Conservation Agriculture as an Alternative for Soil Erosion Control and Crop Production in Steep-slopes Regions Cultivated by Small-scale Farmers in Motozintla, Mexico

Abstract

Agricultural activities in steep-slope regions of the world have been increasing in recent years. When annual crops are produced in these regions, high soil erosion rates become a constant threat. An extended body of literature proposes reforestation or plantations with perennial crops as potential solutions. However, such approaches fail to meet the needs of the small-scale farmers who rely on annual crops to produce the lion’s share of their food. Another commonly used measure to tackle erosion is the construction of physical barriers – a solution that demands substantial investment, for both implementation and maintenance. Analternative solution is conservation agriculture (CA), which is a cropping system based on three principles: 1) minimal soil disturbance; 2) crop rotations and/or intercropping, and 3) permanent soil cover through crop residue management. Using longitudinal statistical analysis this research – based on survey data (154 observations) collected in 1994 and 2008 within two <i>e</i><i>jidos</i> of Motozintla in the state of Chiapas, Mexico – found that under CA, maize (<i>Zea</i><i> </i><i>mays</i>) and bean (<i>Phaseolus</i><i> </i><i>vulgaris</i>) yields remained at minimum consistent, and in some cases increased over time. Maize yields reached 3.3 ton ha<SUP>-1</SUP>, whilst bean reached 262 kg ha<SUP>-1</SUP>. Maize yields were also consistently higher than the long-term state's average (1987-2012) of 2.3 ton ha<SUP>-1</SUP>. Moreover, 90% of the farmers perceived that CA improved soil fertility and 99% observed that CA effectively controlled erosion. The traditional system in these two <i>ejidos</i><i> </i>presented a number of enabling characteristics for facilitating CA implementation: no mechanisation was being utilized, intercropping was already a common practice, and the main competitor for crop residue use (ruminants) could eventually be substituted for other livestock such as pigs. This research provides evidence to demonstrate that long-term adoption of CA in a steep-slope region can help to control soil erosion whilst allowing farmers to produce their staple crops.