**7. Agroforestry in climate change mitigation potential**

Agroforestry system acts as an atmospheric carbon sink and in carbon sequestration process, carbon is captured from the atmosphere and stored as carbon sink such as by oceans, vegetation and soils through certain biological and physical processes. Agroforestry system traps more atmospheric carbon compared to crop plants or pastureland [56, 57]. The capacity of agroforestry systems to sequester carbon depends on different factors such as tree species, age of tree, tree density, climate, geographical location, and management practices. In general, tropical humid climate sequestrates more carbon than arid, semi-arid, temperate region. On an average soil organic carbon pool in the soils of arid climate and cold region below 1 m depth is 30 and 800 tons ha−1 respectively. The total worldwide land area under agroforestry system is 1023 Mha which has potential to sequester carbon

**71**

39.27 Mg ha−1 [69].

**8. Ecosystem services from agroforestry systems**

According to the 2005 Millennium Ecosystem Assessment, human beings are relished by supporting, regulating, provisioning, and cultural services from the ecosystem. They have become the most widely used framework to study the relations between ecosystems (including natural and human-modified ecosystems) and people [70]. Agroforestry has been demonstrated to combine production

*Potential and Opportunities of Agroforestry Practices in Combating Land Degradation*

approximately 1.9 Pg over 50 years [58]. By improving the present management practices involved in agroforestry system, additional 17000 Mg year−1 carbon can be sequestrated by 2040 [59]. In another estimate, the area under agroforestry in world is 8.2% of total reported geographical area (305.6 m ha) and contributes 19.3% of total C stock under different land uses (2755.5 m t C) [60–62]. If worldwide present area of unproductive cropland and grassland of 630 Mha is converted to agroforestry which can harness additional 586000 Mg year−1 carbon by 2040. Riparian buffer, alley cropping and silvipasture system can sequester 4.7, 60.9, and 474 Tg C year−1, respectively. Additional protection of farmland and cropland with windbreak can sequester additional 8.79 Tg C year−1. Therefore, the agroforestry system in USA has a potential to sequester C as 548.4 Tg year−1. By this way, agroforestry system in USA can trap 34% of greenhouse gas in the form of CO2 [63]**.** In India, degraded land amounts over 100 Mha where only bushes and grasses grow only in monsoon season [64]. These lands are low in soil carbon and have ample scope to increase the soil carbon by planting proper tree species and grasses with proper management practices. In India, potential of agroforestry system in storing C is estimated 2400 m tons. It is estimated that the total area under agroforestry in India is 8.2% which contributes 19.3% of total carbon under different land uses [20]. Newaj et al. [65] found that *Albizia procera* under agro-silviculture system sequestered C more than in a pure tree. In this system, 2 crop rotations i.e. black gram-mustard and green gram-wheat were used. Three pruning treatments (70% canopy pruning, 50% pruning, and un-pruned) have been applied. After 3 years, it was found that sequestered carbon amounts 27.97, 22.96, and 21.33 t ha−1 in the un-pruned tree, 70% and 50% canopy pruning in agro-silvicultural system. In a homegarden with bamboo farming system in Assam India, the aboveground average carbon sequestration estimated as 1.32 Mg ha−1 yr.−1 [66], while the presence of organic C was 30% and 114% greater in home gardens in comparison to the coconut plantations and rice fields [67]. Howlett et al. [68] found in a silvipastoral system in northeast spain a greater level of organic C in birch (*Betula pendula*) in comparison to pine (*Pinus radiata*). The reason is attributed to the fact that the subsoil environment created by pine is less conducive for plant growth and decomposition is reduced and the organic C built over time is less. In a study at Bahia, Brazil aboveground and below ground C sequestration had been studied under cacao (*Theobroma cacao* L.) based agroforestry system (AFS). In this cacao-based AFS, cacao was planted with woody species for shade such as *Erythrina spp.* and *Gliricidia spp.* or under these in natural forests. Cacao cultivated under natural forest trees is known as cabruca. The huge amount of belowground C accumulation is due to a large amount of leaf litter, decomposition roots of both cacao and woody trees. It is estimated that total amount of C stored in cacao based AFS in Bahia below 1 m depth was 302 Mg ha−1. It has been reported that shade trees (55 trees ha−1) in cabruca system stores 44% more carbon than the Erythrina trees (35 trees ha−1) though the mean C stored by cacao + Erythrina and cabruca system was similar with a mean of

*DOI: http://dx.doi.org/10.5772/intechopen.97843*

#### *Potential and Opportunities of Agroforestry Practices in Combating Land Degradation DOI: http://dx.doi.org/10.5772/intechopen.97843*

approximately 1.9 Pg over 50 years [58]. By improving the present management practices involved in agroforestry system, additional 17000 Mg year−1 carbon can be sequestrated by 2040 [59]. In another estimate, the area under agroforestry in world is 8.2% of total reported geographical area (305.6 m ha) and contributes 19.3% of total C stock under different land uses (2755.5 m t C) [60–62]. If worldwide present area of unproductive cropland and grassland of 630 Mha is converted to agroforestry which can harness additional 586000 Mg year−1 carbon by 2040. Riparian buffer, alley cropping and silvipasture system can sequester 4.7, 60.9, and 474 Tg C year−1, respectively. Additional protection of farmland and cropland with windbreak can sequester additional 8.79 Tg C year−1. Therefore, the agroforestry system in USA has a potential to sequester C as 548.4 Tg year−1. By this way, agroforestry system in USA can trap 34% of greenhouse gas in the form of CO2 [63]**.** In India, degraded land amounts over 100 Mha where only bushes and grasses grow only in monsoon season [64]. These lands are low in soil carbon and have ample scope to increase the soil carbon by planting proper tree species and grasses with proper management practices. In India, potential of agroforestry system in storing C is estimated 2400 m tons. It is estimated that the total area under agroforestry in India is 8.2% which contributes 19.3% of total carbon under different land uses [20]. Newaj et al. [65] found that *Albizia procera* under agro-silviculture system sequestered C more than in a pure tree. In this system, 2 crop rotations i.e. black gram-mustard and green gram-wheat were used. Three pruning treatments (70% canopy pruning, 50% pruning, and un-pruned) have been applied. After 3 years, it was found that sequestered carbon amounts 27.97, 22.96, and 21.33 t ha−1 in the un-pruned tree, 70% and 50% canopy pruning in agro-silvicultural system. In a homegarden with bamboo farming system in Assam India, the aboveground average carbon sequestration estimated as 1.32 Mg ha−1 yr.−1 [66], while the presence of organic C was 30% and 114% greater in home gardens in comparison to the coconut plantations and rice fields [67]. Howlett et al. [68] found in a silvipastoral system in northeast spain a greater level of organic C in birch (*Betula pendula*) in comparison to pine (*Pinus radiata*). The reason is attributed to the fact that the subsoil environment created by pine is less conducive for plant growth and decomposition is reduced and the organic C built over time is less. In a study at Bahia, Brazil aboveground and below ground C sequestration had been studied under cacao (*Theobroma cacao* L.) based agroforestry system (AFS). In this cacao-based AFS, cacao was planted with woody species for shade such as *Erythrina spp.* and *Gliricidia spp.* or under these in natural forests. Cacao cultivated under natural forest trees is known as cabruca. The huge amount of belowground C accumulation is due to a large amount of leaf litter, decomposition roots of both cacao and woody trees. It is estimated that total amount of C stored in cacao based AFS in Bahia below 1 m depth was 302 Mg ha−1. It has been reported that shade trees (55 trees ha−1) in cabruca system stores 44% more carbon than the Erythrina trees (35 trees ha−1) though the mean C stored by cacao + Erythrina and cabruca system was similar with a mean of 39.27 Mg ha−1 [69].
