以羊草(Leymus chinensis)为优势种的草地是中国北方最重要的草地类型之一, 具有重要的生态系统服务功能。由于长期不合理利用, 草地生态系统中的营养元素持续“入不敷出”, 导致当前的羊草草地普遍处于退化状态, 无法正常发挥其生态及生产功能。已有研究表明, 畜禽草耦合能够促进退化草地生产力恢复, 但对羊草植株个体、种群和群落有何影响尚不清楚。为此, 该研究选取畜禽草耦合样地(LP)、围封打草样地(GM)和传统牛羊放牧样地(CS)开展了对比实验, 结果表明, LP中土壤NO₃^--N含量是GM和CS的2.5-3倍, 土壤速效磷含量是GM的2倍以上, 是CS的6倍以上。土壤养分含量的增加显著改善了羊草植株个体性状和种群特征。LP中羊草叶片的叶绿素含量、比叶面积、氮含量、磷含量等均显著高于GM和CS。LP中羊草种群的重要值在监测的第一年较GM和CS显著升高了29.7%和173.2%; 叶面积指数达到了3.4以上, 而GM在1.0上下, CS则维持在0.2左右; 种群地上生物量在监测的第二年增加到了(431.5 ± 45.3) g·m^-2, 是GM的1.6倍、CS的9倍。羊草种群的发展促进了植物群落的正向演替, LP群落盖度达到90%以上, GM维持在60%左右, CS则维持在40%左右; LP中群落地上生物量则在监测的第二年提高到(597.6 ± 61.3) g·m^-2, 接近GM的2倍、CS的3倍。畜禽草耦合草地利用过程中, 在植物生长季节牧鸡为草地施入的鸡粪有效改善了土壤养分亏缺的状况, 促进了羊草个体的生长和发育, 提高了羊草种群的重要值, 增加了植物群落的盖度和地上生物量, 从而促进退化羊草草地的近自然恢复。

Aims The grassland dominated by Leymus chinensisis one of the most important grassland types in northern China, providing important ecosystem service functions. However, due to long-term irrational utilization, the nutrients in the ecosystem stay in a state where outputs exceed inputs, leading to widespread degradation of the current Leymus chinensis grassland. The degradation affects its ecological and production functions. Previous studies have shown that the coupling of livestock and poultry can promote the restoration of degraded grasslands. This study aims to clarify the impacts of the coupling of livestock and poultry on L. chinensis at the individual, population and community scales.

Methods This study compared the differences in the individual traits, population and community characteristics of L. chinensis in livestock and poultry coupled plots (LP), grass mowing plots (GM), and traditional cattle and sheep grazing plots (CS).

Important findings The results showed that the soil NO- 3-N content in LP was 2.5 to 3 times higher than in GM and CS, and the soil available phosphorus content was more than 2 times that of GM and more than 6 times that of CS. The increase in soil nutrients content significantly improved the individual traits and population characteristics of L. chinensis. The chlorophyll content, specific leaf area, nitrogen content and phosphorus content of L. chinensis leaves in LP were significantly higher than those in GM and CS. The important values of the L. chinensis population in LP significantly increased by 29.7% and 173.2% compared to GM and CS in the first year, respectively. The leaf area index of L. chinensis population in LP reached above 3.4, while GM remained around 1.0 and CS remained around 0.2. The aboveground biomass of L. chinensis population in LP increased to (431.5 ± 45.3) g·m^-2 in the second year, which was 1.6 times that of GM and 9 times that of CS. The development of the L. chinensis population promoted positive communities’ succession, with plant cover in LP reaching over 90%, significantly higher than GM (around 60%) and CS (approximately 40%). The aboveground biomass of the plant community in LP increased to (597.6 ± 61.3) g·m^-2 in the second year, close to twice that of GM and 3 times that of CS. Under the utilization of coupling livestock and poultry, chickens fertilize the degraded grassland with manure during the plant growing seasons, which promotes the individual growth and development of L. chinensis, thereby increasing the important value of the L. chinensis population, as well as enhancing plant community coverage and aboveground biomass, ultimately leading the degraded L. chinensis grasslands toward near-natural recovery.