NMSU researchers determining amount of water needed to raise wine grapes
A study coordinated by New Mexico State University at Santa Ana’s Tamaya Vineyard north of Bernalillo has learned how much water is used by three varieties of wine grapes.
“We are finding out how much water is used by the plant compared to how much was applied,” said Gill Giese, NMSU viticulture specialist. “This year we gathered data regarding how much water three different varieties used. The next step is to monitor how much water is applied to produce the quantity and quality for the desired production goal, as well as the specific type and style of wine.”
As the multi-year study progresses, the researchers will gather data to provide growers and water regulating government agencies with practical quantities of water needed to grow grapes in the Middle Rio Grande region of New Mexico.
The Santa Ana Agricultural Enterprise is gathering data for the U.S. Department of Agriculture’s Natural Resources Conservation Service regarding the amount of water used for growing grapes, alfalfa and corn.
“We received a grant from NRCS to gather data regarding the amount of water we use as well as how much fertilizer and compost is applied,” said Jim Peterson, manager of the Santa Ana vineyard. “We want to learn the optimal amount of times to water with our drip irrigation system.”
NMSU joined in the study to gather additional data.
“This type of study has not been done in this region,” Giese said. “With the wine industry growing in New Mexico, and water availability decreasing, this information will be vital.”
The water requirements of Vitis vinifera wine grapes; Chardonnay, Pinot Meunier and Pinot Noir, were calculated.
“We want to know how much water the plant is actually using versus how much it really needs at each of the growth stages during a given season,” Giese said.
Grapevine stem water potential and volumetric soil water were measured from bud break through harvest to determine vine water stress.
The data was collected by Elda Quintana, a graduate student intern from the Universidad Technologica de Paquime in Casa Grandes, Chihuahua, Mexico.
The stem water potential was determined with a Scholander pressure chamber, also known as a “pressure bomb,” where an increasing level of pressure was placed around a leaf stem until sap bubbled from the stem cut. The higher the pressure applied, the less moisture in the plant, which correlates to degree of plant water stress.
The volumetric soil water was determined with a frequency reflectometry probe measuring percentage of moisture at six depths.
“We compared these measurements with estimated vine water requirements by using growing season reference evapotranspiration adjusted to the grape crop’s evapotranspiration that was influenced by the actual vine canopy size,” Giese said. “This is referred to as the crop coefficient.”
This year’s study was limited to two vines for each variety. Next growing season, Giese plans to replicate the study to gather a wider base of data for statistical analysis.
“We learned that, under this year’s weather conditions, Pinot Noir required less water per vine than the other two varieties,” Giese said. “This result was impacted by the variable soil conditions within the planting and impacted the water required within each variety.”
“This research can serve as a reference for wine growers looking for efficient water management, as well as people who intend to establish a vineyard in a region that has similar characteristics as New Mexico,” Giese said.
“It was nice having Elda working on this study this summer, because the data can eventually be used by grape growers in Chihuahua, Mexico, to make better use of water through the proper management of their irrigation systems in a semi-arid region.”
