Effects Of Different Nitrogen Fertilizer Rate And Different Ratio Of Base And Topdressing On Growth And Development And Yield Of Oats

Oat（Avena sativa L.）is an excellent food and feed crop,with the advantages of strong adaptability,good palatability and high yield.In this experiment,two oat varieties,naked oat（Baiyan 2）and skin oat（Baiyan7）,were used as test materials,and a randomized block experimental design was adopted.Three nitrogen application rates were set as 90 kg/hm²（N90）,180 kg/hm²（N180）,270 kg/hm²（N270）,three basal and topdressing ratios（basic and topdressing ratios）were set under each nitrogen application rate,and the basal and topdressing ratios were 7:3（B1）and 5:5（B2）,3:7（B3）respectively,top-dressing was applied at the jointing stage of oat,and no nitrogen fertilizer（N0）was applied during the whole growth period as a control.The effects of no nitrogen application rate and base topdressing ratio on the growth,development and yield of oat were explored,which provided theoretical basis and technical support for oat nitrogen fertilizer operation.The results of the study are as follows:1.Effects of nitrogen application rate and base-dressing ratio on growth indexes of oatsDifferent nitrogen application rates and basal topdressing ratios had significant promoting effects on the growth of oats.Under the same base-dressing ratio,with the increase of nitrogen application rate,the plant height,stem diameter and leaf area of the two oat varieties showed a trend of first increasing and then decreasing.At the jointing stage,heading stage,grain filling stage and maturity stage,the plant height,stem diameter and leaf area of the two varieties of oats all reached their maximum values when the nitrogen application rate was 180 kg/hm² and the base-dressing ratio was 7:3.significantly increased compared to the control.2.Effects of nitrogen application rate and base-dressing ratio on photosynthetic indexes of oatDifferent nitrogen application rates and base-dressing ratios had significant effects on photosynthetic indexes of oats.Topdressing nitrogen fertilizer can increase the net photosynthetic rate of oats.The net photosynthetic rate of both oats reached the maximum when the nitrogen application rate was 180 kg/hm² and the base topdressing ratio was 7:3.When the base-recovery ratio was constant,the net photosynthetic rate of oat showed a trend of first increasing and then decreasing with the increase of nitrogen application rate.The stomatal conductance,intercellular CO₂ concentration,and transpiration rate of Baiyan No.2 all reached their maximum values when the nitrogen application rate was 270 kg/hm² and the base-to-recovery ratio was 5:5;the stomatal conductance of Baiyan No.7,the intercellular The CO₂ concentration and transpiration rate both reached the maximum value when the nitrogen application rate was 180 kg/hm² and the base-to-recovery ratio was 3:7.3.Effects of nitrogen application rate and base-dressing ratio on oat yieldNitrogen application rate and basal topdressing ratio had significant effects on oat seed yield and yield components.The panicle length,1000-grain weight,number of grains per plant per ear,grain weight per plant per ear,and seed yield of the two oat varieties reached their maximum values when the nitrogen application rate was 180kg/hm² and the base-dressing ratio was 7:3.Nitrogen fertilizer was significantly increased.When the nitrogen application rate was 180 kg/hm²,the seed yield of the two varieties of oat showed a trend of increasing gradually with the increase of the ratio of basal and follow-up.The correlation analysis of oat yield and yield components found that the thousand-grain weight,grains per plant per plant,grain weight per plant per panicle and seed yield of Baiyan No.2 had a very significant positive correlation.There was a very significant positive correlation between the number of grains per panicle per plant and seed yield of Baiyan No.7,and there was a significant positive correlation between panicle length and 1000-grain weight and seed yield.4.Effects of nitrogen application rate and base-dressing ratio on accumulation and distribution of dry matter in oatThe dry matter accumulation of the two varieties of oats increased gradually with the growth period,and the nitrogen application rate and the base-dressing ratio could promote the dry matter accumulation of oat.When the base-to-recovery ratio was constant,the dry matter accumulation of the two varieties of oats at maturity showed a trend of first increasing and then decreasing with the increase of nitrogen application.Among the organ contribution rates of the two oats,the stem contribution rate was the largest,and the root contribution rate was the smallest.Compared with the control,nitrogen topdressing could promote the increase of root and panicle contribution rate.5.Effects of nitrogen application rate and base-dressing ratio on nutritional indexes of oat grainsThe amount of nitrogen application had a significant effect on the nutrient content of oat grains.When the base-to-dressing ratio was constant,the grain soluble sugar and grain soluble protein content of Baiyan No.2 reached the maximum value when the nitrogen application rate was 270 kg/hm².The soluble sugar content of Baiyan No.7reached the maximum when the nitrogen application rate was 270 kg/hm² and the base-to-dressing ratio was 7:3.The soluble protein content of grain reached the maximum when the nitrogen application rate was 180 kg/hm² and the base-dressing ratio was 3:7.