Development And Validation Of A Mechanistic Crop Model For Greenhouse Cucumber

In this paper, the research results and current status related to crop growth and development models, from abroad and homeland, especially for horticultural crops, were systematically summarized and analyzed. Not only some kernel problems on the research of crop modeling were presented, but also a reference for the further development of horticultural crops modeling in our country was offered. Moreover, on the base of the advanced research results of foreign countries, also combining the current situation of Chinese protected horticulture, a simulation model on crop growth and development of greenhouse cucumber was built. Through two seasons' greenhouse experiments in China, some important parameters in the model were made, which offered a theoretical guide for the yield prediction of greenhouse cucumber, the optimal management of greenhouse cultivation and the development of expert system of greenhouse cucumber.(1) In this research, the climatic environment inside the greenhouse and the dynamic changes of cucumber growth and development were observed. Through different radiation treatment experiments, the influences of radiation on cucumber growth and development as well as the quantified relationship between yield formation and radiation were studied and analyzed. Moreover, some important parameters of the model were made through these experiments, which were leaf area index (LAI), specific leaf area (SLA) and the distribution coefficient of total dry matter to the root, leaves, stem and fruits. The accuracy and sensitivity of the model were validated through these experiments. The results showed that: the model could be useful to simulate the photosynthesis and dry matter production of greenhouse cucumber in different growing seasons, the absolute value of the relative error between simulated values and observed values was less than 10%, the accuracy of the model was validated. It showed that the model could predict very well of the growth and development of greenhouse cucumber as well as its relations with the environmental factors.(2) On the base of validating the model, the application of the model in practice was discussed, especially the application in the field of predicting crop potential production. According to the 20 years average radiation data of 29 locations in China, which were all the regional capitals, distributing evenly in China, the greenhouse potential productions of these locations were simulated, and the potential yields of cucumber, tomato, sweet pepper and lettuce in these cites were calculated. Furthermore, example was given by the comparison of potential yields and actual yields of these four crops in Beijing area. The results showed that: the actual yield level in Beijing area was far away from the potential yield level (the actual productions were only 50%-70% of the potential productions) and there was a big space for yield increasing.(3) Based on the results of the simulation model, a regression model was developed to quick predict potential production levels around China. The new model was according to the strong linear relations between crop growth rate and solar radiation with all the locations concerned. It was simple...