Research Center for Facility Agriculture, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang, 110016, Liaoning Province, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang, 110016, Liaoning Province, China.
Environ Sci Pollut Res Int. 2019 Jul;26(19):19241-19249. doi: 10.1007/s11356-019-05125-x. Epub 2019 May 8.
Nitrate excess is common in greenhouse soils, imposing environmental risks and degrading vegetable quality. In this study, the effectiveness of adding sucrose as available carbon through irrigation to cut nitrate excess in lettuce-planted soil was investigated under impacts of soil texture and irrigation type. In the pot experiment using two loam soils of same origin with different clay to sand ratios (50.2% and 39.8%) and nitrate excess (116.1 and 417.7 mg/kg N), three-time sucrose addition through flood irrigation was more effective in lowering net formation of nitrate-based inorganic N and increasing lettuce yield in the soil with the higher clay to sand ratio, and sucrose addition at 150-450 mg/kg reduced nitrate accumulation and leaching, and nitrate content of lettuce at harvest by 62.5-89.6%, 19.3-36.1%, and 11.4-76.0%, respectively. In the micro-plot field experiment with two-time sucrose addition at 0.6-1.2 g/L through furrow irrigation (42 mm) into two other soils of same origin with different clay to sand ratios (56.9%, 48.4%), nitrate accumulation at 0-30-cm depth at the prone-leaching furrow location at harvest decreased by 30.9-36.0% under the higher clay to sand ratio but increased by about 35% under the lower clay to sand ratio. The nitrate content and yield of ridge-planted lettuce was less affected in either soil. Hence, carbon addition rate, irrigation type, and clay to sand ratio all affected the effect of available carbon addition on nitrate accumulation in vegetable-planted soil, and their joint impacts need better quantification for cutting nitrate excess in soil and improving vegetable quality and even yield.
硝酸盐过量在温室土壤中很常见，会带来环境风险并降低蔬菜质量。本研究通过灌溉添加蔗糖作为有效碳源，研究了在土壤质地和灌溉类型的影响下，减少生菜种植土壤中硝酸盐过量的效果。在使用两种来源相同但粘粒与砂粒比不同（50.2%和 39.8%）且硝酸盐过量（116.1 和 417.7 mg/kg N）的壤土的盆栽实验中，通过漫灌三次添加蔗糖更有效地降低了基于硝酸盐的无机 N 的净形成，并提高了粘粒与砂粒比较高的土壤中的生菜产量，添加 150-450 mg/kg 的蔗糖降低了硝酸盐积累和淋失，并分别降低了硝酸盐含量和硝酸盐含量收获时生菜的硝酸盐含量 62.5-89.6%、19.3-36.1%和 11.4-76.0%。在具有两个相同来源但粘粒与砂粒比不同（56.9%、48.4%）的微区田间实验中，通过沟灌（42 mm）两次添加蔗糖（0.6-1.2 g/L），在易淋洗的沟位置，收获时 0-30-cm 土层的硝酸盐积累减少了 30.9-36.0%，但在粘粒与砂粒比较低的情况下增加了约 35%。垄作生菜的硝酸盐含量和产量在两种土壤中均受影响较小。因此，碳添加率、灌溉类型和粘粒与砂粒比都影响了有效碳添加对蔬菜种植土壤中硝酸盐积累的影响，需要更好地量化它们的联合影响，以减少土壤中的硝酸盐过量并提高蔬菜的质量甚至产量。
