龙羊峡库区天然草地动态分析

利用美国陆地卫星T.M图象,对龙羊峡水库库区的天然草地进行了对比分析。结果表明,天然草地面积减少7084.09hm^2。其中减幅较大的为温性草原类和温性荒漠类,10年中分别减少了7299.27hm^2和1015.65hm^2。另外,草地盖度,牧草高度和草地产量也有下降,其中草地盖度下降5%-15%;牧草种数减少4-20种;牧草产量下降73.5-1090.05kg/hm^2。并对变化原因作了分析,提出了治理措施。     

黑河流域草地资源保护与建设

黑河流域除绿洲地区外有160万hm2的草地,进行草地分户、围栏封育、人工改良草地;牧户按地定畜、优化牧场、推广良种、改良畜群;按草定牧、实行休牧和轮牧;革新观念、子羔出栏、加速出栏周期、保障牧民增收等措施可保护草地资源,加速草地建设,繁荣牧区经济.     

喀斯特地区三叶草混播草地群落组分20年动态

三叶草（Trifolium）混播草地群落持久性研究对喀斯特草地建设与石漠化治理具有重要意义。在威宁灼圃示范牧场开展的由白三叶（T. repens）、红三叶（T. pratense）、无芒雀麦（Bromus inermis）、紫羊茅（Festuca rubra）,分别加上多年生黑麦草（Lolium perenne）、鸭茅（Dactylis glomerata）、黑穗画眉草（Eragrostis nigra）、鹅冠草（Elymus kamoji）组成4个5组分混播草地,在绵羊适度放牧下测定牧前、牧后草地现存量,连续进行20年持久性研究。结果表明：时间及组合×利用时间的交互作用对所有混播组合影响极显著,而组合间产量差异不显著,其动态变化与年降水量的动态变化之间无显著的对应关系,但同物种在各混播群落中的生产力和稳定性差异明显,说明各组分之间存在显著的生态位互补和竞争共存关系。各物种中生产力与稳定持久性最好的是紫羊茅和白三叶,其次是多年生黑麦草和鸭茅,最差的是无芒雀麦和鹅冠草;而在草地建植初期表现最好的是多年生黑麦草和红三叶。     

黄河源区“黑土滩”混播草地牧草植物量及营养动态初探

黄河源区的极度退化草地——"黑土滩",改建成人工草地是一种恢复退化草地的重要途径,同时可以收获大量饲草。对"黑土滩"混播草地(垂穗披碱草Elymus nutans+中华羊茅Festuca sinensis+碱茅Puc-cinellia distans+冷地早熟禾Poa crymophila+赖草Leymus secalinus)的生产力和营养价值动态进行了研究,分析了放牧对草地生产力的影响。结果表明,从生长高峰期8月到翌年4月,草地生产力自然损失量为144.3 g/m2,损失率为34.9%。这期间放牧利用导致牧草被采食187.2 g/m2。传统的放牧利用,使该类人工草地利用率为45.2%。冷季草地牧草营养价值全都下降,粗蛋白含量降低了69.86%,粗脂肪降低了65.85%。该"黑土滩"混播草地在夏季属碳氮营养型(CN),冬季属碳营养型(C)。因此建议,"黑土滩"混播草地在夏季生长高峰期适度进行人工割草,冬季进行适度放牧利用。     

陕北水蚀风蚀交错区苜蓿地土壤水分过耗与恢复

采用野外定位观测法研究水蚀风蚀交错区苜蓿(Medicago sativa)草地土壤水分在天然降水作用下的恢复过程。结果显示:苜蓿地翻耕后,在降水作用下土壤水分有明显的恢复过程,第一年,150cm以上土壤水分得到一定恢复,第二年深度达到300cm,但上层土壤含水量并未增加;该地块植被大量消耗土壤储水导致土壤干燥化,高耗水植被消除后,土壤含水量逐渐增加。     

Phytomass estimation using eMODIS NDVI and ground data in arid rangelands of Morocco

The assessment of rangeland productivity in semi-extensively grazed arid rangelands is a prerequisite for livestock management in relation to sustainable use of pastoral resources. The objective of this study was to assess rangeland productivity based on normalised difference vegetation index (NDVI) images. Data on phytomass were measured on 61 field samples in arid rangelands of Morocco, covering various rangeland categories during autumn (November) and spring (April), i.e. when phytomass is at low and high levels, respectively, for two consecutive years (2008 and 2009). Dekadal EROS Moderate Resolution Imaging Spectroradiometer (eMODIS) NDVI data were linearly regressed to field measurements for these four periods. Results show that phytomass values were correlated with NDVI during spring, with R² and RMSE values of 0.82 and 0.3 t ha^?1, respectively. This study indicates there is a high potential for operational use of remotely sensed data to estimate rangeland phytomass of semi-extensively grazed rangelands.     

The Effect of Supplementation with Fresh Browse of Ziziphus mauritiana or Combretum aculeatum on Feed Intake,Nitrogen Utilization and Growth of Grazing Range Sheep

The influence of 0, 60 or 120 min access to a grove of either Ziziphus mauritiana (Ziziphus) or Combretum aculeatum (Combretum) on forage intake and on the digestibility, growth and excretion of nutrients was determined using 40 Oudah rams grazing for 7 h/day on poor-quality dry season pasture in the Sahel. The effects of browse species and browsing duration (0, 30, 60 or 120 min) on the ruminal ammonia content were also evaluated using 8 mature fistulated rams. Ziziphus increased both total digestible organic matter and total dry matter intakes per (kg live weight)^0.75 without decreasing herbage intake, whereas 60 or 120 min access to Combretum reduced herbage intake by 6.3% and 4.2%, respectively. The digestibility of the diet decreased (p<0.05) with the duration of access to the groves. Despite the provision of more nitrogen (N) than in the control diet, ruminal NH₃-N decreased 24 h after browsing commenced. The reduced live weight gain of sheep browsing Combretum may indicate more deleterious compounds in Combretum than in Ziziphus. Ziziphus appears to have more potential than Combretum to increase sheep production in low-input crop/livestock systems.     

岷县草产业发展现状及策略

岷县地处秦岭、黄土高原和青藏高原的交汇带。本研究通过分析其草产业现状,指出岷县草产业发展主要存在天然草地退化严重、栽培草地管理粗放和特色草产业加工技术不完善的问题,提出岷县草产业今后发展的方向是分区管理和分类经营,从建立草地生态补偿基金、发展草地观光旅游业、提高栽培草地生产力、提高草地资源的利用效率和培训农民能手等方面提出了岷县草产业的发展策略。     

青南牧区雪灾危害的防御

为防灾减灾,利用调查研究,分析了降雪量、低温、牲畜膘情、草地产草量、饲草储备、保温、草地载畜量、雪灾预报、抗灾组织等因子,对青南牧区雪灾危害的影响,提出通过人为干预防御雪灾的综合措施,并制定了入冬前进行的抗灾能力评定标准。     

旅游活动对生态环境及牧草资源的影响

随着国家经济快速增长,居民生活水平得到巨大提升,假期出行旅游已成为国民重要的精神文明需求,但当前我国草原旅游业发展不够成熟,旅游活动增加对草原生态环境及牧草资源造成了一定影响,这其中既有积极的影响也包含消极影响,本文通过以当前我国草原生态系统环境承载能力为切入点,以草原生态系统一级牧草资源生长所需条件为前提,深入挖掘旅...