What is the optimal amount of water to raise quality wine grapes?
That is the question New Mexico State University’s viticulture specialist Gill Giese and Pueblo of Santa Ana’s Tamaya Vineyard manager Jim Peterson will investigate this summer when the pueblo’s 30-acre vineyard north of Albuquerque enters its third production year.
“Compared to other crops, such as corn and alfalfa, wine grapes can use less water. In many years they don’t use much more water per acre than cotton, and wine grapes have a greater potential economic return,” Giese said.
With water becoming a valuable commodity, 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,” Peterson said. “We want to learn the optimal amount of times to water with our drip irrigation system.”
Giese is joining the study to gather additional data.
“We want to define the crop quality and quantity and then match the amount of water we need to get to that target,” Giese said.
Giese installed three one-meter-long frequency domain reflectometry probes to track the water as it moves through the soil profile. Data will be gathered weekly. Climate and grape development data also will be recorded.
“In addition, we will do some pressure chamber readings to gauge and correlate vine water status to soil moisture levels to see how irrigation scheduling impacts vine performance and water use,” Giese said. “We plan to gather this data at different periods of growth – bud burst, flowering, veraison (the onset of ripening) and at harvest. We want to know how much water the plant is actually using versus how much it really needs at each of the stages.” Although this has been done in other wine regions, it has not been done under New Mexico conditions.
When growing wine grapes, vineyard managers often withhold water while the grapes are developing to control the berry size.
“When growing wine grapes, your goal is the quality of the skin and its integrity. Because that’s where most of the flavor, aroma, color and the impact of the phenolics are located that define a quality wine,” Giese said. “The seeds are also important, but the fleshy pulp is sugar water.”
But a grower doesn’t want to restrict water too much because that will reduce the yield by physically restricting the berry and vine growth.
“Timing matters,” Giese said. “There is an optimal amount of water needed at specific times to produce the targeted quality and quantity.”
Currently there are 516 vineyards growing grapes on 1,153 acres. Annually the 45 wineries in New Mexico produce approximately 350,000 gallons of wine.
As the wine industry in New Mexico continues to grow, water management will become an important factor in our sun rich and semi-arid environment.
“Working with Jim Peterson at the Santa Ana vineyard will give us real-life data,” Giese said. “This information will help current producers fine tune their irrigation and in the future when someone is planning to put in grapes and they need to know the amount of water that it will take to grow quality wine grapes.”