Study On Effects Of Nitrogen And Magnesium Fertilizers Applied On Rice Yield And Quality

Nitrogen（N）and Magnesium（Mg）were the essential nutritional elements for the normal plant growth and development of rice,which were the important components participating in various physiological and biochemical processes of rice plant,playing an important role in promoting plant development and metabolism.Mg was a component of chloroplast,which could influence the yield and quality of rice as well.The effects of N and Mg on the nutrient content,accumulation,physiological characters,indexes of population quality and yield components was systematically studied in this paper,using LONGJING 20（Oryza sativa L.）as research object and popular fertilizing methods in the field to design different rice populations through the crack zone experiment design（The following amount of N and Mg are all the commodity by urea and Magnesium sulfate respectively for standard）.The main results were as follows: 1.Effects on plant nutrient content of applying N and MgThe plant nutrient content,accumulation and mass production were significantly influenced by the applying amount of N and Mg.The content of N and Mg in every part of the rice plant indicate that the content of N in the over-ground plant and Mg in wax medium-stage plant were significantly improved by the application of N（r = 0.9241 and r = 0.8276）,but the content of N and Mg in grain was not related to the application of N.The increase of dry matter weight in the over-ground plant was promoted by the increased content of N and Mg.The nutritional role of N was obvious lager than Mg.There was an inverse proportion between content of Mg and the value of root/canopy,the value of root/canopy was significantly increased when the amount of Mg was lacked.The content and accumulation of N and Mg was improved by the cooperated application of them when the amount of Mg is little.When the applying amount of N and Mg was abound,it impaired the content and accumulation of them.The content of Mg in the treatment（450.0kg N + 112.5 kg Mg）was more than the treatment（450.0kg N）,the increased ratio was 3.8%,and the accumulated amount was improved at 20.3%.The content of Mg in the treatment（450.0kg N+ 450 kg Mg）was less than the treatment（450.0kg N）,the decreased ratio was 14.4%,and the accumulated amount of Mg was decreased at 16.5%.It indicated that the transfer or content of Mg were restrained,the accumulated amount of nutrient was decreased due to the simultaneously excessive application of N and Mg.During the course of nutritional content,the content of N and Mg was jointly promoted at the lower amount of Mg and inhibited contrarily.The nutritional content of N and Mg for over-ground plant was reciprocally promoted applying fertilizer singly.When the cooperated application of N and Mg was applied,the content of Mg was increased when the content was higher at the case of lower N.After the content of nitrogen was exceeded over 35.8 g·kg^-1,the content of Mg was decreased slightly with the improvement of N.2.Effects on photosynthesis of applying N and MgNet photosynthetic rate was increased for applying N and Mg at appropriate rate.The applying amount of N was 225.0 and 337.5 kg/hm2,then the cooperating application amount of Mg was respectively 112.5,225.0,337.5 kg/hm2,the net photosynthetic rate in booting stage was significantly improved,the increased ratio was 4.3% 29.7%.3.Effects on dynamic of population stems of applying N and MgThe number of harvested ear can be effectively increased for the cooperating application of N and Mg.The applying amount of N was 225,337.5 and 450 kg/ hm2,and the amount of respectively applying Mg was at 225kg/ hm2,the ear number of treatments was increased respectively 15%,10.0% and 14.8% than the un-applied treatment.The ratio of N/Mg and N/（MgK）and the amount of Mg applied were display with the trend of a single curve.The ratio of N/Mg and N/（MgK）could be effectively improved by the apt application of Mg.The content of Mg in leaves during the booting stage was positively correlated with effective tiller rate and tiller spike ratio.The yield could effectively improve with the increase of the N/Mg in nutritional organ..4.Effects on the yield and the yield components of applying N and MgThe results of two-season trial show that the yield was increased for applying singly at the lower content of Mg.The yield was significantly increased with the increasing amount of applied N,but the extent of yield increase was reduced at the excess application of N,and the trend of decreasing yield was even happened.After the cooperated application of N and Mg,N was main factor and the effect of N was larger than Mg.The effect of Mg on yield and interaction of Mg and N was not significant.The yield was evidently improved for the increase of N and Mg in nutritional organ.There was a decreased trend of yield when the content of N and Mg in nutritional organ was excess.Amount of the applied N was positively correlated with ears,spikelet per ear and grain yield,and negatively correlated with seed setting rate and grain weight.The correlation among the amount of Mg and yield component,yield of rice was not significant.The amount of spikelet per ear could be effectively improved by increasing apart the content of N or Mg in leaves at booting stage.The increased extent of yield was different in the treatments with application of N at 337.5kg/hm2 combining application of Mg at 112.5-337.5 kg/hm2.5.Effects on the rice quality of applying N and MgThe N/（Mgk）and N/Mg in grain had no obvious relation with amount of applying N,but obvious relation with amount of applying Mg,applying Mg properly could improve N/（Mgk）and N/Mg efficiently,then the head rice rate improved,too.But when the N/（Mgk）ratio was too high,the head rice rate appears decreasing trend.Two years’ study showed: the chalky rate appeared significant negative correlation with the head rice rate.After applying N and Mg together,N had significantly influence on the chalky rate,Mg’s influence on the chalky rate and the head rice rate both reach a clearly high level during the two yeas’ tests.High level of N combined with applying 228.0kg³37.5kg Mg every hectare decreased the rice’s chalky rate obviously,but improved the head rice rate.Applying fertilizer singly,the taste quality will improved at first,then decrease as applying Mg more and more,no matter low or high amount Mg was,the taste quality will decrease.When applying N singly,low amount of N improved taste quality;high amount of N decrease taste quality obviously,two years’ study showed: dealing with high amount of N combined with low amount of Mg can sincerely improved the taste.Dealing with applying 337,8kgN+112.8kg Mg each hectare and applying 480.0kg N+ 112.5kg Mg each hectare both had less obvious and effective influence on taste quality than dealing with applying Mg,improving separately 0.2% and 2.3% in 2009;3.8% and 1.4% in 2010 6.Effect on yield of whole milled rice yield applying N and MgYield of whole milled rice was one of the comprehensive evaluation indexes on the yield and the quality of rice.The results of two-season trial showed that there was a positively correlation among the ear per unit area,the spikelet per ear in the yield component,and yield of whole milled rice,there was negatively correlation between rate of seed setting and whole milled rice.When the Mg was applied singly,the yield of whole milled rice was decreased at the lower amount of Mg.The effect on improved yield of whole milled rice for application of N was significant.After the cooperated application of N and Mg,the effect on the yield of whole milled rice of N,Mg and the interaction of N and Mg was significant.The more applied amount of N was used,the more yield of whole milled rice was higher.There was a gradually decreasing trend when the amount of N was excess.It was adverse for improved yield of whole milled rice applying excess amount of N and Mg.The yield of whole milled rice applying amount of N at 337.5 + Mg at 112.5 kg/hm2 and N at 450.0 + Mg at 112.5 kg/hm2 was higher than the treatment without applying Mg,the increased extent was respectively 1.9% and 5.0% in 2009 and 9.8% and 16.4% in 2010.The results of this study showed that the effect on dry weight of tillering stage and full heading time,dry weight of root in booting stage,the plumpness of basal second internode,carbon and N metabolism,population dynamics and the relation of “resource” and “sink” was significant.The interaction of N and Mg nutrients was complex,the promoting effects and inhibitory effects were simultaneously existed,the difference was existed in various environments too.The interaction of N and Mg was evident at the lower amount of N,but the content of Mg was decreased when the content of N in over-ground nutritional organ was over 35.8g · kg^-1.It indicated that the proportion and balance of N and Mg could be changed at the different applied amount of them.At present,the application of N was more popular than Mg,however it increased the need of Mg due to the application of N,which could induce the efficiency of Mg for the excessive application of N.Therefore,the balance of nutrients uptake by rice could be achieved by promoting rational application of N fertilizer in the field production and regarding the timely supplement of Mg simultaneously,which could actualize the aim of high yield and quality.