| The distribution of saline-alkali lands in my country is wide,and the management of saline-alkali lands in accordance with local conditions plays an important role in regional economic and social development.In order to solve the problems of high groundwater level and difficult salt leaching in the typical low-lying saline-alkali land in Qingtongxia,Ningxia,which is located in the arid region of Northwest China,different buried depths of dark ditches(D1:0.9 m,D2:1.2 m,D3:1.5 m)+different irrigation quotas(W1:1200 m3/hm2,W2:2400m3/hm2,W3:3600m3/hm2)to analyze the effects of each treatment on the distribution of water and salt in saline-alkali soil and the growth of oil sunflower.The main research conclusions are as follows.(1)Under the same irrigation quota,after irrigation,the soil moisture content in the 0?40 cm soil layer was lower in the shallow ditch treatment,and the soil moisture content in the 40?60 cm soil layer was the largest in the D1 treatment,and the soil moisture content in the 80?100 cm soil layer was not significantly affected by the different ditch burial depths.After irrigation,the desalination effect of 0?40 cm soil layer was as follows:D2>D1>D3,and the desalination effect of 40?100 cm soil layer was as follows:D3>D2>D1.From the perspective of the whole crop growth period,the treatment with a deeper buried ditch is more conducive to soil drainage and desalination of the cultivated layer.(2)Under D1 and D2 conditions,the soil moisture content in 0?100 cm soil layer was the highest in W3 treatment,and the lowest in W1 treatment.Under D3 condition,the soil moisture content in 0?80 cm soil layer increased with the increase of irrigation quota.In 80?100 cm soil layer,the soil moisture content in W1 and W2 treatment changed little compared with that before irrigation.Under the same buried depth of the ditch,the desalination effect of 0?60 cm soil layer was better than that of the soil layer greater than 60 cm.The desalination effect of each treatment in 0?100 cm soil layer was as follows:W3>W2>W1.The average soil water content in the 0?40 cm soil layer of oil sunflower treatment during its growth period was W3>W2>W1,and the soil salt content was W1>W2>W3.(3)After irrigation,the soil salt content of each soil layer generally shows less content near the level of the blind ditch.Compared with the original soil,the contents of Na+,Cl-,SO42-in each treatment in 2019 and 2020 were significantly higher than those of other ions,and the contents of K+,Mg2+in each treatment had little change.The two-year D3W3 and D3W2 treatments had lower salt ions content than other treatments,and there was no significant difference between D3 W3 and D3W2 treatments.The twoyear D1W1 and D1W3 treatments had higher salt ions content than other treatments,and there was no significant difference between D1W1 and D1W3 treatments.(4)The average emergence rate and adult plant rate of D3 W3 treatment were the highest in two years.D2W3,D3W3,and D3W2 treatments are all beneficial to the height growth of oil sunflower.D2W3 and D2W2 treatments were beneficial to stem diameter growth.In the two years,D2W2 treatment had the largest average disk diameter(20.1 cm),followed by D2W3 treatment.The average seed setting rate of D2W3 treatment was the highest in the two years(93.78%),followed by D2W2 treatment.The average value of 100-grain weight in D2W2 treatment was the highest(6.28 g)in the two years,followed by D2W3 treatment.In 2019,the D2W2 treatment had the largest yield(3446.75 kg/hm2),and there was no significant difference from D2W3 treatment.In 2020,the D2W3 treatment had the largest yield(3501.23 kg/hm2),which was not significantly different from the D2W2 treatment.That is,the D2W2 and D2W3 treatments in this experiment could increase the oil sunflower yield.The above research results show that the buried depth of the ditch is 1.2 m and the irrigation quota is 2400 m3/hm2,which is the best combination treatment to adjust the water and salt environment of the saline-alkali land and improve the oil sunflower yield in this area. |
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