Six Sigma in the Vineyard

Six Sigma is a set of techniques and tools for process improvement. I used it a lot as an engineer and was certified as a Six Sigma Black Belt indicating a certain level of expertise. I never thought I might need to use it in the vineyard. But with the recent planting of our 2 acre upper vineyard which includes 1 acre of Pinot noir, 2/3 acre of Chardonnay, and 1/3 acre of Pinot blanc it all came back to me. With numerous irrigation related problems it was clear that our process indeed needed improving.

In order for our young plants to receive the water they need during our hot dry summers, there is an irrigation emitter similar to the one pictured above punched into a water tube which is located about 2 feet above each plant. These particular emitters are designed to deliver 1/2 gallon of water per hour. The trouble started when we noticed most were not flowing any water at all!

Each new vineyard irrigation system should be thoroughly flushed with clean water BEFORE the emitters are installed because there is always a chance that dirt, PVC shavings, or rust might be in the lines. In a hurry to be ready for the arrival of the new vines from the nursery, I failed to do that. Uggh!  The first step in Six Sigma is to Measure the problem. This was easy as nearly ALL 3,300 emitters were plugged. Easy, but not pleasing. Our team worked for hours to pull each emitter and either blow it out or replace it. But as soon as we ran the system most, ~2,000 of them, plugged again.

There was no getting around the need to flush the system out. So we had to back up a step and disconnect all 42 rows of drip tubing and blow the water in the lines to the ground. This required many hours and several trips to the irrigation store, but the water was clearing up. We put everything back together and started the system. To our chagrin about half of the emitters plugged during the first watering. The second step in Six Sigma is to Analyze the data. We knew (1) the emitters we installed in the upper vineyard were of a different make and model than what we have used successfully for 5 years in our lower vineyard, (2) that the emitters were plugging frequently with a very fine grit, and (3) our inline filter was apparently allowing the grit pass to pass through.

We turned our attention to the filter.  It's the very same filter that we have in the lower vineyard and have had virtually no problems with it. It is well designed with the ability to manually clean while the system runs. The red filter screen at the top right of the photo was originally installed inside the black filter housing. I learned from our irrigation expert that the color red indicates a certain hole size or mesh.  While we have always used a red element in our lower vineyard, the manufacturer offers a yellow and black model with progressively smaller mesh. The third step in Six Sigma is Improve. After Measuring the problem and Analyzing the causes and the data, it's time to make some changes. I wish I could say we jumped right on the best solution, but its been more of a process.

The first improvement made was to install a yellow filter element with a finer mesh opening. This helped some but not enough. So we found a dealer online that had a black element and ordered it. Its openings are so small I was wondering how often I would have to clean it to keep water flowing. We installed it on July 31st and made the decision that we would no longer pull and clean the plugged emitters but would instead replace them with a different brand. During the August 3rd watering, I walked the entire vineyard and found 68 emitters plugged which I pulled and replaced with the new model. I cleaned the filter once and noticed some build up, but still good flow. On August 6th, 17 plugged emitters were pulled and replaced.  Again, one filter cleaning during the 3 hour irrigation session. Progress!

The final step in Six Sigma is Control. With improvements in place, what are we going to do to ensure that our good results continue? Plans are to continue to clean the filter once per watering session and to weekly walk through the vineyard counting and replacing any plugged emitters. Next year, all lines will be flushed to remove any build up that develops over the winter. As the plants get older and put down deep roots they are better able to tolerate periodic irrigation interruptions. But this first year especially we have to ensure a reliable water supply.