高寒荒漠草原季节性放牧管理优化模拟研究

【目的】保护中国高寒荒漠草原的生态环境,指导草原牧区的全面可持续发展,从草畜平衡的角度为制定高寒荒漠草原牧区合理的放牧管理政策及实现牧草资源高效利用提供依据。【方法】根据季节性轮牧的特点和牲畜生产节律,考虑了草地资源的时空隔离和牲畜数量的动态变化,对暖季、冷季两个草场放牧时间段进行细化,在现有合理载畜量计算方法的基础上,以载畜量最大为目标,以动态草畜平衡为约束条件,以转场时间和出栏率为优化参数,建立了放牧-管理优化模型,并选取青海省乌兰县牧区作为高寒荒漠草原季节性牧区的典型代表,利用遗传算法寻优,确定乌兰县牧区丰、平、枯3种降水情景下最优放牧条件,进行草畜平衡优化模拟计算和动态草畜平衡分析,并与优化前进行对比。【结果】放牧-管理优化模型对牧区不同降水情景的模拟结果均较好。以未利用饲草量最低为依据,确定乌兰县牧区丰、平、枯3种降水情景下最优放牧条件分别为11月1日转场,出栏率43.4%、11月3日转场,出栏率38.2%和11月3日转场,出栏率36.7%,最优合理载畜量分别为109.92、96.14和83.64万标准羊单位,较优化前合理载畜量分别提高了11.75%、10.44%和10.43%;优化前后乌兰县牧区丰水年的合理载畜量分别为98.38和109.92万标准羊单位,比枯水年的75.74和83.64万标准羊单位的适宜承载量高30%,可见除牲畜出栏率和转场时间外,降水量也是影响牧区合理载畜量的重要因素;通过对牧区产草过程与牲畜动态需草过程的分析,进行乌兰县牧区平水年动态草畜平衡计算后发现,优化前冷季牧场可利用饲草不能被完全利用,放牧过程存在不合理之处,剩余草量超过6 130万kg,而优化后可利用饲草未充分利用问题得到有效解决,牧草资源得到高效利用,对于乌兰县整个牧区而言,调整放牧转场时间和牲畜出栏率是改良放牧制度的可靠方式;利用放牧-管理优化模型对牧区放牧过程进行优化,可以在保证牧区全年合理载畜量较高的同时,能够实现季节性轮牧区动态草畜平衡。【结论】放牧-管理优化模型对高寒荒漠草原季节性牧区的适用性较好,对轮牧区放牧管理过程调控和草畜平衡优化具有一定的优越性;放牧-管理优化模型可有效调控牧区载畜量,其优化结果可为制定合理的放牧制度提供参考,因此可将该模型用于优化单个牧户或牧场的放牧过程,得到单个牧户或牧场的最优放牧条件,从而制定相应的放牧制度,对单个牧户或牧场的生产实践工作更具有实际指导意义和可操作性。     

草地放牧强度遥感解译方法——以和静县高寒草原为例

为研究高寒草原放牧强度,以新疆和静县高寒草原草地为研究对象,利用2013年7—8月野外草地地上生物量采集数据和2013年遥感数据源MDOIS13Q1的归一化植被指数(NDVI),建立了高寒草原草地地上生物量和植被指数(NDVI)的遥感反演模型;并通过分析近10年(2008—2017年)监测点每年NDVI的旬变化特征,解译高寒草原草地的放牧起止时间,通过分析归类各样点NDVI变化特征,并以ΣNDVI值划分放牧强度。结果表明:1)本研究中建立的高寒草原草地地上生物量遥感反演模型,以模型y=523.21NDVI2-82.8NDVI+55.84(R2=0.732 9,P0.000 1)精度最优;2)通过NDVI变化曲线的突变点确定了高寒草原夏季放牧开始时间为6月9—26日,结束时间为8月28日—9月14日,该结果与实际放牧时间基本吻合。3)通过分析NDVI生长季累积总量(ΣNDVI)、生长季NDVI波动下降频数和幅度确定放牧强度,构建了高寒草原草地放牧强度分级标准,与实地判断的放牧强度相比,精度验证达到89.47%,并据此制作了研究区放牧强度等级图。本研究结果可为利用多时相遥感影像快速确定草地放牧强度和放牧管理提供参考。     

准噶尔盆地梭梭沙质荒漠土壤有机碳分布特征的研究

为研究环境因子对梭梭荒漠土壤有机碳含量的影响,采用路线调查和典型样地布设相结合方法,对准噶尔盆地典型梭梭沙质荒漠0—100 cm不同土层土壤有机碳进行测定,揭示其土壤有机碳分布特征及其与环境因子之间的内在关系。结果表明,0—100 cm各土层土壤有机碳含量变化范围为0.00～11.46 g·kg-1,均呈中等变异水平,且随土层深度的增加土壤有机碳含量呈降低趋势。梭梭荒漠土壤有机碳含量是白梭梭荒漠土壤有机碳含量的1.40倍（P<0.05）,由此表明,梭梭荒漠的固碳能力更强。冗余分析结果表明,引起梭梭荒漠土壤有机碳含量空间变异的主要影响因素是土壤pH、植被覆盖度和土壤含水量,为退化梭梭荒漠的恢复治理及可持续利用提供理论依据。     

Grazing behaviour,physical activity and metabolic profile of two Holstein strains in an organic grazing system

The challenge for sustainable organic dairy farming is identification of cows that are well adapted to forage‐based production systems. Therefore, the aim of this study was to compare the grazing behaviour, physical activity and metabolic profile of two different Holstein strains kept in an organic grazing system without concentrate supplementation. Twelve Swiss (H_CH; 566 kg body weight (BW) and 12 New Zealand Holstein‐Friesian (H_NZ; 530 kg BW) cows in mid‐lactation were kept in a rotational grazing system. After an adaptation period, the milk yield, nutrient intake, physical activity and grazing behaviour were recorded for each cow for 7 days. On three consecutive days, blood was sampled at 07:00, 12:00 and 17:00 h from each cow by jugular vein puncture. Data were analysed using linear mixed models. No differences were found in milk yield, but milk fat (3.69 vs. 4.05%, P = 0.05) and milk protein percentage (2.92 vs. 3.20%, P < 0.01) were lower in H_CH than in H_NZ cows. Herbage intake did not differ between strains, but organic matter digestibility was greater (P = 0.01) in H_CH compared to H_NZ cows. The H_CH cows spent less (P = 0.04) time ruminating (439 vs. 469 min/day) and had a lower (P = 0.02) number of ruminating boli when compared to the H_NZ cows. The time spent eating and physical activity did not differ between strains. Concentrations of IGF‐1 and T3 were lower (P ≤ 0.05) in H_CH than H_NZ cows. In conclusion, H_CH cows were not able to increase dry matter intake in order to express their full genetic potential for milk production when kept in an organic grazing system without concentrate supplementation. On the other hand, H_NZ cows seem to compensate for the reduced nutrient availability better than H_CH cows but could not use that advantage for increased production efficiency.     

黄河源区黑土滩人工草地牧草植物量及营养动态研究

对黄河源区黑土滩人工草地在封育和放牧两种不同管理方式下,从8月到翌年的4月进行了地上植物量及牧草营养成分动态研究,结果表明:从8月到翌年4月牧草的自然损失量为138.7g/m~2,损失率为34.3%,家畜的采食量为174.9g/m~2,草地的实际利用率为43.3%;整个冷季牧草总体营养价值呈下降趋势,封育草地粗蛋白降低了56.87%,粗脂肪降低了51.09%。该类草地在夏季属碳氮营养型(CN),冬季属碳营养型(C)。     

近10年来我国草原虫害生物防控综合配套技术的研究与推广进展

草原虫害防治是农业部较早大规模组织开展的防灾减灾工作之一。在长期的实践工作中,草原虫害防治始终坚持“预防为主,综合防治”的植保方针,逐步建立了“以生物防治为主,化学防治为辅”的技术路线。2002年起,全国畜牧总站在全国牧区组织开展了《草原虫害生物防控综合配套技术推广应用》项目。该项目的实施带动了全国的草原害虫防治,为草原可持续发展提供了技术支撑。本文以该项目的进展为基础,简要总结介绍了草原害虫防治的实施背景、开展情况及建设成果,包括以生态系统平衡原理为指导,对虫害监测预警、生物防控和施药技术等进行集成创新与组装配套,使草原害虫密度长期控制在经济阈值以下,实现草原生态系统平衡等。     

温性荒漠草原不同放牧强度草地锰和铜动态变化

为探讨不同放牧强度下温性荒漠草原土-草体系中微量元素锰和铜的变化,对土壤、牧草中锰和铜含量进行了测定。结果表明,除中牧区以外,其他放牧区土壤锰含量随季节的推移极显著下降(P0.01),夏季牧区极显著高于其他放牧区,冬春季和秋季则轻牧区极显著高于其他放牧区(P0.01)。除对照外,轻牧,中牧和重牧区土壤铜含量夏季极显著高于其他两季(P0.01),冬春季和秋季不放牧或轻牧区极显著高于中牧和重牧区(P0.01)。各放牧区牧草中锰和铜(除中牧区)含量均冬春季显著或极显著高于夏秋两季,同一季节不同放牧区则各有变化。     

Increase in plasma total antioxidant capacity of grazing Japanese Black heifers and cows in forestland in Japan

Blood total antioxidant capacity (TAC) has become a key bio‐marker for animal health. Forest‐grazing cattle are known to forage various native plants that have high TAC. This study evaluated differences of plasma TAC between forest‐grazing (FG) and pasture‐grazing cattle (PG). Experiment 1 monitored the plasma TAC levels of 32 Japanese Black cattle. The level in PG did not change throughout the grazing period. However, that in FG, which increased from summer, was significantly higher than that in PG through fall (P < 0.05). In experiment 2, we used nine Japanese Black heifers and investigated their blood antioxidant parameters and the TAC in plants that the cattle consumed in late June and September. The plasma TAC levels in FG were significantly higher than those in PG in both periods (P < 0.05). Plasma levels of lipid peroxidation in FG tended to be lower than that in PG (P = 0.098). Furthermore, the TAC levels in various species of shrubs and trees consumed by FG were higher than those in pasture grasses. Results of this study show that plasma TAC of grazing Japanese Black cattle in forestland increase from summer through fall.     

西藏昌都地区实施草场承包经营责任制的现状和对策

介绍了西藏昌都地区生态环境的基本状况和该地区草场承包经营责任制的发展过程,进一步认识到落实和完善草场承包经营责任制对该地区的重大意义,及其对昌都地区畜牧业发展的重要作用。科学分析了该地区发展草场承包经营责任制的必要性,以及实施草场承包经营责任制进程中存在的问题和所面临的困难,并提出了有利于进一步促进和完善该地区实施草场承包经营责任制的参考性建议。     

Grassland responses to grazing disturbance: plant diversity changes with grazing intensity in a desert steppe

This study quantifies the impact of four different grazing regimes (heavy, moderate, light and ungrazed) on the vegetation dynamics of rangeland ecosystems along the southern boundary area of the Mu Us Desert, China. As the grazing intensities decreased, the soil quality, canopy cover, height, density, above‐ and below‐ground biomass, litter, root/shoot ratio and native plant (Aneurolepidium dasystachys) and grass abundances significantly increased; the above‐ground biomass of grasses increased, but the above‐ground biomass of forbs decreased. Ungrazed grassland has significantly improved from grasslands experiencing three other levels of grazing pressure, especially in the grassland biomass. Species richness increased as the grazing intensity decreased in the grazing grasslands, but peak species richness appeared under moderate and light grazing against lower productivity. Grazing exclusion causes desirable transitions in plant communities of desert steppe rangelands. Therefore, appropriate and efficient grazing exclusion is an available way to counteract local grassland degradation and promote rangeland sustainability.