Studies On Growth And Nutrient Uptake And Accumulation Of Super-high-yield Summer Maize In The Ecological Area Of The Yellow-huaihe-haihe River

Fielid experiments were conducted to study the leaves, yield response and nutrient absorption and utilization of high-yield maize variety (Xundan 20) between super-high-yield field and general high-yield field. Results of the study were expected to find out the characteristics of growth and nutrient absorption and utilization of super-high-yield summer maize. The main results are as followings.1. Dynamic variation of dry matter accumulation of high-yield maize and super-high-yield maize at different growth stages are samblable, amount of dry matter accumulate was increased with the growth of maize; it was increased most quickly between the jointing stage and silking stage. Highest amount of dry matter accumulation was obtained at maturity stage. Super-high-yield maize got the larger dry matter accumulation than high-yield. Summer maize got super-high-yield needed high 100-kernal weight.2. Leaf area index (LAI) of high-yield and ultra-high-yield maize was increased with the growth of maize; it was increased before silking stage and then decreased. LAI of ultra-high-yield maize was larger than high-yield maize. Dynamic variation of SPAD in leaves with growth was similar as the LAI. SPAD value of ultra-high-yield maize was higher than high-yield maize. The content of chlorophyll of super-high-yield maize had a long duration.3. Dry matter accumulation in grains was increased with the growth of super-high-yield summer maize. Highest amount of dry matter accumulation in grains was obtained at maturity stage of super-high-yield summer maize. The ratio of dry matter accumulation in grains at different growth stage was increased at first and then decreased. It was highest at 25 days to 30 days aftert silking stage.4. Amount of nitrogen, phosphorous and potassium content in various organs was different at different growth stage. The variation trend of nitrogen and phosphorus content in leaf were samable, seemed to be the "two peaks a Valley". The nitrogen content in leaves got peak values at jointing stage and 10days after silking, while phosphorous content got maximum values at big trumpeting stage and 20 days after silking stage. The variation trend of potassium content in leaves got three peak values with growth of maize, maximum values appeared at big trumpeting stage, 20 days after silking and 50 days after silking.5. Dynamic changes of amount of nitrogen, phosphorous and potassium accumulation in plant were like to "S" shape with the growth stages of super-high-yield summer maize. The amount of plant nitrogen accumulation reached maximum value at 50 days after silking stage. The amount of plant phosphorous accumulation reached maximum value at maturity stage. The amount of plant potassium accumulation reached maximum value at 10 days after silking stage.6. The distribution and transition at different organs was differently at different growth stage. The distribution centers of nitrogen and potassium was leaves at first, stalks at second and then grains, the distribution centers of phosphorous was leaves and stalks at first, leaves at second, stalks at third, and then grains. The transition of nitrogen and phosphorous in leaves happened at 10 days after silking stage, potassium transition in leaves happened after silking stage. The transition of nitrogen, phosphorous and potassium at stalks happened at 10 days after silking stage.7. The stage of maximum phase accumulation of nitrogen and potassium was between jointing stage and big trumpeting stage, while it was between big trumpeting stage and silking stage. The maximum ratio of nitrogen and phosphorous absorption appeared at big trumpeting stage, while the maximum ratio of potassium absorption appeared between jointing stage and big trumpeting stage.This study results also showed that: ultra-high-yield maize varieties with high yield, mainly due to the more amount of dry matter accumulation, bigger valuc of LAI, and chlorophyll content higher and sustained for a long time. Super-high-yield summer maize need a lot of nitrogen, phosphorous and potassium accumulation, super-high-yield summer maize should absorb 1.91 kilograms nitrogen, 0.42 kilograms phosphorous and 2.20 kilograms potassium while producting 100 kilograms grain-yield.