畜禽草耦合模式初探

A tentative exploration of livestock-poultry-grassland system

草原牧鸡推动畜-禽-草耦合,成为一种新型草地利用方式,在生物灭蝗、土壤培肥和牧民增收等方面发挥良好作用,大范围推广有可能实现退化草地生态和生产功能的双提升.农区散养鸡由来已久,方法简单,易于掌握,能否照搬到草原牧区?这种方式会对草地生态系统有何影响?尚不清楚.为此,本研究通过开展以农区散养鸡方式牧鸡(MJ)和围封(CK)对比实验,探索以农区散养鸡方式开展牧鸡的可行性.结果表明,MJ样地内鸡群的空间分布符合依赖密度的聚集分布幂法则模型.随距离鸡舍由近及远,鸡的密度显著降低,从4000只/hm^2(R<20 m)显著降低到500只/hm^2(20 m<R<60 m)和100只/hm^2(R>60 m).植物群落受MJ、距离和MJ×距离影响显著.距离鸡栖息地20 m以内,MJ对植被的破坏严重,群落高度、盖度和地上生物量均显著低于CK.20~60 m范围内,得益于MJ的养分添加效应,其物种丰富度、盖度和地上生物量均显著高于CK,MJ当年的升高幅度分别为110.0%,54.7%和43.2%,MJ第二年的升高幅度与第一年相当;而当距离大于60 m时,MJ对植被无显著影响.MJ会造成鸡群的不均匀分布和近栖息地附近植被的严重破坏,不宜在畜禽草耦合模式中应用.实际生产过程中牧鸡应尽量做到密度适中和均匀分布,充分发挥其养分添加效应,促进植被的生长与恢复.

The livestock-poultry-grassland （LPG） system, a novel land use of grassland promoted by chicken farming, is important for controlling locust disaster, fertilizing infertile soils, and providing income to herders. It has great potential to improve both ecological and productive functions of degraded grasslands. The common chicken-farming mode used in agricultural regions （M J） is simple and easy to learn. The feasibility of introducing MJ in grassland pastoral regions is unclear, because its effects on vegetation have not been studied. We experimented by comparing MJ and zero grazing （CK）. The results showed that chickens in MJ plots had a clumped pattern and depended on the stocking rate. The stocking rates of free-range chickens significantly decreased with distance from the chicken house, from 4000 birds per hm2 （at R〈20m） to 500 per hm2（20 m〈R〈60 m） and 100 per hmZ（R〉60 m）. The plant community was significantly affected by M J, distance, and MJxdistance. At distances from 0 to 20m, the vegetation was severely damaged by MJ, with community height, coverage, and aboveground biomass significantly lower than those in CK. At distances from 20 to 60m, species richness, coverage, and aboveground biomass of MJ were significantly greater than those of CK because of nutrient addition, with an increase of 110.0%, 54.7%, and 43.2%, respectively, in the current year. These values remained nearly the same in the subsequent year. At distances greater than 60m, MJ had no significant effects on the vegetation. Therefore, considering the uneven distribution of chickens and severe vegetation damage around the chicken house, MJ is not suitable for the LPG system. To promote vegetation growth and grassland restoration, we propose chicken farming with a moderate stocking rate and an evenly distributed mode as well as the maximum possible development of the nutrient addition effect.