Propereties Of Canopy And Root Of Super-high Yield Maize And Regulating Effect Of Potassium

The consumption of corn grew continued, while corn acreage increased limited, we had to rely on improving the yield per unit area further to protect the balance of corn suppling and demanding. Technology of super high has an important role in promoting to further enhance the level of maize yield. The Jinshan 27 was grown under super-high-yield cultivation (SHY) and normal high-yield cultivation (CK) condition in 2009 and 2010, to study canopy and root structure, functional characteristics and regulating effect of potassium, the main results were as follows:1. Spring maize community structure and individual function got cooperative gain in super-high-yield cultivation. The maximum LAI of super- high yield spring maize was 7.42 in 2009 and 7.87 in 2010, and the increasing of LAI in above three-ear leaves and three-ear leaves was obvious, it increased by 26.4% in 2009 and 21.6% in 2010. Periods of LAI≥5 were 72 days and 74 days in 2009 and 2010, 12 days more than the control. The super-high yield spring maize had smaller leaf angle and higher leaf direction value, and above three-ear leaves and three-ear leaves was obvious, light distribution of population were reasonable. From the silking to 40 days after silking, SOD and POD activities were higher than control and MDA content lower than control, net photosynthetic rate was higher. The photosynthetic potential was higher by 20.7% in 2009 and 12.0% in 2010 than that of the control during silking-milking stages, and higher by 34.2% and 34.3% in 2009 and 2010 during the milking-maturity stage.2. Spring maize has higher ability to accumulate material in high yield cultivation, especially significant after silking, promote coordination of accumulation and distribution. The max acccumulation rate of super higher spring maize was higher by 10.7% in 2009 and 11.1% in 2010. The highest increased rate sustained longer 2~4 days than control. The dry material after silking were higher by14.4% in 2009 and 11.2% in 2010 than control, and contribution rate to grain were higher by 2.9% in 2009 and 3.1% in 2010. Transfer rate of leaf was lower by 2.4% in 2009 and 5.9% in 2010, and transfer rate of stalk was lower by 3.2% in 2009 and 3.6% in 2010. The ratio of grain in maturity was higher than control, and economic coefficient was 0.54.3. Roots in deep soil were well-developed and keep them a high physiological activity at late growth stage. The percentage of root weight (0-20 cm soil layer) was lower obviously than the control, and which (>40 cm) was more than the control. The biggest root width tended to go down, the number of root per plant in deep soil layer increased under super high-yield maize, and the difference enlarged with the increase of the soil depth compared with the control. In silking, root vigor (>40 cm) was higher than that of control; in milking, root vigor (0-20 cm soil layer) was similar with control, root vigor (>20 cm) was higher than that of control. The activity of SOD&POD of root system per soil layer were higher than the control at silking and milking stage under super high-yield maize, but MDA activity was reverse.4. The capacity of nutrient absorption and transfer were increased in super high spring maize. The ratio of N absorption of total absorption under super-yield cultivation was higher by11.5% in 2009 and 11.6% in 2010 than that of control after silking stage, and the ratio of P absorption was higher by 15.9% in 2009and 16.7% in 2010, and the ratio of K absorption was higher by 16.5% in 2009 and 10.0% in 2010. Contribution rate of accumulate N after silking stage to grain was higher by 25.6% in 2009 and 11.4 % in 2010, and contribution rate of accumulate P to grain was higher 25.6% in 2009 and 8.4 % in 2010, and contribution rate of accumulate K to grain was higher by 10.9% in 2009 and 10.0 % in 2010. Transfer rate of N of leaf and stalk was higher by 17.3% in 2009 and 13.5% in 2010, transfer rate of P of leaf and stalk was higher by 4.0% in 2009 and 8.3% in 2010, transfer rate of K of leaf and stalk was higher by 2.2% in 2009 and 4.0% in 2010, economic coefficient of N, P and K were higher than control.5. Effect of amount fertilizing K and postponing K application on yield of super high spring maize was not significant, but which could increase lodging resistance and delay leaf senescence. Dry matter to contribution rate to grain and transfer rate of stalk were increased, nutrient absorption and transfer of stalk were promoted. accumulation and transfer of material went down by postponing K application.