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This study establishes a near-ground reference radiation field based on typical radionuclides of the Fukushima accident in response to the need for vehicle-borne environmental radiation measurement equipment that can accurately evaluate the environmental dose of nuclear accidents. The Monte Carlo code FLUKA is used to study the environmental dose of such equipment in the early and mid-late reference radiation fields of nuclear accidents. Results of the air dose rate at 1 m above the ground were corrected to eliminate data difference between diverse measurement platforms. Simulation results show that t he dose correction factor (CF) fluctuates at approximately 0.8813 in the early reference radiation field and at approximately 0.6711 in the mid-late reference radiation field. This deviation of the dose CF in the early and mid-late reference radiation fields is within 2% and is not affected by the change in detector position. This research can be applied to obtain more accurate measurement of an ambient dose in the near-ground radiation field and support the vehicle-borne environmental radiation measurement technology.

High-barrier and antibacterial materials have potential applications in the field of preservative packaging for fresh meat products. In this paper, UV irradiation and silane coupling agent (KH550) were used to modify the surface of SiOx coating on polyester (PET)/SiOx film to prepare the PET/SiOx/chitosan and PET/SiOx/chitosan-nano-ZnO composite film, respectively. The contact angle test revealed that KH550 improved the surface hydrophilicity of SiOx significantly compared to UV irradiation, and thus PET/SiOx/chitosan and PET/SiOx/chitosan-nano ZnO composite films were successfully prepared and their physical and chemical properties were characterized. SEM images showed that the surface of the composite film was a smooth and layered structure. The mechanical performance testing of the films has revealed that mechanical performance of the PET was improved by SiOx deposition while the coating (KH550, chitosan, and chitosan-nano ZnO) does not affect the mechanical performance of PET/SiOx. The oxygen resistance of PET/SiOx films treated with KH550 was enhanced with the addition of chitosan and chitosan-nano ZnO coating, but the moisture resistance was slightly decreased. Furthermore, PET/SiOx/chitosan and PET/SiOx/chitosan-nano ZnO composite films showed excellent growth inhibition against Staphylococcus aureus and Escherichia coli. The PET/SiOx/chitosan-nano-ZnO films had exhibited the strongest inhibition of bacteria.

A SiOx coating prepared via plasma-enhanced chemical vapor deposition (PECVD) technique was used as a transition layer between polylactic acid (PLA) and chitosan (CS) to form a three-layer composite film of PLA/SiOx/CS. The effect of oxygen plasma irradiation time (0 s, 30s and 60s) on SiOx surface and PLA-CS interface was examined based on the contact angle, pull-off test and scanning electron microscope (SEM). The mechanical, barrier and antibacterial properties of PLA/SiOx/CS films were also investigated. The results showed that oxygen plasma irradiation improved the hydrophilicity of the SiOx surface and the adhesive strength between SiOx-CS of PLA/SiOx/CS films in a time-dependent manner. SEM examination revealed a gap between PLA/CS layers, but the interfacial separation among layers in PLA/SiOx/CS films disappeared as the transition layer of SiOx and oxygen plasma irradiation (60s) intensified. Notably, the oxygen barrier property and antibacterial activity of PLA/SiOx/CS films were dramatically enhanced. Additionally, moisture resistance was slightly decreased following the incorporation of the CS coating compared with the PLA film. The tensile strength of the composite film also increased with the number of layers, while elongation at break decreased. The prepared PLA/SiOx/CS films with multifunction are promising applied in food packaging as biobased materials.

Bioactive-packaging films based on polylactic acid (PLA), acetyl tributyl citrate (ATBC), and tea polyphenol (TP) were prepared by melt blending. Results of mechanical-property test revealed that adding ATBC and TP can significantly improve mechanical properties of PLA. The shift of CO to lower wavelengths in FTIR and the morphology of the films in SEM indicated physical or chemical interactions in the PLA/ATBC/TP films. The antioxidant, and antibacterial activities of the PLA/ATBC films increased dramatically (P0.05) with increased TP amount. The antioxidant activity of the films with 1 % TP was equivalent to that of 300 mg/L l-ascorbic acid, whereas PLA/ATBC/TP films with 0.5 % and 1 % TP concentration were effective in inhibiting Staphylococcus aureus and Escherichia coli within almost 5 h (P0.05). The PLA films changed from transparent to opaque and from yellow to red after combining with ATBC or TP, respectively. The overall migration of the films in 3 % acetic acid and 10 % ethanol did not exceed the overall migration limit. All these findings indicated potential of the PLA/ATBC/TP films in active-packaging application.

Rangelands are some of the most widely distributed ecosystems on Earth, covering ~20% of the land surface area. As an important part of terrestrial ecosystems, accurate rangeland classification plays a crucial role in carbon cycling, biodiversity conservation and forage production. The Comprehensive Sequential Classification System of Rangeland (CSCSR), a well accepted rangeland classification system, has attracted global attention and has undergone further development. This paper reviews the origin and development of the CSCSR and its application in the fields of climate change, rangeland and livestock production, even rangeland ecosystem services in detail.

The effect of grazing on leaf photosynthesis has been extensively studied. However, the influence of grazing on photosynthesis in other green tissues, especially spike, has remained poorly understood. This study investigated the impact of different grazing intensities (light grazing (LG), medium grazing (MG), and heavy grazing (HG)) on leaf and spike photosynthesis parameters and photosynthetic pigments of three grass species (Stipa purpurea, Achnatherum inebrians, and Leymus secalinus) on an alpine steppe in the Qilian Mountains. Grazing promoted leaf photosynthesis rate in S. purpurea and L. secalinus but reduced it in A. inebrians. Conversely, spike photosynthesis rate decreased in S. purpurea and L. secalinus under intense grazing, while there was no significant difference in spike photosynthesis rate in A. inebrians. The leaf and spike net photosynthetic rate (Pn) and transpiration rate (Tr) in S. purpurea were the greatest among the three species, while their organ temperatures were the lowest. On the other hand, grazing stimulated leaf chlorophyll biosynthesis in S. purpurea and L. secalinus but accelerated leaf chlorophyll degradation in A. inebrians. Furthermore, spike chlorophyll biosynthesis was inhibited in the three species under grazing, and only L. secalinus had the ability to recover from the impairment. Grazing had a positive effect on leaf photosynthesis parameters of S. purpurea and L. secalinus but a negative effect on those of A. inebrians. However, spike photosynthesis parameters were negatively influenced by grazing. Among the three species investigated, S. purpurea displayed the greatest ability for leaf and spike photosynthesis to withstand and acclimate to grazing stress. This study suggests that moderate grazing enhanced leaf photosynthetic capacity of S. purpurea and L. secalinus but reduced it in A. inebrians. However, spike photosynthetic capacity of three grass species decreased in response to grazing intensities.

The interactions between elements such as Ca, Fe, Si, Na, Mg, Al, and S in a cement sample were analyzed using prompt gamma neutron activation analysis (PGNAA). The actual Ca, Si, and Fe contents in the cement sample and the measured values from the PGNAA were compared in terms of the interactions between the elements using a linear fitting technique, followed by applying a regression analysis correction. The results show that the linearly fitted graphs have more decentralized data points, with relatively larger errors in the measured Ca, Fe, and Si contents (maximum errors are 18.07, 1.68, and 18.47, respectively). However, the interactions between Ca, Fe, Si, Na, Mg, Al, S, and other elements were eliminated after applying the correction. Accordingly, the errors in the measured Ca, Fe, and Si contents were lower (maximum values are 0.97, 0.13, and 0.01, respectively). The correction method helps in improving the measurement accuracy.

To explore the distribution of food demand and the projected trend in future food demand in China, this paper analyzed the change in current (1998–2012) per-capita demand for grain, grain-consuming and herbivorous livestock products, and predicted the food demand in 2020. The results indicated that in 1998–2012, the national per-capita consumption of grain ration declined by about 36.66%, and the per-capita consumption of grain-consu-ming and herbivorous livestock products increased by about 48% and 34.09%, respectively. The grain-consu-ming livestock products have become the primary source of both calories and protein for consumers. The proportion of herbivorous livestock products in consumer diets has increased steadily and there has been huge potential in substituting beef and mutton for pork in this dynamic market. The demand for food in different provinces of China is highly variable, which is important for planning grassland agriculture development and ensuring food safety. The demand for grain, and grain-consuming and herbivorous livestock products will increase by about 3.3%, 20% and 14% respectively by 2020. Based on the food demand and trend in the development of grassland agriculture, the 31 provinces in China are divided into three priority groups for grassland agriculture development.

International audience; John Hodgson (1937-2018) is renowned worldwide as a passionate and principled researcher, dedicated to the study of interactions between grazing livestock and pasture sward, and to whole-system management of grassland. He published over 250 scientific outputs during his 50-year career, and inspired generations of grazing ecologists. Following his upbringing on a mixed-livestock farm in the Yorkshire Dales, John received BSc, PhD and DSc from the University of Leeds, UK. He worked in research institutes in Hurley, England and Penicuik, Scotland, before taking a Chair in Agronomy at Massey University, New Zealand in 1986. There, he progressed to become Head of School for the Environment. John retired from university life in 2002, but never left academia. John's global research legacy is reflected in the international authorship of this memorial review. His international impact is demonstrated by the supervision of over 50 PhD students from all over the world, and by his knowledge-sharing travels to South America and China. His peers will remember him as a thoughtful and collaborative scholar. His students will remember him as an inspiring and caring mentor. He helped to revolutionize the way that grasslands are managed, in the face of global environmental change and increasing demand on grazed systems. John lost a long battle with Parkinson's disease in October 2018 and is survived by his wife, Ruth, and five children. His own research was often dedicated to his father, Dick Hodgson, and the first author of this tribute wishes to do the same.

Pratacultural science refers to the study of grassland agriculture, which is a branch of agricultural science. It was not until 1980s that the modern prataculture took shape in China although the country has a long history of grassland agriculture. China has developed its own discipline system of pratacultural science in assimilating the academic tradition of Europe, North America and Russia. The pratacultural science of China consists of the studies of three major parts, namely the three factor groups (the biotic, abiotic and social factor groups), three interfaces (the plant-land interface, the pasture-livestock interface and the pasture/animal-market interface), and four production subsystems (the pre-plant production, the plant production, the animal production and the post-biotic production subsystems). The functioning of pratacultural science is maintained by its multidimensional structure. In the past three decades, the consumption of cereals as food by Chinese people has been declining while that of food of animal origin has been increasing rapidly, leading to a sharp increase in the demand for feed and forage crops. Grassland agriculture, with its main outputs based on vegetative growth rather than reproductive growth of plants, is more efficient as well as more ecological than the arable agriculture only relying on grain production. Grassland agriculture is bound to gradually replace the traditional arable agriculture in China, becoming the main stream of the agriculture of China, and thus to mitigate the problems in China's agricultural development. With the demand by the society and the unprecedented support from the national government, China's modern pratacultural science has a never-had opportunity for its develop. Currently China is at a leading position in some research areas of pratacultural science in the world. © 2016, Science Press. All right reserved.

The effects of grazing on species reproduction is a fundamental issue of grassland management. We investigated plant density and dry weight changes at community and species levels, and the reproductive strategies of the dominant desirable Stipa purpurea and the undesirable Achnatherum inebrians grass species in response to stocking rate in an alpine steppe with a 10-year grazing history. Results showed complex patterns of plant community and reproductive strategy. Overall plant density increased with increasing stocking rate and dry weight was significantly higher at light and high stocking rates. Plant density and dry weight of A. inebrians peaked at moderate stocking rates. Higher stocking rate had little impact on S. purpurea density but significantly reduced its dry weight. Both species displayed linearly increasing/decreasing or unimodal/bimodal reproductive effort in response to increased stocking rate. The discrepancies in plant reproductive characteristics between S. purpurea and A. inebrians indicated that: (1) light and moderate grazing may promote an adaption strategy of reproduction by desirable species, which may then contribute to their maintenance in grasslands, and (2) undesirable species presence did not lead to the replacement of desirable species in the grasslands. Therefore, light and moderate stocking rates are recommended to maintain the grasslands and to increase the reproductive outputs of desirable species.

China's food security has a great influence on the world, and has always been the top priority in China. In recent years, as the concept of food security is evolving into one of nutrition security and the importance of food diversity is increasing, research based on nutrition security and broad food systems are increasingly needed in today's China. Thus, not only grain for human consumption, but also animal foods have been integrated into the Food Equivalent, which is used to analyze China's current agriculture system and reveal the water resource distribu- tion. The results indicated that the average animal food consumption has risen by 78.6%, and now China's daily supply of animal food per capita has reached about 50% of that in the USA and 80% of that in the South Korea. So there exist an obvious disparity in animal food supply between China and these two countries. It is impossible for the China's current agricultural system to achieve the level in the USA. Under China's current agricultural system, the consumption proportion of feed grain had surpassed the consumption of food grain, increased sharply from 33% in 1992 to 67% in 2011. However, the growth potential of total grain output is approaching an upper limit, so the continued growth of feed grain demand exerts great pressure on the China's food supply. The discordance of the spatial distribution of water resource and virtual water revealed that China's current agriculture system had a low efficiency in being able to achieve food and nutrition security. China's current "grain farming" cannot meet the demand of increasing nutrition and appropriate resource utilization. The implementation of grassland agriculture appears feasible and necessary for saving feed grain, providing a large number of high-quality animal foods and appropriate water resource utilization.

Grassland ecosystems are a significant component of the global carbon cycle. To better understand how grazing affects the carbon cycle of grasslands, soil microbial respiration (Rm) and root respiration (Rr), which are the main soil respiration components, we investigated with a trenching method in grazed grasslands (GG) and fenced (FG) grasslands on the Loess Plateau, northern China in 2008. The annual carbon balance in the two grasslands were also assessed and compared. After exclusion of grazing for about 3 years, soil organic carbon (SOC) and microbial biomass carbon (MBC) in the surface soil increased significantly (P

Bioclimatology based vegetation classification models play an important role in the response of terrestrial ecosystems to global climate change. In this paper, three periods (1911-1940, 1941-1970 and 1971-2000) of Potential Natural Vegetation (PNV) maps were created based on the CSCS (Comprehensive Sequential Classification System) model and the CRU_TS 2.1 datasets. A model of the mean center was used to calculate the shift distance and direction for each broad vegetation category during the three periods. Results indicate that: (i) the area of tundra and alpine steppe and desert decreased by 5.1 and 5.5%, while the area of forest and grassland increased by 2.3 and 3.8% from 1911 to 2000 at global scale, respectively. However, there was a significant difference in the magnitude of area change in northern and southern hemispheres. And (ii) the tundra and alpine steppe, semi-desert, savanna, temperate forest and subtropical forest shifted towards the poles; the frigid desert and temperate humid grassland shifted towards the equator, while the warm desert shifted towards southwest, the tropical forest shifted towards southwest in the northern hemisphere and southeast in the southern hemisphere, and the steppe shifted towards northeast in the northern hemisphere and northwest in the southern hemisphere. The shift distance of the warm desert in the southern hemisphere was the largest among the 10 broad vegetation categories.

Grassland is one of the most widespread vegetation types worldwide and plays a significant role in global carbon cycling. Understanding the sensitivity of grassland to climate change and the effect of climate changes on the grassland ecosystems is a key issue in global carbon cycling. One of the goals of this study was to evaluate the three net primary productivity (NPP)–climate models, i.e. the Miami model, the Schuur model and the classification indices-based model. Results indicated that the classification indices-based model was the most effective model at estimating large-scale grassland NPP. In this research, changes in the spatial pattern of global potential grassland from recent past (1950–2000) to future (2001–2050) A2a scenario were analysed with the integrated orderly classification system of grassland (IOCSG) approach in a Geographic Information System (GIS) environment. NPP was evaluated with the classification indices-based model. Results indicate that under recent past climatic conditions, ...

Long-term series of vegetation change is one of the key study contents for evaluating terrestrial ecosystems and plays an important role in global change study. The CSCS (Comprehensive and Sequential Classification System) model was used in the paper to analyze the change of Potential Natural Vegetation (PNV) types during the period 1951–2000 and for the three future years 2020, 2050 and 2080. The growth conditions for each PNV type were analyzed based on MODIS Normalized Difference Vegetation Index (NDVI) datasets on the Tibetan Plateau (TP) from 2001 to 2010. The results showed that: (i) The mean annual precipitation (MAP) and mean annual temperature (MAT) had increasing trends (1.72 mm year−1 and 0.025°C year−1, respectively) over the past 50 years from 1951 to 2000. (ii) Based on the three general circulation models (CCCMA, CSRIO and HadCM3), the MAT and MAP on TP would increase in the future, with magnitudes 3.54 to 6.08°C and 28.71 mm to 126.84 mm from 2000 to 2080, respectively; it is also predicted that two new vegetation categories: warm desert and savanna would appear in the future and that the area of forest would increase significantly, while the area of grassland would have an obvious decreasing trend. And (iii) Overall, the ecological environment of vegetation in the recent 10 years has been improved in most of the areas in central and southern regions of Qinghai Province, but degraded in some areas of Sichuan Province, and the southwest and south of Tibet.

RAV is a unique transcription factor in higher plants with AP2 and B3-like two distinct DNA-binding domains, but its roles in plant growth and development remains unknown. We have isolated a novel RAV family gene from Galegae orientalis, called GoRAV, which responds to cold induction. Sequence alignment showed that it shares high identity with other RAV family members in AP2 and B3 domain. Transient expression analysis using onion epidermal cells indicated that GoRAV protein is localized in the nucleus. Semi-quantitative RT-PCR (S-Q RT-PCR) analysis indicated that GoRAV is induced by cold, dehydration, high-salinity and abscisic acid, with the strongest induction in G. orientalis leaves during the early response to abiotic elicitors. GoRAV is more abundant in leaf than in stem, but is not expressed in root. This work adds a new member to the RAV family.

The regional hydrology and ecosystems of the northeastern margin of the Qinghai–Tibetan Plateau have changed over the past 40 years driven by intense human activity and regional climate changes. Annual mean air temperature has increased in the region. Streamflow from the northeastern margin of the Qinghai–Tibetan Plateau has decreased significantly. Overall, a number of Alpine step meadows and Alpine frigid meadows have seriously degraded. Degeneration of vegetation and grassland led to desertification and frequently induced dust storms. With the continuous increase in cultivated land area, grassland area in the region has dropped significantly since the 1960s. At present, degraded grassland occupies about 83% of total usable grassland area. As the number of livestock increased, range condition deteriorated and the carrying capacity was reduced. The forest area in the northeastern margin of the Qinghai–Tibetan Plateau has decreased by 20%, and the local ecosystem has become very fragile. Given the relatively stable weather conditions, the northeastern margin of the Qinghai–Tibetan Plateau can be characterized by its three major ecosystems: grassland ecosystem, forest ecosystem and wetland ecosystem, which are crucial in maintaining the ecological stability. Changes in these ecosystems could influence sustainable development in the region. To avoid further deterioration of the environment and ecosystems, it is important to establish and implement ecosystem protection planning. Some effective measures are essential in this respect, including technical and political considerations.

Ecosystem management is to make adaptive management strategy based on full understanding the process of composition, structure and function of ecological system, and to restore or maintain ecosystem integrity and sustainability. Forest ecosystem management attempts to maintain forest ecosystem complex process, path and the interdependent relationship, and maintaining their function good, for sustainable forest management and forest ecological system, and establishing and developing comprehensive theoretical system of forest ecosystem and sustainable forestry management system and decision support system, method and technology system. Grassland ecosystem is the prairie land biological coupling with its survival in nature. Absorbing new achievements of science and technology, to build and to make the new grazing system unit perfect, and make it as the indispensable important component of modern agriculture. Desert ecosystem management needs to solve problems of harmonious interaction and the sustainable development of river basin, as well as the ecological water requirement of river basin security problems. Desert ecosystem management must adopt comprehensive ecological management measures in the process of management, give attention to utilization and protection to optimize economic, social, and environmental benefits. Wetland surface interaction process and the system response, the succession of wetland ecosystem and its ecological effect, and the further research of wetland ecosystem function evaluation becomes scientific foundation to explain wetland process route and wetland ecosystem management. Lake ecosystem is affected by human activities. Controlling food chain control of biological on the basis of the classic and nonclassical biological control theory is one of the important measures to control eutrophication in lake. Aquatic plant restoration is also very important in the process of eutrophication in lake. We developed the marine ecosystem management system in China, including ocean space planning and Marine functional zoning planning, Marine nature reserve construction, fishing intensity control and the closed fishing rule, ecological restoration and resource conservation, maintenance management information system construction, and emphasize more on the ocean in terms of ecosystem management in new pattern. Driven by the interests of the market due to the economic benefit and production effect, ecological environmental benefits are neglected in agricultural ecological system. Using the ecology principle “prevention and control of integrated system”� is the fundamental way for agricultural pest control.

Selectivity by whole plants for K + over Na + in three types (salt excluding, salt secreting and salt diluting) of salt-resistant plants was investigated. An estimating formula of Selective Absorption (SA) capacity of root systems was derived; the Selective Transport (ST n ) capacities between K + and Na + by various parts of the three types of plants were compared. The results showed that the SA value of salt-excluding plants were higher than that of salt-secreting and salt-diluting plants, the ST1 (root:stem) value was much higher, indicating that both the capacity of selective absorption and the capacity of selective transport by root systems were strong. In salt-secreting plants, the SA value lay between salt-diluting and salt-excluding plants, while the ST1 value was the lowest, indicating that the majority of Na + uptake by root systems was transported up to their aerial parts and then the surplus salt was secreted in salt glands. In salt-diluting plants, the SA value was the lowest, indicating that the majority of Na + taken up by the root systems entered into plant body perhaps to satisfy the requirements for osmotic adjustment and growth, and the ST1 value lay between salt-secreting and salt-excluding plants. These data strongly indicate that the SA and ST1 values reflect the K + and Na + selectivity characteristics of salt-resistant plants. Therefore, the various types of salt-resistant plants would be classified by using the values of SA and ST1. We suggest that this provides a way for distinguishing various types of salt-resistant plants. Comparing the ST n values of the six species in our paper, we concluded that the selectivity of transporting K + over Na + into the actively photosynthesizing organs and particularly into the developing ears is extremely high. Our conclusion is in accordance with previous results that demonstrate that the capacities of selective transport by different parts of the plant for K + over Na + are best quantified by ST n values. The necessity, feasibility and wide-ranging applicability of the formulas for estimating SA and ST n values have been discussed in detail.

To assess the variation in distribution, extent, and NPP of global natural vegetation in response to climate change in the period 1911-2000 and to provide a feasible method for climate change research in regions where historical data is difficult to obtain. In this research, variations in spatiotemporal distributions of global potential natural vegetation (PNV) from 1911 to 2000 were analyzed with the comprehensive sequential classification system (CSCS) and net primary production (NPP) of different ecosystems was evaluated with the synthetic model to determine the effect of climate change on the terrestrial ecosystems. The results showed that consistently rising global temperature and altered precipitation patterns had exerted strong influence on spatiotemporal distribution and productivities of terrestrial ecosystems, especially in the mid/high latitudes. Ecosystems in temperate zones expanded and desert area decreased as a consequence of climate variations. The vegetation that decreased the most was cold desert (18.79%), while the maximum increase (10.31%) was recorded in savanna. Additionally, the area of tundra and alpine steppe reduced significantly (5.43%) and were forced northward due to significant ascending temperature in the northern hemisphere. The global terrestrial ecosystems productivities increased by 2.09%, most of which was attributed to savanna (6.04%), tropical forest (0.99%), and temperate forest (5.49%). Most NPP losses were found in cold desert (27.33%). NPP increases displayed a latitudinal distribution. The NPP of tropical zones amounted to more than a half of total NPP, with an estimated increase of 1.32%. The increase in northern temperate zone was the second highest with 3.55%. Global NPP showed a significant positive correlation with mean annual precipitation in comparison with mean annual temperature and biological temperature. In general, effects of climate change on terrestrial ecosystems were deep and profound in 1911-2000, especially in the latter half of the period.

We apply a resource integration approach to address increasing crop and forage production in a semi-arid agroecosystem in northwestern China. A holistic modeling approach was employed to study improvement in agricultural practices with respect to ecosystem conservation. Using a proposed rotational scheme for winter wheat and alfalfa production, portions of arable land are allocated for raising animal forage in order to improve soil productivity. Animal manures are returned to the soil to stabilize the structure further and to maintain fertility. Regional climate and topography are included in the simulation model. A series of 40-yr simulation runs for ravine tablelands and hilly topography were conducted to investigate model behavior. Long-term application of nitrogen fertilizer as an alternative management practice was evaluated using the model, but detrimental effects on primary and secondary production from such a practice were predicted by simulation results. The impact of population pressure on agricultural systems was also considered.

Studies on the food nourishment utilization efficiency of different month aged sheep showed that under same food nourishment condition, the ingested nourishment, weight increase, and nourishment depletion per unit weight increase of sheep were increased with the ingestion of dry matter, and the protein content of 34 months old sheep was significantly higher than that of 22 months old sheep (P0.01), and the latter was significantly higher than that of 10 months old sheep (P0.01). There was a significant difference of utilization efficiency of the ingested nourishment between 34 months old and 22 months old sheep (P0.05) and between 10 months old and 22 months old sheep (P0.01). The weight increase was not significantly different (P0.05) between 34 months old and 22 months old sheep and between 10 months old and 22 months old sheep, but it was significantly different between 34 months old and 10 months old sheep (P0.05). The feed conversion rate among them was not different. All the results showed that 10-22 months old sheep had high production efficiency, and could produce high quality mutton, and hence, this section of age was the suitable age of sheep to be butchered.

The connotation, progress, research frontiers and developmental trend of grassland agroecology are discussed in this paper. The interface theory, structure and function, coupling and discordance, and health assessment of grassland agroecosystems were recognized as the four research frontiers of the discipline. There exist three primary interfaces in a grassland agroecosystem, i.e., vegetation-site, grassland-animal and production-management. Research into a series of the ecological processes that occurred at these interfaces is the key to revealing the features of the system behavior. There are four sections in a grassland agroecosystem, i.e., pre-plant, plant, animal and post-biotic sections. System coupling and discordance are the two important concepts to describe interactions among the production sections. System coupling among the sections can lead to system improvement by exerting the potential of system capacity. Health of an ecosystem is a reflection of its structure and function, and health assessment is a measurement of its orderliness and service value.

Bio-geological temporal zonation can be defined as a subsistent spatial-temporal style that the organisms clip from a geographical zone to break through its limit, and extend their survival extent with the strategy of excluding the environmental period of time which is not suitable to live and intercepting it which is suitable. It is the consequence that organisms temporally adapt the heat distribution pattern caused by the rotation and revolution of the Earth. Bio-geological temporal zonation relies on spatial zone, and the zonation spectrum changes in different spatial zones and has different basal heat zone. It appears as spiral loop based on its own spatial zone, and implies temporally seasonal change of the heat. Similarly, bio-geological temporal zonation relies on the distribution process of water and heat under spatial and temporal scale. The component, range and hierarchy of zonation spectrum change with spatial and temporal scale, and organisms adapt this kind of change with different ecological strategy depended on different ecological strategy. Human being can tune up bio-geological temporal zonation only in small scale.

The fundament of system coupling is heterogeneity, and the basic prerequisite is that there are connective corridors in the same type between ecosystems. The landscape ecological mechanism of system coupling is the spatial difference of non-biotic environment and the heterogeneity caused by disturbances. The force or energy of system coupling is disturbances. From in the view of landscape ecology, system coupling is the merging process of different landscape elements between different landscape ecosystems followed by the process of character changing of landscape elements with scale changing. Based on the essence of disturbances, system coupling can be divided into two types as natural system coupling and artificial system coupling. Natural system coupling is the base of artificial system coupling, and hence, the enhance of eco-productivity of coupling system is based on the optimization of artificial system coupling.

Oasis landscape ecosystem is composed of 10 landscape elements, i.e., residence land, cultivated land, grassland, forestland, water area, water system, road, rocky desert, sandy desert, and gravel desert. Among the elements, cultivated land formed by human being production covers the most of the area, is most connected, and hence, is the matrix of the oasis landscape ecosystem. Residence land, grassland, forestland, water area, rocky desert, sandy desert, and gravel desert are patches. Residence land and forestland generate from human being production, while rocky desert, gravel desert and sandy desert are the remnant with the human being disturbance. Water region and grassland are the environmental resources remnant after natural disturbance. Water system and road are corridors. Cultivated land dominated in plant production should be utilized with more productive layers through developing animal production other than expanding used-area to maintain the landscape heterogeneity and diversity of the oasis landscape ecosystem. For remnant and environmental resource patches, it should be profitable in preserving and stabilizing landscape heterogeneity and diversity, exploiting the functions of water and soil conservation, tourism, windbreak and sand fixation. For landscape elements remnant only, it should be fruitful in avoiding degeneration of the landscape pattern to explore their preceding plant production with moderate plant production.

Herders’ desirable stocking rates and their opinions of overstocking were studied using survey and multi-regression methods in the meadow steppe, typical steppe and desert steppe regions of northern China. It was found that individual herders had their own perception of their particular ‘desirable stocking rate’, which referred to the number of livestock that the herders thought they could keep or maintain on an area of rangeland over a specified period of time. These perceptions were not in line with the ‘balancing animals and grass’ policy of the Chinese government, and herders used them as a guide to adjust stock-breeding practices. Most herders admitted that they bred more livestock now than 10 years ago, but insisted that there was no overstocking and many even thought that their rangelands could still carry more livestock. They also held the view that they took into account the carrying capacity of rangelands when making decisions about livestock-breeding practices. Individual herders thought that the reasonable stocking rate range should be 0.75–1.50 sheep units ha–1 (meadow steppe), 0.60–1.50 sheep units ha–1 (typical steppe), and 0.50–0.75 sheep units ha–1 (desert steppe), respectively. The herders from the desert steppe regions were most concerned about the overstocking of rangelands, and the concern of herders was in the order desert steppe > typical steppe > meadow steppe. The herders with more formal education and those who worked in a village council and had smaller areas of rangelands, were more concerned about the overstocking of rangelands. It is argued that such herders should be given more access to policy and market information, including extensive grazing and modern stall-feeding technologies, and encouraged to reduce their desirable stocking rates, leading to more sustainable rangeland management in northern China.

Net primary productivity (NPP) of grassland is one of the key components in measuring the carrying capacity of livestock. Not only are grassland researchers concerned with the performance of NPP simulation models under current climate conditions, they also need to understand the behaviour of NPP–climate models under projected climatic changes. One of the goals of this study was to evaluate the three NPP–climate models: the Miami Model, the Schuur Model, and the Classification Indices-based Model. Results indicated that the Classification Indices-based Model was the most effective model at estimating large-scale grassland NPP. Both the Integrated Orderly Classification System of Grassland and the Classification Indices-based Model were then applied to analyse the succession of grassland biomes and to measure the change in total NPP (TNPP) of grassland biomes from the recent past (1950–2000) to a future scenario (2001–2050) in a geographic information system environment. Results of the simulations indicate that, under recent-past climatic conditions, the major biomes of China’s grassland are the tundra and alpine steppe, and steppe, and these would be converted into steppe and semi-desert grassland in the future scenario; the potential grassland TNPP in China was projected to be 0.72 PgC under recent-past climatic conditions, and would be 0.83 Pg C under the future climatic scenario. The ‘safe’ carrying capacity of livestock that best integrates a wide range of factors, such as grassland classes, climatic variability, and animal nutrition, is discussed as unresolved. Further research and development is needed to identify the regional trends for the ‘safe’ carrying capacity of livestock to maintain sustainable resource condition and reduce the risk of resource degradation. This important task remains a challenge for all grassland scientists and practitioners.

China possesses vast grassland resources that include alpine meadow, tundra, steppe and desert. It is, therefore, desirable to establish a grassland classification system that involves the formative factors contributing to this diversity. This paper reports a grassland classification system called the Integrated Orderly Classification System of Grassland (IOCSG), which was formulated through grouping or clustering units with similar properties. The IOCSG involves a hierarchy of three classification levels. At the first level, grasslands are grouped into classes according to an index of moisture and temperature. At the second level, grasslands are differentiated as subclasses by the edaphic conditions. At the third level, grassland types within a subclass are distinguished by vegetation types. Under the IOCSG, seven thermal zones and six humidity zones have been identified and used to differentiate grassland classes. The IOCSG recognises 42 grassland Classes, of which 41 are present in China.

The integrated crop-livestock production system provides most of the food needed by the people of China. Five types of integrated production systems are recognised; rangeland, grain crops, crop/pasture, agro-silvopastoral and ponds. Development of more sustainable and integrated crop-pasture-rangeland-livestock production systems has been recently achieved. Demonstrations of the integrated systems at household, village and regional levels are occurring for rain-fed agriculture on the Loess Plateau, the Hexi Corridor, north-western China and the Karst region of Guizhou Province, south-western China. These indicate that integration of crop, livestock and forage are effective means of improving agricultural productivity, environmental sustainability and farmers’ incomes. Widespread adoption of integrated farming systems should also reduce rangeland degradation.