| The consumption of leafy vegetables is huge in China.As a result of that factory cultivation was born to break through the traditional production mode.Factory production can accurately regulate the environmental conditions through the control models,so the accuracy of the parameters of control models are particularly critical.Multiple varieties of lettuce(Lactuca sativa L.)and pakchoi(Brassica campestris ssp.chinensis)were used to conduct the whole year cultivation experiments,variety experiments together with nutrient solution concentration experiments.By establishing basic growth models,studying the variation of seasons,varieties,and nutrient solution concentration changes on the growth of leafy vegetables and model parameters,conclusions are shown as follows:1)The growth models of three leafy vegetables conform to exponential model y=aebt,of which the lettuce model is y=0.242e0.192t,the Chinese cabbage of pakchoi model is y=0.362e0.191t,the Green grocery of pakchoi model is y=0.410e0.137t.By comparing the parameters,change in parameter b is significantly related to the temperature change in different seasons.2)Season has a significant impact on the growth model parameter b of leafy vegetables.In general,the annual change of parameter b of the three leafy vegetables growth models are similar.The early stage conforms to the law of trigonometric function and increases over time.In the middle period,it conforms to the law of quadratic function,b value first decreases and then increases over time.In the later period,it still conforms to the law of trigonometric function and decreases over time.The finally model of parameter b varies with seasons is a piecewise function.3)The selection of new leafy vegetable varieties can be based on the relationship between its growth model parameter b and the final cluster centers of the leafy vegetable growth model parameter b.The new varieties can be divided into three types:"winter numerals leaf type","summer heavy leaf type" and "spring and fall type".The timely application of new varieties in production can maximize the growth potential of new varieties and meet the needs of quality and high yield requirements.4)The relationship between the nutrient solution concentration and the parameter b of the growth model conform to quadratic function,that is,as nutrient solution concentration(0-100%)increases,the parameter b shows a trend of first increasing and then decreasing.The optimal nutrient solution concentration in different seasons can reduce the input of raw materials and obtain higher yields,meeting the requirements of green agriculture and maximizing economic benefits. |
