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'+' denotes reduced emission or enhanced removal (positive mitigating effect), '—' denotes negative mitigating effect, '±' denotes uncertain or variable effect.

'+' denotes reduced emission or enhanced removal (positive mitigating effect), '—' denotes negative mitigating effect, '±' denotes uncertain or variable effect.

agriculture from a net contributor to GHG emission to a net sink via C sequestration (Reicosky et al. 2000).

a. Tillage and residue management: Advanced crop growing techniques now allow many crops to be grown with minimal tillage (reduced tillage) or without tillage (no-tillage). Since soil disturbance tends to stimulate soil C losses through enhanced decomposition and erosion, reduced or no-tillage agriculture often results in soil C gain (Ogle et al. 2005). At least, in the short-term, tillage induces CO2 emission proportional to the volume of soil distributed (Reicosky and Archer 2007). During the course of 14 years, all tillage and cropping treatments lost SOC compared to the initial SOC levels, while conservation tillage and no-tillage lost the least (Huggins et al. 2007). Collectively, these results suggest that C sequestration due to no-tillage or conservation/reduced tillage depends on depth of soil sampling, crop management and duration of continuous low-intensity tillage system.

b. Water management: About 18% of the world's croplands now receive supplementary water through irrigation (Millenium Ecosystem Assessment 2005). Expanding this area or using more effective irrigation measures can enhance C storage in soils through enhanced yields and residue returns (Lal 2004). In a long-term experiment, the long period of soil sub-mergence under rice cultivation conferred recalcitrant character to the SOC, leading to its stabilization in non-labile pools which results into an enrichment of the SOC stock and restriction to the gaseous C loading into the atmosphere (Mandal et al. 2008). However, some of these gains might be offset by CO2 from energy used to deliver the water (Mosier et al. 2005).

c. Land-use change: One of the most effective methods of reducing emissions is to allow or encourage the reversion of cropland to another land cover, typically one similar to the native vegetation. Such land cover change often increases storage of C, e.g. converting arable cropland to grassland typically results in the accrual of soil C owing to lower soil disturbance and reduced C removal in harvested products (Paustian et al. 2004). Similarly, converting drained croplands back to wetland can result in rapid accumulation of soil C (removal of atmospheric CO2). Planting trees can also reduce emissions and may also increase the soil C sequestration (Mutuo et al. 2005). However, since land conversion comes at the expense of loss of agricultural productivity, it is usually an option which banks on surplus agricultural land or crop lands of marginal productivity.

d. Bioenergy: Agricultural crops and residues are being increasingly seen as sources of feedstocks for energy to displace fossil fuels. These products can be burned directly, but are often processed further to generate liquid fuel (Richter 2004). Biomass fuels are C-neutral, because they release recently fixed CO2 (via photosynthesis) which does not shift the C-cycle. The net benefit of atmospheric CO2, however, depends on energy used in growing and processing bioenergy feedstock (Spatari et al. 2005).

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Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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