中国南方亚热带丘陵地区草地植被重建

以实验生态学和生态工程相结合的措施,按照人为设计理论和生态恢复的一般程序,在中国南方亚热带丘陵地区研究截叶胡枝子(Lespedeza cuneata)草地和宽叶雀稗(Paspalum wettsteinii)草地植被的重建,并探讨了这一生态恢复模式在恢复初期的生态学过程和规律.主要结果如下:     

重新认识农区山羊放牧饲养

文章从山羊养殖历史、生物学特性、自然社会、经济效益、生态环保、市场消费及国外养殖进展等方面进行研究,认为我国南方农区山羊饲养应回归放牧养羊,可以实现社会生态经济的可持续发展。同时提出放牧养殖的标准化建设思路。     

基于涡度相关法的中国草地生态系统碳通量研究进展

草地生态系统碳循环研究是全球碳循环研究的热点,涡度相关法使草地生态系统碳通量的长期和连续观测成为可能。本研究介绍了以涡度相关法为手段的中国草地生态系统碳通量的研究进展,重点阐述了中国草地生态系统碳通量在不同时间尺度上的变化特征,同时概括了不同的环境因子对草地生态系统碳通量控制机理方面的研究成果,并在此基础上对今后中国草地生态系统碳通量研究提出了建议。     

Causes of death in beef cattle in southern Brazil

We determined the prevalence of diseases and pathogens associated with mortality in beef cattle in the State of Rio Grande do Sul, Brazil, based on pathology laboratory submissions. Postmortem examinations were conducted on 1,277 beef cattle that died between 2008 and 2018. Information regarding age, time of the year, breed, and regional location were analyzed statistically. Most cattle were from the surrounding region of Porto Alegre, and 78.7% of the analyzed cases had diagnostic value. The diagnostic category with most cases was infectious and/or parasitic diseases (60%), followed by toxic and toxicoinfectious (25%). Most cases occurred in the fall. Major disease conditions identified included hemoprotozoal infection (18.2%), rabies (8.2%), and plant intoxications by Senecio spp. (8.5%) and Pteridium arachnoideum (4.6%). Hemoprotozoal infection occurred at a higher frequency in young cattle, mainly in animals up to 1 y old. Intoxication by Senecio spp. was more frequent in cattle 2–3 y old.     

Osteomalacia as a result of phosphorus deficiency in beef cattle grazing subtropical native pastures in Uruguay

We investigated 2 outbreaks of osteomalacia as a result of phosphorus (P) deficiency in herds of lactating beef cows grazing subtropical native pastures in Uruguay. Cows exhibited pica, difficulty to stand and walk, rib fractures, and body weight loss even with adequate forage availability. Osteopenia and severe osteomalacia were observed on gross and histologic examination. The concentrations of bicarbonate-extractable P in soil (4.0, 4.1 mg P/kg), total P in pasture (0.9, 1.1 g P/kg), inorganic P in serum (1.0, 0.71 mmol P/L), and P in bone (73 mg P/mL) were all low. Although injectable and mineral salt supplements provided additional P in both outbreaks, these supplementary amounts were insufficient to prevent P deficiency. The P ingested by the cows from the pasture and supplements would have provided 20–55% of their daily P requirements of ~21 g P/d. Osteomalacia occurred in cattle at the 2 ranches as a result of severe P deficiency in the soil and forage, and inadequate P supplementation. Following diagnosis, control of P deficiency in beef cattle requires estimation of the amount of pasture P ingested and provision of sufficient additional supplementary P to meet the animals’ requirements.     

岩溶石漠化问题的全球视野和我国的治理对策与经验

对岩溶石漠化问题的认识起源于我国明朝徐霞客时代,我国的岩溶石漠化研究、综合治理技术方法对国际岩溶理论研究、其他岩溶区石漠化治理都具有示范性。在阐述岩溶石漠化分布区域性,我国岩溶石漠化现状、特点的基础上,提出治理对策,总结已有的岩溶治理对策和经验,同时提出石漠化综合治理中需要解决的科学技术问题。     

散养模式下白羽肉鸭屠宰性能与体尺指标相关性研究

本研究对30只94日龄中畜小型白羽肉鸭(CMD)在大群地面散养方式下的屠宰性能和体尺指标进行了测定,并对测定结果进行了相关分析,结果发现活重与体斜长、龙骨长、胸宽、胫围、半潜水长等体尺指标的相关系数分别达到0.588、0.660、0.618、0.654、0.582,均达到极显著水平(P<0.01);全净膛重与体斜长、龙骨长、胫围、半潜水长等体尺指标的相关系数分别达到0.476、0.566、0.552、0.455,均达到显著(P<0.05)或极显著水平(P<0.01)。此外,研究分别建立了活重与体斜长、龙骨长、胸宽、胫围、半潜水长以及全净膛重与体斜长、龙骨长、胫围、半潜水长的回归模型,两个回归模型经F检验均达到显著水平(P<0.05)。     

中国牧草新品种选育的回顾与展望

从 194 9年以来 ,中国牧草新品种选育已取得很大成就 ,到 2 0 0 0年底 ,经全国牧草品种审定委员会审定登记的牧草新品种共计 90个。其中包括沙打旺、苦荬菜早熟品种 ,杂花苜蓿、红豆草抗寒品种 ,苜蓿抗霜霉病、柱花草抗炭疽病品种 ,苜蓿耐盐品种、耐牧根蘖型品种 ,白三叶抗旱耐热品种 ,小黑麦、多花黑麦草多倍体品种 ,青贮玉米、青贮高粱杂种一代品种 ,高粱与苏丹草杂交种等新品种。存在问题主要是育成品种数量少 ,不能满足生产多方面的需要 ;育种技术和方法有待进一步提高 ;良种繁育体系不健全 ,新品种扩繁缓慢 ,推广面积较小。展望 2 1世纪 ,我国牧草育种应从高产、优质、抗病虫和抗逆性几方面努力 ,培育出更多更好的新品种。建立和完善牧草种质资源保护体系、牧草育种体系和良种繁育体系 ,以加速我国牧草种子产业的发展     

云南南亚热带多雨区引进禾本科牧草的适应性及评价

引进国外优良牧草栽培种14个在云南南亚热带多雨区进行种植,结果表明:贝斯莉斯克俯仰臂形草、纳罗克非洲狗尾草、海密尔大黍、海琴绸纹孔颖草、帕春青绿黍和无芒臂形草6个牧草品种在适应性,草产量和质量方面表现较好,适宜在该地区推广种植。