Effects Of Different Sowing Densities And Fertilization On Tiller Characteristics And Yield Of Direct-seed Rice

Direct-sowing rice is mainly produced by mechanical sowing and manual sowing in production,and there is no perfect theoretical support for the selection of nitrogen fertilizer management methods and density.Therefore,in this study,starting from the sowing method,sowing rate and fertilization method to study the characteristics of tiller characteristics and yield characteristics of direct seeding rice,in order to provide theoretical guidance for the production of regional direct rice.The experiment was conducted in 2016 and 2017 in the Huazhong Agricultural High-tech Development Zone with the hybrid rice Quanliangyou681,Huanghuazhan and the conventional rice Huanghuazhan as the materials,and the photosynthetic characteristics and dryness of the main growth period were determined according to the conditions of tillering and spike formation.With regard to the ability to accumulate substances,the effects of different cultivation methods on the tillering characteristics and yield of direct-seeded rice were studied.The result shows:1?The leaf position at the time of one tiller was 1/0⁶/0,of which the 3/0⁶/0leaf position was the dominant leaf position of panicles;the 2/0⁵/0 leaf position was the dominant leaf position of panicles,among which 3/0,4/0 had the highest rate of spike formation;secondary tillers,with 2/1,3/1 and 2/2 leaf position as the dominant leaf position,3/1 had the highest rate of emergence,exceeding 40%,2/1 and 3/1 are the main spikes in secondary tillers,and the percentage of spikes is low.2?Appropriate cultivation methods facilitate direct-seeding rice2?The main tillers were 3/0⁶/0,2/1,3/1,and 2/2,and the average incidences of live direct and secondary tillers were about 27.2%and 29.7%,respectively.The average tiller rate of tillers was about 14.1%and 27.5%higher.The dry matter accumulation of mechanically broadcast rice during the main growth period was significantly higher than that of artificially sown rice,and the difference was extremely significant.During the mature period,the dry matter accumulation of mechanically broadcasted rice reached the maximum,which was 18.06t/hm²,which was 2.83t/hm² higher than that of artificially sown rice.In the aspect of net dry matter accumulation,the mechanical direct-seeding rice to the full heading stage reached the highest.The main spikes,such as grain density,single ear weight,number of branches and branches,number of grains,and seed setting rate of mechanically broadcast rice,were all superior to those of artificially sown rice.The quality of single ear and number of grains per panicle The difference reached a significant level.The live broadcast of machinery is higher than that of artificial sowing.The difference is extremely significant.3?The occurrence rate of primary and secondary tillers and spike rate in the sowing volume of 22.5 kg/hm2 was higher in Quanliangyou 681 and Quanyouhuazhan.Among them,2/0⁵/0,2/1,3/1,and 4/1 leaf positions were the main spike positions,and the average tillage rate of one-two tillers was 13.4%and17.4%higher;Huanghuazhan accounted for 45.0kg.The incidence of primary and secondary tillers under/hm2 had an advantage,and the dominant till position for one tillering was 2/0⁵/0,3/1,and the average tiller success rate for one and two times was 12.6%and 15.5%.Appropriate sowing density facilitates dry matter accumulation in direct-seeded rice Quanliangyou 681 and Quanyouhuazhan maintained a higher dry matter accumulation capacity in the middle and late reproductive stages at the sowing volume of 22.5 kg/hm².The average dry matter accumulation during the mature stage was the highest,1.34 t/hm² higher than that of the photosynthetic indicators.Significant advantages were obtained at the full heading stage,in which the average population growth rate was 0.05 t·d^-1·hm^-2,the net assimilation rate was 0.54 g·m^-2,the effective leaf area rate was 3.79%higher and the photosynthetic potential at ripening stage.The largest is 38.75m²·d·m^-2.The suitable sowing density is conducive to optimizing the panicle traits and yield of direct-seeded rice.With the total volume of 22.5 kg/hm²,the total grain number of the primary branches was higher and the seed setting rate was higher;the secondary branch stems had obvious differences due to variety,and the advantage was not obvious.Huanghuazhan had a longer panicle elongation at the sowing rate of 45.0 kg/hm²,and the single panicle quality was greater;the overall branch stem had an overall advantage;the QuanLiangliangyou681 had a lower yield at the sowing volume of22.5 kg/hm²;the Quanyouhuazhan accounted for the opposite output,but The difference is not significant.Huanghuazhan had a significantly higher yield at a sowing rate of 45.0 kg/hm²,and the difference was not significant.4?The four fertilization methods are conducive to the tillering of direct seeding rice.The average tillering rate of 4 fertilization direct seeding rice was 72.2%,which was 8.9%higher.The highest and lowest average incidence of secondary tillering was3/1,1/3 leaf position,which was higher by 10.0%and 8.6%respectively.The highest frequency of 4 fertilization direct seeded rice was in the 3/0 and 4/0 leaf position.The highest tiller rate of secondary tiller in 4 fertilization direct seeded rice was 3/1 leaf position,which was 57.7%,and the lowest was less than 10%.4-timesfertilization methods facilitate the accumulation of photosynthetic substances in direct-seeding rice.Direct fertilization for 4 times in direct seeding rice has higher leaf area index,net assimilation rate,and photosynthetic potential in the late middle stage of reproduction.The relative growth rate of the population at the jointing stage to the panicle stage is obvious;therefore,photosynthetic material accumulation ability is strong,dry matter accumulation,and net dryness Material accumulation is large.4-times fertilization methods facilitated the spike traits and yield of direct-seeded rice.The four-time fertilization direct-seeded rice had superior spike characteristics,yield,and constituent elements than three fertilization direct-seeded rice.The grain density,single ear mass,and number of branches and numbers and grain number of one and two branches of each treatment were strong.The trends presented by the rates are basically the same:there are advantages in four-pass fertilization of direct-seeded rice,in which the difference in the quality of individual panicles reaches a significant level.The yield of direct-seeded rice with 4 times fertilization and the performance of all factors were better than that of the direct seeded rice with 3 fertilization.The number of panicles was the most obvious.In direct-seeded rice production,the suitable density is selected according to the variety characteristics in the region.The mechanical direct-sowing and 4 fertilization is favorable to the construction of quality and yield of rice.4 fertilization of water and fertilizer management for direct rice population construction and yield formation.In the production,it is possible to adopt the mechanical live broadcasting method of 22.5kg/hm² of hybrid rice and 45.0kg/hm² of conventional rice,and 4fertilization fertilization strategies.