(Wines&Vines) - Whether a potential grapegrower has just inherited Grandpa’s farm or decided to plant vines on a newly purchased piece of property, that future grower has hundreds of questions. While the ultimate goal usually is to produce the best quality grapes possible on the land available, many factors and dozens of decisions will determine if a given site can produce the level of quality that a grower has set as his or her ideal. Growers with existing vineyards also look for advice about differences they observe within a given varietal block or vineyard and what they can do when their vineyard has already been planted.

Lucie Morton, a well-known Virginia viticulturist, brought together a team of soil scientists, a geologist, and a winemaker currently making wine in three international locations for an intense, information-packed day-long workshop that addressed the relationships between soils, vines and fine wines. The workshop was held March 8, the first day of this year’s annual Eastern Winery Exposition in Lancaster.

Basic soil information

Alex Blackburn and Ryan Reed, two soil scientists from Blackburn Consulting Services in Berryville, Va., kicked off the workshop with a review of many different aspects of soil. Blackburn provided a basic primer on the wide range of soil and landform characteristics that should be examined in evaluating a vineyard site, including information about soil depth, color, texture, structure and chemistry as well as geomorphology considerations such as ridgetops, streams, concave and convex areas.

Blackburn noted that the Natural Resources Conservation Service at the U.S. Department of Agriculture has a web soil survey available online that provides information about general geology and type of soils. However, he cautioned that the survey “was mapped between 1930 and 1990, and was prepared for farmers who were growing corn, soybeans and wheat.” A detailed, site-specific soil mapping done by an experienced soil scientist would provide more useful information for a proposed vineyard, Blackburn stated. “They would understand the specific soils and help you lay out blocks for uniform management of the vines.”

According to Reed, the physio-chemical properties of soils include the soil organic matter (SOM), texture and mineralogy. The labile pool of SOM is the direct energy, the food source that microbes use to create other nutrient materials for vine roots or other crops, while the stable pool—comprising one-third to one-half of the organic material—helps create structure. If a grower wants (or needs) to improve the organic matter in the soil, Reed stated, “Do it pre-plant if you can. You have to decide if you want to rip the soil or not, because if you rip, it will affect the amount of organic material in the soil. Post-planting, once lost, it’s hard to re-establish the organic matter.”