[Pollutant production and discharge from livestock and poultry industries and land carrying capacity in Zhejiang Province].

Based on the investigation of pollutant production and discharge from a typical scale pig farm in Zhejiang Province at three pig growth stages (piglets, fattening pigs, and sows) in the autumn and winter 2007 and the spring and summer 2008, the coefficients of pollutant production and discharge from the pigs as well as the total annual pollutant production and discharge from the farm were estimated. In the meantime, the annual application amount of animal manure to the farmlands in Zhejiang Province was estimated by using these coefficients and the livestock and poultry inventories in Zhejiang Province in 2007. It was estimated that the total amount of applied animal manure in the Province in 2007 was 2106.8 x 10(4) t x a(-1), containing 13.57 x 10(4) t x a(-1) of N, 6.7 x 10(4) t x a(-1) of P, 0.11 x 10(4) t x a(-1) of Cu, and 0.20 x 10(4) t x a(-1) of Zn. The pig-manure-equivalent farmland carrying capacity in the Province was 16.66 t x hm(-2) a(-1), and the average alarm limit was 0. 37. The application of animal manure in some areas of Zhejiang Province had exceeded the alarm limit for the land carrying capacity, and made a potential environmental threat.