水分胁迫与光照条件对棉花干物质和产量形成影响的数学模型

A mathematical model of water stress and light condition effects on cotton dry matter and yield formation.

从作物冠层净同化速率入手 ,通过引入对CO2 浓度、空气湿度、光照强度和土壤含水量反映较敏感的光能利用系数 (β) ,建立了考虑水分胁迫和光照条件对作物干物质积累与产量形成影响的数学模型 .模型考虑了水分胁迫与低光照下冠层阻力增加的设定 ,将反映作物冠层水分状况的功能叶水势 (Ψl)作为参数纳入本模型 .通过对土壤相对含水量 (Aw)、气温 (Ta)、水汽压差 (VPD)的多元回归估算出Ψl,并将空气动力学阻力 (Ra)简化为风速 (u)的函数 .盆栽试验应用实例和敏感性分析表明 ,该模型在诊断环境因子特别是土壤水分与光照因子对作物生长和产量构成的影响具有一定的实用性 .

A mathematical model was developed to analyze the effects of water stress and light condition on crop dry matter accumulation and yield formation based on canopy carbon net assimilation rate. The function leaf water potential ( Ψ l ) indicating the water status of canopy was incorporated into this model, according to the assumption that the canopy resistance ( R c ) was increased under the conditions of water stress and low light density. Ψ l was estimated by a simplified regression equation,in which,the independent variables were relative soil moisture ( A w ),ambient temperature ( T a ),and vapor pressure deficit ( VPD ). The aerodynamic resistance ( R a ) in the model was defined as a function of wind speed ( u ),and the yield was calculated by a linear increase in harvest index ( h i ) with time. The modeled data agreed well with the data observed from pot experiment. Sensitivity analysis and simulation results suggested that the model could be useful in identifying environment factors,especially soil water content and light density effects on crop growth and yield formation.