基于畜禽粪便养分含量的畜禽承载力研究

Study onLivestock Carrying Capacity Based on Manure Nutrients

为了减少畜禽养殖带来的环境污染,许多发达国家规定畜牧场周围必须配备农田来消纳畜禽粪便,同时也有成熟的畜禽承载力的研究方法。根据我国区域养殖畜种较多、农田分散、农牧脱节等情况,本研究确定了适合我国国情的用特定地理区域范围消纳畜禽粪便氮(N)、磷(P2O5)能力的方法来确定畜禽承载力。本研究根据不同畜种平均每头(只)存栏动物每年的粪便养分产生量、每公顷作物每年的养分移走量,计算出每公顷大田作物地、蔬菜地和园地每季所能承载的各种畜禽数量,然后根据各地区的复种指数估算出作物地每年承载的畜禽数量。结果表明:牛、羊的年产粪便N/P2O5较大,禽类比值较小,其他畜种比值居中;蔬菜地可以承载的畜禽数量最多,大田作物地次之,园地承载的最少;以N作为承载标准时,农用地所承载的畜禽数量比以P2O5作为标准时多(最高为6.6倍)或者两者持平。可以根据区域需要,通过提高作物对肥料的利用率、调整化肥与粪肥用量、调整种植结构等方式改变畜禽承载力的大小。

In order to prevent the husbandry environmental pollution, each livestock farm is matched with proportional cropland to digest animal manure in many developed countries, correspondingly with suitable methods of evaluating livestock carrying capacity based on the livestock farm level. However, those methods could not be adapted to China. An appropriate method to measure the environmental load of livestock, which is the ability to digest manure-N and manure- P2O5 by a particular geographic region, was determined in this study according to domestic circumstances. We determined the annual manure nutrients excreted by each animal species and seasonal amounts of different livestock which could be carried by a hectare of croplan nutrients removed by crops to calculate the d, vegetable field and orchard land annually. The results showed that（1）the ratio of N and P2O5 was increased gradually from poultry, swine, beef, sheep to dairy cow; （2）livestock carrying capacity was decreased gradually from vegetable field, cropland to orchard land;（3）livestock carrying capacity based on N was higher than that of based on P2O5, the highest ratio of the livestock carrying amount based on N to P2O5 was 6.6. Livestock carrying capacity could be adjusted through increasing the fertilizer＇s utilization efficiency, accommodating the application rate of manure and chemical fertilizer, and restructuring the crop types.