| The Hetao Irrigation District which is characterized by less rainfall,high evaporation and soil salinity issue,is a main grain production region in China.These problems seriously affect the development of local agriculture.Plastic film mulching can improve soil water and heat environment,affect field microclimate,promote crop growth and development,and increase crop yield and water use efficiency.Film mulching is widely used in arid and semi-arid areas with insufficient water resources and less rainfall.Ridge tillage can promote the horizontal and vertical infiltration of soil water,fertilizer and salt due to its loose soil structure.Ridge with plastic mulch-furrow irrigation planting model has been widely used in Gansu,Ningxia and other areas.However,there are differences between the Hetao Irrigation District and the above-mentioned areas in climate conditions,soil types and so on.In order to explore the most suitable irrigation and fertilization scheme in this region,two-year(2017-2018)ridge with plastic mulch-furrow irrigation experiment was conducted at Shuguang Experimental Station,located in the west of the Hetao Irrigation District,the inner Mongolia,china.This experiment included six treatments: high water and high fertilizer(I1F1),high water and low fertilizer(I1F2),medium water and high fertilizer(I2F1),medium water and low fertilizer(I2F2),low water and high fertilizer(I3F1),low water and low fertilizer(I3F2).Through observing the characteristics of soil moisture,salinity,soil nitrate nitrogen content,plant height,leaf area index,aboveground biomass and yield of spring maize under different treatments,evaluate soil water,fertilizer and salt transport and spring maize yield characteristics under different treatment,select the most suitable irrigation and fertilization scheme.The main conclusions obtained from field experiment data analysis are as follows:(1)The trend of vertical dynamic change of soil water content is basically the same.After irrigation,the soil water content of all treatments increased,especially in 0-40 cm soil layer,while that of 60-100 cm layer remained basically unchanged.Irrigation mainly affecte shallow soil moisture.Soil water content in 40-60 cm soil layer was lower than that in other soil layers.Crops use more water in 40-60 cm soil layer.(2)The difference of soil water content between different irrigation treatments is large.With the increase of irrigation times,the difference of soil water content between high and medium water treatments becomes smaller.The difference of soil water content between different irrigation treatments in furrow is smaller than that on ridge.The difference of soil water content between different fertilization treatments was smaller than that between different irrigation,and the soil water content of low fertilizer treatment on ridge was higher than that of high fertilizer treatment.(3)The variation of soil conductivity with soil depth is basically the same in different treatments.The soil conductivity decreases with the increase of soil depth.The soil conductivity in 0-60 cm layer is significantly higher than that in deep layer,especially in 0-40 cm layer.Irrigation mainly affects the distribution of shallow soil conductivity,which is smaller in furrow than in ridge.With the increase of soil depth,the difference of soil conductivity between different treatments becomes smaller.Low fertilizer treatment is beneficial to maintain low salt content in soil.Soil salinity in the treatment of medium water and low fertilizer has been stable and low level,which is conducive to the growth and development of crops.(4)Irrigation and fertilization amounts have influence on soil nitrate nitrogen content.The leaching amount of nitrate nitrogen in the later stage of medium water treatment was significantly lower than that in other treatments.Ridge with plastic mulch-furrow irrigation has good fertilizer storage effect,saving water and conservating fertilizer,and has high fertilizer use efficiency in low fertilizer treatment.(5)The difference of plant height and leaf area index between medium and high water treatment was not significant,which were significantly higher than that of low water treatment.There was little difference between different fertilization treatments in the same irrigation water treatment,and the plant height and leaf area index of medium water and low fertilizer treatments were always at a high level.There was no significant difference in dry matter quality between different fertilization treatments,but there was a significant difference between different irrigation treatments.The cumulative effect of above-ground dry matter in medium water treatment was better than that of other treatments,among which the effect of medium water and low fertilizer treatment was the most obvious.Compared with high and low water treatment,the cumulative effect of above-ground dry matter increased by-5%-15%,50%-90%.(6)The indexes of kernel row number,kernel number per row,1000-kernel weight,yield,water consumption and water use efficiency were mainly affected by irrigation amount.The number of kernel row number,kernel number per row,1000-kernel weight,yield of medium water had no significant difference with that of high water treatment,but higher than that of low water treatment.The crop water consumption of high and medium water treatment was higher than that of low water treatment,and there was no significant difference in water use efficiency between different treatments.(7)When irrigation amount is 300 mm,fertilizer amount is 600 kg/hm2 diammonium phosphate and 300 kg/hm2 urea,soil water,fertilizer and salt condition is better and yield is higher.This is a suitable irrigation and fertilization scheme for the ridge with plastic mulchfurrow irrigation to cope with local water shortage and soil salinization in order to stabilize crop yield. |
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