Study On The Effect Of Multi-factor In Greenhouse Environment On Tomato Growth Regulation And Model Construction

At present,the cultivation of tomatoes in the greenhouse mainly considers the influence of temperature,humidity,light,C0₂ concentration,water,fertilizer and other factors.From the perspective of a single factor,each factor has a great relationship with the metabolism in the process of crop growth,especially the final fruit yield.However,when studying the influence of multiple factors on yield,the influence mechanism of each factor on crop growth and final fruit yield is complex,rather than the simple superposition of the influence of single factors,which is a nonlinear interaction mechanism.Therefore,it is very difficult to accurately predict the yield of crops under the action of various factors.At present,there are many researches on the prediction model of crop yield under the action of multi factor coupling,but most of them only stay on the analysis of the accuracy of the prediction model and yield prediction.In this paper,taking the growth data of tomato crops as the research object,using the linear regression theory,the prediction regression model of Tomato Yield Based on the four factors of temperature,light,humidity and C0₂ concentration has been established In addition to the significance analysis of each variable factor,the contribution degree of each factor to the final yield is obtained.Genetic algorithm is used to optimize the parameters of each variable factor,and the multi factor allocation scheme which makes the highest yield of Tomato in the current greenhouse environment is obtained.The main research results of this paper are as follows:1.The effects of temperature,humidity,light and CO₂ concentration on the net photosynthetic rate,transpiration rate and dry matter accumulation of tomato growth index were studied under the condition of artificial control.The main conclusions of environmental factors and growth indexes are as follows:?1?CO₂ concentration in seedling stage,flowering and fruit bearing stage and fruit bearing stage always plays an inhibitory role on photosynthetic rate,and the mechanism of temperature and light in different growth stages is different.?2?seedling stage,flowering and fruit bearing stage and fruit bearing stage The higher the temperature is,the faster the transpiration rate is.The experimental data show that there is no significant correlation between the CO₂ concentration and the transpiration rate,and there is no significant correlation between the humidity and the transpiration rate in the seedling stage,the flowering and fruit bearing stage;?3?the experimental data in the seedling stage and the fruit bearing stage show that there is no significant correlation between the humidity and the dry matter accumulation,and the experimental data in the seedling stage show that the light and the dry matter There was no significant correlation between the accumulation of dry matter.The period when humidity and light intensity had obvious influence on tomato was flowering and fruit setting period,in which humidity and light intensity had obvious inhibition on dry matter accumulation.2.In this paper,the optimal combination of environmental factors is a2b3c1d2 through four factors and three levels of orthogonal test,that is,through the control of greenhouse environmental control equipment,the environmental temperature of Tomato in the result period is controlled at 26.4?,the air humidity is controlled at 77.8%,the light is controlled at 360 umol·m^-2·s^-1,and the concentration of C0₂ is controlled at 800 ppm It can ensure the highest yield under the experimental conditions,and the final fitting regression equation can also reflect the relationship between each factor combination and yield.Then,on the basis of the quadratic orthogonal experiment,the improved genetic algorithm is used to optimize the parameters after the parameters are quantized and encoded according to the final quadratic regression equation,and a more accurate multi environment factor configuration scheme is obtained.By solving the optimal value of the fitting equation between tomato yield y and environmental control factors,the feasible optimal solution of operation is temperature factor X₁=24.9024?,humidity factor X₂=69.7781%,light radiation X₃=356.7683 umol·m^-2·s^-1,C0₂ concentration factor X₄=1021.2 ppm.At this time,the corresponding theoretical output is 181071.66 kg.hm^-2?The result of optimization is close to that of the orthogonal experiment,and the optimal combination of environmental factors is A₂B₂C₃D₁,which also verifies the correctness of the orthogonal experiment to some extent.