College of Resources and Environment, Academy of Agricultural Sciences, Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Southwest University, Chongqing, 400716, PR China.
College of Resources and Environment, Academy of Agricultural Sciences, Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Southwest University, Chongqing, 400716, PR China.
Environ Pollut. 2021 Jan 15;269:116098. doi: 10.1016/j.envpol.2020.116098. Epub 2020 Nov 20.
Overuse of phosphorus (P) fertilizer and the resulting soil P accumulation in vegetable production increases the risk of P runoff and leaching. However, P transformations under continuous fertilization and their effects on environmental risk are unclear. The current study examined the effects of long-term P fertilizer application on P fractions in different soil layers, and assessed the correlations between P fractions and environmental risks in intensive vegetable production in a subtropical region. A total of 32 fields were studied, including 8 uncultivated fields and 24 fields continuously used for vegetable production for 1-3, 4-9, or 10-15 years. The results showed that excessive P fertilizer input caused soil P surpluses ranging from 204.6 to 252.4 kg ha yr. Compared to uncultivated fields, vegetable fields contained higher levels of labile P, moderately labile P, sparingly labile P, and non-labile P. The combined percentage of labile P and moderately labile P increased from 55.2% in fields cultivated for 0-3 year to 65.5% in fields cultivated for 10-15 years. The concentrations of soil P fractions were higher at 0-20 cm soil depth than at 20-40 and 40-60 cm soil depth. Soil available P was positively correlated with all soil P fractions except diluted HCl-P or concentrated HCl-P. Long-term vegetable production increased CaCl-P downward movement, which was positively correlated with levels of labile and moderately labile P. The P index indicated a high risk of P losses from the vegetable fields. The P index was on average 3.27-fold higher in the vegetable fields than in uncultivated fields, and was significantly correlated with soil available P and organic and inorganic P fertilizer input. The environmental risk caused by P in vegetable production should be reduced by reducing P fertilizer input so as to maintain soil available P within an optimal range for vegetable production.
磷（P）肥料的过度使用以及由此导致的蔬菜生产土壤 P 积累增加了 P 径流和淋失的风险。然而，连续施肥下的 P 转化及其对环境风险的影响尚不清楚。本研究考察了长期 P 肥施用对不同土层 P 形态的影响，并评估了亚热带集约化蔬菜生产中 P 形态与环境风险之间的相关性。共研究了 32 个地块，包括 8 个未开垦地块和 24 个连续种植蔬菜 1-3、4-9 或 10-15 年的地块。结果表明，过量的 P 肥料投入导致土壤 P 盈余量在 204.6 至 252.4 kg ha yr 之间。与未开垦的田地相比，菜地含有更高水平的易解 P、中效解 P、缓效解 P 和非解 P。易解 P 和中效解 P 的综合比例从种植 0-3 年的 55.2%增加到种植 10-15 年的 65.5%。土壤 P 形态的浓度在 0-20 cm 土壤深度比在 20-40 和 40-60 cm 土壤深度更高。土壤有效 P 与除稀释 HCl-P 或浓 HCl-P 以外的所有土壤 P 形态呈正相关。长期蔬菜生产增加了 CaCl-P 的向下移动，这与易解和中效解 P 的水平呈正相关。P 指数表明蔬菜田 P 损失的风险很高。蔬菜田的 P 指数平均比未开垦田高 3.27 倍，与土壤有效 P、有机和无机 P 肥投入显著相关。通过减少 P 肥投入来降低蔬菜生产中 P 引起的环境风险，从而将土壤有效 P 维持在有利于蔬菜生产的最佳范围内。
