Characteristics of nitrogen and phosphorus losses from farmlands through surface runoff under different cropping patterns in the Three Gorges Reservoir area of Hubei Province

• Main Authors: LIU Fang-yi, XIA Ying, HUANG Min, LEI Qiu-liang, LIU Hong-bin, FAN Xian-peng, ZHANG Fu-lin, WU Mao-qian
• Format: Article
• Language: zho
• Published: Agro-Environmental Protection Institute, Ministry of Agriculture 2018-11-01
• Series: Journal of Agricultural Resources and Environment
• Subjects: Three Gorges Reservoir area, cropping patterns, surface runoff, fertilization, nitrogen and phosphorus losses
• Online Access: http://www.aed.org.cn/nyzyyhjxb/html/2018/6/20180609.htm

Designating cropping patterns as a unit in which to study the characteristics of surface runoff nitrogen and phosphorus losses in the regional field have important guiding significance to manage farmland nutrients and reduce the agricultural non-point source pollution. By using the loss coefficient method, this paper analyzed the loss of nitrogen and phosphorus in soil background and fertilizer loss in 18 main cropping patterns of 4 counties(districts) in Three Gorges Reservoir area(TGRA) of Hubei Province. The results showed the loss of nitrogen and phosphorus in TGRA were 2 035.0 and 213.2 t, where the Yiling District was the highest, which accounted for 53.8% and 50.5% of the total area, not only had the largest farmland area, but also nitrogen and phosphorus loss intensity was the highest. Flat-open vegetables and flat-garden were the two cropping patterns with the largest nitrogen loss, which accounted for 53.2% of total reservoir loss. Plain-open vegetables were the largest pattern of phosphorus loss, accounting for 43.3% of the TGRA. The fertilizer loss in-season of nitrogen and phosphorus accounted for 29.6% and 26.3% of the total loss respectively. The loss of nitrogen and phosphorus in the flat was the highest among the three kinds of slope farmland(flat, gentle slope land and steep slope divided by cropping patterns) because of high agricultural intensification, which accounted for 56.1% and 57.1% of the total loss, followed by the gentle slope, the steep slope was lowest due to low planting intensity. In all land use, plain dry land accounted for 38.5% and 48.5% of nitrogen and phosphorus loss in TGRA, and the nitrogen and phosphorus loss intensity were 17.1, 2.3 kg·hm^-2, much higher than that in the garden, sloping fields, and paddy fields.