Effects Of Cultivation Methods On Yield And Income Of Different Types Of Rice Varieties

Improving nitrogen fertilizer were propitious to increase rice unit yield.Understanding the fertilizer requirement of different types of varieties and the relationship between fertilization and yield is of great significance to reduce the amount of nitrogen,resulting in improving the utilization rate of nitrogen,which would reduce the waste of resources and protect the ecological environment,as well as to reduce cost and gain more profits.In this study,eight different types of late-mature japonica varieties in Taihu rice planting region were treated with three fertilization levels and three densities,and the effects of nitrogen levels and planting densities on yield,quality and nitrogen use efficiency of different varieties were studied.Furthermore,the economic benefits of different treatments were analyzed.These results can provide useful information for rice breeding and production in future.The main results are as follows:1.A three-way ANOVA showed that nitrogen application had the greatest impact on yield,followed by varieties,fertilization × density interaction,fertilization × variety interaction and planting density.The interaction between planting density and variety was not significant,but the interaction between fertilization × density xvarieties was significant.2.With the increase of nitrogen application and planting density,the yield of varieties increased f-irstly,then decreased.All varieties gained the highest yields by treating with the medium fertilizer level(12 kg pure nitrogen/667m2)and medium planting density(20,000 plants/667m2).These results showed that planting density and nitrogen application levels should be reasonably arranged for high yield.When nitrogen application level was low,planting density should be increased properly.In contrast,planting density should be reduced appropriately when nitrogen application level was high.3.The number of effective panicles was increased with the increasing nitrogen application and planting density,but the seed setting rate and 1000-grain weight decreased under the condition of high fertilizer(22kg pure nitrogen/667m2)and high density(30,000 plants/667m2).Obviously,the medium fertility level and medium planting density can coordinate the contradiction among the yield components effectively,so as to obtain higher yield.4.With the increase of nitrogen application,the growth time and plant height of cultivars increased,and the effect of nitrogen application on the growth time was greater than that on heading date,which may be resulted from the increase of nitrogen concentration in plant and the extension of grain filling period.The difference of plant height between high fertilizer treatment and medium fertilizer treatment was relatively small.In comparison,planting density had little effect on growth time and plant height.5.The nitrogen use efficiency and nitrogen productivity decreased significantly with the increase of nitrogen application level.With the increase of planting density,the nitrogen use efficiency decreased significantly,and the effect of planting density on partial productivity of nitrogen was not significant.Nitrogen use efficiency of Yongyou 1540,Changyou 4 and Changyou 6 were higher,following by Wuyunjing 30,Wuyunjing 23 and Changnongjing 8,three conventional japonica rice varieties.And the lowest nitrogen use efficiency was observed on Laolaiqing and Nongken58.6.The application of nitrogen fertilizer improved brown rice rate,milled rice rate,head rice rate.But,it increased protein content of milled rice and decreased amylose content,resulting in the decreased rice taste quality.High nitrogen fertilizer level contributed to the improvement of rice appearance quality,chalky rice rate and chalkiness,but no significant difference was observed on these quality traits between moderate nitrogen application and no fertilizer application.7.As the cultivation methods concerned above,medium fertilizer and medium planting density were benefit for high income.The high fertilizer and high density needed the large input,resulting in the relatively low income.For different types of varieties,the yield and income of hybrid rice were the highest.Without fertilization,the better yield of hybrid rice could be obtained by increasing the planting density.The yield and income of the conventional new varieties were medium,and the yield and income of old varieties were the lowest.8.Considering the income,the better cultivation methods for hybrid rice varieties showed a tendency of medium-fertilizer and medium-density>medium-fertilizer and low-fertilizer>medium-fertilizer and high-density>high-fertilizer and medium-density>no-fertilizer and high-density.The better cultivation methods for conventional new varieties were medium-fertilizer and medium-density>high-fertilizer and medium-density.