1. Agronomy College, Shihezi University, Shihezi, Xinjiang 832003, China; 2. Key Laboratory of Featured Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Construction Corps, Shihezi, Xinjiang 832003, China
Abstract：In order to explore the response mechanism of nitrogen application amount to the root structure, yield and quality of processing tomatoes, based on the critical nitrogen concentration model, four treatments were set up: no nitrogen application(N0), nitrogen application(200 kg/hm2)(N1), nitrogen application(300 kg/hm2)(N2)and nitrogen application(400 kg/hm2)(N3). The results showed that the total dry weight, total length, total surface area and total volume of processing tomato roots in 0-60 cm soil layer all increased first, then decreased with the growth stage advancing. The growth rate of dry weight and length of roots showed a trend of ″slow increase-rapid increase-slow increase-slow decrease″. From the planting to flowering stage, there was no significant difference in the dry weight and length of root system of processing tomatoes in each soil layer. After flowering, N2 treatment promoted the increase of total dry weight, total length, total surface area and total volume of root system, mainly reflecting the increase of dry weight of root system in 0-20 cm soil layer after flowering and the increase of length of root system in 20-40 cm soil layer at the seedling pulling stage. Compared with other treatments, N2 can significantly improve the yield of processing tomatoes, and has higher soluble sugar and lycopene. Based on the critical nitrogen concentration model, 44 kg/hm2 of nitrogen can be reduced and applied according to N1 treatment from planting to flowering stage of processing tomatoes, and 234 kg/hm2 of nitrogen can be applied according to N2 treatment at the fruit setting stage, red maturity stage and seedling pulling stage to ensure the best growth state of root system.
