Study On Simulation Model Of The Relationship Between Growth Development And Soil Nitrogen Level In Peanut

Nitrogen test was got in 2006. Through fertilizing different quantities of nitrogen, the difference between soil nitrogen levels was caused. The study the measured the dynamic changes of nitrogen, phosphorus , potassium in soil, and their content and accumulation developments in each plant organ, and plant growth dynamics. Then study the connection between plant nutrition content, growth and nitrogen level. Based on the classical principles and methods of analysis, a peanut growth model is established. The main findings are as follows:1. The dynamics of soil nuitrient in different nitrogen application levels Nitrogen of 360, 240, 120, 0 kg/hm2 were applied before painting, and available soil N contents were 117.8,110.2,89.6,83.9 ,117 mg/kg in Seedling period, then gradually reduced to 73.4,75.1,68.9,62.2 mg/kg of harvest period. The growth speed is related to the decline speed in reproductive stage. Different disposals of nitrogen levels cause differences of available nitrogen, potassium, organic matter's content and their reduce rate. The phosphorus and potassium's content of high levels decline faster related to the growth amount of plant.2. The accumulation dynamic of nitrogen, phosphorus and potassium in plant organs at different nitrogen application levels The content of nitrogen, phosphorus and potassium in peanut's organs is effected by nitrogen application level, with the level of nitrogen improved, leaves and stems's content of nitrogen, phosphorus, potassium increase significantly, as seeds'content of nitrogen, but phosphorus of seeds is not significantly affected. The dynamics of plant's average nitrogen content are as follows: From Seedling period to harvest period, it increases from 4.7%-5.0% to 2.2%-2.4% in leaf, reduce from 2.86%-3.10% to 0.88%-1.1% in stems. N, P, K'accumulation of different disposal all shows the S-curve growth laws that go with plant dry matter increasing. Accumulation peak of potassium appears on the 40th after seeds emerging, and nitrogen, phosphorus is later, about on the 50th day. Nitrogen of high levels accumulation peak appears earlier, but phosphorus and potassium have no significant difference. The largest accumulation speed of nitrogen, phosphorus and potassium increase with the nitrogen level's improving. Accumulation of nitrogen, phosphorus and potassium in harvest period increase with the level of nitrogen's improving. The proportion of Leaves, stem and seed's accumulation to the total plant's respectively are: 14.98%,11.77%,64.88% for nitrogen, 17.02%,19.83%,43.71% for phosphorus, 13.71%,34.32%,33.66% for potassium.3. The affect of nitrogen levels on growth dynamic in peanutPeanut's plant height, leaf area and dry matter accumulation increase significantly with nitrogen level improved. And the dynamic of main stem high and dry matter accumulation accord with S-shaped curve, which can be expressed compatibly by logistic equation. The period of their biggest growth speed among different disposals have no significant difference. The period which main stem grows fastest is 37 days after germinating, and dry matter accumulates 50 days after germinating. The largest growth speed of Main stem and dry matter accumulation increase with nitrogen level improved. Dry matter accumulation speed of Leaf and stem get to the maximum peak on the 40th day after germinating, but pod's on the 60th day.4. Simulated model of plant dry matter in PeanutBy measuring the dry matter accumulation and available nitrogen content in soil in the four different growth process at their different nitrogen fertilizer treatments levels in the test of nitrogen fertilizer in 2006, through regression analysis and curve fitting, we find that dry matter accumulation dynamic accord with S-shaped curve, which can be expressed by logistic equation W = Wm /(1 +ae?bt). Then make use of it to establish respective dry matter accumulation dynamic model for different nitrogen fertilizer levels. The derivation of equation is dry matter accumulation rate ?W and relative growth rate ?W W--(RGR). Make available soil nitrogen content for each stage in the four different nitrogen levels as variables to set up the fitted equations RGR = A ?(Ni ?30)e∧( B*(Ni?30)),which expresses the relation between RGV and available soil nitrogen content in different growth period. Then get the corresponding parameters A, B for each period. By curve fitting, we find that in different growth stage A=0.00281 +8.378E -05dj-2.200 E-06dj^2+9.272E-09dj^3+1.707E-11dj^4,B=-0.016686+0.000116dj -0.000005 dj^2, so bring in the independent variable of growth period. Then a simulation model for dry matter accumulation relative growth rate is set up: RGV=f(Ni,dj) (Ni is soil nitrogen content at different growth stages, dj is growth period). Finally, the dry matter accumulation prediction model is established as W=f(Ni,dj,t)=W0*(1+RGV). After being validate by the test data of N dry matter accumulation in 2005, the respective RMSE for forecasts values and measured values of the three different N treatment are 2.217g/plant,3.585g/plant,3.253g/plant,which are all smaller than 5g/plant. So the model has a successful prediction effect.Because the model uses the classic analysis principle for growth, as long as the initial biomass in some period is known, the dry matter accumulation in any day since then will be predict by the soil available nitrogen content in the period. Therefore, the model is adapted to all various production conditions.