Study On Shallow-buried Drip Irrigation System For Maize And Agricultural Water Saving Potential In Tongliao

Water shortage is a major factor limiting the sustainable development of agriculture in Tongliao City,Inner Mongolia,and proposing a reasonable irrigation system and analysing its water-saving potential is crucial to developing efficient water-saving irrigation technology,improving the efficiency of irrigation water use on farmland and alleviating the contradiction between supply and demand of local agricultural water resources.The shallow buried drip irrigation project has been carried out in Tongliao since 2018 and has achieved considerable results so far,however,the irrigation system varies depending on regional soil,climate and other factors.For better promotion of shallow-buried drip irrigation technology in Tongliao,six shallow-buried drip irrigation water treatments were set in maize fields in the korqin district of Tongliao city to study the effects of irrigation quotas on maize growth indicators,root traits and water use efficiency,compare their comprehensive benefits,and propose a better irrigation system for water saving and efficiency.On this basis,the water saving potential of shallowly buried drip irrigated maize at 25%hydrological frequency in the region was analysed using the status quo level（2021）as a benchmark.The main conclusions are as follows:（1）Maize plant height and stalk thickness did not show a clear pattern at 46 and 64d after sowing for the different irrigation treatments,and generally tended to increase at77 and 90 d after sowing as the irrigation rate increased;The average leaf area index at the end of the rapid growth stage of maize was 881.93%higher than at the beginning of the period;leaf dry matter accumulation,stalk dry matter accumulation and cob dry matter accumulation were all positively correlated with irrigation water within a certain range.（2）The root dry matter weight,root length,root surface area and root diameter of maize at maturity in the 0-40 cm soil layer showed a trend of increasing and then decreasing with decreasing irrigation.root dry matter weight,root length and root surface area of maize in the 0-40 cm soil layer decreased with increasing soil depth,while root diameter showed a small increase in the 10-20 cm soil layer.（3）The water consumption of maize with shallow submerged drip irrigation tends to decrease with decreasing irrigation water,with the largest difference between the tasseling stage and the filling stage;maize yield and irrigation quota can be described by y=-0.2606x²+94.997x+4679.2;water use efficiency tends to increase and then decrease with increasing irrigation quota.（4）Combining the economic,social and ecological benefits,shallow buried drip irrigation technology is a suitable water-saving irrigation technology to be promoted in Tongliao region of Inner Mongolia or in maize growing areas with 250-450 mm precipitation,with the highest maize benefit of 18,323 yuan·hm^-2 for the W2 treatment.In a good water year,the recommended irrigation quota for maize shallow drip irrigation in Tongliao is 170 mm and the number of irrigation times is 5,where the time and proportion of irrigation should be mainly concentrated on the jointing stage-tasseling stage and the tasseling stage-filling stage.（5）The agricultural water saving potential for the development of shallowly buried drip irrigated maize to an advanced level in Tongliao City at 25%hydrological frequency is 153 million m³.