Abstract
Sustainable use of water resources is of increasing importance in container plant production as a result of decreasing water availability and an increasing number of laws and regulations regarding nursery runoff. Soil moisture sensor-controlled, auto- mated irrigation can be used to irrigate when substrate volumetric water content (u) drops below a threshold, improving irrigation efficiency by applying water only as needed. We compared growth of two Gardenia jasminoides cultivars, slow-growing and challenging 'Radicans' and easier, fast-growing 'August Beauty', at various u thresholds. Our objective was to determine how irrigation can be applied more efficiently without negatively affecting plant quality, allowing for cultivar-specific guidelines. Soil moisture sensor-controlled, automated irrigation was used to maintain u thresholds of 0.20, 0.30, 0.40, or 0.50 m 3 ·m L3 . Growth of both cultivars was related to u threshold, and patterns of growth were similar in both Watkinsville and Tifton, GA. High mortality was observed at the 0.20-m 3 ·m L3 threshold with poor root establishment resulting from the low irrigation volume. Height, width, shoot dry weight, root dry weight, and leaf size were greater for the 0.40 and 0.50 m 3 ·m L3 than the 0.20 and 0.30-m 3 ·m L3 u thresholds. Irrigation volume increased with increasing u thresholds for both cultivars. For 'August Beauty', cumulative irrigation volume ranged from 0.96 to 63.21 L/plant in Tifton and 1.89 to 87.9 L/plant in Watkinsville. For 'Radicans', cumulative irrigation volume ranged from 1.32 to 126 L/plant in Tifton and from 1.38 to 261 L/plant in Watkinsville. There was a large irrigation volume difference between the 0.40 and 0.50-m 3 ·m L3 u thresholds with little additional growth, suggesting that the additional irrigation applied led to over- irrigation and leaching. Bud and flower number of 'Radicans' were greatest for the 0.40-m 3 ·m L3 u threshold, indicating that overirrigation can reduce flowering. The results of this study show that growth of the different G. jasminoides cultivars responded similarly to u threshold at both locations. Similarities in growth and differences in irrigation volume at the 0.40 and 0.50-m 3 ·m L3 u thresholds show that more efficient irrigation can be used without negatively impacting growth.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have