Row Spacing and the Use of Plant-Available Water in Sugarcane Cultivation in Water-Abundant Louisiana

Abstract

Optimizing row spacing can potentially improve yields when resources such as light and water are limited. Sugarcane in Louisiana is principally grown on rows spaced 1.8 m apart, but interest in planting on 2.4 m rows is increasing. In this study, we hypothesized that wider row spacing would have greater water availability. Soil moisture sensors were placed at 15, 30, and 45 cm depths in treatments: 1.8 and 2.4 m row spacings, two varieties (L 01-299 and HoCP 04-838), and two planting dates. Soil moisture was monitored in 15-min intervals from 2017 to 2020. Mean volumetric water content was slightly greater in 2.4 m than 1.8 m row spacing at 15 and 45 cm, but the biggest difference was observed when soil water content reached its lowest levels where 2.4 m rows had 1.1, 3.1, and 9.8 times more water available at 15, 30, and 45 cm, respectively, compared to 1.8 m row spacing. However, in both row spacings, plant-available water was always present in the top 45 cm, even during periods of low rainfall. Potentially, high water availability provides an opportunity to increase photosynthesis in sugarcane varieties by selecting for greater photosynthetic capacity and CO2 uptake through increasesd stomatal conductance.