The Study Of Cotton Ecosystem Phosphorus Supplying Dynamic Simulation Model

The field test was held in the Hunan Agricultural University of cotton test base,Laboratory used soil was from the Hunan Agricultural University of cotton research base.By setting different phosphorus volume of cotton processing parameters for the phosphate, the impact of dry matter and the dynamic absorption of phosphate fertilizer.The main conclusions are as follows:1. Available phosphorus content in the soil is changed with the quantity phosphorus fertilization,the higher the quantity supplies the higher phosphorus can be examined in soil, under low-phosphorus condition(60-120mg/kg).The crops mainly absorb the available phosphorus in soil.Therefore, when available phosphorus in the soil is at low level, the crop production will reduced.2. Phosphate fertilizer can stimulate the growth of cotton root, the cotton root will grow longer ,thiner,and the surface area will increased too, thus, the absorption of phosphorus will be promoted. However, excessive phosphorus application will lead to nutrient imbalance in the proportion of crop growth and development adverse. This is because excessivethe phosphate fertilizer will have negative effect in nitrogen, potassium and other nutrients absorption, and inhibiting the growth of crops.3. Appropriate rate from view of cottion growth, this experiment concluded that 480mg/kg is the most.With higher supply the efficiency will decreased,not conducive to the growth of cotton.4. Different phosphorus levels of cotton dry matter and phosphorus nutrient accumulation are in line with the growth Logistic function model, the handling of the curve fitting Logistic equation R² are related index above 0.98, to a=0.01 a significant level.5. Research shows that in the experimental area, the volume of phosphorus (P₂O₅) 90.5kg/hm² is best, its vigorous vegetative growth period is in early July to early August.In this growth period,the crops can be accelerated during the topdressing vegetative biomass accumulation.To regulate Cotton ground vegetative growth parameters,and to obtain a higher yield. The critical management period of cotton fertilizer is in mid-July.6. By useing fertilizers dynamic equation,regulating the function of the environment of soil, we established ecosystem dynamic model for the supply of the supply of phosphorus in cotton field. First Order dynamic equation:s₁,s₂ are respectively the soil organic phosphate rock-hard components, derived from the differential form its integral form:Phosphorus chemical fertilizers process is also in line with a band dynamic equation,the same rate also is affected by in soil environmental functions. The potential for phosphorus fertilizer can be expressed as the product of utilization of fertilizers and supply quantity of phosphorus, chemical fertilizers for phosphorus form of differential equations:7. Field tests with the use of literature established by the soil and phosphate fertilizers for model testing, The actual crop will absorb phosphorus as observations to verify. Cotton growing season phosphorus accumulated dynamic simulation and growing season total phosphorus absorption simulation, the correlation coefficient R were 0.96 ^*** (n=148), 0.87 ^*** (n=20), two aspects of the verification Have reached a very significant correlation.8. Through statistic analysis in the past 10 years China's major cotton field trial, we established the statistical model between and the average volume of phosphorus (Pi_input,kg.ha^-1) related to the utilization of phosphorus (PUE):This model can calculate the phosphate fertilizer phosphorus potential in the entire crop growing season.