2017 ASHS Annual Conference

Citrus production in the Lower Rio Grande Valley (LRGV) faces many challenges, including drought, heavy clay soils, weeds, pests, and diseases. The semi-arid subtropical climate of the LRGV makes maintaining adequate soil moisture for plant growth and yield especially difficult. Traditional flood irrigation is the most common method of irrigation used by growers in this area; this method of irrigation leads to higher evaporation rates, fertilizer runoff and leaching, and lower water use efficiency. Microjet and drip irrigation systems are expensive to install and often require land to be taken out of production in order to create holding ponds for water, which is not feasible for many growers. The alternative method of narrow border flood irrigation reduces the amount of water applied without the expense of irrigation equipment or systems. In narrow border flood, the trees are planted on top of raised beds while furrows are irrigated. In addition to this alternate irrigation practice, plastic mesh groundcovers are installed to help conserve soil moisture by reducing the evaporation loss from the soil surface while suppressing weeds. To illustrate the effectiveness of this type of management practice, we partnered with a local citrus producer to install a demonstration plot on his property and monitored growth of trees over time. Trees were planted in beds with four treatments, raised bed with ground cover (RBGC), raised bed, no cover (RBNGC), flat bed with ground cover (FBGC) and flat bed, no ground cover (FBNGC), to determine growth rate and eventually yield in each treatment. Data were collected on soil volumetric water content, trunk diameter and plant height every month throughout the duration of the experiment. Preliminary results show that, the ground cover treatments have significantly higher tree height and trunk diameter compared to the conventional flat bed with no ground cover. The relative growth rate is higher with RBNGC followed by FBGC and RBGC. Both raised bed treatments showed more consistent soil moisture at 6 inches and 18 inches compared to the conventional flat bed treatments. Preliminary results show that by implementing these new irrigation and management practices we can promote water conservation, reduce input costs and improve plant growth.