Response Of Water-Nitrogen Coupling And Establishment Of Greenhouse Tomato Growth Model

The purpose of this study is to investigate the applicability of SIMDualKc model in greenhouse and to know the applicability of dry matter production and distribution model in greenhouse environment in northwest of China, we conducted a tomato deficit irrigation experiment in 2013-2015 in Yangling Shaanxi Province.We conducted a deficit irrigation experiment in greenhouse in Yangling Shaanxi Province in 2013—2015. Four treatments were arranged, i.e. full irrigation treatment, deficit of 50% only in the development stage, deficit of 50% both in the development stage and middle stage, deficit of 50% in the whole stage. In order to explore the applicability of the critical nitrogen dilution curve model of tomato under different water treatment in yangling of shaanxi province area, water and nitrogen treatments were carried out in greenhouse in 2013-2015. Water treatments set two levels, for the whole growth period full irrigation treatment and 50% water losses in the whole stages, respectively; Nitrogen treatments set three levels, nitrogen amounts as 0 Kg/hm2, 150 Kg/hm2 and 300 Kg/hm2, respectively. Critical nitrogen concentration dilution curve was built by the test data from 2013 to 2014, and the model parameters and corresponding water treatment potential in the whole stages of aboveground dry matter quality gets better relationship by the date of 2014-2015.1)The model parameters were correct by the experiment date of 2013-2014, and were verified by the experiment date of 2014-2015. We simulated evapotranspiration and evaporation by using the data collected in the deficit irrigation experiment. The basal crop coefficient of each stage was calibrated by SIMDualKc model as follows, 0.34(initial stage), 0.34~1.16(crop development stage),1.16(mid season stage), 0.63(late season stage). The model can simulate soil evaporation and crop transpiration respectively. There is a good consistency between simulated evaporation and measured evaporation, the mean absolute error(MAE) is 0.016 ~ 0.024 mm/d, root mean square error(RMSE) is 0.013 ~ 0.034 mm/d and decision coefficient(R2) is 0.63 ~ 0.84. We can conclude that the SIMDualKc model can accurately simulate evapotranspiration of tomato under nonsufficient irrigation in greenhouse in northwest China, and through simulation results under the nonsufficient irrigation can analyze the response of tomato deficit and compensation mechanism recovery after water to provide theoretical basis under the condition of nonsufficient tomato cultivation.2)We analyzed the dynamic changes of tomato stems, leaves, fruits and roots under different irrigation treatment in 2013-2014, and established a dry matter production and distribution model by using water consumption, aboveground and root distribution index, aboveground organ allocation index. Then experiment data in 2014-2015 was used to validate the dry matter production and distribution. The results show that total cumulative of thermal effectiveness and PAR(TEP) and water condition influence tomato’s dry matter most. This model can be used to simulate production and distribution of tomato’s dry matter under different water and nitrogen condition. This research provides a theoretical basis for greenhouse tomato production under different water conditions.3)Critical nitrogen concentration dilution curve was built by the test data from 2013 to 2014, and the model parameters and corresponding water treatment potential in the whole stages of aboveground dry matter quality gets better relationship by the date of 2014-2015, the test data and the fitting relationship estimate the critical nitrogen concentration and the actual calculated results have good consistency. Using the method can improve the universality of the critical nitrogen concentration dilution model estimation. The critical nitrogen concentration dilution model can accurately diagnose different water processing tomato plant nutrition, diagnosis results show that non-full irrigation treatment and full irrigation, the increase of N application rate will increase nitrogen nutrition index.4) According to fit between leaf SPAD values and leaf nitrogen content, NNI under different nitrogen and water treatments, the results shows that the correlation coefficient between the median leaf SPAD values and leaf nitrogen concentration and NNI is higher than the upper and lower leaf SPAD values and leaf nitrogen concentration and the NNI. The correlation coefficient between the median leaves sensitive to nitrogen, nitrogen can be used as a monitoring is too much ideal blades.5) Tomato leaf POD, SOD, MDA and Pro contents would increase when reduce N application and irrigation water. Root POD, SOD and MDA content increases when decrease N application rate, but the root activity, root length and root surface area decrease along with the reducing of N application rate. When the transpiration evaporation and nitrogen uptake increases, tomato leaf POD, SOD, MDA and Pro content or root POD, SOD, MDA and RC content of different stage would reduce. Sensitive coefficient of flowering period of tomato leaf POD, SOD and Pro content or root POD, SOD, MDA and the RC content to water and nitrogen is the largest.6)When non-full irrigation treatment, the optimal N application rate of 150 Kg/hm2; and full irrigation treatment, the optimal N application rate of 300 Kg/hm2. The study of different water treatment when critical nitrogen dilution model for the region of greenhouse tomato for nitrogen nutrition diagnosis and provides a good theoretical reference.