Faced with regional water shortages compounded by drought conditions, farmers in South Australia and other areas need to optimize irrigation systems in order to maintain crop productivity. The potential for deficit irrigation (DI) to contribute to the dual goals of water conservation and greenhouse tomato yield maximization was explored by University of South Australia researchers.

Under DI, irrigation is applied during drought-sensitive growth stages of a crop and is limited outside these The experimental setup. Source: Jeet Chand et al.The experimental setup. Source: Jeet Chand et al.periods if rainfall provides a minimum supply of water. The water restriction is typically limited to the vegetative stages and the late ripening period of plant growth. Any crop yield reduction is largely offset by increased irrigation water productivity.

Groundwater, recycled wastewater and a mixture of these resources were applied by drip irrigation to pot-grown tomatoes. Irrigation scenarios were designed to maintain soil moisture content at 60%, 70%, 80% or 100% of field capacity. Recycled wastewater outperformed both groundwater and a mix of 50% groundwater/50% recycled wastewater. While the highest growth levels were realized at 100% field capacity, DI strategies ensured maximum water efficiency and desirable crop growth and yield at 80% field capacity.

The research is published in Agriculture.

To contact the author of this article, email shimmelstein@globalspec.com