Global achievements in soil and water conservation: The case of Conservation Agriculture

In response to the dust bowls of the mid-thirties in the USA, soil and water conservation programmes involving reduced tillage were promoted to control land degradation, particularly soil erosion. The farming and land management practices that were considered to adequately address soil and water conservation objectives were based on no-till seeding and maintenance of soil mulch cover. This collection of practices led to what became known as conservation tillage, although no-till systems by definition avoid soil disturbance by no-till direct seeding, and maintain an organic mulch cover on the soil surface. This article is an overview of achievements in soil and water conservation on agricultural lands through the experience derived from the adoption and spread of Conservation Agriculture (CA) world-wide. CA is an agro-ecological approach to sustainable production intensification. It involves the application of three inter-linked principles that underpin agricultural production systems based on locally formulated practices: (i) permanent no or minimum mechanical soil disturbance, which in practice entails direct seeding through mulch into no-till soils; (ii) maintenance of soil cover with crop residues and green manure crops, particularly legumes; and (iii) diversified cropping system involving annuals and perennial in rotations, sequences and associations. In 2011, CA had spread over 125 million hectares (9% of the global cropped land) across all continents and most agro-ecologies, including small and large farms. In addition, there is a significant area of CA orchards in the Mediterranean countries. CA is now considered to be a practical agro-ecological approach to achieving sustainable agriculture intensification. It offers environmental, economic and social advantages that are not fully possible with tillage-based production systems, as well as improved productivity and resilience, and improved ecosystem services while minimizing the excessive use of agrochemicals, energy and heavy machinery. While there are challenges to the adoption of CA, there is also increasing interest from producers, the civil society, donors and private sector institutions to further promote and service the uptake and spread of CA globally.