Nitrogen Regulates The Growth And Development Of Soda Saline Soil Rice And The Impact Of Production

In order to explore the effect of nitrogen regulation on the growth,development and yield of rice in soda saline-alkali land,a pot experiment was conducted in 2021 at the College of Agriculture,Heilongjiang Bayi Agricultural University.A field-testing experiment was carried out in 2022 at the demonstration base of Heilongjiang Salt land improvement Engineering and Technology Research Center（Shidifangzi Village,Saertu District,Daqing City）.Using“Longdao 10”as the test material,5 treatments were set up:N1（N150 kg/hm²,basal tiller fertilizer:panicle fertilizer=15:0）,N2（N150 kg/hm²,basal tiller fertilizer:panicle fertilizer=11:4）,N3（N 150 kg/hm²,basal tiller fertilizer:panicle fertilizer=7:8）,N4（120 kg/hm²,basal tiller fertilizer:panicle fertilizer=7:5）and N0（no nitrogen fertilizer）.The results of two-year experiment showed that:（1）Nitrogen regulation improved the population quality of rice in soda saline-alkali soil.Compared with N1 treatment,N2,N3 and N4 treatments significantly decreased rice plant height at booting stage and heading stage,while N3 and N4 treatments increased rice root volume.N2,N3,N4 treatments significantly decreased rice plant height and root length,while N2,N3treatments increased rice root volume.At filling stage,N3 and N4 treatments in pot experiment significantly decreased rice plant height and increased rice root volume and root surface area,while in plot experiment N2,N3 and N4 treatments significantly decreased rice plant height and increased rice root volume.Both N3 and N4 treatments in pot and field-testing experiments effectively reduced the ineffective tillering of rice and promoted the early growth and rapid development of rice.N4 treatment had a better effect on the improvement of rice population quality.（2）Nitrogen regulation improved the photosynthetic characteristics of rice in soda saline-alkali soil.Compared with N1 treatment,N2,N3 and N4 treatments increased net photosynthetic rate（Pn）,transpiration rate（Tr）,intercellular CO₂ concentration（Ci）and stomatal conductance（Gs）in late growth stage of rice leaves,while N2,N3 and N4 treatments increased SAPD value and leaf area index in late growth stage of rice in plot experiment.（3）Nitrogen regulation improved the stress resistance of rice in soda saline-alkali soil.Compared with N1 treatment,the activities of antioxidant enzymes and osmotic regulation substances in rice leaves of N2,N3 and N4 were tested in plot experiment.At heading stage,APX activity in rice leaves treated with N2,N3 and N4 in pot experiment increased significantly by 41.38%,82.73%and 100.39%,respectively.In plot experiment,APX activity in rice leaves treated with N4 increased significantly by 23.84%.During the filling stage,the contents of proline and soluble protein in rice leaves treated with N4 in pot experiment increased significantly by 82.54%and 20.55%,respectively.In the plot experiment,the contents of proline and soluble protein in rice leaves treated with N4 increased by 36.39%and 19.84%,respectively.The stress resistance of N4 treatment was stronger in pot and field-testing experiments.（4）Nitrogen regulation improved the utilization of nutrients in soda saline-alkali soil.Compared with N1 treatment,N2,N3 and N4 treatments significantly decreased soil electrical conductivity at booting stage,significantly increased soil available potassium,available phosphorus and alkali hydrolysable nitrogen content.In the plot experiment,N2,N3 and N4treatments significantly reduced soil electrical conductivity,and N3 and N4 treatments significantly increased alkaline phosphatase activity by 86.01%and 52.98%,respectively.At heading stage,the absolute value of ZETA potential in pot experiment was N0>N4>N1>N2>N3,and that of ZETA potential in plot experiment was N0>N3>N4>N2>N2.（5）Nitrogen regulation increased rice yield in soda saline-alkali soil.Compared with N1treatment,the yield of N3 and N4 treatments in pot experiment increased significantly by 12.82%and 25.4%respectively,the seed setting rates of N3 and N4 increased by 7.2%and 17.15%,respectively.Compared with N3 treatment,N4 treatment increased the number of grains per panicle,seed setting rate and yield by 20.00%,16.19%and 11.09%,respectively.Compared with N4 treatment,N3 treatment decreased the number of panicles,increased the number of grains per panicle and 1000-grain weight,and further increased rice yield.In the plot experiment,the yield of N2,N3 and N4 treatments increased by 1.21%,7.03%and 7.66%respectively,and the seed setting rates of N3 and N4 increased by 0.25%and 0.85%,respectively.（6）Nitrogen regulation increased the absorption and utilization of nitrogen fertilizer in soda saline-alkali soil.Compared with N1 treatment,pot and field-testing experiment N2,N3 and N4increased nitrogen absorption and utilization efficiency,nitrogen agronomic use efficiency and nitrogen partial productivity in soda saline-alkali soil,N4 treatment reached a significant level.