Effects Of Nitrogen Application Time On Lodging Resistance Of Summer Maize

Lodging is an important limiting factors of high and stable yield of maize, in order to solve this problem, the experiment was conducted in the experimental farm of Henan University of Science and Technology from June 2013 to September 2013. Planting density and nitrogen application time were researched to study on the growth characteristics and lodging resistance ability of maize under the condition of different densities and applying time of nitrogen fertilizer. The main results are as follows:(1) Compared with no nitrogen treatment(N0), the average spike grain number and grain weight of nitrogen treatment increased significantly, separately at the percentage of 15.23% and 7.62%, and the yield of nitrogen treatment increased by an average of 29.85% than no nitrogen treatment. The influence of the different nitrogen application time on yield varied with each other, the overall performance wss N2 > N3 > N1, and the difference of N2 and N3 yield were not significant, but significantly higher than that of N1.It showed that spinning fertilizer can significantly increase production.(2) With the increase of the density, the plant tensile resistance and bending strength were significantly lower, and stalk bending rate significantly increased. Significant difference was found in different section bending force, characterized by section 3 > section 4 > section 5. Compared with no nitrogen treatment, bending strength of nitrogen treatment significantly increased by 14.06%, of those the N3 treatment showed flexural strength, significantly higher than that of N1 and N2. The stalk bending rate of nitrogen treatment significantly decreased than that of N0. Under the different were characterized by highest N3, increased by 2.71% and 7.58% than N1 and N2. Nitrogen processing stem rate decreased significantly by an average of 52.70%. Stems bending rate varied significantly among nitrogen treatments, characterizing by N2 > N1 > N3. The mechanics characteristic of stem of Jointing nitrogen(N1, N2) went bad and stalking bending rate went higher. The lodging resistance of seeding manure treatment(N3) was significantly superior to jointing fertilizer treatment.(3) The plant height, ear height, high center of gravity, internode length and diameter of nitrogen treatment increased to some extent under different densities, such as the basal internodes length, high center of gravity and strain salience of jointing fertilizer processing(N1, N2) was higher than seed manure treatment(N3), and the diameter and stem diameter coefficient was significantly less than the N3. There was no significant difference in ear position coefficient of each nitrogen processing treatment. The dry matter accumulation of internodes increased significantly, but there was no significant difference among different nitrogen treatment, the overall performance showed N1 > N2 > N3.The unit stem dry weight of N3 treatment was 0.48 g/cm, significantly higher than other processing.(4) The vascular bundle number and thickness of mechanical tissue of all nitrogen treatments were significantly higher than no nitrogen treatment under different densities. The vascular bundle number and thickness of mechanical tissue of N3 were respectively 643.56 and 643.56 microns.(5) With the increase of planting density, stem lignin, cellulose and soluble sugar content lower down, nitrogen could promote the synthesis of lignin, cellulose, soluble sugar and the accumulation in stem, of which every index of N3 treatment were significantly higher than other treatments.(6) There was a significantly positive correlation between stalk bending rate and bending strength and tensile resistance. The unit longth dry weight of stems, internodes coefficient of dry weight, stem diameter, the diameter of internode, lignin content, cellulose content, soluble sugar content, carbon and nitrogen ratio, number of vascular bundles and the thickness of the mechanical tissue all had a significantly negative relationship with lodging rate, and could be used as a resistance ability evaluation index. Lodging rate and coefficient of ear position height, plant height, ear position, high center of gravity and internode length showed varying degrees of positive correlation, but did not reach significant level.