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1、Research ArticleA landscape perspective on sustainability of agricultural systemsAbstractAgricultural sustainability considers the effects of farm activities on social, economic, and environmental conditions at local and regional scales. Adoption of more sustainable agricultural practices entails de
2、fining sustainability, developing easily measured indicators of sustainability, moving toward integrated agricultural systems, and offering incentives or imposing regulations to affect farmer behavior. Landscape ecology is an informative discipline in considering sustainability because it provides t
3、heory and methods for dealing with spatial heterogeneity, scaling, integration, and complexity. To move toward more sustainable agriculture, we propose adopting a systems perspective, recognizing spatial heterogeneity, integrating landscape-design principles and addressing the influences of context,
4、 such as the particular products and their distribution, policy background, stakeholder values, location, temporal influences, spatial scale, and baseline conditions. Topics that need further attention at local and regional scales include (1) protocols for quantifying material and energy flows; (2)
5、standard specifications for management practices and corresponding effects; (3) incentives and disincentives for enhancing economic, environmental, and social conditions (including financial, regulatory and other behavioral motivations); (4) integrated landscape planning and management; (5) monitori
6、ng and assessment; (6) effects of societal demand; and (7) integrative policies for promoting agricultural sustainability.KeywordsContext Farm Incentives Indicators Scale Spatial heterogeneity SystemsIntroductionAgriculture is the oldest way in which humans interact with natural systems, particularl
7、y through alteration of land for crop and livestock production and the redirection of energy, nutrients, water, or biomass flows towards human consumption. As people began to alter the land to produce food, fiber, and fuel, these activities started a process in which settlement patterns, land-manage
8、ment practices, crop selection, animal production, and landscape heterogeneity influenced each other over time in a continuous process of adjustment and development.Current estimates of cropland and pasture vary between 24 and 38 % of the Earths land. Crop production occurs on about 1500 million ha
9、of the Earths land surface FAO (Food and Agriculture Organization) 2012a. This area includes arable land and land under permanent crops and is about 30 % of the land estimated to be suitable for rain-fed crop production FAO (Food and Agriculture Organization) 2003. World crop production is expected
10、to increase primarily through crop intensification complemented by the ongoing reallocation of land uses and expansion of arable land. Some studies suggest that increasing production to feed the world in 2050 could be achieved by closing “yield gaps” (e.g., Lobell et al. 2009; Snchez 2010; Foley et
11、al. 2011; Mueller et al. 2012). For example, yield of 17 major crops could be increased by 4575 % if all lands planted to those crops achieved current attainable levels (Mueller et al. 2012). To feed the world in 2050, the Food and Agriculture Organization projected arable land area could increase b
12、y about 5 % as the result of expansion in the developing world of 120 million ha and a loss of 50 million ha in developed countries for a net expansion of 70 million ha FAO (Food and Agriculture Organization) 2010. About 90 % of the anticipated growth in crop production is expected to result from hi
13、gher yields and cropping intensities FAO (Food and Agriculture Organization) 2010. Changes in climate, disturbance regimes, markets, management and other factors will affect the production and location of agricultural systems and add uncertainty to future projections.Agricultural systems have expand
14、ed and contracted in response to the needs of a growing population and by becoming specialized for specific regions with favorable soils and weather conditions, such as rice in lowlands, sugar cane in Brazil and maize in the United States. Water-management practices include irrigation and drainage.
15、Large areas of the landscapes with rain-fed agriculture, like the upper midwestern United States or low-lying regions of northern Europe, are drained to remove excess water, while Mediterranean and arid landscapes around the world require irrigation for intensive production. Some agricultural practi
16、ces are similar to those employed hundreds or even thousands of years ago. For example, cultivation of Mayan gardens based on ancient farm practices continues to sustain production in some regions of Central America today (e.g., shifting cultivation and participatory land-use planning) (Dalle et al. 2011).Increased human population has placed great pressure on agriculture by increasing demand for food, feed, fiber and energy and by displacing some of the best agricultu
