October 5, 2015

This report covers conditions and observations made between Monday, August 31 and Sunday, October 4, 2015. The next report is scheduled for Monday, November 2, 2015. However, in the event of any significant occurrences prior to that date, this site will be updated as soon as possible.

Taken in San Joaquin County, this report’s photos for the central region present an orchard float smoothing the orchard floor after harvest, a windrow of nuts on the ground following the rain that swept over the region during the final week of the month and a conditioner removing the leaves and soil from the crop to assist in drying the excess moisture from the nuts after the rain.

Temperatures varied widely in the northern San Joaquin Valley during September as the region transitioned into the fall season and the last few weeks of the 2015 harvest. Daily maximum temperatures followed a cyclical pattern, peaking over the century mark on the 10th and 20th of the month, with readings alternately dropping into the lower 80’s and upper 70’s. Coolest maximum readings were reported in the low to mid 70’s during the period’s final week when a cut-off low pressure system drew sub-tropical moisture over the region on October 1st, dropping from trace amounts to as much as 0.25 inch of rainfall across the area.  Morning low temperatures followed similar pattern, ranging from the lower 50’s to mid and upper 60’s throughout the period.

With the exception of the final week of the period, harvest operations in the region proceeded with little difficulty, owing to the generally supportive conditions. The dry conditions that prevailed during the majority of the period were well received by growers throughout the region as they dealt with accelerated maturity in several pollenizer varieties, making the variety separation at harvest a challenge for some. While the harvest has been completed in the early cultivars such as Nonpareil, Sonora, Price and several of the California type varieties, operations continue in the last of the later maturing plantings of the Butte, Padre, Monterey and Fritz. Yields in the various pollenizer varieties are generally stronger than reported in the Nonpareil. However, production is widely reported at levels below those experienced in the 2014 crop. Growers are reporting that best yields have been reported in several of the California types, most notably the Aldrich, while the Carmel in particular has proven disappointing in many cases.

The rain received during the final week of the month has brought harvest operations in the orchards to a temporarily halt. As seen in the photo accompanying this report, growers with conditioners available were sending the machinery into the orchards to remove leaves and soil from the windrowed crop to support drying in areas receiving the greatest rainfall. Observers are reporting that barring any additional rain, field operations are expected to be completed by the middle of October.

Growers who have completed their harvest have already moved into a post-harvest mentality and have begun applying fertilizers and soil amendments for next year. Growers are also rushing to complete their post-harvest irrigations before local irrigation districts complete their delivery season in coming week. Both the Modesto and Turlock Irrigation Districts cut allocations to one-half of normal amounts, forcing growers to supplement their needs with ground water from deep wells provided by the Districts or from their own, privately owned sources. Nevertheless, signs of stress can be found in all areas of the region, especially along the west side of the valley where salinity and pH levels in the water have caused leaf burning and premature defoliation.  Anyone traveling through the region can find mounds of calcium sulfate piled along-side many orchards and spreaders applying the material to the orchard floor as growers work to combat the salt levels in the soil. Calcium sulfate works to increase water penetration, allowing the salt to leach from the root zone during the winter rains, which everyone is hoping will be plentiful.

Current weather at the National Weather Service
Mel Machado, Jereme Fromm
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