Kuang Wenhui

Spatial patterns and driving forces of land use change in China during the early 21st century

Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science (LCS) in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km × 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the “Grain for Green” policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of “Western Development”, “Revitalization of Northeast”, coupled with rapidly economic development during this period.

The climatic impacts of land use and land cover change compared among countries

Land use and land cover change (LULCC) strongly influence regional and global climate by combining both biochemical and biophysical processes. However, the biophysical process was often ignored, which may offset the biogeochemical effects, so measures to address climate change could not reach the target. Thus, the biophysical influence of LULCC is critical for understanding observed climate changes in the past and potential scenarios in the future. Therefore, it is necessary to identify the mechanisms and effects of large-scale LULCC on climate change through changing the underlying surface, and thus the energy balance. The key scientific issues on understanding the impacts of human activities on global climate that must be addressed including: (1) what are the basic scientific facts of spatial and temporal variations of LULCC in China and comparative countries? (2) How to understand the coupling driving mechanisms of human activities and climate change on the LULCC and then to forecasting the future scenarios? (3) What are the scientific mechanisms of LULCC impacts on biophysical processes of land surface, and then the climate? (4) How to estimate the contributions of LULCC to climate change by affecting biophysical processes of land surface? By international comparison, the impacts of LULCC on climate change at the local, regional and global scales were revealed and evaluated. It can provide theoretical basis for the global change, and have great significance to mitigate and adapt to global climate changes.

Forage-livestock status in farms and ranches of ecological grass-animal husbandry construction and allocation model of grain-warp-feed in Hulunbuir Agricultural Reclamation Group

In order to increase of husbandry production and to have a sustainable development of pastures, it is important to accelerate the construction of ecological grass-animal husbandry, to promote the grassland ecological carrying capacity and to reach the equilibrium in the grassland-livestock balance. We chose twenty-four farms and ranches in Hulunbuir Agricultural Reclamation Group as study area, satellite imagery from 500-m MODIS, 30-m Landsat, and 4-m GF-2 are used together with annual report data of farms and ranches. We mapped the spatial distribution and the status of degradation of grassland and we computed the net primary productivity (NPP) of farms and ranches in Hulunbuir Agricultural Reclamation Group, using remote sensing images as input data in a Vegetation Photosynthesis Model (VPM). We then analyzed the carrying capacity of grassland and its over-grazing degree and proposed the construction of artificial grassland mode of ecological grass-animal husbandry in farms and ranches. We found that about 66.16% of natural grassland has been subject to serious degradation in different degrees in the twenty-four farms and ranches, mainly manifested in the decline of grassland vegetation productivity and coverage. The grassland fragmentation area was about 1.55% of the total grassland area. Based on remote sensing the result that annual average grassland yield was about 34.07×104 t, ranging from 27.43×104 t in 2001 to 48.89×104 t in 2013 of farms and ranches in Hulunbuir Agricultural Reclamation Group. The actual grazing capacity was 164.19×104 sheep units while the theoretical grazing capacity was only 86.83×104 sheep units in Hulunbuir Agricultural Reclamation Group in 2015. The forage gap was 42.35×104 t and overload rate reached 89% without the consideration of the silage grass and purchased forage. The cultivated land area is 3.95×103 km2 in Hulunbuir Agricultural Reclamation Group. Converting 10% of the cultivated land area into artificial grassland could provide grass yield amounting to 5.86×103 km2 of the natural grassland, which would meet with the forage demand of livestock in Hulunbuir Agricultural Reclamation Group. The implementation of the Grain-Warp-Feed and the Grass-Crop rotation production mode, and the establishment of artificial grassland on cultivated land can improve the grassland quality, grassland-livestock balance, and reduce grassland degradation, which is critical to promoting the ability of the sustainable development of husbandry and ecological protection in pastures. As a measure of agricultural supply side reform, the strategy of transforming grain into forage aims to achieve effective allocation of resources.

Strategic transformation of regionalization for the agricultural comprehensive development: The example of Ningxia Hui Autonomous Region in China

Strategic transformation of regionalization for agricultural comprehensive development (ACD) was presented by the Ministry of Finance of the People’s Republic of China (MOF) in 2014. The regionalization is the premise and basis of the sustainable development and improved competitiveness for agriculture. Based on the environmental resources related to agriculture, such as cropland, climate, water resources, terrain, geomorphology, patterns of the ACD projects, distribution of ecological planning, etc., we devised 13 indices using the geographic comprehensive regionalization method. The indices took into account a combination of dynamic and static, qualitative and quantitative, as well as agricultural and ecological factors. The strategic transformation of regionalization for the ACD in Ningxia Hui Autonomous Region of China was performed; seven types were included: prioritized regions, prioritized and restricted regions, protected regions, protected and restricted regions, restricted and prioritized regions, restricted and protected regions, and restricted regions. A further 24 subtypes were used based on locations and ecological zones. The regionalization results showed that prioritized regions were mainly in northern Ningxia, the most suitable area for agriculture. The protected and restricted regions were in central and southern Ningxia. In the central part, drought was the limiting factor for agriculture, and water conservation projects there should be supported. The ecological environment is fragile in southern Ningxia, so there is a need for ecologically sound agriculture to be developed in this region. Such regionalization could achieve two goals, namely agricultural conservation and eco-environmental protection. It was performed following the requirement for scientific regionalization to include three types of regions (prioritized regions, protected regions, and restricted regions), and was applied at the township scale in a provincial or autonomous region for the first time. The results provide both guidance for the strategic transformation of the ACD in Ningxia, and a reference for similar work in other provinces.