Fusarium oxysporum is one serious soil-borne pathogenic fungus and is listed as one of the top ten plant fungal pathogens in the world. This fungus can infect more than 100 economically important crops such as cotton,soybean,watermelon,banana,tomato and alfalfa,causing wilt and root rot. The detection and quantification of F. oxysporum in soil and plant root tissues is the basis for early diagnosis and effective control of the disease. This article summarizes the research progress and application of F. oxysporum detection and quantification methods at domestic and overseas,mainly including medium colony plate dilution method,conventional PCR and real-time fluorescent quantitative PCR,etc. This review provides theoretical guidance for F. oxysporum detection and quantification in agriculture.

Grassland accounts for about 40% of the total land area in China,but the long-term excessive resource utilization by farmers and herdsmen results into large-scale grassland degradation,as output and input of grassland ecosystem in terms of energy flow and material circulation are out of balance. Since the 18th National Congress of the Communist Party of China,great efforts of grassland protection and restoration have been continuously made,and therefore the deterioration of grassland ecology has been preliminarily prevented. The construction of perennial mixed sowing artificial grassland is an important measure for animal husbandry development and ecological restoration of degraded grassland,and has great strategic significance for the sustainable development of grassland ecosystem and the construction of ecological civilization. In this paper,we reviewed the progress of the relevant researches in the recent 20 years,and put forward a theory of Quasi-stable state for the mixed sowing artificial grassland. We define the contents and significance of Quasi-stable state,and construct a technological system to maintain the Quasi-stable state in perennial mixed-sowing artificial grassland. This work provides guidance for the healthy and sustainable development of animal husbandry and ecological restoration in China.

Forage is of the indispensable importance to herbivores. The strategy of utmost spurring the development of the high-quality forage industry can be adopted by the measures of expansion of the forage sources,increment of the forage yields and extension of the animal products application in the line of the vital technical approaches such as,increasing grain production with the exploring of forage,saving grain supply with the exploring of forage,and replacing grain supply with the exploring of forage. In this way,we can achieve the conversion of forage into grain,and make an important contribution to enhance the level of national food security and comprehensively consolidating the foundation of food security.

Soil microorganisms are sensitive factors of soil ecological environment changes, and their community composition and structure are easily affected by human disturbance. This study compared the differences in soil microbial community composition and structure under different utilization methods such as enclosure, mowing, continuous grazing, and rest grazing in Hulunbuir grassland in Inner Mongolia, combined with changes in soil physical and chemical properties to clarify the main factors affecting soil microbial communities, and explored the grassland utilization method which was conducive to the soil micro-ecological environment. The results showed that:(1) The total amount of PLFA in the soil under the no-grazing treatment during the growing season was higher than that of other utilization methods. With the delay of the no-grazing time, the number of soil microorganisms showed an upward trend;(2) The ratio of gram-positive bacteria/gram-negative bacteria was the largest, indicating that continuous grazing reduced the nutrient supply capacity of soil substrates and affected the growth of microorganisms;(3) Redundant analysis of soil physical and chemical properties and microorganisms showed that soil pH and electrical conductivity were the main factors affecting the structure of soil microbial community. High conductivity and alkaline soil was more conducive to the survival of soil microbes. Therefore, soil salinity and pH could be used as key predictors for the structure and function of soil microbial community in Hulunbuir grassland.

Grassland is an important ecosystem and a natural ecological security barrier in the north of China with its important ecological and production values. In recent years, due to the unreasonable use of grasslands and abnormal changes in climate, grassland pests have been aggravated year by year, which seriously restricted the livestock production and ecological civilization construction in China. Based on historical data, this article summarized the characteristics of China grassland pests with many types, strong damages, and heavy losses, analyzed the staged effects of prevention and control, and objectively pointed out the current prevention and control work's lack of monitoring capabilities, funding, equipment, scientific research support, and lagging policies and regulations, and other major issues. It then systematically put forward working goals and specific measures for strengthening grassland pest control in terms of rationalizing management systems, strengthening system construction, improving monitoring and early warning levels, innovating control mechanisms and technologies, and increasing publicity and training efforts, which provide ideas for the next step in grassland biological disaster prevention and control.

Oat ( Avena sativa L.) is one of the main sources of roughage for ruminants,and it is beneficial to rumen health and production performance of cows because of it is rich in carbohydrates. Silage is one of the main forms of safe storage of oat,which has the advantages of good palatability and high digestibility. As for oat silage,predecessors have carried out a lot of researches,mainly focusing on the moisture,harvest period,additives,mixing and feeding of oat silage. Based on these,this paper summarized the researches on oat silage. The constraints affecting the fermentation and nutritional quality and the utilization value of oat silage were summarized,which would promote the concoction and utilization of high-quality oat silage.

The policy of subsidy and reward for grassland ecological protection(PSRGEP) aims to maintain the grassland ecological function and promote the herdsmen’s income,which is one of the important actions of grassland ecological compensation in China. In accordance with the main idea of the policy,this article made an overall effect evaluation of the current situation of China’s PSRGEP while combing the existing policy effect evaluation research. The results showed that the current PSRGEP in China still has problems such as the lack of institutional system and low compensation standards. There are regional differences in the degree of satisfaction of herders with the policy. Although the compensation funds have increased herders’ income to a certain extent,it has limited effect on motivating herders to reduce livestock. Since 2010,the overall ecological quality of grassland in China has improved,but the effect in some areas makes no sense. Future research can appropriately focus on the economic benefits of the restoration of grassland ecological functions. These research should cover a wider range of policy pilot areas on the existing basis,and ascertain the baseline values of herdsmen’s livelihoods and grassland ecology before the policy was initiated.

Based on the multi-source remote sensing,meteorological and social statistical data,the evaluation system of grassland ecosystem service value was constructed to evaluate the ecosystem service value of China's grassland ecosystem from 2000 to 2016,including organic matter production,nutrient cycling,soil conservation,carbon fixation and oxygen release,and water conservation. The results showed that:during the study period,the average total value of grassland ecosystem services in China was 1381.565 billion yuan·a ^-1,and the average total value per unit area was 412 400 yuan·km ^-2·a ^-1. The proportion of water conservation value of grassland was higher (28.95%),but the nutrient cycling value was lower (9.98%). The high value areas of grassland ecological value were concentrated in Yunnan,Guangxi and Western Sichuan. The total value of ecological services of Alpine subalpine meadow was the highest (415.688 billion yuan · a ^-1),while that of plain grassland and slope grassland was the lowest (138.861 billion yuan · a ^-1 and 144.998 billion yuan · a ^-1). The most prominent value of water conservation was observed in Ningxia,Inner Mongolia,Shaanxi,Tibet and Yunnan,while the most prominent value of organic matter production was mainly found in Qinghai,Gansu and Shanxi. The value of grassland ecological services showed a significant increasing trend during the 17 years ( P=0.01;2 200 yuan·km ^-2). The value of grassland ecosystem services increased in 54.69% of the areas,mainly in the south of Qinghai Province and its border with Tibet.

To examine the effects of different grazing intensities on interspecific association and species niches,we performed three grazing intensities,e.g.non-grazing (CK),moderate grazing (MG) and heavy grazing (HG). We used the method of “Levins” to calculate plant species niche characters,and used variance ratio ( VR) to analyze all interspecific associations on the plant community. Finally,we calculated the species association coefficient ( AC),Ochiai index ( OI) on dominant plant species and used the Chi-square test to detect the significance of the interspecific association. The results showed that CK and MG had enhanced the niche width of dominant plant species,but HG decreased the niche width of dominant plant species. According to the Chi-square test,53.3%,52.4%,and 50.5% of the 15 dominant plant species showed negative association under the three treatments,respectively. The species association coefficient showed that Pennisetum centrasiaticum negatively associated with Kobresia pygmaea and Carex atrofusca under the three treatments,it indicated that P. centrasiaticum had a strong competition on resources with them. The result of OI value showed that interspecific association was decreased with the increased grazing intensity,and the OI value of HG was lowest among three treatments indicating that the interspecific relationship was looser under the heavy grazing condition. In conclusion,HG altered grassland plant species niche width and overlapping value in the plant community,and modified the plant interspecific association in friable condition,the plant community is in an unstable state.

NAC transcription factor has many functions such as regulating plant growth and abiotic stress. In order to screen NAC transcription factors related to drought resistance in Agropyron mongolicum Keng,the structure,physical and chemical properties,evolutionary relationship and conservation of NAC transcription factors in Agropyron mongolicum Keng were analyzed by bioinformatics based on transcriptome sequencing data. Then,the differential expression of two NAC genes related to drought resistance was analyzed by qRT-PCR. The results showed that 26 NAC family members were screened out from Agropyron mongolicum Keng,15 of them had complete NAC transcription factor domains,and most of them were located in the nucleus. The protein phosphorylation sites of 15 NAC transcription factors from Agropyron mongolicum Keng contain serine,threonine and tyrosine. Phylogenetic comparison showed that AmNAC100 and AmNAC102-2 proteins had high homology with NAC proteins with known drought resistance function and their secondary and tertiary structures were mainly random coil. Two NAC proteins contain motif 1,2,3,and motif 8,and they contain subdomains A-E of conservative domain. Differential expression analysis showed that the relative expression of AmNAC100 and AmNAC102-2 genes were higher than CK,indicating that they played positive regulatory roles in Agropyron mongolicum Keng drought stress.

Thesium chinense Turcz.,known as “plant antibiotic”,is an important Chinese herbal medicine plant for its purgative and detoxifying effects in China. Based on the characteristics of semi-parasitism,seed deep dormancy,short growth cycle,long dormancy period and low reproductive efficiency,this review summarized the research progress on the parasitic biology,growth of live plants,tissue culture and rapid propagation,cultivation of Thesium chinense Turcz. The main factors limiting the artificial cultivation of Thesium chinense Turcz. are climate,soil type,seed germination and the amount of nutrient accumulation in the roots of the plant,etc.,thus the corresponding cultivation methods are proposed. It would provide some valuable information for the future studies on the tissue culture reproduction,cultivation and utilization of Thesium chinense Turcz.

In this study,48 accessions of 14 species of Vicia were studied,17 seed phenotypic traits were used to reveal the genetic diversity of Vicia phenotypic traits,and to classify and identify them. The results showed that the phenotypic traits of seed had great variation among species,the coefficient of variation of hundred-grain weight in quantitative traits was the largest,which was 81.92%,and the Shannon diversity information index of the seed form index was the largest,which was 1.94. Among the quality traits,the umbilical color had the largest variation coefficient,which was 75.12%,and its Shannon diversity information index was also the largest,which was 1.56. The results of principal component analysis showed that the cumulative contribution rate of the first six principal components was 86.09%. The correlation analysis between quantitative traits showed that seed length,seed width,seed thickness and hundred-grain weight were extremely significantly positively correlated with each other ( P<0.01),and they were also positively correlated with radicle length and umbilical length. The cluster analysis divided the 14 species of Vicia into five groups. According to the analysis of the phenotypic shape of Vicia,hundred-grain weight,hilum color,testa color,testa texture,hilum-seed ratio,cotyledon color,radicle base markings,hilum shape,radicle width/radicle length can be used as the basis for the classification and identification of the 14 species of Vicia,and the classification key can provide a basis for the identification of the Vicia.

The high-quality forage is the basis of the healthy development of modern animal husbandry, which requires scientific control of planting, field management, harvesting, and processing. Drying is a key link in the post-harvest processing of forage, which significantly affects the quality of forage. To provide reference and technical support for the development of China's forage post-production processing industry, this paper summarizes the technology of forage harvesting and drying, and reviews and analyses the research advances of forage drying characteristics and drying equipment under the main drying methods in China and other countries. The main drying methods of forage grass include natural drying, hot air drying, high-temperature-fast-drying, solar drying, etc. In recent years, domestic scholars have studied the drying characteristics of forage grass under different drying methods. The domestic forage drying technology has been gradually improved, but it still lags behind the mechanized production technology of forage drying in foreign countries. There are problems of domestic forage drying technology, such as the mismatch between harvest and drying process, the lack of design standards for drying equipment, and small enterprise scale. Thus, the development direction of our country's forage mechanized drying processing industry is to formulate standardized forage drying processing technology, strengthen the research of forage drying technology, realize intelligent and integrated forage drying equipment.

Grassland is the largest terrestrial ecosystem. It is not only an important ecological security barrier for China,but also a home for farmers and herdsmen. In order to thoroughly implement Xi Jinping's thought on ecological civilization,implement the concept of a holistic approach to the conservation of mountain,river,forest,farmland,lake,grassland,and desert ecosystems,and promote grassland conservation,restoration and efficient utilization,combining with the "14th Five-Year" forestry and grassland protection and development plan outline,this research proposes the establishment of grassland governance systems, including grassland monitoring and evaluation system,grassland protection system,grassland ecological restoration system,grassland law enforcement and supervision system,modern grass industry system,and supportive guarantee system.The purpose of this article is to provide references for promoting the modernization of grassland governance systems and governance capabilities.

Grassland rodent pests seriously threaten the healthy and sustainable development of grassland in China,therefore,China had done a lot of work with grassland rodent research,and published many papers. This study used bibliometrics to count the numbers and citations of the grassland rodent pests papers included in the WOS (Web of Science) and CNKI (China National Knowledge Infrastructure) databases from 1977 to 2021,and this study also used the CiteSpace software to analyze the research strength and research hotspots of these papers. This study showed that there were 1 140 papers about grassland rodent pests during the period 1997—2021,in which CNKI had published 584 papers and WOS had published 556 papers,in addition,this study showed that the number of the papers increased year by year. The results of the research hotspot showed that the main research forces were the Chinese Academy of Sciences and Lanzhou University,and there was no close connection between different research institutions and different authors in the research forces. Meanwhile,the results of the research hotspot also showed that the main research object was plateau pikas and plateau zokors,the main research location was Qinghai-Tibet Plateau and alpine meadows,and the main research content related to population density,diversity,and soil organic carbon.

Melatonin is a small molecule indolamine hormone that widely exists in plants,and the studies have already clarified its synthetic pathway,catabolism and physiological functions. Melatonin can act as a signaling molecule to regulate plant circadian rhythms,seed germination,root and flower development,and also help to enhance the resistance of plants to various stresses. In this paper,the physiological functions of melatonin in regulating growth and development of herbaceous plants were summarized up,and its regulatory effects in response to abiotic and biotic stresses were particularly focused on. Additionally,functional study on melatonin in growth,development and stress resistance,as well as its application in stress resistance breeding in forage species were prospected. This review is expected to provide insight into improving the stress resistance,yield and quality enhancement of forage plants by using melatonin.

The monitoring of grassland aboveground biomass is an important basis for the rational utilization of grassland resources and understanding of the grassland ecological succession process.However,real-time observation of grassland aboveground biomass requires a lot of manpower and material resources,so it is urgent to use remote sensing,mathematics,and other indirect observation methods.This review systematically concluded the domestic and foreign methods of grassland aboveground biomass estimation including statistical models and mechanism models such as grassland growth models,crop growth models,light use efficiency models,and ecological process models for grassland aboveground biomass estimation.We summarized the characteristics and applicable conditions of the current models,and the relevant scientific concepts and strategies in researches.By reviewing researches on agricultural remote sensing data assimilation meeting the realistic requirements of grassland yield estimation,this review presents a less popular approach of estimating grassland yield based on the remote sensing data assimilation method,which provides a large-scale and high-precision way on grassland growth simulation.

Low temperature and drought are two abiotic stress factors that limit growth,development and yield of forage grass. Understanding the stress resistance mechanisms and breeding forage grass with strong cold and drought resistance is an important basis for the high-quality development of animal husbandry and the restoration of degraded grassland ecosystems in the cold and arid regions. At the morphological level,forage grass can form a variety of stress-resistant morphological structures under low temperature and drought stresses,and the changes of these morphological structures can reflect the response ability and adaptability of forage grass to adversity. At the physiological and biochemical level,forage grass can respond and adapt to low temperature and drought stresses by regulating superoxide dismutase,peroxidase,catalase,free proline,soluble sugar,soluble protein,abscisic acid,ethylene,gibberellin and cytokinin. At the molecular level,forage grasses adapt to cold and drought stresses through a combination of signaling transduction,response and resistance gene expression. In conclusion,this study reviewed the response and adaptive mechanisms of forage to low temperature and drought stresses from the levels of forage morphology,physiology and biochemistry and molecular level to provide an important reference for a comprehensive understanding of the stress resistant mechanisms of forage grass.

To investigate the characteristics of plant root pull-out resistance of alpine grassland in the source region of the Yellow River,six dominant grass species were selected from the alpine grassland in the source region of the Yellow River in Henan County,Qinghai Province. Through in-situ pull-out test,single root tensile test and root-soil composite system direct shear test,the root pull-out resistance characteristics of six grasses were analyzed. The comprehensive effects of root diameter,root number,root length,soil density,moisture content,compactness,root content,single root tensile strength and cohesion of root-soil composite system on pull-out resistance were investigated. The results showed that:the root pull-out resistance of Kobresia humilis K. was the highest (46.50 N),followed by Kobresia pygmaea C. B. Clarke. (37.50 N), Poa crymophila Keng. was the smallest (16.45 N). There was a significant positive correlation between root diameter,root number,root length and root pull-out resistance,with correlation coefficients ( R) of 0.881,0.727,and 0.969,respectively. There was a positive correlation between soil density,soil compactness,root content,cohesion of root-soil composite system and root pull-out resistance,and a negative correlation between moisture content and root pull-out resistance. The results of this study provide theoretical guidance for exploring the mechanical mechanism of alpine grassland degradation in the source region of the Yellow River,and provide theoretical basis and practical guidance for effectively preventing and controlling of grassland degradation,soil erosion and other shallow surface disasters in the region.

Facing the increasing risk of ecological degradation, it is urgent to establish a standardized framework of remote-sensing image interpretation to conduct grassland investigation and management. This study summarized the history of grassland resource investigation and analyzed the development of investigation technology in China through literature collection and historical data collation. Taking advantage of spectral endmember space, the correlation and scale effect among grassland resource typology, investigation, and management were established. We also proposed an interpretation framework of spectral endmember space based on a multiscale fusion strategy for grassland and made a suggestion of a sharing platform of grassland systematic knowledge, which would provide a support for the researches of management and other practices of grassland resources.

In order to explore the estimation method and driving factors of carbon storage in the Tibetan Plateau, carbon storage was estimated according to the measured data on basis of InVEST model, and then the driving forces were analyzed via structural equation model including meteorological and soil factors. The results showed that the overall carbon density in the Tibetan Plateau tended to be high in the southeast but low in the northwest. Furthermore, the carbon storage of alpine Kobresia and weedy meadow was the largest, reaching to 1.97×10 ¹¹ Mg. The aboveground carbon density was most sensitive to the change of total carbon density, with a slope of 44.73. Besides, precipitation, pH, cation exchange, organic matter, total nitrogen and available nitrogen were the important driving factors of carbon density in the Tibetan Plateau. The results can provide a scientific basis for the carbon pool management and human activities regulation of alpine ecosystem.

Species diversity and biomass are two important indicators to characterize the quantitative characteristics of grassland ecosystem. The changes of species diversity and biomass are discussed in depth to provide a theoretical basis for species protection and productivity maintenance of grassland ecosystem. In this paper, taking Xilingol grassland as the research object, the vegetation characteristics of meadow steppe, typical steppe and desert steppe were investigated by sample method. The changes of above-ground biomass and species diversity of different steppe types and the relationship between them and environmental factors were analyzed. The results showed that the above-ground biomass was significantly positively correlated with community coverage, community height and plant density, except that the community density was the highest in typical steppe, and the characteristics of each community were meadow steppe>typical steppe>desert steppe ( P < 0.05). The diversity and richness of plant species increased from desert steppe to typical steppe and then to meadow steppe, and the evenness of species distribution was the highest in desert steppe. Soil nutrients and precipitation had great influence on plant growth. Precipitation and altitude had great influence on species diversity and richness, and evenness was mainly affected by altitude, soil pH and climate.

Samples of frozen-thaw patch and the area between the grass patches in different degraded alpine wetlands were taken from Maqin Dawutan in the source zone of the Yellow River. The soil humus and its relationship with soil factors in the samples were determined. The results showed that the soil humus of the frozen-thawing patch and the grass patches decreased with the intensification of the degree of degradation of the alpine marshland. There was a significant difference between the humus carbon,humin and humic acid of the frozen-thaw patch in undegraded wetland and those in the light and heavy degradations ( P<0.05). It is more sensitive to the degradation than that of between patches. The contents of humus carbon,humic acid,fulvic acid and humin in the frozen-thaw patch and in the areas among the grass patches were all significantly positively correlated with soil water content and total nitrogen ( P<0.05). The frozen-thaw patch had a significant negative correlation between the humus components of mound soil and soil bulk density ( P<0.01). The cellobiohydrolase (CBH), β-1,4-xylosidase (BXYL), α-1,4-glucosidase ( αG), β-1,4-glucosidase (BG),leucine peptidase (LAP), β-1,4-N-acetylglucosaminidase (NAG) and urease (UR) for humin and the formation of humic acid had a significant promoting effect in the frozen-thawing patch,and the enzyme activity and microbial biomass between the grass patches had a significant promoting effect on the formation of soil humus. In summary,the degradation of alpine marshland leads to the reduction of soil humus,and the supplement of soil moisture and organic fertilizer should be strengthened in the restoration of alpine marshland in the source zone of the Yellow River.

Nitrogen (N) addition experiment is one of the effective measures for assessing the effects of N deposition on terrestrial ecosystems. Though hundreds of N addition experiments have been conducted during the last decades,the differences of methods could cause large uncertainty for the comparison among the study results and global meta-analysis. Thus,we collected 302 N addition experiments in terrestrial ecosystems and performed a global analysis of their methods. Our results showed that only 8% of N addition experiments were conducted in tundra,wetland and desert ecosystems. Experiments implemented below the N rate of 2 g N·m ^-2·a ^-1 made up 4.4% and 17.5% for those solely using NH ⁺ ₄ or NO ^- ₃ form fertilizer. 13.6% for experimental duration above 20 years,and 5.1% for those with more than 4 levels of N addition. Based on these results,we presented some suggestions for the design and the methodoly of future N addition experiments.

The type and quantity of silage microbes play an important role in the whole fermentation of silage. Exploring and utilizing of silage beneficial microbes has become an important research direction to improve the fermentation quality. The microbial species in the different types of mixed silage are quite different,which makes the fermentation characteristics diverse. The succession process and community structure of fermenting microbes often determine the fermentation quality. Monitoring the dynamic changes of the composition of microbial flora can provide a theoretical basis for regulating the fermentation of silage. In this paper,the succession process of silage microbial community,the microbial diversity of different mixed silage types,and the factors affecting microbial diversity of mixed silage were reviewed. At the same time,the problems of antibacterial activity of lactic acid bacteria,the promotion of mixed silage and the performance of mixed silage on animal production are pointed out and the prospects were put forward,which could provide reference and new ideas for the practical application of silage microbes.

In order to investigate the effects of Biological soli crusts (BSCs) on soil nutrients and enzyme activities in grassland and desert ecosystems, 11 characters from 30 Chinese and English literatures were selected for meta-analysis. Subgroup analysis was conducted to identify the effects of different types of the BSCs on soil nutrients and enzyme activities in grassland ecosystem and desert ecosystem separately, and soil nutrient recovery index (NRI) and random forest analysis were used to evaluate those effects. The results showed that the effect of BSCs on NRI in desert ecosystem was greater than that in grassland ecosystem, and the effect of the lichen crust >mixed crust >moss crust >algal crust in desert ecosystem. Moreover, through random forest analysis and fitting regression analysis on annual mean rainfall (MAP) and annual mean temperature (MAT), it was found out that the contribution of phosphatase, urease and invertase to NRI was significantly higher than that of other selected characters, further the phosphatase and MAP, and invertase and MAT were significantly positively correlated, while the urease and MAP, the phosphatase and MAT negatively correlated with each other. In the coming studies, it is possible to match desert ecosystem and grassland ecosystem with different types of the BSCs, so as to make more effective usage of BSCs to prevent the land degradation and desertification.

In order to assess the influence of grazing intensity to grassland actual and potential carbon sequestration, this study coupled pool-flux model with CASA light-efficiency model, Shiyomi grazing model, Raich soil respiration model, etc., establishing the annual sample-scaled coupled human and natural carbon cycle model within the systematic dynamic modeling framework, which involved three sub-systems and four carbon pools. Results showed that under the background of ‘cooling and wetting’ trends in Xilingol County, Inner Mongolia, the NPP showed a trend of increasing;and the annual NEP of typical grassland showed a trend of decreasing. The productivity was the lowest and potential carbon sequestration was the highest under the grazing intensity of 3 sheep·ha ^-1, which was -16.2 gC·m ^-2 and 24.84TgC, respectively. Thus we suggested that the grazing intensity in the western typical grassland of Xilin Gol (Nambaolige station, League) in Inner Mongolia should not exceed 1.5 sheep·ha ^-1, and the grazing intensity in the eastern typical grassland (Duolun County, East Ujumchin, West Ujumchin, Xilinhot) should not exceed 4.5 sheep·ha ^-1.

In this study,3 annual forage grasses ( Avena sativa L., Vicia sativa L., Zea mays L.) and 4 main crops ( Avena chinensis Metzg., Triticum aestivum L., Sesamum indicum L., Solanum tuberosum L.) were planted in Chabei Precinct of Hebei Province,the differences in water use efficiency between annual forage grasses and crops were compared through planting experiments. Conclusions were as follows:The yield of annual forage grass is higher than that of crops,and its average water use efficiency (52.93%) is 16.60% higher than that of crops (36.33%). The yield of maize (t·hm ^-2) is the highest,the water use efficiency (141.80%) is the highest,and the water use efficiency of potato (19.53%) is the lowest;Water use efficiency of annual forage grass was explained by plant phosphorus content,plant potassium content,temperature,intercellular CO ₂ concentration and fresh dry ratio;Crop water use efficiency is explained by stem leaf ratio,plant nitrogen content and intercellular CO ₂ concentration.

Grassland classification is the foundation for scientific grassland management. It can provide sound basis for the rational exploration of the grassland resources and the efficient protection of grassland ecosystems. The existing grassland classification system in China is rooted on the single dimension of grassland occurrence to define the connections and differentiations. However,it can not be properly used for grassland managements in the dimensions of grassland function,utilization direction and land tenure. In order to adapt to the transformation from productive orientation to ecological orientation in grassland management and from the contradiction to harmony between grassland management and support the systematic governing of mountain,water,forestry,farmland,lakes and grasslands in the new era of Ecological Civilization Construction,it is imperative to develop the multi-dimensional grassland classification systems,which are scientific,systematic and integrated. In this paper,we absorbed the advanced theories and technologies in the grassland classification in the world and referred to the multiple forestry classification systems to develop the principles,methods and indicators and to structure the frameworks for the multi-dimensional grassland classification from the perspectives of grassland occurrence,land tenure,functions and utilization degree. We also explored the integration and compensation of the multi-dimensional grassland classification systems forwarded in this study. The objectives were to provide the fundamental support for grassland research,protection,restoration,utilization,construction programs,and to serve as the scientific basis for the rational grassland resources and ecosystem management and the systematic governing of mountain,water,forestry,farmland,lakes and grasslands in the new era of Ecological Civilization Construction.

Grazing and fencing field were sampled to explore their effects on vegetation characteristics and forage nutritional quality by the combined analytical method in the temperate desert steppe. The results showed that, grazing significantly decreased the height, coverage and biomass of the plant community, and significantly increased the species richness index ( P<0.01). Moreover, grazing significantly increased the Crude protein (CP), Crude fat (CF), Dry matter digestibility (DMD) and Metabolic energy (ME), and significantly decreased the Neutral detergent fibers (NDF) and Acid detergent fibers (ADF) ( P<0.01). The species richness index was positively correlated with CP, CF, DMD and ME, but negatively correlated with NDF and ADF ( P<0.01). CP, CF, DMD and ME were negatively correlated with NDF and ADF ( P<0.01). In summary, grazing significantly increased species richness index and forage nutritional quality. Therefore, it is recommended to carry out appropriate grazing on the fencing temperate desert steppe to make full use of grassland resources and protect species diversity.