藏系绵羊自然放牧条件下生长发育规律观察

在冬春季节自然放牧条件下,对藏系绵羊不同管理水平下的体重变化、羔羊成活率、繁殖成活率、成畜保活率进行对比研究。在不采取任何补饲措施的情况下,试验组夜间圈于标准化暖棚羊舍,对照组圈于简易羊舍。实验结果表明,在12月21日到次年5月21日的150d时间内,对照组羊自试验期开始的第一个月起,体重逐渐下降至4月份到最低体重。然后逐渐增重,但到6月份体重仍未恢复到期初水平。试验组当年羔羊、育成羊和成年羊体重下降幅度比对照组分别低0．57kg、2．25kg和2．61kg;羔羊成活率、繁殖成活率和成畜保活率比对照组分别高1．02、4．70和2．29个百分点。对照组羊体重减少9．83kg,减少产肉4．52kg,只均损失117．57元;试验组羊体重减少5．94kg,减少产肉2．73kg,只均损失70．98元,比对照组低46．59元。说明藏系羊在寒冷季节采取必要的保暖措施,可以减轻体重损失,提高羔羊成活率、繁殖成活率和成畜保活率。     

放牧强度对土-草-畜系统的影响研究进展

针对我国草地存在严重的退化问题,重点阐述了对国内外学者关于放牧强度对草地生态系统中植物、土壤、家畜影响的研究。研究者认为,适度的放牧,有利于植物物种的延续,植物群落生产力的提高及生物多样性的增加;有利于土壤C、N的积累;有利于家畜生产性能的提高。因此,寻求当前不同退化程度草地最适放牧强度是持续利用草地,保护草地生态、提高草地经济效益的必要措施。     

模拟酸雨对水稻种子发芽及幼苗生长的影响

通过模拟不同pH值(分别为3.0,4.0,5.0)的酸雨胁迫处理水稻(Oryza sativa)种子和幼苗,以了解酸雨对水稻种子萌发及幼苗生长的影响。结果显示:pH值5.0的模拟酸雨对水稻种子发芽率影响不明显,但pH值4.0和pH值3.0处理下种子萌发率显著下降;幼苗对不同程度的模拟酸雨胁迫均敏感,各生长指标包括叶长、苗高、植株鲜重、不定根数等被显著抑制,且随着pH降低,被抑制程度越甚。试验结果表明,模拟酸雨对水稻种子萌发和幼苗生长发育均有影响,且幼苗阶段较种子萌发阶段对酸雨的影响更为敏感。     

我国水土流失典型区土壤溅蚀特征研究

基于室内模拟降雨试验,分析了我国水土流失典型区代表性土样的溅蚀特征,探讨了溅蚀与土壤理化性质的关系.结果表明,溅蚀量明显受土壤理化性质的影响,黑土土样因团聚体含量及稳定性高,溅蚀量最低;采自内蒙古自治区东胜市的黄土土样因砂粒含量(易被溅蚀的颗粒范围)高,溅蚀量最高;其它黄土土样、红壤土样及紫色土土样或因粉粒含量为主或因团聚体稳定性差而导致溅蚀量居中.模拟降雨条件下,除黑土土样和内蒙古自治区东胜市的黄土土样外,其它土样均发育表土结皮,导致溅蚀率呈现波动态势.     

集配货一体化VRP问题的具记忆功能的模拟退火算法研究

针对集配货一体化车辆路径问题的特性,建立了考虑配送车辆出行固定成本、车辆出发满载系数等因素的更加符合实际的数学模型;并设计了一种带记忆功能的模拟退火算法求解模型,确保输出结果是每次寻优的最优解;最后通过算例计算,结果表明,算法求解更优,稳定性更好,计算效率也较高。     

人工草地绵羊系统优化研究Ⅴ人工草地划区轮牧考尔木怀孕母羊群体采食量研究

丰草季人工草地划区轮牧条件下,考尔木(Cormo)成年母羊群体采食量与怀孕日龄间呈显著正相关,回归方程Y=0.002 6X+0.642 2,相关系数r=0.812 3,受孕前采食量0.64 kg/羊,产羔前采食量1.03kg/羊,平均采食量0.84kg/羊.     

Food habits and selective grazing of Mongolian gazelle (Procapra gutturosa) in Hulunber Grassland

IntroductionMongoliangazelle(PrOCSPraguttuross)isaspecialruminantspeciesthathasnumerouspopulationsintheeasternpaFtofNetMonggolGrasslandandasignificantcomponentofthegrasslandecosystem.Thisspecieshasthehabittoselectspeciesandqualityofplantstograze.However,thepopulationhasdecreaseddramaticallyandfacesextinctioninChina(JiangetSI.1998).Therefore,itisveryimportanttostudythefoodhabitsandfoodchoicebyMongoliangazelleforpromotingtheprotectionandmanagementofremainingpopulation.Inapreviouspaper(Gao…     

高山草原绵羊放牧生态及消化代谢系列研究Ⅱ.放牧绵羊排尿量收集方法的新改进--纸尿裤法

利用纸尿裤法和常规法对６只甘肃高山细细毛羊成年竭羊，分别在祁连山东段高山草原７、８、１０、１月牧草生长的青草期、黄草期、葳草期共四期排尿量收集对比试验研究。实验表明，纸尿裤法收集收牧绵羊排尿量是常规法的１．６５－１．９４倍，纸尿裤法全面优于常规法，该方法的应用可以使放羯羊排尿量计量更加客观准确。     

黄土高原沙化草地牧草飞播技术的试验研究

通过在黄土高原沙化草地上进行牧草飞播试验，结果表明，要使飞播成功，播期要选择在雨季进行，播区植被盖度超过20％，需进行播前地面处理；植被盖度低于20％，播前不做地面处理，可直接飞播。播后网型镇压嚣镇压，出苗率高，飞播效果好。     

Earthworm surface casts affect soil erosion by runoff water and phosphorus transfer in a temperate maize crop

To test the hypothesis that earthworm surface casts contribute to soil erosion and nutrient transfers in a temperate maize crop, two rainfall experiments were set up. One was focused on the erodibility of earthworm casts, the second examined in how casts affect water runoff and nutrient transfers. Casts produced from anecic and endogeic earthworm species were both analyzed. Visual observations in the field showed no cast transport but only cast disintegration and transfers of particles. Erodibility of newly deposited casts was high and differed significantly between age groups. Cast erosion was significantly positively related to initial mass when young but not when old. The paradox is that despite a high cast abundance (25% of the area) and obvious cast erosion, amounts of sediment and nutrient losses (C, N and P) in the runoff were at least twice as high without, than in the presence of, surface casts. Earthworm activities were shown to act as a physical brake for soil erosion by (i) creating a surface roughness with the deposition of surface casts and (ii) reducing water runoff by associated enhanced water percolation. Once the breaking-down point of the physical resistance of casts was reached, all surface casts were quickly disintegrated and finally completely washed away. The amount of particulate phosphorus recovered in water runoff was 34.7 mg P m^{− 2}, while 128.5 mg P m^{− 2} was estimated to have been released from casts. The transfers were found to occur over a short-distance through successive deposition/suspension of soil particles in the water runoff.