Whole-plant wheat ( Triticum aestivum) has high feeding value,and it has become one of the main sources of roughage for ruminants in some countries or regions. The purpose of this study was to screen high-yield and high-quality wheat varieties,and to determine the differences in yield,nutrition and silage fermentation quality among varieties and correlation between measured characteristics. For 24 wheat varieties tested,their dry matter (DM) yield ranged from 5.20 to 9.81 t·hm ^-2,and the crude protein (CP) ranged from 0.40 to 0.85 t·hm ^-2. Among them,‘SM1’ and ‘CM61’ had high DM and CP,and ‘SM1’ and ‘HG35’ had high relative feed value. The relative feed value of ‘CM61’ and ‘HG35’ was significantly lower than ‘SM1’ ( P<0.05). The thousand-seed weight of wheat had positive effect on the DM yield of whole-plant ( P<0.05). The DM yield of whole-plant wheat had negative effects on lactic acid and butyric acid contents of silage ( P<0.01). The CP content of whole-plant wheat had positive effect on butyric acid content of silage,but neutral detergent fiber had negative effect on butyric acid content ( P<0.05). The result showed that ‘SM1’ and ‘HG35’ were more suitable for planting in winter fallow fields in Guangdong Province.

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.

Grazing is one of the most important uses of grassland ecosystems,and different grassland types,grazing intensities,herbivore assemblages,grassland use types and climate change all influence the structure and function of grassland ecosystems. It is very important to understand the mechanisms of grazing and climate change on grassland ecosystems for their sustainable development. In order to provide a theoretical reference for the adaptive management and sustainable development of grassland ecosystems,this paper provided a systematic review of the mechanisms by which grazing affects the structure and function of grassland ecosystems,and provided an outlook on several important research directions in this theme,and future research issues as the following:(1) to improve spatial coupling analysis in grazing grassland ecosystems;(2) to focus on multifunctionality studies of grassland ecosystems;(3) to elaborate the multi-factorial nested experiments on grasslands in the context of global change;(4) to refine the mixed grazing experiments with different herbivore assemblages;(5) to standardize the methods of grassland ecological experiments.

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.

In recent years,due to the continuous development of urban industry and the excessive use of chemical fertilizers,the lack of mineral elements and pollution in soil have seriously affected the sustainable development of agriculture. As a natural biological bacterial fertilizer,arbuscular mycorrhizal fungi (AMF) is able to effectively promote the absorption of mineral elements and improve growth conditions around plants. At the same time,in heavy metal contaminated soils,AMF can reduce the toxicity of heavy metal to plants and enhance the adaptability of plants to environmental changes. Up to now,great progress has been made in the researches on the physiological and molecular mechanism of AMF regulating the absorption of mineral elements by plants. A large number of mycorrhizal-induced genes have been identified,but a systematic and comprehensive summary is still lacking. Based on this,this paper summarized the relevant studies on AMF regulating the absorption of mineral elements in plants at home and abroad,and reviewed literature on the physiological and molecular mechanisms of AMF affecting the uptake of macroelements and trace elements by plants,and the mechanism of AMF alleviating the heavy metal toxicity to plant. According to the challenges and deficiencies of existing researches,the outlook is put forward,which aims to provide a certain scientific basis for the in-depth understanding of the mechanism of AMF affecting the absorption of mineral elements by plants and the agricultural application of biological bacterial fertilizer.

Vegetation change caused by environmental change has a significant impact on ecosystem processes. However,the research on vegetation growth and its response to multiple related control factors is still insufficient. This paper explored spatial-temporal variation and driving factors of grassland Normalized Difference Vegetation Index (NDVI) using Theil-Sen median trend analysis,Mann-Kendall test,coefficient of variation,ridge regression analysis and structural equation model. The results showed that from 2001 to 2020,the spatial variation of grassland Normalized Difference Vegetation Index (NDVI) gradually decreased from southeast to northwest in the Qinghai-Tibet Plateau (QTP),the interannual variation showed an upward trend,the distribution of grassland was more concentrated in the area with smaller slope,and the growth of shady slope grassland was better. In the region,grassland growth improved due to the increase of water use efficiency (WUE) and temperature,and the grassland WUE was the main factor affecting the change of grassland NDVI on the QTP. This study improved our understanding on how multiple variables worked together to influence grassland growth and highlighted the importance of WUE for vegetation growth.

In order to study the alleviating effect of VitaCat ^® (GA·IAA·BR 0.136%WP) on seed germination and seedling growth of turfgrass under low temperature stress, two turfgrass species, Festuca arundinacea and Lolium perenne were used as the experiment material. The seeds were soaked into 2 500~15 000 times VitaCat ^® for 24 hours at room temperature (25℃/25℃), then their germination were observed under room temperature (25℃/25℃) and low temperature (15℃/10℃). The seedling were foliar-applied with 2 500~15 000 times VitaCat ^®, then their growth performance was observed under room temperature (25℃) and 10-day outdoor low temperature stress. The results showed that seed germination potential, seed germination rate and sprout length and root length of two turfgrass species under both low and room temperatures were significantly improved after the soaking-up in 7 500~10 000 times dilution of VitaCat ^®. The root length, root weight, as well as chlorophyll content, proline content and superoxide dismutase activity of those turfgrasses were significantly increased, and malondialdehyde content and relative electrical conductivity were significantly decreased under low temperature stress by spraying 5 000~7 500 times VitaCat ^®. From the above results, it can be concluded the seed soaking-up with 7 500~10 000 times dilution of VitaCat ^® improved the seed germination and growth of two turfgrasses. The foliar spraying of 5 000~7 500 times dilution of VitaCat ^® alleviated the injury of seedlings by low temperature stress and enhanced the cold resistance of seedlings.

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.

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.

To explore the winter survival and production performance of autumn-sown oat in Henan Province,this experiment was carried out to measure agronomic traits such as winter survival rate,tillering characteristics,hay yield,lodging resistance,and nutritional quality for 21 autumn-sown oat varieties. The results showed that the winter survival rates of oat varieties ranged from 33% to 86%,with above 60% in thirteen oat varieties. Autumn-sown oats had a strong tiller capacity with two tillering peaks before and after winter respectively,and only the tillers before winter were effective ones. The plant height of each variety was 1.04～1.42 m and the hay yield was 9.95～18.69 t·hm ^-2. Among the 21 varieties,'Titan' had the tallest plant height,and 'Baler' was with the highest hay yield. Correlation analysis showed that hay yield was significantly positively correlated with plant height,and there was no significant correlation between tillering and hay yield. The principal component analysis for nutritional indicators showed that the principal components could be used to score nutritional quality quantitatively. The comprehensive evaluation by combining lodging resistance,hay yield,and nutritional quality showed that 'Baler' 'Haymaker' and 'Baler' II obtained higher scores,and they were appropriate for autumn sowing in Henan Province and Huang-Huai-Hai Plain.

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 whether artificial grassland can be established in Nagqu area and what kind of forage species is suitable for planting,this experiment selected the cold and drought-resistant forage species to carry out an introduction and screening test artificial grassland in the area. Through the comparison and evaluation of the harvested forage yield with the yield of natural grassland in Nagqu and other artificial grassland in the four major grassland areas in China,it can be seen that the yield of the harvested forage in the experiment is exponentially higher than that of the natural grassland in Nagqu,and the average yield of the artificial grassland in the experimental area is not lower than that of the artificial grasslands in the other grassland areas in China,which indicate that high yielding artificial grassland can be established in Nagqu region under adequate water and fertiliser management conditions. At the same time,the screening of suitable pasture species was carried out based on the seedling emergence and growth of different pasture species in the year of sowing and the seedling emergence of perennial pasture species in the following year (i.e. overwintering ability). The results showed that Avena sativa, Triticum secale, Brassica rapa and Brassica napus were suitable for planting in the Nagqu area. Elymus sibiricus and Elymus nutans,which were able to overwinter successfully,can be used as screening species for perennial grassland,but their stability in the second and subsequent years after overwintering remains to be studied.

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.

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.

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.

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.

Arbuscular mycorrhizal fungi (AMF) are a kind of important soil microorganisms which can form mycorrhizal symbiosis within plant roots and have the function of promoting plant growth and development. Alfalfa,known as "the king of forage",is a high-quality leguminous forage crop,which is characterized by high protein content,rich nutrition,strong palatability,and a wide range of adaptation. In this paper,the progress of effects of AMF on promoting the growth and development of alfalfa,boosting the resistance of stress and disease,and improving soil was reviewed,and the existing problems and application prospects were discussed. It provided a reference basis for the application of AMF in the cultivation of alfalfa.

Qilian Mountain is an important ecological security barrier in China. The study of different types of grassland vegetation can provide a reference for the rational utilization of grassland resources. In this study,we collected and analyzed the characteristics of different types of grassland vegetation communities in the eastern part of the Qilian Mountains,and evaluated the nutritional value of the grasses. The results showed that there were differences in vegetation and functional communities among different types of grasslands,among which,the Shannon-Wiener,Dominance index,and species richness index of alpine meadow was significantly higher than those of others. The aboveground biomass of alpine meadow and swamp meadow was significantly lower than that of steppe meadow and cultivated grassland,while the underground biomass was the opposite. The nutrient and carbon,nitrogen and phosphorus contents of herbage were different in different grassland types. The results showed that alpine meadow had better community stability and forage nutritional value,followed by the marsh meadow and steppe meadow.

Based on the adaptive management technology platform of the alpine grassland-livestock system, in order to reveal the response mechanism of Kobresia humilis population to the regulation of grazing mode, this research studied the traits of leaves, resource input and the potential relationship between reproductive branches and vegetative branches of K. humilis. The results showed that:the height, number, and weight of vegetative branches of K. humilis in Yak:Tibetan sheep as 1:6 grazing treatment were significantly higher than those in Yak:Tibetan sheep as 1:4 grazing treatment, single Yak or Tibetan sheep grazing treatment. The vegetative branch weight and reproductive branch weight per unit length of K. humilis were not affected by grazing, and there was a positive correlation between vegetative branch weight per unit length and reproductive branch weight per unit length. The characteristics of individual reproductive branches and vegetative branches showed a cooperative relationship, and the weight of vegetative branches significantly affected the number of vegetative branches, and the number of reproductive branches significantly affected the weight of reproductive branches. In summary, this study suggests that under grazing disturbance, there is no trade-off between the resource input of the reproductive branch and vegetative branch. Kobresia humilis improves the resource allocation by increasing the resource input of the reproductive branch and vegetative branch per unit length.

AT-hook motif nuclear localized (AHL) protein, a small DNA-binding protein, is widely found in plant and plays an important part in plant growth and development, responses to adversity stress and hormone signaling. In order to comprehensively understand the structure and function of the AHL gene family of Populus euphratica, the physicochemical properties, gene structure, subcellular localization and expression characteristics under stress of the AHL family members of P. euphratica were analyzed by bioinformatics methods and qRT-PCR. It was showed by the physicochemical property analysis that there were 19 members of the AHL family, and all PeAHL proteins are basic and unstable hydrophilic proteins except for PeAHL16. It was showed by the gene structure analysis that all PeAHL members were intron deletion type genes. It was showed by the phylogenetic tree analysis that the members of the PeAHL family could be split into 8 subgroups based on gene types. It was showed by the conservative motif analysis that PeAHL genes clustered in the same branch had essentially the same motif composition and arrangement order. In the analysis of cis-acting elements, the most diverse and abundant elements within the PeAHL genes were found out in response to drought stress. It was showed by the quantitative real-time fluorescence analysis that the expression of PeAHLs was significantly induced by low temperature, high temperature, NaCl as well as PEG, and the expression of PeAHLs was highest under PEG treatment compared with the control-check. The results of this study provide a theoretical basis for the in-depth study of the AHL gene family of P. euphratica and offer a reference to a further analysis on the molecular mechanism of the involvement of PeAHL genes in response to abiotic stresses.