After three years of drought (2007-09) and two wet years (2010-11) — this year is shaping up to be another very dry year. There were two decent rains that somewhat recharged the soil profile, unfortunately they occurred as the 2011 harvest was wrapping up. Those were followed by one rain in November and a shower in December, which provided much of the fall rainfall total (about 45 percent of average). January did not add much more and a good number of vineyards received winter irrigation.

The total rainfall total for the months of October, November and December ended up at 3 inches for the north county and 1.7 inches for the south county. Not since 1976-77 has it been this dry, especially as December was the third driest on record. Dry conditions look to continue and irrigation is probably a good investment right now. Grapes are a low-demand crop for water and nitrogen, compared to most other fruits and nuts, but extremely dry conditions can affect the strength and uniformity of bud push in addition to negatively affecting the final development phases of this year’s fruit buds.

With that in mind, even if you put on a good solid irrigation of 24 to 36 hours or more last month, it would not hurt to put another 24 hours or so, depending on your emitter spacing, size of the emitters, soil type and variety/rootstock. Although this won’t recharge deep soil profiles, we still have a ways to go before the “rainy” season ends and things can turn around very fast. So it’s easy enough to apply some more water at or after bud break, if the drought continues.

Checking out the irrigation system is neither a bad idea nor a waste of time. Checking out the soil profile with an auger or even just a little digging with a shovel may help confirm how well the winter rains and irrigation may have managed your soil profile. Overall it seems there is decent moisture in the top 2 or 3 feet in most vineyards, but that is about it.

Even though January was close to average in total rainfall, seasonal totals are falling behind again. As of the first week in February the north county is at 6.1 inches (44 percent of historical average to date) and the south county is just at 3.2 total inches (approximately 37 percent). Last year at this time there was a total of 13.5 inches of rain in the Lodi area.

The curious weather pattern this winter (besides extreme dryness) is that most daytime maximum temperatures have been slightly above average, while most night time minimums have been well below average; giving the area a summer-like days with winter-like nights.

http://westernfarmpress.com/grapes/grape-growers-looking-rain-2012