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Evaluation of the healthy productivity of cultivated land in China, analysis of key problems of different regions that endangers cultivated land health is of great significance to explore sustainable cultivated land utilization path and safeguard national food security and ecological security. The evaluation of cultivated land healthy productivity should be executed base on integration of existing evaluation indicators system and evaluation method achievements and clarification of key factor states and driving processes that affecting cultivated land health from the perspective of cultivated land components. And interaction characteristics between cultivated land health and cultivated land productivity should be analyzed by coupling them with each other. In this paper, we selected 65 counties (cities) nationwide as research regions with considering the difference of climate conditions in different regions of China, and used 5 categories of indicators including topographic characteristics, soil properties, tillage conditions, environmental conditions and biological characteristics to present the cultivated land health status. And on that basis, we defined critical health threshold and critical sub-health threshold of different indicators by analyzing counties’ indicator standard deviation convergence characteristics and scoring rules. We divided all pilot counties into three statuses: Health, sub-health and unhealth, and analyzed spatial distribution features of counties with different health status. Furthermore, regional climate conditions indicator, cultivated land natural conditions indicator and tillage technique level indicator had been synthetically integrated to evaluate the productivity of cultivated land, and regional cultivated land health-productivity interaction characteristic had been analyzed. Experimental result showed that counties whose cultivated land in sub-healthy or unhealthy status expressed significant regional features, and the key factors of limiting cultivated land health were different among pilot counties. On the one hand, the sub-health status cases caused by inferior farming conditions indicator were more common (accounting for nearly 40% of pilot counties) than other indicators, which was not only manifested by serious fragmentation of cultivated land and imperfect farmland infrastructure, but also reflected the urgent requirement for promoting high-standard farmland construction. On the other hand, the form of biological characteristics was severe, indicating that under the interaction of climatic conditions, soil structure and tillage technology, the ability of cultivated land to guarantee the healthy growth of animals was facing degradation. Furthermore, through coupling analysis of cultivated land health and cultivated land productivity, we divided the cultivated land healthy productivity characteristics of pilot counties into six categories: “health-high productivity”, “health-low productivity”, “sub-health-high productivity”, “sub-health-low productivity”, “unhealth-high productivity” and “unhealth-low productivity”, and respectively analyzed the regional farmland protection directions for each category. “Sub-health/unhealth-high productivity” type was widely distributed, which was the core region for implementation of “storing grain on land and storing grain in technology” strategy in China. Therefore, it is necessary to give consideration to the health and productivity of cultivated land in this region, and strengthen the research and practice on methods to improve the health of cultivated land. This study provides scientific basis for improving cultivated land healthy productivity and provides effective support for designing protection paths of cultivated land resources in different regions. [ABSTRACT FROM AUTHOR]

Evaluation of the healthy productivity of cultivated land in China, analysis of key problems of different regions that endangers cultivated land health is of great significance to explore sustainable cultivated land utilization path and safeguard national food security and ecological security. The evaluation of cultivated land healthy productivity should be executed base on integration of existing evaluation indicators system and evaluation method achievements and clarification of key factor states and driving processes that affecting cultivated land health from the perspective of cultivated land components. And interaction characteristics between cultivated land health and cultivated land productivity should be analyzed by coupling them with each other. In this paper, we selected 65 counties (cities) nationwide as research regions with considering the difference of climate conditions in different regions of China, and used 5 categories of indicators including topographic characteristics, soil properties, tillage conditions, environmental conditions and biological characteristics to present the cultivated land health status. And on that basis, we defined critical health threshold and critical sub-health threshold of different indicators by analyzing counties’ indicator standard deviation convergence characteristics and scoring rules. We divided all pilot counties into three statuses: Health, sub-health and unhealth, and analyzed spatial distribution features of counties with different health status. Furthermore, regional climate conditions indicator, cultivated land natural conditions indicator and tillage technique level indicator had been synthetically integrated to evaluate the productivity of cultivated land, and regional cultivated land health-productivity interaction characteristic had been analyzed. Experimental result showed that counties whose cultivated land in sub-healthy or unhealthy status expressed significant regional features, and the key factors of limiting cultivated land health were different among pilot counties. On the one hand, the sub-health status cases caused by inferior farming conditions indicator were more common (accounting for nearly 40% of pilot counties) than other indicators, which was not only manifested by serious fragmentation of cultivated land and imperfect farmland infrastructure, but also reflected the urgent requirement for promoting high-standard farmland construction. On the other hand, the form of biological characteristics was severe, indicating that under the interaction of climatic conditions, soil structure and tillage technology, the ability of cultivated land to guarantee the healthy growth of animals was facing degradation. Furthermore, through coupling analysis of cultivated land health and cultivated land productivity, we divided the cultivated land healthy productivity characteristics of pilot counties into six categories: “health-high productivity”, “health-low productivity”, “sub-health-high productivity”, “sub-health-low productivity”, “ill-health-high productivity” and “ill health-low productivity”, and respectively analyzed the regional farmland protection directions for each category. “Sub-health/ill-health-high productivity” type was widely distributed, which was the core region for implementation of “storing grain on land and storing grain in technology” strategy in China. Therefore, it is necessary to give consideration to the health and productivity of cultivated land in this region, and strengthen the research and practice on methods to improve the health of cultivated land. This study provides scientific basis for improving cultivated land healthy productivity and provides effective support for designing protection paths of cultivated land resources in different regions. [ABSTRACT FROM AUTHOR]

The Yellow River flows through an extensive aeolian alluvial plain in Ningxia and Inner Mongolia plateau, which extends from Xiaheyan in Ningxia to Toudaoguai in Inner Mongolia. The Hedong sandy land, the Ulanbuh Desert and the Kubuqi Desert all border on the Yellow River. Frequent strong winds and erodible surfaces cause extreme wind-erosion process in the watershed of Ningxia-Inner Mongolia reach of the Yellow River. A large amount of aeolian sediment flows into the main stream and tributaries of the Yellow River by particle saltation and dune avalanche, which result in the continuous elevation of riverbed. Especially since 1986, the combined operation of Longyangxia Reservoir and Liujiaxia Reservoir has decreased the number and discharge of the flood crest, and lowered the erosiveness of the flow in the upper reach of the Yellow River. In this situation, the siltation of the Ningxia-Inner Mongolia reach of the Yellow River is severer and severer. To resolve the silting problem in this reach, it is urgent to estimate the spatial and temporal variations of wind erosion hazards and the quantities of aeolian sediment fed into the river in this watershed. In this study, the models of IWEMS (integrated wind-erosion modelling system) and RWEQ (revised wind erosion equation) were selected to estimate the wind erosion modulus in this watershed. The observed data in the field in 2011 and 2012 were used to calibrate the models, and the calibration result showed that the simulation accuracies of the 2 models were both satisfactory. Using the calibrated models, the wind erosion moduli in this watershed were obtained. The results showed that the wind erosion moduli in this watershed ranged from 0 to 27 780.6 t/(km2-a) in the period from 1986 to 1995, from 0 to 33 673.1 t/(km2-a) during 1996-2002, from 0 to 37 251.3 t/(km2-a) in the period from 2003 to 2007, and from 0 to 16 111.4 t/(km2-a) in the period from 2008 to 2013, respectively. Since 1986, the wind erosion hazards mainly occurred in the sandy lands such as the Ulanbuh Desert, the Kubuqi Desert and the Hedong sandy land. The wind erosion modulus of the Hedong sandy land gradually dropped from 1986 till now, but the wind erosion modulus of the Ulanbuh Desert was increasingly highlighting in this period, and this desert became to the region with severest wind erosion hazard in the whole watershed. The results also showed that the areas having wind erosion risk in the watershed of the Ningxia-Inner Mongolia reach of the Yellow River were diminishing gradually in these years. The average wind erosion modulus of this watershed was also decreasing, and the fitting regression function between average wind erosion modulus and time showed that the slope was high to -182.81. Based on the estimated wind erosion modulus in watershed of Ningxia-Inner Mongolia reach of the Yellow River, the quantities of aeolian sediment blown into the different reaches of the Yellow River were calculated by aeolian sediment transport equations. The results showed that the Shizuishan- Bayangol reach had the highest value, and the average quantity of aeolian sediment blown into the Yellow River was 9.31 x 106 t/a. The quantity in the Xiaheyan-Qingtongxia reach was lowest, and it was only 7.6 x 105 t/a. Excluding in Shizuishan- Bayangol Reach, in the other reaches, the quantities of aeolian sediment blown into the river did not show the trend of obviously decreasing with time. Through analyzing the relationship between wind erosion modulus and changes of climate and land use, we found the dropping wind erosion modulus in watershed of Ningxia-Inner Mongolia reach of the Yellow River was mainly affected by the climate change. The study results in this paper are not only meaningful for solving the siltation in Ningxia-Inner Mongolia reach of the Yellow River, but also important to the complete the protection systems of wind-blown hazards in this watershed. [ABSTRACT FROM AUTHOR]

Cultivated land is an important indicator of landscape changes driven by human activities. Mapping the spatio-temporal changes of cultivated lands will help us to understand its corresponding environmental and ecological changes in their downstream areas. The Manas drainage basin is the key area of agricultural region in the northern slope of the Tianshan Mountains. However, the drastic farmland reclamation in the last 50 years makes irrigation water increasing rapidly, leading to environmental degradation in the downstream of the Manas River. In this paper, remote sensing and GIS technologies are used to analyze the spatio-temporal characteristics of farmland changes in the Manas drainage basin under the condition of intense soil-water utilization. Firstly, remote sensing images in 1962, 1977, 1989, 2000 and 2010 are applied to map land use changes with the cognition classification software and manual edition. Then the temporal process and spatial pattern of land cover changes are analyzed by geo-statistics and landscape analysis. On the temporal scale, the cultivated land changes and its mutual transition relationships with other land types are analyzed with areal ratio and transition matrix methods; on the spatial scale, GIS spatial analysis tool and landscape class level index are used to describe the characteristics of farmland expansion or shrinking changes in different regions and different land patches. Finally, hydrological data and irrigation construction data are used to explain the impact of climate change and human activities on the farmland landscape. The results show that: (1) The overall land use changes of the Manas drainage basin in the last 50 years are as follows: cultivated land and built-up areas increase continuously, while the unutilized land, wetland and snow/glacier have been decreasing steadily; grassland area is increasing in the former 20 years and then decreasing gradually in the last 30 years; the intensity of land use changes keeps stable after dramatic changes. (2) The overall cultivated land transformations have shifted from outward and inward transformations to single inward transformation; in inward land types, grassland and unutilized land are the main inward land types to farmland, and woodland and wetland take larger percentages in the first 20 years, while less percentages in the later 30 years; in outward land types, built-up land and grassland are the main outward land types, and grassland and unutilized land have larger percentages in the former 20 years due to cultivated land degradation; the total area of inward land types far exceeds than that of the outward land types, and the cultivated land area is steadily increasing in the last 50 years. (3) The focus of cultivated land expansion has shifted from the margins of cities to desert regions, and the newly-increased farmland gradually from the upstream to the downstream; cultivated land expansion firstly begins at the Changji Hutubi and Manas County in the former 20 years, then shifts to Shawan County, the river's surrounding areas and northern deserts; the cultivated landscapes are characterized from discrete and messy pieces into continuous land patches, so the advantage of cultivated landscape is increasing, while the landscape diversity and heterogeneity are decreasing due to land parcel combinations. (4) The increasing precipitation and runoff in the Manas drainage basin provide more water resource for cultivated land reclamation, and reservoir and irrigation channel construction have positive effects on spatial expansion of the cultivated land; when reservoirs and channels are built up, cultivated land will expand correspondingly in a rapid rate in the next decade, and hence the spatio-temporal processes of farmland expansion have high relations with the irrigation facilities. (5) The increasing water resource induced by climate change cannot keep up with the increasing speed of the farmland, and water resource is in the state of over exploitation; measures must be taken to reduce the amount of irrigated water, so as to improve ecological environments in the downstream of the Manas River. [ABSTRACT FROM AUTHOR]

Cultivated land is an important indicator of landscape changes driven by human activities. Mapping the spatio-temporal changes of cultivated lands will help us to understand its corresponding environmental and ecological changes in their downstream areas. The Manas drainage basin is the key area of agricultural region in the northern slope of the Tianshan Mountains. However, the drastic farmland reclamation in the last 50 years makes irrigation water increasing rapidly, leading to environmental degradation in the downstream of the Manas River. In this paper, remote sensing and GIS technologies are used to analyze the spatio-temporal characteristics of farmland changes in the Manas drainage basin under the condition of intense soil-water utilization. Firstly, remote sensing images in 1962, 1977, 1989, 2000 and 2010 are applied to map land use changes with the cognition classification software and manual edition. Then the temporal process and spatial pattern of land cover changes are analyzed by geo-statistics and landscape analysis. On the temporal scale, the cultivated land changes and its mutual transition relationships with other land types are analyzed with areal ratio and transition matrix methods; on the spatial scale, GIS spatial analysis tool and landscape class level index are used to describe the characteristics of farmland expansion or shrinking changes in different regions and different land patches. Finally, hydrological data and irrigation construction data are used to explain the impact of climate change and human activities on the farmland landscape. The results show that: (1) The overall land use changes of the Manas drainage basin in the last 50 years are as follows: cultivated land and built-up areas increase continuously, while the unutilized land, wetland and snow/glacier have been decreasing steadily; grassland area is increasing in the former 20 years and then decreasing gradually in the last 30 years; the intensity of land use changes keeps stable after dramatic changes. (2) The overall cultivated land transformations have shifted from outward and inward transformations to single inward transformation; in inward land types, grassland and unutilized land are the main inward land types to farmland, and woodland and wetland take larger percentages in the first 20 years, while less percentages in the later 30 years; in outward land types, built-up land and grassland are the main outward land types, and grassland and unutilized land have larger percentages in the former 20 years due to cultivated land degradation; the total area of inward land types far exceeds than that of the outward land types, and the cultivated land area is steadily increasing in the last 50 years. (3) The focus of cultivated land expansion has shifted from the margins of cities to desert regions, and the newly-increased farmland gradually from the upstream to the downstream; cultivated land expansion firstly begins at the Changji Hutubi and Manas County in the former 20 years, then shifts to Shawan County, the river's surrounding areas and northern deserts; the cultivated landscapes are characterized from discrete and messy pieces into continuous land patches, so the advantage of cultivated landscape is increasing, while the landscape diversity and heterogeneity are decreasing due to land parcel combinations. (4) The increasing precipitation and runoff in the Manas drainage basin provide more water resource for cultivated land reclamation, and reservoir and irrigation channel construction have positive effects on spatial expansion of the cultivated land; when reservoirs and channels are built up, cultivated land will expand correspondingly in a rapid rate in the next decade, and hence the spatio-temporal processes of farmland expansion have high relations with the irrigation facilities. (5) The increasing water resource induced by climate change cannot keep up with the increasing speed of the farmland, and water resource is in the state of over exploitation; measures must be taken to reduce the amount of irrigated water, so as to improve ecological environments in the downstream of the Manas River. [ABSTRACT FROM AUTHOR]