Study On Simulation Of Cucumber Growth In Greenhouse

Following the thoughts of establishment process of crop model, based on the theory of effective temperature sum and method of crop growth analysis, a dynamic model system(CUMGROW) is developed for simulation of the greenhouse cucumber growth and development. This computer simulation system is developed in software of Visual C++ 6.0 on MS-Window operating system.1.Cucumber were cultivated in solar Greenhouse and plastic greenhouse respectively in 2002 and 2003. Cucumber growth data were collected every 3 or 4 days and environment data in greenhouse were collected automatism every 10 minutes. Some parameters were gained from the observed data, SLA(Specific Leaf Area) is 0.028 m2g-1 , LDD(leaf Degree Day) is 25.2℃d, the coefficient of photosynthesis biomass to dry matter is 0.65. Based on the observed data ,the relationships between fresh weight and dry weight of every organs were gained. Also the dynamic model and static model of single leaf area were gained.2.In the model,there are several submodels,such as photosynthesis, respiration , cumulation and partition. There are two ways to get radiation: data from weather station and reckon from formula. In the canopy photosynthesis submodel, the effect of temperature,carbon dioxide and soil moisture content are taken into account. In respiration submodel include light respiration except for maintenance respiration and growth respiration. Based on Growing Degree Day, the whole development stage is divided into five growth stages. That is planting, flowering, initial fruit picking, flourishing fruit picking and last picking. Day dry matter partition distributed in 4 parts, The partition indexes(0~1) of different organs are varied in every growth stage. The fresh weights of every part are gained through dry weight multiply by respective coefficient.3.Simulation system CUMGROW1.0 was developed in software of Visual C++ 6.0, in the system, user can set parameters by himself to run the system, the result can be show in list or in graph. Also the result can be saved in file by excel format. In the help file, providing general knowledge of the cucumber cultivation, including management, prevention and cure of disease and disease photos.4.Using a number of experiment data to test of the model indicate that the absolute value of relative error between simulated values and observed values were less than 14%. Which implies that CUMGRO can predict the growth of cucumber well.