Conservation agriculture increases soil organic carbon and residual water content in upland crop production systems

Abstract

Conservation agriculture involves minimum soil disturbance, continuous ground cover, and diversified crop rotations or mixtures. Conservation agriculture production systems (CAPS) have the potential to improve soil quality if appropriate cropping systems are developed. In this study, five CAPS including different cropping patterns and cover crops under two fertility levels, and a plow-based system as control, were studied in a typical upland agricultural area in northern Mindanao in the Philippines. Results showed that soil organic carbon (SOC) at 0- 5-cm depth for all CAPS treatments generally increased with time while SOC under the plow-based system tended to decline over time for both the high (120, 60 and 60 kg N P K ha-1) and moderate (60-30-30 kg N P K ha-1) fertility levels. The cropping system with maize + Stylosanthes guianensis in the first year followed by Stylosanthes guianensis and fallow in the second year, and the cassava + Stylosanthes guianensis exhibited the highest rate of SOC increase for high and moderate fertility levels, respectively. After one, two, and three cropping seasons, plots under CAPS had significantly higher soil residual water content (RWC) than under plow-based systems. Results of this study suggest that conservation agriculture has a positive impact on soil quality, while till systems negatively impact soil characteristics.

Keywords

• Upland agriculture
• soil quality
• climate change adaptation
• cropping systems