| Climate drought and soil salinization are two important factors that limit the sustainable development of green agriculture.By systematically analyzing the effects of irrigation and nitrogen application on the soil environment and crop growth and development,it can provide scientific basis and theoretical support for high-efficiency production of salinized dryland farmland.In this study,oats were used as the test material,and the variety was Bayou No.18.The field experiment was carried out at the Saline Alkali Land Improvement Experiment Base of Shanxi Academy of Agricultural Sciences from May to August 2019;the pot experiment was carried out at the Scientific Research Base of the School of Water Conservancy Science and Engineering,Taiyuan University of Technology from April to August 2019.Two factors were set in the field experiment:the amount of irrigation water and the amount of nitrogen applied.Irrigation quotas are 300 mm(W1)and 200 mm(W2).The nitrogen application rate is 0(N0),70 kg/hm~2(N1),140 kg/hm~2(N2)and 210 kg/hm~2(N3).In the pot experiment,the irrigation level was 120%ET(W1)and 100%ET(W2),and the nitrogen application rate was(N0,N1,N2,and N3).Determine the soil moisture content,nitrate nitrogen and ammonium nitrogen,electrical conductivity,growth and yield indicators of oats in different growth periods,and calculate water consumption and water and nitrogen use efficiency.The main conclusions are as follows:(1)For the 0-100cm soil layer,the volumetric water content of the soil profile in each measurement period is expressed as:W1>W2.For the 0-40cm soil layer,at the W1 irrigation level,the soil volumetric moisture content is expressed as:N0>N1>N2>Under N3 and W2 irrigation levels,the volumetric water content of the soil after the jointing stage is as follows:N0>N1>N3>N2;in the 40?100cm soil layer,except for seedling stage,the volumetric water content of the soil treated with N1,N2and N3 is significantly lower(p<0.05)than In the N0.0-40cm soil layer,from the jointing stage to the mature stage,the soil electrical conductivity is all expressed as W1<W2.Under the two irrigation levels,soil electrical conductivity increased with the increase of nitrogen application rate.In the 40-100cm soil layer,the soil conductivity of W1 is lower than that of W2 during the grouting and mature stages,and the soil conductivity of N1,N2 and N3 treatments is significantly higher(p<0.05)than the N0.0-40cm soil layer,at the jointing stage At the maturity stage,the soil nitrate nitrogen and ammonium nitrogen content both behave as follows:W1<W2.The content of soil nitrate nitrogen and ammonium nitrogen increased with the increase of nitrogen application rate.The N1,N2,and N3 treatments were significantly higher than N0(p<0.05);the soil nitrate nitrogen content was different among the various nitrogen treatments in the early growth period Significantly(p<0.05),N3 was significantly higher(p<0.05)in the late growth period than N1 and N2,and the difference between N1 and N2 was not significant.In the 40-100cm soil layer,there is basically no significant difference in the content of nitrate nitrogen and ammonium nitrogen between W1 and W2 soils.The content of nitrate nitrogen in soil treated with N1,N2 and N3 in each growth period was significantly(p<0.05)higher than N0.The soil ammonium nitrogen content of N3 treatment was higher than that of N0 and N1 treatments,the difference was significant(p<0.05),and the difference between N2 and N3 was not significant.(2)The plant height,stem diameter and leaf area index of oats in each growth period showed W1>W2,and they basically increased with the increase of nitrogen application rate.Under the irrigation levels of W1 and W2,the grain yield of oats under N2 and N3 treatments was significantly(p<0.05)higher than that of N1treatment,and there was no significant difference between N2 and N3 treatments.The biological yield of oats in N1,N2 and N3 treatments was significantly higher(p<0.05)than N0 treatment.Under W1 irrigation level,the difference between N2 and N3 was not significant;under W2 irrigation level,the difference between N1,N2 and N3 was not significant(P>0.05).The water consumption of oats in the growth stage after the jointing stage and the whole growth period is as follows:W2<W1,the difference is significant(p<0.05).Under the same irrigation level,the water consumption of oats in each growth stage and the whole growth period gradually increased with the increase of nitrogen application rate.The water use efficiency of oats:W2>W1,the difference was significant(p<0.05),the water use efficiency of N1,N2,and N3 treatments was significantly(p<0.05)higher than N0.The partial productivity of nitrogen fertilizer of each nitrogen application was as follows:N1>N2>N3,the difference was significant(p<0.05).The nitrogen fertilizer agronomic utilization efficiency of N1 and N2treatments was higher than that of N3,and the difference was significant(p<0.05).(3)The pot experiment showed that the plant height and stem thickness of oats increased first and then decreased with the increase of nitrogen application.Under the irrigation level of W1,the plant height and stem thickness of N1,N2 and N3treatments were significantly higher than N0(p<0.05).The difference between N2and N3 is not significant;it is expressed as N0<N1<N3<N2.Under W2 irrigation level,the plant height of oats was N0<N3<N1<N2,and the stem thickness was N0<N1<N3<N2.Under the two irrigation levels,water consumption showed that N1<N3<N2,N2 and N3 were significantly higher than N1(p<0.05),and the difference between N2 and N3 was not significant;under the same nitrogen application conditions,W2 was significantly lower than W1.Nitrogen application will significantly increase the yield of oats and its components.The grain yield of oats under different nitrogen treatments is N0<N1<N3<N2,and the difference between N2 and N3 is not significant(p>0.05).Irrigation has little effect on the yield of oats..Under the W1 irrigation level,the biological yield was N0<N1<N2<N3,and under the W2 irrigation level it was N0<N1<N3<N2.There was no significant difference between the various nitrogen treatments.The water use efficiency of oats increased first and then decreased with the increase of nitrogen application rate,showing N2>N3>N1>N0.The partial productivity of nitrogen fertilizer of W1 and W2nitrogen treatments were 5.9-14.4 kg/kg and 5.3-14.2 kg/kg,respectively,and the difference of each nitrogen treatment was significant(p<0.05).The agronomic utilization efficiency of nitrogen fertilizer in N1 and N2 treatments was significantly(p<0.05)higher than that in N3 treatment.Based on the above analysis,it is recommended to use W2 irrigation level in this test area,and control the nitrogen application rate to 140kg/hm~2. |
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