Potential and challenges of conservation agriculture in sequestration of atmospheric CO 2 for enhancing climate-resilience and improving productivity of soil of small landholder farms.

Abstract

Abstract The projected climate change, caused by emissions from fossil fuel combustion and land use change, may adversely impact the agronomic yields and aggravate food insecurity of small landholder farms. About 500 million small landholder farms have depleted and degraded soils, while having low soil organic carbon (SOC) pools, low plant nutrient reserves, low plant-available water capacity and low agronomic yield, yet high vulnerability to changing and uncertain climate. Projected climate change may reduce rice yield by 10% for every 1°C increase in temperature, and total maize production may decline by 10% by 2050. Agronomic yield of wheat in South Asia may be adversely affected by increase in temperature during spring. Yield of other cereals (sorghum, millet) and root crops (cassava, yam) may be adversely affected by aggravation of other biotic stresses (smut, fungi, viruses, etc.). Thus, climate-resilience may be a key component of sustainable intensification of small landholder agriculture. It is in this context that conservation agriculture (CA) can be an important option. With fine-tuning for adaptation to site-specific conditions, CA has numerous benefits including erosion control, water conservation, SOC sequestration and increase in profitability and farm income. Further, CA can be implemented in synergism with other practices such as forestry and forest plantations (during early stages of tree establishment), and integrated crop-livestock (ley farming). In several farm operations, CA builds upon the traditional systems and indigenous technology. Widespread adoption of CA could sequester 1 Pg C/year globally, which could create another income stream for small landholders. Further, CA fits in with the '4 per Thousand' programme proposed at the COP-21 in Paris.