Study On The Relationship Between Maize Grain Quality And Nitrogen Supply

Maize is an important cereal crop in the world.While ensuring high yield of maize,high quality maize is also the main development direction of maize production in China.Production practice shows that high quality maize varieties are related to genetic basis and also affected by cultivation measures or environmental conditions,and the impact of cultivation measures on maize quality is very important.Excessive or small application of nitrogen fertilizer will reduce maize yield and quality,and even cause pests and diseases,which will affect the application in feed or food processing.Therefore,it is very necessary to optimize fertilization.There are many studies on maize yield in China,but the research on maize grain quality is still easy,especially about how fertilization affects maize grain quality is rare.This paper takes the common maize varieties in Liaoning Province as the research subjects,and takes the nitrogen application rate and fertilizer methods as the cultivation measure,studies the influence of different cultivation measures on the quality of maize,providing theoretical and practical basis for high-yield,high-quality and efficient production of maize.The main findings are as follows:1.Effect of nitrogen application rate on maize quality.Nitrogen fertilizer has little effect on the appearance quality of maize,but it also improved.With the increase of nitrogen fertilizer,the appearance indexes such as perfect grain,100-grain weight and bulk density content of maize were all increased,among which the indicators of perfect kernel and bulk density changed greatly.When the amount of nitrogen applied was 210 kg/hm~2,the appearance quality of maize grain is the best,and further increasing the amount of nitrogen fertilizer would decrease the appearance quality of maize grain.The amount of nitrogen fertilizer has a great influence on the nutritional quality of maize grain.As the amount of nitrogen fertilizer increased,the soluble sugar and protein content of maize grain continued to increase。When the amount of nitrogen applied was 315 kg/hm~2,the soluble sugar content was 1.28%,and the protein content was 12.49%,both of which were the highest.With the change of total protein content,the content of total protein also changed among components.Among them,the changes of albumin and globulin are not obvious,and the content was0.5%-1%.the content of prolamin and glutenin gradually increased,and the proportion of total protein also increased.When the amount of nitrogen applied were 210 kg/hm~2 and 262.5kg/hm~2,the essential amino acids is relatively high,more than 40%,which can be used as a higher quality protein resource.However,with the increase of nitrogen fertilizer,starch content gradually decreased,in which amylose had the same trend as total starch,and the amylose-amylopectin ratio also decreased.When the amount of nitrogen applied was 315kg/hm~2,the amylopectin content was 61.83%and the amylose-amylopectin ratio was 0.32.The ratio is the lowest,which is more beneficial to human absorption after consumption.The amount of nitrogen fertilizer has little effect on crude fat and aflatoxin B1.The characteristic indexes of starch gelatinization are also related to nitrogen application.With the increase of nitrogen application,the peak viscosity,trough viscosity,breakdown viscosity,final viscosity and setback viscosity show the trend of increasing first and then decreasing,other indexes change not obviously.When the amount of nitrogen applied was 262.5 kg/hm~2,most of the gelatinization characteristic index reached the largest and its quality is the best.The appearance quality of maize grain is closely related to the gelatinization characteristics of starch,which is helpful to the development of industry.2.Effect of fertilization methods on maize quality.The three fertilization methods had little effect on the grain appearance quality of maize.The results of length-width ratio,100-grain weight and bulk density showed that the maize grain quality of farm manure is better than that of the other two methods.Fertilization methods have a great influence on the nutritional quality of maize grain.When the amount of nitrogen applied was 210 kg/hm~2,the soluble sugar content of maize grains of the three fertilization methods changed.Among them,under the way of farm manure combined with nitrogen fertilizer,the content of soluble sugar was 1.71%,and the change was the largest,with an increase of 26%,followed by straw returning to the field.In fresh food and maize processing industry,we can choose two ways of organic manure combined with nitrogen fertilizer,which can not only improve the palatability of food,but also increase the efficiency of industrial production.However,the results of crude protein content showed that the contents of pure chemical fertilizer,farm manure and straw returning increased compared with the control group,increase of 7.40%,9.34%and 12.85%respectively.In the way of farm manure and straw returning to the field,the content of prolamin and glutenin increased by similar margin,which was larger than that of pure chemical fertilizer.The change of amino acid content is consistent with the conclusion of prolamin and glutenin.Among them,straw returning to the field increased by a greater margin.In terms of nutrition and processing and production,it is the best maize grain quality in farm manure.The total starch content of the three fertilization methods decreased with the increase of nitrogen application rate.When the amount of nitrogen applied was 210 kg/hm~2,the total starch content was 81.03%and the amylose-amylopectin ratio was 0.47,its value is the lowest,showing the best absorption.The crude fat content is the highest at 4.21%.Different fertilization methods also have certain effects on the gelatinization properties of maize starch.Under the condition of no nitrogen fertilizer,the peak viscosity,trough viscosity,breakdown viscosity and final viscosity of farm manure and straw returning are lower than those of the control group.However,the gelatinization characteristics of farm manure and straw returned to the field changed after the application of nitrogen fertilizer.Under the pure application of chemical fertilizer,most of the gelatinization index values are the highest.This method is suitable for processing industries that require high starch viscosity.There is a strong correlation between maize grain nutritional quality and starch gelatinization properties.In a word,different fertilization methods can change the quality of maize grain.Both in terms of consumption and processing,they meet different needs.