Analysis of Grassland Productivity and Carrying Capacity of Natural Warm-temperature Tussock in the Central Region of Guizhou Province

[Objective] This study aimed to investigate the influences of grazing and fencing on grassland productivity and carrying capacity of subtropical natural warmtemperature tussock. [Method] With the natural warm temperature tussock in Longli County of Guizhou Province as study area, monthly, seasonal and annual dynamics of grassland productivity were investigate continuously during 2010 -2012, and the data were analyzed. [Result] Under grazing and fencing conditions, grassland present biomass and forage growth of warm temperature tussock in Longli County of Guizhou Province both increased first and decreased, reaching the maximum from August to October. Fencing significantly improved the productivity of natural grassland but had little effect on the vegetation composition. [Conclusion] From the perspective of grass-livestock balance, the suitable stocking capacity of warm-temperature tussock in the central region of Guizhou Province was 3.45 -4.66 sheep/hm2 , which has high ecological efficiency and can be borne by farmers and herdsmen.

Effects of converting natural grasslands into planted grasslands on ecosystem respiration： a case study in Inner Mongolia, China

With increasingly intensifying degradation of natural grasslands and rapidly increasing demand of high quality forages, natural grasslands in China have been converted into planted grasslands at an unprecedented rate and the magnitude of the conversion in Inner Mongolia is among the national highest where the areal extent of planted grasslands ranks the second in China. Such land-use changes（i.e., converting natural grasslands into planted grasslands） can significantly affect carbon stocks and carbon emissions in grassland ecosystems. In this study, we analyzed the effects of converting natural grasslands into planted grasslands（including Medicago sativa, Elymus cylindricus, and M. sativa＋E. cylindricus） on ecosystem respiration（F（eco）） in Inner Mongolia of China. Diurnal F（eco） and its components（i.e., total soil respiration（F（ts））, soil heterotrophic respiration（F（sh）） and vegetation autotrophic respiration（F（va））） were measured in 2012（27 July to 5 August） and 2013（18 July to 25 July） in the natural and planted grasslands. Meteorological data, aboveground vegetation data and soil data were simultaneously collected to analyze the relationships between respiration fluxes and environmental factors in those grasslands. In 2012, the daily mean F（eco） in the M. sativa grassland was higher than that in the natural grassland, and the daily mean F（va） was higher in all planted grasslands（i.e., M. sativa, E. cylindricus, and M. sativa＋E. cylindricus） than in the natural grassland. In contrast, the daily mean F（ts） and F（sh） were lower in all planted grasslands than in the natural grassland. In 2013, the daily mean F（eco）, F（ts） and F（va） in all planted grasslands were higher than those in the natural grassland, and the daily mean F（sh） in the M. sativa＋E. cylindricus grassland was higher than that in the natural grassland. The two-year experimental results suggested that the conversion of natural grasslands into planted grasslands can generally increase the F（eco） and the increase in F（eco） is more pronounced when the plantation becomes more mature. The results also indicated that F（sh） contributed more to F（eco） in the natural grassland whereas F（va） contributed more to F（eco） in the planted grasslands. The regression analyses show that climate factors（air temperature and relative humidity） and soil properties（soil organic matter, soil temperature, and soil moisture） strongly affected respiration fluxes in all grasslands. However, our observation period was admittedly too short. To fully understand the effects of such land-use changes（i.e., converting natural grasslands into planted grasslands） on respiration fluxes, longer-term observations are badly needed.

Grasslands Response to Livestock Grazing Intensity in the Austral Pampas(Argentina):Testing the Intermediate Disturbance Hypothesis

Livestock grazing has a significant impact on natural grasslands,with approximately one-third of the world’s land area dedicated to this industry.Around 20%of global grasslands are highly degraded due to overgrazing,affecting their productivity and conservation capacity.Best practices are required to ensure sustainable livestock production that supports biodiversity.The Intermediate Disturbance Hypothesis(IDH)suggests that environments with moderate levels of disturbance exhibit a higher species diversity.Moderate grazing can reduce the dominance of certain species,thereby enhancing plant diversity.However,concerns arise regarding the increase of exotic and unpalatable species under moderate grazing levels,complicating grassland conservation efforts.The impact of livestock grazing on the functional structure of grasslands depends on factors such as grazing intensity,livestock species,and environmental conditions.Variations in grazing intensity may increase specific and functional diversity under moderate grazing,potentially masking the presence of invasive exotic species.In the Austral Pampas(Pampean phytogeographic province,Buenos Aires,Argentina),grasslands face various pressures from domestic livestock grazing that endanger their integrity if not properly managed.Therefore,our study aims to investigate potential differences in species richness and diversity,functional diversity,exotic plant abundance,and the number and distribution of plant functional groups across varying grazing intensities.The IDH is utilized as a tool to regulate livestock pressure for grassland conservation.Species and functional diversity indices were used to assess the impact of grazing on grassland diversity.Moderate grazing increased species and functional diversity,while intensively grazed or ungrazed areas showed reduced diversity.Livestock presence influenced the balance between native and exotic plants,with ungrazed areas having higher native plant abundance and grazed areas exhibiting higher exotic plant abundance.Grazing also influenced the composition of functional groups,with grazing-avoiding species being more prevalent in heavily grazed areas.Principal Component Analysis revealed a clear association between vegetation composition and livestock grazing intensity.These findings offer valuable insights into effectively managing grazing intensity for biodiversity conservation purposes.

Biomass of Natural Grassland under Different Enclosure Conditions

Taking natural grassland on the northern slope of the Qilian Mountain for example, this paper investigated and compared aboveground and belowground biomass of grassland in multi-year enclosure(20 years), one-year enclosure, control areas(natural grazing areas). The results showed that coverage and height of the enclosure sample plots were significantly higher than that of natural grazing area(P <0.05); mean aboveground biomass of grassland: multi-year enclosure(316.58 g/m^2) > one-year enclosure area(299.07 g/m^2) > multi-year enclosure control area(254.39 g/m^2) > one-year enclosure control area(187.37 g/m^2); belowground biomass: multi-year enclosure(2,906.90 g/m^2) > one-year enclosure area(2,587.26 g/m^2) > multi-year enclosure control area(2,378.93 g/m^2) > one-year enclosure control area(2,029.17 g/m^2); mean aboveground biomass of natural grassland was 263.60 g/m^2, mean belowground biomass 2,225.56 g/m^2; ratio of belowground biomass to aboveground biomass varied between 6.79 and 12.90, distribution of belowground biomass and aboveground biomass in each plot showed significant differences(P <0.05). Enclosure was favorable for improving the coverage and biomass of natural grassland plant communities in the Qilian Mountains.

Assessing the Effect of Farmers＇ Supplementation Strategy on Feed Intake and Liveweight of Goats Grazing Natural Range and Crop Fields of Zamfara Reserve in Semi-Arid Nigeria

This on-farm study was conducted in Zamfara reserve of north western Nigeria between July, 2002 and June, 2003 to assess feed intake and liveweight of 12 indigenous Red Sokoto castrated bucks, separated into two groups of six, supplemented and nonsupplemented respectively. The nonsupplemented group grazed natural pasture and crop stubble of crop fields, whereas the supplemented group grazed natural pasture, crop stubbles and received concentrate supplementation. Concentrate supplement （wheat offal） was fed at 1% of the metabolic weight of the animals which corresponds to the mean of the farmers offer. The total faecal collection method and grab samples of feed were used to estimate total intake of dry matter （DM）, organic matter （OM）, crude protein （CP） and metabolizable energy （ME）. Liveweight of the animal was recorded at five weekly intervals. Results of the study indicated that nutrients intake of supplemented animals were generally higher than those of the nonsupplemented group, but not significantly different （P 〉 0.05）. However, it was observed that supplementation significantly （P 〈 0.05） affected the liveweight of the supplemented bucks during early dry season in December, During this period feed became more available to the grazing animals from crop residues. It was therefore concluded that supplementation with wheat offal at 1% metabolic weight may not be enough to counteract weight loss of grazing goats during the other periods of dry season in this environment.

Forage Forest in Natural Grassland:Important Role and Development Recommendations

In order to increase the productivity of grassland animal husbandry,reduce natural disasters,curb grassland degradation and solve some problems of animal husbandry development in Inner Mongolia,we should actively develop feed shrubs.Forage forests can supplement the shortage of feed caused by seasonal difference and natural disasters in natural grasslands in winter and spring,solve the difficulties in storage and transportation of feed and shortage of funds,regulate the climate,improve the soil fertility,proof wind and fix sand,thereby promoting the benign cycle of grassland ecology.In the natural grasslands of Inner Mongolia,shrubs or small arbors such as Caragana microphylla,Caragana korshinskii Kom,Hedysarum scoparium Fisch et May,Hedysarum mongolicum Turcz,Lespedeza bicolor Turcz,Hippophae rhamnoides Linn,Ulmaceae macrocarpa Hance and Kochia prostrata(L.)Schrad can be used to create forage forests.Scientific research should be actively carried out on the harvesting and cutting period,planting scale,feeding methods and breeding of improved varieties of forage forests.

Effects of Grazing Exclusion on Soil Carbon and Nitrogen Storage in Semi-arid Grassland in Inner Mongolia, China

The semi-arid grasslands in Inner Mongolia, China have been degraded by long-term grazing. A series of ecological restoration strategies have been implemented to improve grassland service. However, little is known about the effect of these ecological restoration practices on soil carbon and nitrogen storage. In this study, characteristics of vegetation and soil properties under continued grazing and exclusion of livestock for six years due to a nationwide conservation program—′Returning Grazing Lands to Grasslands(RGLG)′ were examined in semi-arid Hulun Buir grassland in Inner Mongolia, China. The results show that removal of grazing for six years resulted in a significant recovery in vegetation with higher above and below-ground biomass, but a lower soil bulk density and pH value. After six years of grazing exclusion, soil organic C and total N storage increased by 13.9% and 17.1%, respectively, which could be partly explained by decreased loss and increased input of C and N to soil. The effects of grazing exclusion on soil C and N concentration and storage primarily occurred in the upper soil depths. The results indicate that removal of grazing pressure within the RGLG program was an effective restoration approach to control grassland degradation in this region. However, more comprehensive studies are needed to evaluate the effectiveness of the RGLG program and to improve the management strategies for grassland restoration in this area.

Long-term effects of mowing on plasticity and allometry of Leymus chinensis in a temperate semi-arid grassland,China

Mowing is an important land management practice for natural semi-arid regions. A growing body of empirical evidence shows that different mowing regimes affect the functioning of grassland ecosystems. However, the responses of plant functional traits to long-term mowing and their allometric scaling under long-term mowing are poorly understood. For a better understanding of the effects of mowing on grassland ecosystems, we analyzed the allometric traits of leaves and stems of Leymus chinensis （Trin.） Tzvel., a dominant grass species in eastern Eurasian temperate grassland, at different mowing intensities （no clipping, clipping once every two years, once a year and twice a year）. Experiments were conducted on plots established over a decade ago in a typical steppe of Xilinhot, Inner Mongolia, China. Results showed that most of the functional traits of L. chinensis decreased with the increased mowing intensity. The responses of leaves and stems to long-term mowing were asymmetric, in which leaf traits were more stable than stem traits. Also significant allometric relationships were found among most of the plant functional traits under the four mowing treatments. Sensitive traits of L. chinensis （e.g. leaf length and stem length） were primary indicators associated with aboveground biomass decline under high mowing intensity. In conclusion, the allometric growth of different functional traits of L. chinensis varies with different long-term mowing practices, which is likely to be a strategy used by the plant to adapt to the mowing disturbances.

Effects of spring fire and slope on the aboveground biomass, and organic C and N dynamics in a semi-arid grassland of northern China

The aboveground primary production is a major source of carbon(C) and nitrogen(N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass(AGB) and the soil C and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern China to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic C and total N contents in different plant functional groups(C_3 grasses, C_4 grasses, forbs, Artemisia frigida plants, total grasses and total plants).The dynamics of AGB and the contents of organic C and N in the plants were examined in the burned and unburned plots on different slope positions(upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of C_3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of C_4 grasses and A.frigida plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of C_3 grasses and total grasses in July, and the AGB of forbs and C_4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic C and N contents in the plants. The lower and upper slopes differed with respect to the organic C and N contents of C_3 grasses, C_4 grasses, total grasses, forbs, A. frigida plants and total plants in different growing months. Slope position and spring fire significantly interacted to affect the AGB and organic C and N contents of C_4 grasses and A. frigida plants. We observed the AGB and organic C and N contents in the plants in a temporal synchronized pattern. Spring fire affected the functional AGB on different slope positions, likely by altering the organic C and N contents and, therefore,it is an important process for C and N cycling in the semi-arid natural grasslands. The findings of this study would facilitate the simulation of ecosystem C and N cycling in the semi-arid grasslands in northern China.

Simulation of soil erosion dynamics in grassland ecosystem of semi-arid China using the CENTURY model

Soil erosion can cause considerable effect on global natural resources and eco-environment. In the paper, the CENTURY model has been used to simulate soil erosion in Xilin Gol Grassland of Inner Mongolia. The results showed before the 1960s, the soil erosion amount was over 2 kg /m2.a in grassland ecosystem in the study area because no trees had been planted. But after the 1960s the mean annual accumulator C lost from soil organic matter due to soil erosion was only 0.3 kg /m2.a in forest ecosystem. So afforestation has exerted notable effect on decreasing soil erosion amount in Xilin Gol Grassland.

How to Build Artificial Grassland in the Cold and Semi-Arid Regions? ——A Case Study in Naqu

Construction of artificial grassland is a key factor to solve the shortage of grass and forage balance in cold and semi-arid areas of high plateau,and it is the key measure to ensure the sustainable development of grassland animal husbandry in this area. At present,the artificial grassland construction is neither reasonable nor scientific,which restricts the healthy and rapid development of artificial grassland in the cold and semi-arid areas of high plateau. In this research,with Naqu Area in Tibet as a case,problems and current status in construction process of artificial grassland are analyzed in cold and semi-arid areas of high plateau. Suitable artificial forage species in Nagqu are elaborated,and recommendations for the construction and development of artificial grassland are discussed.

近20年北方草原生态价值核算及其时空差异特征

草原是我国重要的陆地生态系统和自然资源,具有多元生态服务,探索草原生态价值核算方法对于草原保护修复与可持续管理具有重要意义,但当前草原生态价值尚未形成公认的评估框架和准确的核算方法。定位于北方草原,以内蒙古天然草原为典型案例区,提出了“支持-供给-调节-文化”服务价值四类共计19项的草原生态价值评估体系,基于地面采样、野外观测、遥感解译、模型模拟和统计等多源数据,在像元尺度上核算了2000—2020年草原生态价值并分析其空间分异特征和动态演变规律。结果表明:近20年来内蒙古草原生态价值多年均值为17640.60亿元/a,约为自治区同期国内生产总值(GDP)(8607.23亿元/a)的2.05倍,每公顷草原提供的生态价值为2.34万元/hm^(2),总体呈现“东北高—西南低”的空间分布格局特征。其中,草原调节服务价值最高,多年均值6676.44亿元/a,占比53.68%;其次为草原支持服务价值,多年均值为6293.96亿元/a,占比35.13%;草原供给和文化服务价值多年均值分别为3796.27亿元/a(6.24%)和873.93亿元/a(4.95%)。从具体指标来看,防风固沙价值量最高(5858.86亿元/a和33.21%);从各地区来看,锡林郭勒盟草原生态价值最高(4701.81亿元/a和26.65%)。20年间,草原生态价值呈显著增加趋势(439.45亿元/a,P<0.05),其中以草原文化服务价值增加最为明显。本方法和案例可为量化草原生态价值提供参考范式,并有助于生态产品价值实现机制的建立,推动草原侵占用等生态补偿方案的优化。

高寒沙化草地自然演替恢复下土壤有机碳矿化及其温度敏感性研究

青藏高原东缘草地沙化态势严重,开展草地沙化退化与自然恢复土壤有机碳矿化及其温度敏感性(Temperature Sensitivity,Q_(10))对比研究,可为草原碳库管理提供理论支撑。本试验在若尔盖县分别选取典型沙化草地和长期自然恢复(10年)沙化草地,采集表层0~10 cm和底层20~30 cm土壤样品带回室内进行控温(5℃,15℃和25℃)矿化培养实验。结果表明:与沙化草地相比,自然恢复途径下土壤有机碳(Soil organic carbon,SOC)的矿化速率降低了40%,土壤有机碳储量提高了2.23~2.57倍,SOC分解的温度敏感性由0.55~1.57增加到0.80~2.73,且底层土壤Q_(10)显著高于表层土壤。两种草地土壤有机碳累积矿化量与土壤初始SOC含量呈极显著的负相关关系,且底层土壤SOC矿化速率均显著高于表层土壤。未来气候变暖影响下自然恢复沙化地底层SOC矿化分解成为碳源的风险更高,应重点加强其草地深层土壤碳库的管理和调控措施。

宁夏天然草地有机碳固存现状及提升策略

阐述了宁夏天然草地有机碳储量的固存现状,分析了天然草地碳储量分布特征、影响因素,从加强现有草地资源管护、开展退化草地修复、探索草地固碳潜能提升的技术措施、完善草原碳汇计量监测体系及草原碳汇核算机制方面提出减少草地有机碳损失等有利于碳固存的草地管理建议,以服务黄河流域生态保护和高质量发展先行区建设。

草地生态系统保护、修复与功能提升的关键科学问题

草地占我国国土面积的27.6%,在保障我国生态安全中发挥着重要作用。本文梳理了我国从单一追求草地资源的物质生产功能,到生产和生态兼顾,再到目前的生态优先、多功能目标管理的发展历程,分析了草地保护与修复政策施力点及其在遏制草地退化中的作用,分析了我国草地修复过程中的乡土草种质资源、土壤养分和土壤微生物等制约因素,介绍了依靠自然过程,将退化草地恢复到生物多样性、稳定性与地带性群落接近的草地近自然恢复理念与途径;凝练了我国草地保护和修复亟需解决的关键科学问题。建议在新时代草地保护与修复政策的保障下,尊重自然、顺应自然、践行近自然恢复理念,引领新时代由植被到生态系统的草地保护与修复工作。

新疆天然草原分类系统调整合并的探讨

【目的】草地类型的划分是草地经营管理中的基础性工作,是人们有效保护、科学开发、合理利用和培育草地的理论基础。为了简化原有繁杂的分类系统,紧紧围绕林业、草原和国家公园“三位一体”融合发展的总体要求,着眼新疆草地资源特点,统筹推进“山水林田湖草沙”系统治理,提出新的草地分类系统和标准势在必行。【方法】本文参照2016年农业部《草地分类》行业标准,结合现阶段林草融合机制与草原生态修复治理的需求,草地类的名称与全国草地分类系统及农业部《草地分类》行业标准保持基本一致,并与国土三调土地分类标准相协调,取消亚类和组的分类;型的命名减少优势种数量的原则进行归并;面积小于平均值、仅分布局部地区、代表性不强的型归并到临近草地型或者删除;具有地方特色植物种类组成的特有型保留。【结果】新疆原天然草地分类系统的11类687个型,调整归并为9类106个型。【结论】新疆原天然草地分类系统及草地资源资料是30多年前形成的,之后未系统地开展全疆草地调查,实际的草地类、型或分布范围可能已经发生了一些变化。本分类系统具有较强的实用性和可操作性,为推动草地资源本底数据的更新和数字化管理提供技术依据。

宁夏天然草地土壤有机碳分布格局及驱动因素

【目的】草地作为重要的土壤碳库,探究其有机碳的分布格局及影响因素对缓解温室效应、草地生态系统评价以及退化草地生态恢复具有重要意义。【方法】以宁夏3种类型天然草地(草甸草原、典型草原、荒漠草原)为研究对象,在195个样地测定0~20 cm和20~40 cm土层土壤有机碳(Soil Organic Carbon,SOC)含量,利用分段结构方程模型(Segmented structural equation model)揭示土壤SOC含量与地理、气候、植被、和土壤因子的关系。【结果】在水平方向上0~20 cm和20~40 cm土层SOC平均含量分别为9.46和8.25 g/kg,草甸草原>典型草原>荒漠草原;在垂直剖面上SOC平均含量随土层深度增加而减少;由南到北呈递减的变化趋势。分段结构方程表明:在0~20和20~40 cm土层中SOC含量与TN、TP和丰富度指数呈极显著正相关(P<0.01),与pH值和年均温(MAT)呈极显著负相关(P<0.01),与年降水量(MAP)没有显著关系。0~20 cm土层中,总效应由大到小依次为:气候因子(0.38)>土壤因子(0.21)>丰富度指数(0.12)。20-40 cm土层中,总效应由大到小依次为土壤因子(0.39)>气候因子(0.23)>丰富度指数(0.13)。【结论】分段结构方程结果显示雨热条件是影响表层土壤SOC含量的主要因子,TN和TP是影响深层土壤SOC含量的主要因子。

保水剂在牧草生产和草地沙化治理中的应用现状与前景

保水剂是一类具有快速吸水,缓慢释水特性的高分子聚合物,在传统农业生产中应用较多,但在牧草生产、天然草地恢复及生态建设等方面的研究报道较少。通过对国内外保水剂相关研究的分析,阐明保水剂的作用机制、保水剂在牧草生产及沙化治理中的作用效果和应用前景,旨为保水剂在牧草生产与生态建设中的应用提供参考。

海拔梯度对两河源自然保护区草地群落组成及多样性影响

【目的】为探讨随海拔增加,草地群落的数量特征如何变化以及物种多样性指数受海拔的影响程度。【方法】对两河源自然保护区海拔1500~2500 m的区域运用Margalef指数、Simpson指数、Shannon-Wiener指数和Alatalo指数进行分析。【结果】两河源自然保护区共有草类植物123种,隶属于43科101属,冰草(Agropyron cristatum)、蒲公英(Taraxacum mongolicum)和草原老鹳草(Geranium pratense)是本区域的优势种。草地植物的数量结构随海拔梯度的增加表现为先下降后升高再下降再升高趋势,海拔梯度与多样性各指数均表现为极显著相关(P<0.01),其中Margalef指数、Simpson指数、Shannon-Wiener指数均表现为随海拔升高而增加,但Alatalo指数随海拔升高而降低。【结论】随海拔梯度升高,草地群落数量结构及特征呈波动趋势且海拔梯度变化对群落多样性影响较大,其中菊科、茜草科、蔷薇科、紫草科草类植物宜作为生态恢复与草地重建的首选种。

云南山地牧业草地资源特点与利用

[目的]研究滇东北草地资源的现状和特点,为该区域草地生态建设提供依据。[方法]采用线路踏查和样方调查相结合的方式,对研究区物种构成、植被高度、生物量及饲用等级等项目进行调查分析。[结果]研究区共有植物50科136属162种(不含3个待定种),其中饲用植物21科98种,饲用等级优等的植物23种(23.47%),良等19种(19.39%)。研究区3种类型人工草地豆禾比例严重失调,野艾蒿入侵严重,存在退化现象。研究区人工草地鲜草产量(29.23 t/hm^(2))和可食草产量(25.21 t/hm^(2))分别比天然草地(7.95 t/hm^(2)、5.28 t/hm^(2))提高了2.68和3.84倍,产量显著提高。[结论]建议加强对人工草地的管理、利用及恶性杂草的防控,以实现草地资源的可持续利用。