| Soil salinization is one of the main factors that restrict the high yield of crops and the increase of agricultural income,Selecting varieties with good comprehensive resistance such as salt tolerance and scientific application of nitrogen nutrition are the key measures to improve the production efficiency of oat in saline alkali land.In this study,the differences of biomass accumulation,quality and nitrogen absorption characteristics of different oat varieties(lines)in saline alkali land were studied by field experiment in tumechuan plain,and the varieties with better comprehensive characters were selected;Set different proportions of urea combined with controlled-release nitrogen fertilizer:NO(0:0)、N1(10:0)、N2(0:10)、N3(3:7)、N4(5:5)、N5(7:3).To study the effects of saline alkali stress on Oat Growth and development,soil nitrogen nutrition and soil biological properties,The optimal ratio of nitrogen fertilizer to promote salt and alkali tolerance of oats was selected.The results showed that:1.The performance of 26 oat varieties(lines)in saline alkali soil varies greatly in different growth stages.Mengyan 1 and G142 are the best oat hay yield at heading stage,which can be used as varieties to produce high-quality oat grass.The principal component analysis showed that the main identification indexes of salt and alkali tolerance of different varieties were grass yield,grain nitrogen content,grain number per panicle and grain weight per panicle;Through membership function analysis and cluster analysis,26 oat varieties(lines)are divided into four categories:The first is a strong comprehensive variety,with 13 varieties,of which Mengyan 1 is better;The second type is G144,which is more comprehensive;The third category is medium comprehensive varieties,with 7;The fourth category is poor comprehensive varieties.2.Under saline alkali conditions,the combined application of urea and controlled-release nitrogen fertilizer in the same amount and different proportion can promote the growth and development of oats.Compared with the application of the same amount of urea,taking the production of oat grass as the main purpose,the optimal nitrogen fertilizer ratio of hay yield at the heading stage of oats is urea ratio,and the ratio of controlled-release nitrogen fertilizer is "5:5";In the mature stage of oats for the purpose of grain production,the optimal proportion of nitrogen fertilizer is "3:7".Oat showed significant improvement in plant height,leaf area,SPAD,yield,plant nitrogen accumulation,grain nitrogen accumulation,nitrogen harvest index,nitrogen partial productivity,soil enzyme activity and soil nitrogen content under the optimal combined application ratio in different periods,Mengyan 1 was the best variety.With the absorption of nitrogen and salt in soil by oat growth,the chemical properties of soil decreased from heading stage to maturity stage,and the content of soil decreased with the deepening of soil layer due to the distribution characteristics of root system;The soil enzyme activity,nitrogen content and variation range in 0～20 cm soil layer were higher than that in 20～40 cm soil layer,while the soil pH was opposite;The soil urease activity,sucrase activity and catalase activity of Mengyan 1 were higher than those of Caoyou 1.The total nitrogen,nitrate nitrogen,ammonium nitrogen and pH of soil were lower than those of Caoyou 1,showing strong saline alkali resistance and soil improvement.The comprehensive study showed that oat varieties and nitrogen fertilizer ratio had significant effects on Oat Growth Characteristics,biomass accumulation,quality,nitrogen absorption characteristics and soil properties.Under saline alkali conditions,varieties and combined application ratio varied with the purpose of harvest.If forage is harvested at heading stage,the ratio of urea to slow-release nitrogen fertilizer is recommended to be"5:5",and Mengyan 1 is recommended.If the grain is harvested at maturity,the ratio of urea to slow-release nitrogen fertilizer is recommended to be "3:7",and Mengyan 1 is better.Considering the characteristics of nitrogen utilization and grain yield,G144 is recommended.Which can be flexibly applied in the planting process. |
