滴灌施肥时水肥顺序对番茄根系分布和产量的影响

利用田间试验，在日光温室内研究了滴灌施肥灌溉系统运行方式和施氮量对番茄根系分布和产量的影响。取先施氮和先灌水两种运行方式；施氮量取372 kg/hm²和204 kg/hm²两个水平。收获后取根样，用WinRHIZO软件对各处理的整根特征参数和根密度垂直分布进行分析。结果表明，随着施氮量的增加整根的根长、根表面积、根体积和根干重均显著增加，各层土壤的根密度也随之增加。施氮量一定时，先施氮处理中整根的根长大于先灌水处理，而根表面积、根体积和平均直径都小于先灌水处理。在垂直剖面上，先灌水处理使上层土壤的根密度增加，而先施氮处理使下层土壤的根密度增加。运行方式对根长和各土层根长密度的影响主要体现在直径小于1 mm的根系上，这部分根系占整个根系的比例和产量之间有很好的相关关系。各处理间产量的差异未达显著性水平。

Effects of drip fertigation strategies on root distribution and yield of tomato

Field experiments were conducted in a solar-heated greenhouse to investigate the effects on tomato root distributions and yield of drip fertigation strategies. The treatments included different nitrogen application levels and fertigation strategies that varied the order in which water and nutrient were applied. Two nitrogen application levels of 204 and 372 kgN/hm² and two fertigation strategies of applying nutrient at the beginning and applying water at the beginning of irrigation cycle were used. Tomato roots were sampled at harvest and analyzed by using the software of WinRHIZO. The experimental results show that the total root length, surface area, volume, weight of an individual plant and root density significantly increased with the amount of nitrogen applied. For a given nitrogen level, the strategy of applying nutrient at the beginning resulted in a greater total root length and smaller total root surface area, volume than the strategy of applying water at the beginning. In the profile, the increase of root density was seen in upper layer of soil for the strategy of applying water at the beginning, whereas for the strategy of applying nutrient at the beginning the increase appeared in lower layers of soil. The variation of root with fertigation strategy was more significant for a diameter of less than 1mm. A good correlation between tomato yield and the ratio of the thin root with diameter of less than 1mm to the total root was seen. No significant influences of nitrogen application level and fertigation strategy on tomato yield were observed in the experiments.