| Planting/Redeveloping Vineyards With HI-TECH Tools | ||||
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By Ken Freeze |
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| Looking across
the 32 acres of Bouchaine Vineyards (Napa, CA), the toll that phylloxera is taking on
Chardonnay and Pinot Noir vines is apparent. For many California winemakers on the
North Coast, it's a much too common sight. But when John Montero, Bouchaine's
winemaker for over a decade, looks out at the vineyards, he also sees an opportunity to
make better wine by using soil analysis as a guide to replanting the vineyard. "In 1993, I noticed weak vines and test holes confirmed that phylloxera had hit. I was pretty unhappy," Montero recalls. "I figured it was just a matter of time, but I was hoping we still had a few more good years left." Until that time, Montero had been satisfied with the vineyard. "We were yielding three to four tons per acre, most of it reserve quality, but I had always noticed uneven growth, maturity, and flavor within the vineyard." Like many winemakers in the same situation, Montero agonized over what course to take to replant the vineyard. In 1995, Montero attended the annual meeting of the American Society for Enology & Viticulture in Portland, OR, and heard Dr. Paul Skinner of Terra Spase (Napa, CA) present a new method of looking at the soil in vineyards that he called "Terrior." "Skinner began his talk by saying, 'Soil diversity is the rule, not the exception,'" Montero remembers. "Just looking around our own vineyard, I was beginning to understand that for myself. That one statement really struck a cord with me." Faced with the expensive task of replanting, Montero was anxious to find the best tools available to help make the many decisions that lay ahead. Interested in more than just replanting and soil diversity, he was also concerned with whether the ground had been properly prepared when it was replanted (1981). There were signs of soil compaction and problems with soil moisture variability, so he was already planning to do some sort of soil analysis when he and vineyard manager Al Buckland began working with Skinner in 1995. "I had no feeling for the size of the projects Skinner was working on, and whether 32 acres would provide him with enough soil diversity to be of interest," Montero recalls. "I was also concerned about the cost, but the cost (less thatn $100 per acre) was acceptable in light of the overall costs of replanting and other associated management costs. The cost was equivalent to sending a crew through the vineyard to perform a thinning operation." Before Skinner began the soil analyses by digging 12 pits with a backhoe in the vineyard, he and Montero walked the vineyard as Montero explained some of the variation in vigor he saw and pointed out other problem areas. Skinner scouted the vineyard twice more to determine exactly where to dig the six-foot deep pits. Just before the 1995 harvest, he and his team went to work. what Terra Spase does |
report for over a year now,
and I'm still digesting it." Montero put this new information to work in the vineyard almost immediately with post-harvest soil augmentations, ripping the soil three ways with a five-foot shank, and making other pre-plant decisions before the rains came. Using the information from Terra Spase, Montero's plan calls for replanting Bouchaine's vineyard in five phases. The first phase was completed in 1996 with replanting of six acres. The report convinced Montero that deep ripping was called for in this area to break up a barrier at the two to three foot depth that was affecting plant growth. There were some tremendous chemical imbalances, prompting Buckland to add nutrients and soil amendments including organic materials that were recormmended by Skinner. The topsoil had a pH of 7.0+ while the subsoil ranged from 4.6 to 6.6, mostly around 5.0. Prior to ripping the six-acre repland block, gypsum, grape compost, potassium/sulfate, and triple super phosphate were broadcast. The report also greatly affected Montero's choice of rootstock. "It didn't come right out and tell me which stock to select, but it did narrow the field quite a bit, making selection much easier," Montero said. "It was important that we choose a rootstock and Chardonnay selections with vigor appropriate for the site. The report also helped me decide to space the vines 8x5. Based on the vigor potential indicated by the report, I determined we could replant with a tighter spacing than before. "We chose 101-14Mgt rootstock which can handle 'wet feet' in the spring, high clay content in topsoil and subsoil, is a good micronutrient scavanger, will tolerate low phosphate in the soil, and has good graft-ability (low in graft rejection). The three Chardonnay selections were 'Stony Hill,' Dijon 76 and Dijon 96, each in two acre blocks. All planting material was green-growing bench grafts." Although each of the next four replanting phases will appear to be the same on the surface, thanks to the report, each site will be treated quite differently. The report is allowing Montero not only to make preplanting decisions, but also preremoval decisions. "We are already going into the rest of the vineyard and making modest soil amendments to areas that we feel are problematic," he says. After the 1996 harvest, an old six-acre Pinot Noir block received gypsum and super phosphate that were broadcast and disked in. Gypsum application was avoided in a delineated swale which appeared to have sufficient calcium and potassium. "One of the beauties of having this report is they way it is laid out graphically - so we can specifically target an area," montero explains. " We don't have to make broad applications of soil amendments or chemicals. We can apply only what we need where we need it. That one factor makes the cost savings substantial, and the benefits to the environment are terrific." Based on the report, Montero will restructure the entire vineyard. He plans to plant mre Pinot Noir, increaseing the planting from 20% to 50% or 60% of the acreage. "We have five Pinot Noir selections planted. We plan to keep three of them and add two Dijon selections." Also, changes to the layout of the vineyard in terms of irrigation blocks, spacing managing runoff and erosion control are all being considered. In the future, Terra Spase will provide follow-up reports. "We need to do follow-ups every four or five years to monitor what we have accomplished," Montero notes. "As our replanting program continues, we want to do a report with a little more detail, to define some questionable areas, especially where there's a transition between one major soil type and another. In the future, I also want to collate better what goes on between plant growth, grape flavor and ultimetely wine flavor with what goes on in the vineyard." Montero appreciates the assistance that the Terra Spase report has given in selective applications of soil augments or chemicals. "But ultimately it is up to the winemakers or vineyard managers to use the report in ways most appropriate to their situation." As Montero points out, other Terra Spase users are using Skinner's work in some very different ways. Hess Collection Winery |
looking at developing." In the first phase, there were several blocks from nine acres to 25 acres and totaling 50 acres that needed amendments. Some areas received more gypsum and others more potassium. For the secord phase, other adjacent areas will reveive their own tailor-made recommendations. "The same analysis helped determine ripping depth and whether other types of soil preparations were necessary," Skinner explains. "The need for subsurface drainage or slipplowing can often be indicated or excluded by the soils analysis." The soil analysis also goes a long way toward determining rootstocks and scions. What variety the grower wants to plant, coupled with the percentage of clay or sand, mottling of soil particles, and how the soil strata are arranged, will lead to indentification of rootstocks that would do best. It can also bring into focus which scion varieties are planted. Some may not be suitable for part of a site due to soil charactheristics, and others that the grower may not have thought of may thrive. "What can be called vineyard architecture can also be fine-tuned using this analysis," says Camera. How wide should the rows be for a rootstock? How far apart should the vines be spaced in the vine row? What crop level range will this produce? The soil vigor potential evaluation from Terra Spase, which combines many of the soil factors, giving each an appropriate priority, is a great tool." "We are planting three different rootstocks in out first 50 acres, 101-14, 16-16 and Tiparia Gloire. There will be seven different clones and selections of Chardonnay. The next 50 acres will have two more rootstocks, 3309 and SO4, with three more Chardonnay clones and one field selection. The vines will be vertically trellised with a seven-foot wide tractor row and five feet between vines. "Once the vineyard is planted, I will add petiole analysis to the soils data," Camara concludes. "This will allow us to see how our soil additions worked and any nutrition needs that we have and allow us to track grapes to the winery and evaluate wine quality based on the location where it was grown." Louis M. Martini Winery Conclusion |
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