Impact of soil variability on evapotranspiration of wine grapes
Large wine grape vineyards typically have only one irrigation system covering land with a range of soil characteristics. As a result, the same timing and irrigation application is used for the entire block even though this practice may be less than ideal. We conducted a 4-year experiment to determine if soil characteristics affect vineyard evapotranspiration (ET) and if changing the irrigation system to better match the crop needs could improve yield and quality. The study was done in two different vineyards with each having two contrasting soils but one irrigation block covering the vineyard. ET was measured as the residual of the energy balance equation using a sensible heat flux measured with sonic anemometers and the surface renewal method. One vineyard had two contrasting soil types, one fine textured and gravel free, the other coarse textured and very gravelly. At the other vineyard, part of the crop was close to a large unlined irrigation canal, with a shallow water table, and the other part was far from the canal. Our results showed that plant size and evapotranspiration were reduced by the gravelly soil, presumably due to the reduced soil water holding capacity. Near the canal, the vines had lush growth and higher ET than the vineyard area that was far from the canal. We hypothesize that irrigation was unnecessary in the vineyard near the canal. Irrigation was however needed in the other part of the same vineyard. In this paper, we will discuss the methodology and results from these experiments.
Snyder, R.L. and Lambert, J.J. (2016). Impact of soil variability on evapotranspiration of wine grapes. Acta Hortic. 1112, 217-224
crop coefficients, water stress, water management, surface renewal, irrigation