| At present,China’s maize planting area and output rank first among the three major food crops.Climate drought and soil salinization are important factors restricting the healthy and sustainable development of agriculture.By systematically analyzing the effects of planting methods and nitrogen application rates on the soil environment and maize growth and development,it can provide scientific basis and theoretical support for the high-yield and high-efficiency maize in saline-alkali farmland.Spring maize was used as the research material,and the variety was Zhongdi 88.2018 and 2019April-September at the Shanxi Province Academy of Agricultural Sciences to carry out field trials,and the pot experiment was conducted at the rain shelter of the Scientific Research Base of the School of Water Conservancy Science and Engineering,Taiyuan University of Technology from May to September 2019.Two factors were set in the field experiment:planting method and nitrogen application rate.The planting methods are full-film double-ditch furrow sowing(W)and half-membrane flat hole sowing(H);nitrogen application rates are 0(N0),225(N1),275(N2)and 325(N3)kg/hm~2.The setting factor for the pot experiment is the amount of nitrogen applied(N0,N1,N2 and N3).The soil water,nitrogen,salt content,growth indicators and yield indicators of maize at different growth stages were measured,and the water consumption and water and nitrogen utilization efficiency of maize were calculated.The main conclusions were obtained as follows:(1)The soil moisture content of the soil profile(0-100 cm soil layer)in each measurement period is as follows:full-film double-ditch furrow sowing>half-membrane flat hole sowing.In the 0-60 cm soil layer,under the same planting method,the soil volumetric water content is:N0>N1>N2>N3;60-100cm soil layer,the soil volumetric water content of each nitrogen treatment is significantly(p<0.05)low No nitrogen treatment.In the 0-60 cm soil layer,the electrical conductivity of the soil in each growth period is as follows:full-film double-ditch furrow sowing<half-membrane flat hole sowing.The soil electrical conductivity of the two planting methods increased gradually with the increase of nitrogen application.In the soil layer of 60-100 cm,the full-film double-ditch furrow sowing planting method had significantly higher soil conductivity(p<0.05)than the half-membrane flat hole sowing in the tasseling stage and maturity stage.Moreover,the soil electrical conductivity of each nitrogen treatment was significantly(p<0.05)higher than that without nitrogen treatment.In the 0-40 cm soil layer,the nitrate nitrogen and ammonium nitrogen content of the soil in each growth period are as follows:full-film double-ditch furrow sowing<half-membrane flat hole sowing.The content of soil nitrate nitrogen showed a gradual upward trend with the increase of nitrogen application rate;the content of ammonium nitrogen in soil under each nitrogen treatment was significantly(p<0.05)higher than that without nitrogen treatment,and the difference between each nitrogen treatment was not significant.The soil nitrate nitrogen and ammonium nitrogen content of the 40-100 cm soil layer,full-film double-ditch furrow sowing and half-membrane flat hole sowing planting methods were basically not significantly different.The nitrate nitrogen content of soil treated with nitrogen was significantly higher(p<0.05)than that without nitrogen treatment in each growth period;the ammonium nitrogen content of soil treated with N3(p<0.05)was significantly higher than that of corresponding N0 and N1 treatments.(2)The plant height,leaf area index and stem thickness of maize at all growth stages are as follows:full-film double-ditch furrow sowing>half-membrane flat hole sowing.The plant height,leaf area index and stem thickness basically conformed to the increasing trend with increasing nitrogen application.The biological yield and grain yield of maize treated with WN2 and WN3 were significantly(p<0.05)higher than that of WN1,and there was no significant difference between WN2 and WN3.The biological yield of maize treated with HN2 and HN3 was significantly(p<0.05)higher than that of HN1,and there was no significant difference between HN2 and HN3.The grain yield of maize treated with HN3 was significantly(p<0.05)higher than that of HN1treatment,and there was no obvious rule for HN2 and HN3 treatment.The water consumption of each growth stage and the whole growth period is basically as follows:full-film double-ditch furrow sowing<half-membrane flat hole sowing.Under the same planting method,the water consumption of each growth stage and the whole growth period showed a gradual upward trend with the increase of nitrogen application.Maize water use efficiency,partial nitrogen fertilizer productivity and nitrogen fertilizer agronomic use efficiency are as follows:full-film double-ditch furrow sowing>half-membrane flat hole sowing,the difference is significant(p<0.05).The water use efficiency of the two planting methods treated with nitrogen was significantly higher(p<0.05)than that without nitrogen treatment.The partial productivity of nitrogen fertilizer for each nitrogen application is:N1>N2>N3,the difference is significant(p<0.05).The agronomic utilization efficiency of nitrogen fertilizers treated by N2 and N3was significantly(p<0.05)higher than that of N1 treatment.(3)The pot experiment showed that the soil water content(0-40 cm soil layer)in each measurement period showed a gradual decrease trend with the increase of nitrogen application.The N0,N1,N2,and N3 treatments had a conductivity of 56.7-151.8%higher than that of the surface layer(0-20 cm soil layer)in the bottom layer(20-40 cm soil layer)at the completion stage.Except for the N2 and N3 treatments during the tasseling period,the soil conductivity(0-40 cm soil layer)in the other measurement periods showed:N3>N2>N1>N0.The content of soil nitrate nitrogen and ammonium nitrogen(0-40 cm soil layer)showed a gradual upward trend with the increase of nitrogen application.The plant height and leaf area index of N1 treatment at the maturity stage were lower than those of N2 and N3 treatment,and the difference was significant(p<0.05);the difference between N2 and N3 treatment was not significant.The difference between each nitrogen treatment was not significant.The chlorophyll content of the maize treated with nitrogen was 46.3,42.5,and 37.6 mg/g,and the difference was significant(p<0.05).The biological yield,grain yield,water consumption and water use efficiency of maize with different nitrogen treatments were significantly(p<0.05)higher than those without nitrogen treatment,and the differences between N1 and other two nitrogen applications were significant(p<0.05),there was no significant difference between N2 and N3 treatments.The partial productivity of nitrogen fertilizer for each nitrogen application was 29.6,27.8,and 24.4 kg/kg(p<0.05).The agronomic utilization efficiency of nitrogen fertilizers treated by N2 and N3 was significantly(p<0.05)higher than that of N1 treatment,and there was no significant difference between N2 and N3 treatments.Based on the above analysis,it is recommended to use a full-film double-ditch furrow sowing method in this experimental area,and control the nitrogen application rate to 275kg/hm~2. |
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