定植密度对日光温室甜椒干物质生产与分配影响的模拟研究

Impact of planting density on the dry matter formation and partition in sweet peppers in a solar greenhouse

2007年10月—2009年5月,在中国山东省寿光市日光温室内设计不同定植密度和不同定植日期的甜椒栽培试验,系统收集温室环境数据和作物生长数据,分析定植密度对日光温室甜椒干物质生产与分配的影响。结果表明,定植密度在2.0—6.7株·m-2范围内,不同定植密度处理的甜椒叶面积指数与定植后天数的关系较好地符合logistic模型,收获时最大叶面积指数与定植密度呈线性正相关。研究发现,不同密度处理的单位面积甜椒生物量与冠层累计截获的光合有效辐射日积分呈线性正相关,单位面积植株干物质增长率和叶片的干物质分配指数随定植密度增加而增加,果实的干物质分配指数随密度增加而减少,茎的干物质分配指数受密度影响不显著。在此基础上,首先构建甜椒叶面积指数模型和冠层光截获模型,然后建立以冠层截获的PAR日积分为尺度的温室甜椒干物质生产与分配模型,并利用独立试验数据对模型进行检验,表明定植密度为2.0、4.0、6.7株·m-2的总干重、叶干重、茎干重、果实干重和产量的模拟值与实测值间基于1:1线的决定系数(R2)分别为0.946、0.891、0.945、0.923和0.867,回归估计标准误差(RMSE)分别为51.97g·m-2、3.53g·株-1、4.72g·株-1、16.4g·株-1和910.8g·m-2,说明所建模型的模拟值与实测值有较好符合度,能够较准确地模拟日光温室甜椒的干物质生产与分配,模型参数少,实用性强,可以为日光温室甜椒产量预测提供决策支持。

Dry matter production and partition are the bases of yield formation of sweet peppers.In order to quantitatively investigate the effects of plant densities on the dry matter production and partition of sweet peppers,a model was developed for the decision support to optimize the crop and environmental management in solar greenhouse.Experiments with different plant densities and planting dates were conducted in a solar greenhouse from November 2007 to May 2009 in Shouguang region of Shandong Province（36°53＇N,118°43＇E,30.2m asl）,wherein environmental and plant data were collected and analyzed.Results indicated that there is a logistic relationship between leaf area index（LAI） and the number of days after the planting date of sweet peppers at the plant densities of 2.0-6.7 plants m^-2,and the maximum leaf area index at the harvesting date was relevant to the planting densities.There was a positive linear correlation between the crop biomass per unit area and the daily integral of photosynthetic active radiation（PAR） intercepted by the canopy.The dry matter partition index（DMPI） in leaves（fruits） increased（decreased） with the increasing density,and there was no significant effect of intensity on the stem DMPI.The harvest index related linearly to the corresponding accumulated daily integral canopytrapped PAR.Therefore,the effects of plant densities on the canopy LAI and the light intercepted by canopy were quantified.Then a daily-scale model of solar greenhouse-grown sweet pepper was established to simulate the dry matter production and partition based on the integral PAR.The model was validated according to the independent experimental data and showed good performance.The determination coefficients（R^2） between the simulations and measurements for the dry weight of whole plant,leaves,stems,fruits and yield were 0.946,0.891,0.945,0.923 and 0.867 at the intensity of 2.0,4.0 and 6.7 plant m^-2 respectively,with RMSE 51.97g m^-2,3.53g plant^-1,4.72g plant^-1,16.4g plant^-1 and 910.8g m^-2.The precision in dry weight prediction for single-plant leaves was lower than those of stem and fruits,because leaves at lower levels turnd yellow and dropped off earlier,which cannot be simulated accurately.Marked by fewer parameters,higher precision and stronger applicability,the model can simulate the dry matter partition and prediction of the crop yield under sufficient water and fertilizer supply,and will provide decision-making support to the photo-temperature control management for sweet peppers in solar greenhouse.