江苏省规模化肉鸭旱养全饲养周期污染物产生量及其环境效应

Manure excretion coefficient based on the complete process of duck production and estimation of environmental effects of duck breeding in Jiangsu,China

为完善肉鸭养殖产排泄系数体系,准确计算肉鸭养殖粪尿产生量与氮磷排泄量并评估其环境效应,本研究通过对高架养殖模式下,肉鸭全饲养周期(育雏-生长-育肥)持续开展42 d的粪尿全量收集试验,获得了肉鸭育雏期、生长期和育肥期产排污系数,并基于江苏省各市畜禽养殖量和耕地面积估算了2021年江苏省畜禽粪尿产生量及区域分布情况,评估了肉鸭养殖对耕地、水体污染负荷贡献。结果表明:肉鸭不同生长阶段粪尿产生量及氮磷排泄量差异显著,其中育雏期、生长期、育肥期粪尿产生量分别为56.3、311.5、474.9 g·只^(-1)·d^(-1),化学需氧量(COD)产污系数分别为4.48、20.82、30.22 g·只^(-1)·d^(-1),总氮(TN)产污系数分别为0.31、2.03、3.75 g·只^(-1)·d^(-1),总磷(TP)产污系数分别为0.19、0.85、1.41 g·只^(-1)·d^(-1)。徐州、宿迁、南通、淮安、盐城是江苏肉鸭养殖粪尿排泄总量最大的5个市,其总量占全省肉鸭粪尿排泄量的92.9%。2021年,江苏肉鸭粪尿中COD、TN、TP产生量分别为13.47万、1.19万、0.57万t。单位耕地面积肉鸭养殖氮、磷负荷最大的市为徐州,占比分别为23.31、28.53%。南通市、盐城市畜禽粪便耕地磷污染负荷高于欧盟磷限量标准,水体污染预警等级为Ⅳ级。研究表明,在肉鸭生产中应根据群体结构和相应的产排污系数科学核算其污染物排放量,盐城、南通在产业发展规划时要充分考虑畜种配置与环境承载力,适当减小肉鸭养殖规模,防止局部养殖污染风险的出现。

The present study aimed to improve the manure production and excretion parameter system applied to duck breeding to accurately calculate related manure total nitrogen(TN)and total phosphorous(TP)excretions.A manure collection experiment was performed during an entire 42 d breeding period of duck production using an elevated net bed breeding system in Jiangsu.Based on the number of livestock and poultry breeding,and the area of cultivated land in each city in 2021 in Jiangsu Province,the amount and regional distribution of TN and TP from livestock breeding and the contribution of duck breeding to environmental pollution by livestock manure were calculated.The results indicated that ducks had significantly different manure production and pollutant excretion rates at different growth stages,with 56.3,311.5 g·d^(-1),and 474.9 g·d^(-1) for manure excretion;4.48,20.82 g·d^(-1),and 30.22 g·d^(-1) for COD excretion;0.31,2.03 g·d^(-1) and 3.75 g·d^(-1) for TN excretion,and 0.19,0.85 g·d^(-1),and 1.41 g·d^(-1) for TP excretion at the weaning,quick growth,and fattening stages,respectively.Xuzhou,Suqian,Nantong,Huai′an,and Yancheng represented the five cities with the largest total manure excretion of duck breeding in Jiangsu,accounting for 92.9%of total manure excretion of duck breeding.In 2021,the production rates of COD,TN,and TP in duck manure in Jiangsu Province were 134.7,11.9 kilotons,and 5.7 kilotons,respectively.Xuzhou showed the largest TN and TP loads per unit cultivated area for duck breeding,accounting for 23.31%and 28.53%of the TN and TP emissions from the animal breeding industry.The TP pollution loads of livestock and poultry manure on farmland was higher than the TP standard in EU,and the water pollution warning level was fourth in Nantong and Yancheng.Therefore,the emissions of pollutants should be calculated accurately according to the population structure,and the corresponding production and excretion coefficient for duck breeding and the environmental carrying capacity should be fully considered in the breeding industry development planning in Yancheng and Nantong.The scale of the duck industry should be reduced to prevent local environmental pollution risks.