In the past 100 years, Kazakhstan’s social system has undergone a series of changes through the sequence of the Russian Federation, the Independent Republic, the Soviet Union, and the collapse of the Soviet Union. At the same time, during the period from 1941 to 2011, the seasonal temperature in Kazakhstan showed an increasing trend, while the annual precipitation showed a downward trend, and the warming and drying trends were significant (Salnikov et al., 2015). Affected by climate change and changes in social institutions, Kazakhstan has become the country with the most severe ecological degradation and conflict between grass and livestock in Central Asia (Jiang et al., 2017; Fan et al., 2012; Luo et al., 2017; Zhang et al., 2018). After the 1940s, the Soviet government expanded the size of available pastureland in order to restore and develop the livestock industry. The grazing activities in Kazakhstan extended from the typical grassland area to the southern desert steppe area (Alimaev et al., 1986). Between 1954 and 1963, 23 million hectares of grassland was reclaimed due to the “virgin land movement” incident, and the number of livestock continued to increase, leading to further degradation of desert grassland; and biomass decreased from 483 kg hm^-2 to 100 kg hm^-2, which led to extensive desertification (Zhao et al., 2004;Kraemer et al., 2015). After the collapse of the Soviet Union, most herders were restricted to grazing only near their settlements, leading to plaque-like degradation that was very pronounced in localized areas (Abuduwaili et al., 2015). Those grasslands of Kazakhstan are now facing ecological problems such as biodiversity loss and productivity reduction (Li et al., 2015; Wu et al., 2018).

The changes in grazing patterns, the occupation of agricultural reclamation lands, and the effects of climate change due to warming and drying have given the changes in spatio-temporal patterns of various grassland ecosystem in Kazakhstan distinct characteristics. Therefore, as an important country along the “Belt and Road”, ecological changes (Luo et al., 2017) and desertification (Zhang et al., 2018) of the grasslands in Kazakhstan and central Asia have attracted increasing attention from researchers.

For animal husbandry production activities, grassland utilization and consumption represent the key elements of grassland ecosystems. When this rate of extraction exceeds the rate of replenishment, the capital of the ecosystem itself gradually shrinks. Therefore, a quantitative evaluation method is needed to measure the balance between ecosystem supply and consumption, and then to measure the carrying capacity of the ecosystem for human activities and the current carrying status. At present, the mainstream evaluation methods for carrying capacity have their own emphases. For example, the energy value analysis method focuses on unifying various natural resources and social resources into the same evaluation standard, and comprehensively analyzes the utilization status of the various resources. The ecological footprint law focuses on the space problem of sustainable human survival from the perspective of “ecological occupation”. In 2004, Imhoff et al. (2004) published a study on the net human primary productivity of terrestrial ecosystems in the journal Nature, in which the ecological supply capacity was measured by Net Primary Production (NPP). Determining human consumption of the ecosystem productivity supply by NPP, by exploring the support capacity and self- sustainability of ecosystems for human production and life, became one of the main methods for ecological assessment of regional sustainable development (Haberl et al., 2007; Yan et al., 2012 ;Du et al., 2018), and it gradually developed into an important method for assessing ecological carrying capacity (Zhao et al., 2004; Zhang et al., 2018). This method differs from the traditional methods of ecological footprint, energy analysis and material flow analysis in that this assessment method based on supply and consumption balance is more focused on finding a sustainable ecological threshold, while NPP is directly observable by remote sensing. It also uses estimated indicators, so “NPP consumption” becomes an indicator of ecosystem consumption that can both represent the human occupation of the ecosystem and reflect its spatial pattern. Remote sensing data are used to estimate the supply of grassland resources. Statistical data are used to calculate the consumption of grassland resources by animal husbandry. Then the balance of the grassland ecosystem is judged by the important means of grassland balance, which is calculated by the balance of grassland supply and consumption (Smart et al., 2010; Zhang et al., 2017; Lu et al., 2018).

Based on the supply and consumption of NPP, this study uses the statistics of animal husbandry to estimate the changes in the pattern of grassland resource consumption in each year, analyzes the spatial patterns and historical evolution of grassland consumption in Kazakhstan, and uses the net primary productivity of vegetation for many years as a measure grassland resources. The carrying capacity of the grassland ecosystem was evaluated from three dimensions: grassland resource supply, consumption and the human-land relationship, in order to understand the current status, the causes of the current grassland carrying status in Kazakhstan, and the corresponding effects on grassland ecosystems of climate change and human activities.

From 1941 to 2011, the temperature in Kazakhstan showed an increasing trend, while the annual precipitation showed a downward trend, so the climate became warmer and drier (Beurs et al., 2003; Bolch, 2006; Eisfelder et al., 2014). Many researchers have found that vegetation growth has a strong correlation with precipitation (Chen et al., 2013; Propastin et al., 2007). Although the precipitation time scale is reduced, Jiang's research (Jiang et al., 2017) shows that the vegetation in eastern Kazakhstan has an increasing trend. The trends of productivity fluctuations coincide with the volatility of Kazakhstan's supply capacity during 2000-2016 (Luo et al., 2017). The ecological carrying capacity has been increasing, but the ecological carrying status has always been rich and surplus. We think the reasons are as follows. On the one hand, because only a small amount of feed used by livestock takes up part of the ecological supply of the farmland ecosystem, there is a certain amount of error. On the other hand, compensating for the low level of labor production in Kazakhstan requires a large amount of imported meat, such as beef and horse meat (Balabaykin et al., 2015), which consumes supply resources from other regions and reduces the ecological carrying pressure to a certain extent. As early as 1930, about 80% of the livestock died due to the government's mandatory collective ownership policy; and after that incident, nomadic settlements accounted for only a small part of nomadic existence (Olcott, 1995). After the collapse of the Soviet Union, most of the herders were restricted to grazing only near their settlements, resulting in plaque-like degradation in local areas (Abuduwaili et al., 2015), and the number of livestock declined sharply. After 1991, livestock production was mainly transferred from corporate farms to individually- and family-owned farms (International, 2013). After 2000, in response to policy reforms and government support for agriculture, Kazakhstan’s crop and livestock production began to recover (Nora et al., 2007;International, 2013), and the Kazakhstan government implemented agricultural diversification to support animal husbandry production, including the development of livestock feed bases. Due to local natural conditions and technical capabilities, despite a certain degree of recovery after 2000, it is still difficult to deal with the serious natural disasters that occur in this country. After research by Alimaey and collaborators (Alimaev et al., 2008) confirmed that seasonal rotational grazing can make more rational and efficient use of pasture resources, the government has formulated some policies to implement seasonal rotational grazing in order to reduce the increasing ecological pressure.

This study takes Kazakhstan grasslands as the research object, applies large-scale remote sensing models and statistical data, and describes the grassland carrying status of each region of the country. By comparing the ecological supply-consumption relationship, we analyze the nature, policies, etc. leading to the formation of ecological load pressure patterns and laws. The possible causes of these patterns provide a basis for understanding the balance of grass and livestock in various regions of Kazakhstan and the relationship between people and the land. The discussion in this paper is an assessment of the supply capacity and current consumption patterns of local natural grassland resources, and is the basis for analyzing local grassland development and the replenishment needs of remote resources. The regional grassland carrying status is a complex phenomenon formed under the influence of many factors such as the economy, policies and the natural environment. Resources co-exist between different ecosystems in the same region (cultivated land, etc.) and flow between different regions (cross-regional pasture trading, etc.). Building on the base of this research, we can further analyze the grassland resource feeding process caused by grassland heterogeneity and the grassland resource flow process brought on by ecosystem externality, in order to more accurately grasp the grassland carrying capacity achieved through local resource endowment.

Based on the balance between the supply and consumption of grassland ecosystems, the structure and scale of animal husbandry in Kazakhstan, the grassland resource consumption caused by animal husbandry and the pressure on the supply capacity of grassland resources, the carrying status of the grassland ecosystem in Kazakhstan was assessed for 2003-2017. The study results show that:

(1) The number of livestock in Kazakhstan has increased from about 4.99×10⁷ sheep units in 2000 to about 75,391,100 sheep units in 2017. The main livestock (sheep and goats, cattle, horses, camels, etc.) have a balanced spatial distribution, with a certain proportion of the distribution found in all regions of the country. Ten of the 14 states in Kazakhstan are dominated by cattle, goats and sheep. The proportion of these two livestock types accounts for more than 75% of the entire region. The horses are distributed throughout Kazakhstan and the proportions are similar. Camels account for less in the north and east, and more in the southwest.

(2) The average annual supply of grassland resources in Kazakhstan is 5.07×10¹³ gC, the lowest year was 44.41% below the average, and the highest year was 46.55% higher than the average grassland supply capacity.During 2003- 2017, the grassland resource consumption in Kazakhstan continued to increase, with an overall increase of 52.56%. The total grassland consumption in East Kazakhstan, South Kazakhstan and Almaty was significantly higher than that of the other 11 states. The growing grassland consumption has always been less than the grassland supply, accounting for less than 30% of the grassland supply.

(3) During 2003-2017, although the grassland carrying pressure in Kazakhstan has increased, the overall pressure is still relatively small and it has remained in a state of richness and surplus. From 2003-2017, the number of wealthy areas decreased from 13 to 11, and the critical overload areas mainly appeared after 2012. The areas with high grassland carrying pressure are mainly located in Kizils Odal, where grassland productivity is low, and in South Kazakhstan and Northern Kazakhstan, where cultivated land is centralized, but the high-pressure areas have gradually expanded into the agro-pastoral zone and semi-desert zone.