Water Characteristics And Water Saving Effect Of Potato Field In Cold And Drought Zone Of Northwest Hebei Province

The northwestern cold and dry region of Hebei is the main producing area of potatoes in northern China,which has a cool climate and a short frost-free period,suitable for the growth of potatoes.However,the region's poor agricultural production conditions,low precipitation,high evaporation in the spring drought and windy,extremely unstable precipitation in summer and autumn,resulting in difficult crop seedlings,low yield levels,moisture is the main factor limiting potato production in the region.North China is one of the most water-scarce regions in the country,and in order to protect groundwater resources,it is necessary to reduce water use for agricultural irrigation and recharge only in limited quantities during the critical period of potato growth.Exploring the temporal and spatial movement characteristics of soil moisture in regional potato fields and the effects of potato water consumption under different water supply scenarios are key to adopting and innovating agronomic measures to conserve soil moisture in agricultural fields and improve the WUE.This study was carried out at Zhangbei Experimental Station,Hebei Agricultural University,from 2018 to 2019,setting up two irrigation methods and using the drought farming method as a control,setting up mulching farming,mulching drip irrigation 22.5mm mulching drip irrigation 45 mm,drip irrigation 45mm and drip irrigation 67.5mm.By comparing the changes in soil thermal dynamics of farmland under different water supply scenarios,as well as potato growth dynamics,yield and water utilization effects,the characteristics of temporal and spatial changes in soil water and utilization effects under different scenarios were clarified,which provided a theoretical basis for the improvement of efficient water utilization techniques for potato fields in semi-arid areas.The main findings of this study are as follows:1.The main water supply layer of potato field is 0?80 cm soil layer,the key period ofirrigation is from tuber formation to expansion stageThe difference in water consumption between the dry cover and recharge treatments was not significant compared to the dry open-land controls,and the variability of soil water storage was smaller than that of the dry open-land controls.The main water supply layer in the Meadow Chestnut Calcium Soil Potato Field was influenced by the precipitation year type,with 0?40cm soil layer being the main water supply layer in 2018 and 0?80cm in 2019.The peak water consumption for the overlay treatment in 2018 was during the tuber formation period,the peak water consumption for the open field treatment was during the tuber expansion period,and the peak water consumption for each treatment in 2019 was during the tuber formation period.The tuber-forming period is critical for hydration.2.Film mulching can increase the temperature of farmland and reduce the temperature of farmland by irrigationCovering can significantly increase the soil temperature of potato fields in the pre-fertility and post-fertility periods,with less impact on potato fertility in the medium term;compared with the open-land dry crop,covering can increase the soil temperature of farmland by-0.12??3.14?;the soil temperature after rehydration in the open-land is 0.01?4.20? lower than the dry crop;there is no difference in the average daily soil temperature after rehydration by submembrane drip irrigation treatment and covering.3.Mulching and irrigation can promote potato growth obviouslyMulching cover significantly increases the leaf area index throughout the fertility period of the potato and promotes height growth at seedling stage.The leaf area index increased by 1.13%?75.16%in the dry crop compared to the open crop;the height of the plants increased by 6.17%-35.43%in the emergence period compared to the open crop,and the height of the covered plants was always lower than that of the open crop after the tuber formation period.In 2018,the height,stem thickness and leaf area index of potatoes increased by 0.18%?24.34%,-8.33%?19.28%and 5.69%?128.05%,respectively,compared to the dry crop after watering.4.Mulching and irrigation can increase potato yield and big potato rateThe yield of mulching was 13.71%?76.44%higher than drought farming,the yield of DI and MDI was 38.07%?90.39%and 28.34%?123.47%higher than drought farming.Mulching and irrigation can increase the big potato rate,and the effect on commercial potato is not obvious.In 2018,the big potato rate of mulching was 106.25%higher than drought farming,the big potato rate of DI and MDI was 138.02%?194.86%and 186.60%?191.23%higher than drought farming.In 2019,the big potato rate of DI was 7.45%?9.63%higher than drought farming.If the potato tuber formation stage is subjected to drought,the effect of mulching and irrigation measures to increase yields is significant,and if the tuber formation stage has sufficient precipitation,the mulching and water replenishment measures to increase yields is small.5.Mulching and irrigation significantly improve WUE of potatoThe WUE and precipitation production efficiency of mulching significantly was 22.17%?83.33%and 13.71%?76.46%higher than drought farming.The WUE of DI and MDI was 27.73%-80.61%and 27.97%?122.51%higher than drought farming.Compared with the irrigation utilization rate of four irrigation treatments,the irrigation utilization efficiency gradually decreased with the increase of irrigation quota.Compared with the irrigation benefit of the four treatments,the MDI 22.5mm treatment was the highest and the MDI 45mm treatment was the lowest.To sum up,the water supply layer of Meadow chestnut soil field in the cold and dry area of northwest Hebei is affected by the annual precipitation pattern,which is mainly 0?80 cm soil layer;the key period of potato irrigation for MDI is tuber formation stage,and the key period of irrigation for DI is tuber expansion stage.Mulching and irrigation improve the yield and WUE of potato,and mulching can improve the precipitation production efficiency of potato,and the irrigation utilization efficiency of potato shows decreasing trend with the increase of irrigation quota.Mulching drip irrigation with 22.5mm yield,water use efficiency and irrigation efficiency is highest compared to the four irrigation treatments.In the potato tuber formation period,22.5 mm of mulching watering can become the best hydration scheme for limited watering of potato fields in the cold and dry areas of northwest Hebei.