Establishment Of Nutrient Absorption Model Based On Dry Matter Accumulation Of Cherry Tomatoes

It is of great significance for the intelligent production during the soilless cultivation of the greenhouse cherry tomatoes（Lycopersicon esculentum Mill）in China to quantify the relationship between growth and nutrient absorption,and establish growth and development models and nutrient absorption models.This study was conducted in the solar greenhouse of the College of Agriculture in Shihezi University from 2018to 2020.According to the dynamics of the growth and development of cherry tomatoes in soilless culture,a cherry tomato nutrient absorption model was constructed based on the dry matter accumulation.The established model is expected to provide a theoretical basis for the real-time nutrient monitoring and the staged regulation in the integration of water and fertilizer in cherry tomatoes.（1）Through the quantitative analysis of the growth and development process of cherry tomatoes in the solar greenhouse and its response characteristics to light and temperature.The Clock Model（TCM）,Product of Thermal Effectiveness and Photosynthetically Active Radiation（TEP）,Physiological Development Time（PDT）and Growing Degree Day（GDD）were used to simulate the dynamic of the growth and development of cherry tomatoes in the solar greenhouse,and the independent experimental data was used to verify the accuracy of models.The normalized Root Mean Square Error（n RMSE）and Root Mean Square Error（RMSE）of the observed and simulated values of cherry tomatoes by TEP method in seedling stage,flowering stage,fruit setting stage,maturation stage,harvest stage,and full growth period were 33.76%,3.53 d,4.39%,2.54 d,7.94%,1.33 d,8.22%,2.54 d,5.06%,2.55 d,7.28%,5.74 d,respectively.The R² of 1:1 straight line were 0.82,0.98,0.95,0.95,0.96,0.99,respectively.The results showed that the TEP method has higher accuracy in simulating the growth period of cherry tomatoes in solar greenhouse.（2）Summarizing the effects of light and temperature on the cherry tomato leaves,a photosynthesis and dry matter accumulation model was established based on the TEP and Specific Leaf Area（SLA）methods.The independent experimental data was used to verify the accuracy of the model.The n RMSE and RMSE of the observed and simulated values of the Leaf Area（LA）by the TEP method were 8.32%,0.07m²·plant^-1,and the R² of 1:1 straight line was 0.95;The n RMSE and RMSE of the observed and simulated values of the dry matter accumulation by TEP method were 24.62%and 770.66 kg·hm^-2,and the R² of 1:1line was 0.93.The results showed that the TEP method has higher accuracy for simulating the LA and the dry matter accumulation of cherry tomatoes in solar greenhouse,which is proportionally and practical.（3）A model for simulating the dry matter allocation and yield of cherry tomatoes in the solar greenhouse was established based on the Allocation Index（AI）and Harvest Index（HI）.The independent experimental data was used to validate the accuracy.The n RMSE and RMSE of the observed and simulated values of the root,stem,leaf,dry fruit mass and yield were 35.97%,68.49 kg·hm^-2,29.00%,395.86kg·hm^-2,23.54%,232.89 kg·hm^-2,19.83%,181.54 kg·hm^-2 and 21.20%,7.32 t·hm^-2,respectively.The R²of 1:1 straight line were 0.81,0.93,0.94,0.94,0.97,respectively.The results showed that the simulation model of dry matter allocation and yield prediction of cherry tomatoes in solar greenhouse based on AI and HI has high accuracy.（4）Based on the dry matter accumulation and allocation simulation model,a model of nutrient absorption of cherry tomatoes in a solar greenhouse was developed by quantifying the dynamic relationship between the TEP and the nutrient content of different organs during the whole growth period,And the independent test data was used to simulate the accuracy of the model.The n RMSE and RMSE of the observed and simulated values of nitrogen,phosphorus,and potassium uptake by the whole cherry tomato plant were 16.85%,24.80 kg·hm^-2,10.01%,4.11 kg·hm^-2,10.27%,23.65 kg·hm^-2,respectively.The R² of1:1 straight line were 0.83,0.90,and 0.87,respectively.The n RMSE and RMSE of the observed and simulated values of nitrogen uptake in roots,stems,leaves and fruits of cherry tomatos were 25.04%,0.71kg·hm^-2,11.49%,4.38 kg·hm^-2,14.58%,12.62 kg·hm^-2,21.34%,4.32 kg·hm^-2,respectively.The R² of 1:1straight line were 0.73,0.84,0.84,0.91,respectively.The n RMSE and RMSE of the observed and simulated values of the phosphorus absorption were 24.03%,0.27 kg·hm^-2,13.44%,1.60 kg·hm^-2,19.19%,4.71 kg·hm^-2,27.74%,1.01 kg·hm^-2,respectively.The R² of 1:1 straight line were 0.86,0.73,0.81,0.83,respectively.The n RMSE and RMSE of the observed and simulated values of potassium absorption were20.60%,0.89 kg·hm^-2,22.86%,13.20 kg·hm^-2,13.44%,18.84 kg·hm^-2,21.45%,5.63 kg·hm^-2,respectively.The R² of 1:1 line were 0.85,0.81,0.75,0.86,respectively.The results showed that he TEP method has higher accuracy in predicting the nutrient absorption of the whole plant and different organs of cherry tomatoes during the whole growth period in the solar greenhouse.The model constructed in this study was simple in calculation and had strong mechanism,explanatory and practicality.It can provide decision support for the precise management of soilless cherry tomato production in solar greenhouses in China.