草地放牧饲养要素分析

饲养牲畜是草地放牧的目标,放牧饲养牲畜是草地饲草资源利用的最有效途径。放牧饲养要素包括草地生产率、适宜载畜率、饲草质量、牲畜生长需要和采食量及放牧方式。本文对这些要素进行了归纳分析,目的在于推进发展草地放牧饲养理论并推导草地生产和保护性利用的关键技术。本文介绍了草地生产率研究方法、适宜载畜率确定标准、划区轮牧区块数计算方法及间歇休牧期和放牧期确定方法。草地放牧饲养理论：基于土壤和气候,改善草地生产和饲草质量,制定适宜载畜率,确定合理放牧方式,满足放牧牲畜最佳生长需要,并维持草地健康,实现“双赢”或“三赢”。草地保护性利用关键技术：放牧场或割草场施肥,调整适宜的载畜率,延迟放牧及间歇休牧,确切的划区轮牧体系,放牧场和割草场等量配置,二时段饲养模式。     

划区轮牧的若干研究进展

主要综述了基于草畜平衡的划区轮牧的研究进展和困境以及划区轮牧对土壤理化性质的影响。基于草畜平衡的划区轮牧发展至今,已实现由非适应性的放牧方式(维持预先定好的载畜量)到适应性的放牧策略(通过实际追踪饲草供给量而灵活改变载畜量)的改进,同时也应认识到划区轮牧区块规模、载畜量的确定非常复杂,未来要想真正达到草畜之间的适应性动态平衡,需要对划区轮牧进行更深入的研究。划区轮牧能够减轻牲畜的踩踏作用,有利于土壤保持稳定的物理结构。划区轮牧对土壤有机质和磷含量的影响表现为增加和无影响;对土壤表层全氮和速效氮的含量表现为降低。     

不同物候期刈割对羊草再生和根形态及产量的影响北大核心CSCD

刈割是羊草草地一种常见的利用方式,为探究不同物候期刈割对羊草再生和产量的影响程度,分别设置了对照组(CON)和刈割组。刈割组包括拔节期刈割(ES)、抽穗期刈割(HS)和开花期刈割(FS)。对照组不刈割,8月15日收获;刈割组起始刈割后,8月15日收获。结果表明,与对照相比,HS和FS刈割处理增加了(P<0.05)羊草干物质(DM)总产量而ES刈割处理则降低了(P<0.05)DM总产量。此外,所有处理均提高了(P<0.05)羊草的粗蛋白总产量。不同物候期刈割羊草的再生过程是不同的,ES处理羊草细根长、根表面积和体积最低。FS处理羊草再生后期净光合速率高于其余处理(P<0.05),导致其后期再生效率较高,但根中水溶性碳水化合物(WSC)含量最低(P<0.05)。HS和CON处理在羊草根形态和WSC含量上则无显著差异。尽管不同物候期刈割后羊草的再生过程不同,但其再生产量是接近的,特别是ES和HS处理,这是因为较长的再生周期被较低的再生效率所抵消,因此,总DM累积量主要由刈割前的DM来决定。综上所述,应在抽穗期进行刈割,能提高羊草产量并保持其持久性。     

放牧场和饲草场管理的原理与实践

为了深化理解我国北方草原的保护与利用,发展体系化的放牧及放牧场管理理论和技术,建立适宜的饲草场生产系统及其利用途径,文章概括总结了北美的放牧场管理原理和欧洲的饲草场管理实践。放牧场和饲草场的研究及管理属于应用生态学范畴,放牧场需要针对具体单元或区域、具体牲畜种类及其牧食行为,研究其管理原理及管理实践;饲草场需要针对具体单元或区域,基于特定土壤,选择适宜的饲料作物种类或品种,研究其自然生长及再生长的产量过程及营养动态,利用途径及可持续性。依据相关标准,划分了我国放牧场及饲草场潜在的空间分布,及我国需要发展区域性放牧场和饲草场管理原理及实践。     

The influences of reseeding date and mowing prior to reseeding on establishment of alfalfa in Leymus chinensis meadows北大核心CSCD

This research studied the effects of sowing date and cutting prior to sowing on establishment of the leguminous forage，alfalfa（Medicago sativa），in a lightly degraded Leymus chinensis meadow and investigated the sowing date×cutting interaction. The factorial experiment comprised four sowing dates（May 1，June 1，July 1，August 1）and cutting treatment（cut or uncut）prior to sowing，and evaluated the establishment performance of alfalfa and the ecological mechanisms related to establishment. It was found that soil moisture during emergence of alfalfa was the greatest when sowing occurred on July 1，and clipping prior to sowing significantly decreased the plant height of L. chinensis during emergence and seedling growth of alfalfa. There was a significant sowing date×cutting interaction effect on alfalfa establishment. Clipping prior to sowing significantly increased the emergence percentage of alfalfa through reducing the plant height of L. chinensis and associated above-and below-ground competition，and the seasonal soil moisture change resulted in a 20% higher（P<0. 05）alfalfa emergence rate when sowing occurred on July 1. With cutting，the number of surviving alfalfa seedlings and seedling survival rate were greatest（83 plants· m−2 and 53%，respectively）when sowing occurred on July 1. For later sowing，owing to the shortened growing time，the development and overwintering survival rates of alfalfa seedlings were significantly reduced. Cutting prior to sowing significantly increased the overwintering rate of alfalfa seedlings through improving their development. In the cutting treatment，the number of overwintered alfalfa seedlings（22 plants·m−2）when sowing was on July 1 was significantly higher than for other reseeding dates. In the second year，a botanical composition measurement showed that clipping prior to reseeding significantly increased the alfalfa biomass within the meadow，and the alfalfa biomass was significantly greater than in other treatments when sowing occurred on July 1 after cutting. Cutting prior to sowing also significantly increased the crude protein content of forage. Based on these research results，normal production practice should include cutting when alfalfa is sown into L. chinensis meadow. Combined with cutting，a sowing date around July 1 is the most favorable for the establishment of alfalfa. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.