Experimental Study On Irrigation With Different Water Sources And Straw Returned Joint Model In Salinized Farmland

In view of the shortage of water resources in the Yellow River in Inner Mongolia Hetao Irrigation District,the seriousness of soil salinization and the low utilization rate of straw recovery,according to the field experiment,the idea of alternately controlling the salt in the Yellow River water and underground brackish water,and returning the straw to the field to inhibit salt The effects of two kinds of water source combined irrigation modes,such as underground brackish water(well water)and surface yellow river water(canal water),and the effect of straw returning on soil water and salt transport,corn growth and yield,and screening of better integrated irrigation models,Investigate the suitable straw returning method under the optimized irrigation mode,and initially propose the local optimized irrigation mode and the corresponding straw returning method.The main conclusions are as follows:(1)Effects of different water source irrigation model on soil water and salt transport,corn growth and yield:a)The soil salt accumulation in the irrigated underground brackish water is significantly higher than that in the irrigated surface of the Yellow River;the soil accumulation in the plough layer is greater than that in the deep soil;The treatment of groundwater twice and above was reduced by 25.77%?31.61%compared with the water use efficiency of irrigation and non-irrigation groundwater.During the whole growth period,the soil salinity change of the treatment of the canal is lower than that of other underground brackish water.Treatment,water use efficiency is higher than other treatments,and both are less different from the treatment of all Yellow River water irrigation.b)The inhibitory effect of underground brackish water on the growth of maize in different growth periods is from jointing stage to filling stage,filling stage and tasseling stage;the number of irrigation groundwater increases,the yield decreases obviously,and the treatment of irrigation groundwater is more than that of the whole Yellow River.The treated corn yield decreased by 0.57%?17.67%;the treatment of groundwater with two or more irrigations decreased by 24.80%?37.40%compared with the treatment of whole Yellow River irrigation.The order of corn growth index and yield from high to low is the Canal-Canal-Canal>Canal-Well-Canal>Canal-Canal-Well>Well-Canal-Canal>Canal-Well-Well>Well-Well-Canal>Well-Canal-Well>Well-Well-Well>blank treatment.(2)Effects of straw returning on soil water and salt transport,corn growth and yield under optimized irrigation mode:a)Straw mulching treatment effectively inhibited soil moisture loss and increased soil moisture content in 0-20 cm soil layer.The deep burying treatment can significantly increase the soil moisture content of the straw layer and above.b)Straw mulching inhibited the surface aggregation of salt;the soil salt accumulation in the 0?40 cm soil layer and the deep burying treatment was small,0.27%.The change of soil salinity in the deep burial treatment of 20?60cm soil layer was 10.36%lower than that of straw mulching treatment.Compared with the treatment without straw stalk,the soil salt accumulation in straw mulching treatment was lower.c)The growth index of corn under straw mulching increased rapidly in the early stage of corn growth,and the deep burying of straw had a great influence on the growth index of corn in the late growth stage.The yield of corn under deep burying treatment was 8.67%,39.75%and 491.64%higher than that of straw mulching,no straw and blank treatment,respectively.The growth index and yield variation of corn under straw returning were all under straw burying>straw mulching>no straw>blank treatment.The effects of comprehensive different water source irrigation mode and straw returning method on corn growth,yield and soil water and salt transport,preliminary screening of surface yellow river water(canal water)-underground brackish water(well water)-surface yellow river water(drain water)The treatment is suitable for the local preferential irrigation mode.On this basis,the straw is deeply buried as a better straw returning method.That is to say,under the deep burying condition of the straw,the water is filled for 3 times,and the total irrigation amount is 270mm.Among them,the salinity of the first and third water irrigations is 0.608g/L,and the salinity of the second water irrigation is 2.0?2.5 g/L brackish water,each time is 90mm.