Everyone associated with the wine industry knows that labor has become more expensive, and it seems that wages are accelerating upward. The pool of largely unskilled or untrained labor is drying up, while those who remain available want more money for their work—and are getting it. Hence, there is absolutely no doubt that vineyards will increasingly adopt mechanical means to replace operations traditionally done by hand. Fortunately, necessity drives invention and innovation, and there are better versions of vineyard machines available all the time. Buying this equipment requires a significant cash investment, so growers will be willing to do so only when the return on the investment makes good business sense. But it is a little more complicated than simply substituting a machine for a human, especially in the fine-wine production sector. We have convinced ourselves that hand-farming is better than machine-farming, and wineries and winemakers are often reluctant to yield to the growing need for mechanization. In some cases, this is justified, but in others, it’s not.

In June 2019, the Oregon Wine Research Institute (OWRI) hosted a webinar featuring Clark Seavert, professor of applied economics at Oregon State University. Seavert conducted a study on the economic benefits of replacing farm labor with mechanical methods. He did his studies on real vineyards, with real equipment and with real numbers, using Pacific Northwest regional vineyards. His labor rates seemed a bit higher than ours in California, but not all that different; he also seemed to use reasonable assumptions of future overhead costs and wage projections. Of course he did—he’s an economist. Though he targeted Oregon and Washington vineyards for his study, I found his study to be well thought-out, and his results can readily be applied to vineyards in California.

One thing I appreciated is that he used four different vineyard size scales: 20- and 40-acre vineyards in Oregon and 100- and 500-acre vineyards in Washington. For all but the 500-acre vineyard, the study had the participating grower purchase add-ons to be used with existing tractors, including a harvester. For the 500-acre vineyard, however, a harvester was purchased from Pellenc Americas, Inc. for harvest and some of the other mechanical operations. The results are quite detailed, and so I will not cover each and every outcome here. I urge you to take a half-hour of your time and view the webinar that is available online.

Pre-pruning

Cane-pruning was looked at for the two Oregon vineyards, as it is a common practice in northwestern Oregon. Seavert found that pre-pruning machines did not present a savings over hand work for cane-pruning. I might suggest that this is because cane-pruning using a pre-pruning machine is not really machine pre-pruning. Rather, hand-pruners must go through and make the main cuts to the vines, and the pre-pruner serves as no more than a brush puller and chipper. While pulling brush is slow, the fact that cane-pruned vines cannot be truly pre-pruned results in no savings. It actually ends up being more costly than traditional methods.

On the other hand, pre-pruning is quite possible and feasible with cordon-trained, spur-pruned vineyards. Trimming canes to long spurs is rather easy to do and has the added benefit of making the final pruning pass using hand labor quick and, therefore, inexpensive. The late pruning has been shown to reduce susceptibility to trunk fungal pathogen infections. There was a small benefit to even the 20-acre vineyard, with a savings of about $140 per acre, per year. There was a 10.9-year payback on the equipment for this small vineyard, which casts doubt on its benefit. However, jumping to only a 40 acre vineyard reduced the payback on the equipment purchase to just 3.7 years. Of course, pre-pruning larger vineyards makes even more sense, with payback periods on the equipment at one year and a cost saving on the order of $400 per acre, per year.

There is really no downside to pre-pruning spur-pruned vineyards because there is absolutely no downside to wine quality, and there is a disease management benefit. It’s not a slam-dunk, however, in wet climates like northwest Oregon or California’s North Coast. Climates like these have wet conditions in late fall and winter, so getting a tractor, especially a wheel tractor, into many vineyards can be difficult, if not detrimental, to the vineyard. This can sometimes be remedied with crawler tractors, but driving any tractor in wet conditions and clay-based soils might nevertheless be inadvisable. On the other hand, drier climates, like those found in eastern Washington, southern and eastern Oregon, as well as the Central Coast and Central Valley of California, are perfectly amenable for pre-pruning.

Suckering and Shoot-Thinning

These two practices were grouped together in the study, but they are quite different practices. Suckering is relatively mindless and requires the removal of trunk, crown and head suckers. This often requires no more than a gloved hand wiping off the suckers, so its mechanization can be done easily with nylon brushes. Cordon-suckering is more demanding, as one must discern suckers from desired shoots. Likewise, shoot thinning, or removal of the undesired shoots (not necessarily suckers), requires skill that is difficult to replicate by machine. Current suckering machines consist of flexible paddles that brush off shoots at intervals, depending on the rotational speed of the paddle rotor, as well as the translational speed of the  tractor they are mounted on. Those suckering tools are fine for fully mechanized vineyards, or at least those that have been fully machine-pruned. But hand-pruned vineyards are unlikely to adopt the mechanical suckering implement anytime soon.

In fact, suckering and shoot thinning provided the least attractive payback of all those studied. Seavert found a 25-year payback on suckering/shoot thinning for a 20-acre vineyard and a 6.2-year payback for a 40-acre vineyard and for a 100-acre vineyard. The payback interval was less than a year for the 500-acre vineyard, though the costs saved were modest—mainly because the larger vineyards do not typically shoot-thin their vineyards. Personally, I see a reasonable attraction to machine-suckering, as it is relatively easy to do, and the machines are inexpensive.

Shoot thinning is a painstaking process requiring great skill. For high-end vineyards, I don’t see a rush into mechanical shoot thinning, and the study shows that this category is only of marginal benefit anyway. That said, there will be a point when skilled labor is so expensive that even shoot thinning may be adopted by high-end vineyards. I just don’t see that happening in the foreseeable future.

Leaf Pulling 

Here is a practice that could make a lot of sense to mechanize, even though our thoughts about leaf removal shifts from year to year. We shudder at the thought of fully exposed fruit on a scorching hot day or during an excessively warm growing season, but we shudder just as hard when our fruit becomes infested with mildew due to insufficient light getting into the fruit zone. A lot of us are moving to very selective leaf removal now, removing only modest amounts of leaves and laterals, sometimes leaving “umbrellas” over the fruit or “tunneling” out leaves from the interior of the canopy. While leaf removal machines are continually improving, most cannot produce the finessed leaf removal that we require in some of our vineyards. But most vineyards are not farmed with such finesse, and mechanical leaf removal provides an excellent replacement for hand labor. New machines can produce a fruit zone that looks almost identical to a hand-pulled job, with little leaf residue and minimal damage to berries.

Seavert found good savings enjoyed by mechanical leaf removal. Even for small vineyards, the savings ranged between $250 and $275 per acre, per year. Payback interval on the machines was between three and five years, with smaller intervals for the larger vineyards. But for the 100-acre vineyard, the payback was reduced to only 1.5 years and for the 500-acre vineyard only 0.3 years. For those Washington vineyards, the savings was smaller, at about $200 per acre, per year—but still seemingly worthwhile.

Aside from its more brute-force leaf removal, mechanical leaf removal provides the benefit of getting the job done in a timely manner. As leaf removal is usually conducted during the time of year when shoot thinning and other canopy management is also in high gear, oftentimes labor is in temporarily short supply. Delaying leaf removal can result in disease, high pyrazine levels and poor light- and heat-acclimated fruit, so the benefits of mechanical leaf pulling may be greater than the labor savings alone.

Harvest 

The mechanization first widely adopted by high-end growers and wineries, mechanical harvesting is no longer only for production growers. Seavert’s study found the greatest savings in mechanical harvesting, which is not a surprise to me. For even the smallest vineyard there was a savings of about $775 per acre, per year, and as much as about $1,300 per acre, per year for the second-smallest vineyard studied. Payback on the machinery was a long 13.5 years for the 20-acre vineyard but only four years for the 40-acre vineyard, and just under two years for the 100-acre vineyard. The largest vineyard, the 500-acre vineyard, saw paybeck in less than one year, even for the larger, over-the-row Pellenc machine it utilized. A savings between $1,100 and $1,200 per acre per year was realized for the larger vineyards, which is nothing to sneeze at.

We still find some winemakers resist machine harvesting. While I can understand their reluctance to mechanically harvest varieties, like Pinot Noir, Zinfandel and Chardonnay, why there is reluctance to machine-pick Bordeaux varieties boggles my mind.

Those varieties pick well without extensive juicing and skin breakdown, and destemming them in the vineyard provides one less source of vegginess to the wines. There is no doubt that more wineries and winemakers (as well as growers) will get on board with machine-harvesting and will plan vineyards with that in mind from the beginning.

Overall, Seavert found a 1.5 year payback on the machines purchased for the vineyards under study that were 100 acres or less. For the 500-acre vineyard, the payback period was less than one year. I find that to be astounding and compelling and a motivation to acquire some or all of these tools. While the slightly lower labor costs in California would make these numbers a little less attractive, they’re not that far off as to change the decisions.

They have put together an online tool at www.agbizlogic.com. Their tool is intended to aid growers in determining if some of these mechanization practices should be adopted into their own operations by plugging their own numbers into the economic model. I suggest taking a look at it. 

Check out Mark's full article in the March issue of Wine Business Monthly.