Carbon farming
This can also aid plant growth, improve soil water retention capacity[2] and reduce fertilizer use.
Agricultural methods for carbon farming include adjusting how tillage and livestock grazing is done, using organic mulch or compost, working with biochar and terra preta, and changing the crop types.
Some countries have government policies that give financial incentives to farmers to use carbon farming methods.
[7] It is important to maximize environmental benefits of carbon farming by keeping in mind ecosystem services at the same time.
[8] Agricultural sequestration practices may have positive effects on soil, air, and water quality, be beneficial to wildlife, and expand food production.
[10] Globally, soils are estimated to contain >8,580 gigatons of organic carbon, about ten times the amount in the atmosphere and much more than in vegetation.
This is done by selecting farming methods that return biomass to the soil and enhance the conditions in which the carbon within the plants will be reduced to its elemental nature and stored in a stable state.
Ruminants like cows and sheep produce not only CO2, but also methane due to the microbes residing in their digestive system.
By contrast, allowing animals to range over a large area for an extended period can destroy the grassland.
[25] The reduction or complete halt of tilling will create an increase in the soil carbon concentrations of topsoil.
[25] A 2013 study found that a single compost application significantly and durably increased grassland carbon storage by 25–70%.
Soil N2O emissions from temperate grasslands amended with chemical fertilizers and manures were orders of magnitude higher.
[29] Another study found that grasslands treated with .5" of commercial compost began absorbing carbon at an annual rate of nearly 1.5 tons/acre and continued to do so in subsequent years.
Globally up to 12% of the anthropogenic carbon emissions from land use change (0.21 gigatonnes) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char.
[30] Cover crops are fast-growing species planted to protect soils from wind and water erosion during the off-growing season.
[31] Forestry and agriculture are both land-based human activities that add up to contribute approximately a third of the world's greenhouse gas emissions.
[38] Compared with other fast-growing tree species, bamboo is only superior in its ability to sequester carbon if selectively harvested.
[39] Bamboo forests are especially high in potential for carbon sequestration if the cultivated plant material is turned into durable products that keep the carbon in the plant material for a long period because bamboo is both fast growing and regrows strongly following an annual harvest.
Because reduction of atmospheric CO2 is a long-term concern, farmers can be reluctant to adopt more expensive agricultural techniques when there is not a clear crop, soil, or economic benefit.
Individual land owners are sometimes given incentives to use carbon farming methods through government policies.
When ecosystem restoration is used as a form of carbon farming, there can be a lack of knowledge that is disadvantageous in project planning.
[citation needed] Another criticism says that no-till practices may increase herbicide use, diminishing or eliminating carbon benefits.
[26] Composting is not an NRCS-approved technique and its impacts on native species and greenhouse emissions during production have not been fully resolved.
[25] The country's Direct Action Plan states "The single largest opportunity for CO2 emissions reduction in Australia is through bio-sequestration in general, and in particular, the replenishment of our soil carbons."
In studies of test plots over 20 years showed increased microbial activity when farmers incorporated organic matter or reduced tillage.
[25] In California multiple Resource Conservation Districts (RCDs) support local partnerships to develop and implement carbon farming,[2] In 2015 the agency that administers California's carbon-credit exchange began granting credits to farmers who compost grazing lands.
[25] In 2016 Chevrolet partnered with the US Department of Agriculture (USDA) to purchase 40,000 carbon credits from ranchers on 11,000 no-till acres.
[25] In 2017 multiple US states passed legislation in support of carbon farming and soil health.
