Effects Of Plant Density, Potash Fertilizer On Lodging Resistance Ability Of Summer Maize

Experiment was conducted on the relationships between different ratios of fertilizer and stem character and lodging resistance ability (LRA) under different plant densities with different kinds of hybrids. And the effect of artificial lodging treatment on yield was also conducted. The results were showed as follows:1. There was significant difference in LRA among hybrids. Hybrid with higher LRA should hold lower ear height of plant, smaller ratio of length/diameter of base internode, the higher value of hardness of base internode, higher breaking resistance and bending resistance of stem, there was significant difference on hardness of base internode with different maize hybrids internodes from the third to the sixth, while they have no obvious difference on different sides of the same internode.2. Lodging rate was closely related with planting density, and it would increase with the increase of planting density. The effect of density on character of stem showed that plant height, ear height would be increased; internode of base internode would be elongated and thinned, and the value of internode length/diameter would be increased; Root number and number of brace root will be decreased along with the planting density increase. LRA of stem would be weakened. Density had a great influence on length and diameter, especially on the third length of base internode which would be obviously elongated under the high density. It was observed that stem lodging was closely associated with length of base internode and internode length/diameter could incline with the increasing of length of base internode, which may lead to stem lodging. Hardness of base stem internode, breaking resistance, bending resistance were significantly influenced by density and it particularly influenced on the third and the fourth of base internode, and it will be obviously decreased along with the density increase. Therefore, it was crucial for improving the ability of LRA under high plant density that how to shorten internode length/diameter ratio of base internode, strengthen the hardness of base internode, breaking resistance and bending resistance of stem.3. Nitrogen-potassium combining application could increase stem diameter and shorten internode longth/diameter ratio of base internode and lower the height and ear height under fertilization. Hardness of base internode, breaking resistance, bending resistance was significantly influenced by fertilization and it particularly influenced the third and the fourth base internode. Nitrogen-potassium combining application could strongly increase the hardness of base stem internode and breaking resistance. Consequently, Nitrogen-potassium combining application could improve the LRA of plant.4. Lodging of maize significantly influenced grain number per ear and 1000-grain weight, and the yield would be strongly lowered after maize lodging. Grain number per ear, 1000-grain weight and yield could be decreased to 19.4%~30.2%, 29.6%~31.8% and45.0%~50.8%, respectively, when lodging occurred in one week after silking.