The effect of changing patterns in soil-moisture availability on grapevine root distribution, and viticultural implications for converting full-cover irrigation into a point-source irrigation system

Abstract

Improvements in the efficiency of water use in Australian vineyards have included a move away from diffuse or ‘total cover’ irrigation techniques to drip irrigation systems. This change in irrigation method has a significant effect on moisture distribution within the soil profile, with implications for root growth, root‐system architecture, and soil‐water acquisition. Those issues are addressed in this paper. Our report is based on grapevines that had been established under a diffuse irrigation system (overhead sprinklers or microjets) and subsequently converted to drippers. Results are also presented to show the influence of soils with different water holding capacities on root distribution within a single vineyard. Variations in soil texture within a vineyard were found to influence the vertical distribution of roots, whereas irrigation history had more influence on horizontal variations in root density within a depth range. Conversion of vines from sprinkler irrigation to drippers resulted in a marked increase in total root mass (volume) under the drip line, particularly 25–50 cm below the surface. Roots were differentially influenced by irrigation history according to their diameter class. Under drip irrigation, the largest increase in root‐length density occurred with roots in diameter classes between 1 and 4 mm diameter. Grapevines established under sprinklers, and subsequently converted to drip irrigation, had significantly larger root systems (within the volume of soil sampled) than did vines maintained under sprinklers throughout. Therefore, vines established under sprinkler irrigation and then converted to drippers may be better equipped to cope with deficit irrigation during drought (via either RDI or PRD), by virtue of those additional roots.

Identifying the future water and salinity risks to irrigated viticulture in the Murray-Darling Basin, South Australia

“…Total amount of irrigation thus applied (10 mm/day/event) is similar to the amount normally applied to grapevine in the Loxton region (ICMS, 2007). The trigger point in this study was located at a 30-cm soil depth, which is similar to other field (Soar and Loveys, 2007) and modeling (Phogat et al, 2017) studies in this region and coincides with the maximum root activity for viticulture. Other studies also used a similar suction for irrigating grapevines (Edwards and Clingeleffer, 2013) at a 30-cm soil depth for well-watered conditions.…”

Evaluation of crop coefficients, water productivity, and water balance components for wine grapes irrigated at different deficit levels by a sub-surface drip

“…Location of maximum root uptake was assumed to be concentrated mainly near the drip emitter where water and nutrients were applied, although not right at the dripper (x* = 30 cm, z* = 25 cm). Soar and Loveys (2007) reported the maximum root density of drip-irrigated vines between soil depths of 25 and 50 cm. Similarly, Styles et al (2015) reported the maximum root mass density at the 30 cm depth in a drip-irrigated vineyard in South Australia.…”

Response of grapevine cv. Syrah to irrigation frequency and water distribution pattern in a clay soil

“…Viticultural research on this aspect has focused on comparing how different irrigation techniques (drip and furrow irrigation - Araujo et al, 1995, drip andmicro-sprinkler irrigation systems -Myburgh, 2012) affect root distribution and vineyard performance, or on analyzing the effect that changing from one irrigation system to another had on grapevine root distribution (Soar and Loveys, 2007), or studying the effect on yield and quality of partial root drying (Dry and Loveys, 1998;McCarthy et al, 2002).…”