conditions that spur local action towards natural resource improvements, and an understanding of this dynamic is needed to effectively support local initiatives. Stabilizing and improving the natural resource base of agriculture are essential preconditions  for investing in technologies  for long-term adaptation to climate change (Stocking, 2003; Sanchez, 2005).

Reduction of greenhouse gas emission for agriculture. Re­duction of N2O emissions from agriculture could be achieved by better matching fertilizer application with plant demand through the use of site-specific nutrient management that only uses fertilizer N to meet the increment not supplied by indigenous nutrient sources; split fertilizer applications; use of slow-release fertilizer N; and nitrification inhibitors (DeAngelo et al, 2005; Pampolino et al., 2007). Another op­tion to address N2O emissions would be the use of biological means to inhibit or control nitrification in soils. Gene trans­fer from species exhibiting biological nitrification inhibition to cultivated species could offer another way to reduce N2O emissions to the atmosphere and nitrate pollution of water bodies (Fillery, 2007; Subbarao et al., 2007).
        Improved management of agriculture and rangelands targeted  at  soil conservation,  agroforestry,  conservation tillage (especially no-till), agricultural intensification, and rehabilitation of degraded land can yield C sequestration benefits (IPCC, 2000; Izaurralde et al., 2001; Lal, 2004). Carbon sequestration potential in soils is greatest on de­graded soils (Lal, 2004), especially those with relatively high clay content (Duxbury, 2005; Lal, 2004).
        Another promising approach would be to use plant material to produce biochar and store it in soil (Lehman, 2007a). Heating plant biomass without oxygen (a process known as low-temperature pyrolysis) converts plant mate­rial (trees, grasses or crop residues) into bioenergy, and in the process creates biochar as a coproduct. Biochar is a very stable compound with a high carbon content, surface area, and charge density; it has high stability against decay, and superior nutrient retention capacity relative to other forms of soil organic matter (Lehmann et al., 2006). The potential environmental benefits of pyrolysis combined with biochar application to soil include a net withdrawal of atmospheric CO2, enhancement of soil fertility, and reduced pollution of waterways through retention of fertilizer N and P to bio­char surfaces (Lehmann, 2007b). Future research is needed to more fully understand the effect of pyrolysis conditions, feedstock type, and soil properties on the longevity and nu­trient retention capacity of biochar.
        The robustness of soil carbon sequestration as a perma­nent climate change mitigation strategy has been questioned because soil carbon, like any other biological reservoir, may be reverted back to the atmosphere as CO2 if the carbon sequestering practice (e.g., no till practice) were to be aban­doned or practiced less intensively. Increasing soil organic matter through carbon sequestering practices contributes directly to the long-term productivity of soil, water, and food resources (IPCC, 2000; Lal, 2004). Thus it would seem unlikely that farmers would suddenly abandon systems of production that bring so many economic and environmen­tal benefits. Other reports suggest that certain soil carbon sequestering practices, such as no till, may increase N2O

emissions (Ball et al., 1999; Duxbury, 2005). This outcome, however, may be location specific (e.g., humid climatic con­ditions) as revealed by a comprehensive review of Canadian agroecosystem studies (Helgason et al., 2005).
        Globally, farmers continue to adopt no-till as their con­ventional production system. As of 2001, no-till agriculture had been adopted across more than 70 million ha worldwide with major expansion in South America (e.g., Argentina, Brazil, and Paraguay) (Izaurralde and Rice, 2006). With an area under cropland estimated globally at 1.5 billion ha, there exists a significant potential to increase the adoption of no-till as well as other improved agricultural practices, which would have other environmental benefits such as im­proved soil quality and fertility, reduced soil erosion, and improved habitat for wildlife. Much work remains to be done, however, in order to adapt no-till agriculture to the great variety of topographic, climatic, edaphic, land tenure, land size, economic, and cultural conditions that exist in agricultural regions of the world.
         In developing strategies all potential GHG emissions need to be considered for example, efforts to reduce CH4 emissions in rice can lead to greater N2O emissions through changes in soil nitrogen dynamics (Wassmann et al., 2004; DeAngelo et al., 2005; Yue et al., 2005; Li et al., 2006). Similarly, conservation tillage for soil C sequestration can result in elevated N2O emissions through increased fertilizer use and accelerated denitrification in soils (Ball et al., 1999; Duxbury, 2005). However, one of the most comprehensive long-term studies of GHG emissions across several land use practices in Michigan (Robertson et al., 2000) revealed that no-till agricultural methods had the lowest Global Warm­ing Potential when compared to conventional and organic agricultural methods.
          From a GHG mitigation standpoint, strategies that em­phasize the avoidance of N2O and CH4 emissions have a permanent effect as long as avoided emissions are tied to higher productivity, such as through increased energy effi­ciency and better factor productivity (Smith et al., 2007). In­deed, many of the practices that avoid GHG emissions and increase C sequestration also improve agricultural efficiency and the economics of production. For example, improving water and fertilizer use efficiency to reduce CH4 and N2O emissions also leads to gains in factor productivity (Gupta and Seth, 2006; Hobbs et al., 2003) while practices that promote soil C sequestration can greatly enhance soil qual­ity (Lal, 2005). Improved water management in rice produc­tion can have multiple benefits including saving water while maintaining yields, reducing CH4 emissions, and reducing disease such as malaria and Japanese encephalitis (van der Hoek et al., 2007). There is significant scale for achieving this "win-win" approach, with the approach largely determined by the size and input intensity of the production system, e.g., N-fixing legumes in smallholder systems and precision agriculture in large systems (Gregory et al., 2000).
         There is potential for achieving significant future reduc­tions in CH4 emissions from rice through improved water management. For example, CH4 emissions from China's rice paddies have declined by an average of 40% over the last two decades, with an additional 20 to 60% reduction possible by 2020 through combining the current practice of mid-season drainage with the adoption of shallow flooding,