single irrigation;the cultivation of the original soil in the medium test area and the cultivation of the sand holes in the medium and heavy study areas when using the brackish water for irrigation B irrigation level is suitable for irrigation,i.e.30mm for single irrigation. |
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