不同施氮量对滴灌加工番茄根系构型的影响

为了探讨施氮量对加工番茄根系构型及产量品质的响应机制,基于临界氮浓度模型的施肥方案,设置不施氮(N0)、施氮200 kg/hm²(N1)、施氮300 kg/hm²(N2)和施氮400 kg/hm²(N3)4个处理,结果表明:0-60 cm土层中的加工番茄根系总干质量、总长度、总表面积和总体积都随生育期的推进呈先增加后降低的趋势,根系干质量和长度的增长速率均呈“缓慢增加-快速增加-缓慢增加-缓慢下降”的变化趋势.在定植至开花阶段,加工番茄根系干质量和根系长度在各土层中差异不具有统计学意义,开花后,处理N2促进了根系总干质量、总长度、总表面积和总体积的增加,主要体现在开花后0-20 cm土层中根系干质量和拉秧期20-40 cm土层中根系长度的增加.N2相比其他处理可以显著提高加工番茄的产量,且具有较高的可溶性糖和番茄红素.在基于临界氮浓度模型的施氮比例下,加工番茄定植至开花阶段可减氮施肥按处理N1施44 kg/hm²,在坐果期、红熟期、拉秧期施氮按处理N2施234 kg/hm²便可保证根系的最佳生长状态.

Effects of different nitrogen application rates on root architecture of processing tomatoes

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.