Studied On Population Quality Indicators And Nitrogen Fertilizer Application Of The Wheat Under Rice Stubble In Southern Henan Province

In order to explore suitable population quality indicators and cultivation techniques,and clear the key parameters with 6000 kg ha-1 of wheat yield in southern Henan Province,a experiment that focused on field plot experiment and field investigation was conduted to provide theoretical technical basis for the improvement of yield and scientific farming management.The investigations have be made on the screening of varieties,planting pattern,reasonable range of nitrogen application and appropriate population-quality.On this foundation,we had proposed suitable sets of high-yield cultivation techniques of yhe wheat under rice stubble.Main results for this study are as follows:1.Screening of suitable varietiesThe field experiment of varieties comparision was conduted for two consecutive growth seasons from 2012-2014.The results show that the wheat yield of all the varieties increased and then decreased with the increase of nitrogen application.When the nitrogen rate is120-225kg/hm2,the yield of the nineteen varieties(except Xinong 979)are all higher.The yield of Lankao198 and Zhoumai26 were relatively higher than others.The experiment primarily established the suitable wheat varieties include Lankao 198 and Zhoumai 26.2.Planting patternThe field experiment of planting pattern was carried out from 2014-2015.The results show that comparing with the artificial sowing,sowing by field equipments can increase the yield through increasing grain number per spike and the thousand grain weight respectively by 3.8-8.5% and 4.1-7.8%.Comparing with the artificial seeding,sowing by field equipments can significantly increase the yield of winter wheat by 4.8-7.2%.3.Effect of nitrogen rate on plant growth and yield of the wheat under rice stubble in southern Henan Province(1)The secondary roots of winter wheat increased with nitrogenous fertilizer employment quantity the increase,and reach the maximum at anthesis stage.There is no significant difference at the wintering period;but after the standing stage,great difference begins to appear.(2)In the whole growth period,the nitrate nitrogen content increased and then decreased with the increase of nitrogen application.Before jointing stage,the difference of nitrate nitrogen content is insignificant.After jointing stage,the nitrate nitrogen content increased with nitrogenous fertilizer employment quantity the increase.(3)Field plot experiment shows that nitrogen can significantly increase the grain yield,specifically speaking,N225>N150>N0.Through the analysis of three composing ingredients of yield,it is found that the reason why nitrogen can increase grain yield is mainly it can increase the number of ear bearing tiller and the per ear grain number;but the thousand grain weight has no significant effect.4.Established population-quality indicatorsThe result showed that 6000 kg ha-1 of wheat yield was realized with the factors.(1)At winter surviving,standing,joingting and anthesis stage,the main stem leaf age is5.4-6.0,7.9-8.7,9.5-10.5 and 11.1-11.5;the amount of secondary root per plant is 4-5,13-16,15-19,and 20-25.At standing and jointing stage,when the NO3-N content in soil is 12-24mg/kg,the nutritional requirement for wheat growth and development was satisfied.AT anthesis and maturity stage,the dynamics of plant N content(%)of winter wheatis respectively 1.96-2.1% and 0.84%-0.92%.(2)The basic seedling is 0.45~0.57 time of the ear number.The optimal stem and tiller number in the standing stage is 1.17 ~ 1.36 times of the number of ear.The earing rate of stem and tiller is 79.5% ~ 81.8%.Tiller earing rate is 63.1% ~ 67.2%.The most appropriate LAI value in the standing stage,the jointing stage and the flowering period are respectively2.9~3.2,4.1~5.6 and 6.1~7.6.The dry matter accumulation in the flowering period is 12000~ 14500 kg/hm2.The dry matter accumulation in the mature period is 20000~24500 kg/hm2.The total number of spikelet is above 210×106grain/hm2.The suitable grain-leaf area ratio is above 0.38 grain/cm2 per leaf and 9.5 mg/cm2.The three composing ingredients will reach the following respective indicator range.The final the number of ear bearing tiller is490×104~620×104hm-2;the per ear grain number is 37-40;and the thousand grain weight is above 37 g.The results of surveying peasant household from 2014 to 2015 show that in order to realize the transition from low wheat yield to middle wheat yield,all of the three composing ingredients of the yield need to be improved,especially the thousand grain weight because its effect is more significant;in order to realize the transition from middle wheat yield to middle high wheat yield,the ear number and the grain per ear need to be improved,especially the ear number;in order to realize the transition from middle high wheat yield to high wheat yield,the ear number plays the most important role and the grain per ear and the thousand seed weight should be coordinated.Under this experimental condition,with equal nitrogen application,Lankao 198 in the main growth period is relatively high in LAI value,dry matter weight,grain-leaf area ratio and the total number of spikelet,which may be the reason why Lankao 198 has relatively high yield.According to this experiment results,it is initially thought that seeding by field equipments is helpful to increase yield,and that Lankao 198 is more suitable to be weeded in wheat following rice region in southern Henan Province even with wheat yield of more than 6000 kg/hm2.In addition to meeting the need for soil fertility and the required suitable population-quality indicators for the main growth periods,it is needed to make the nitrogen application rate in the whole stage be about 225 kg/hm2,and make sub-base fertilization and topdressing in standing and jointing stage with the topdressing ratio of 5:5 or 6:4.