Nickels Soil Laboratory (NSL) Season Summary - 1998

 The 1998 growing season was characterized by an unusually wet winter with high amounts of springtime precipitation. Each of the months of March, April, and May received 2+ inches of rain bringing the season total to 32 inches, nearly twice the seasonal average. This replenished the rootzone to a depth of about four feet and reduced the irrigation requirement early in the season. Typical application rates for almonds in the past have been 30-40 inches, depending on yield potential. Almonds received only 26 inches for the 1998 season. The walnuts received nearly normal amounts of irrigation, 40 inches, while the prunes received 30 inches. Soil moisture conditions combined with mild temperatures to produce vigorous vegetative growth despite the sizable almond crop load. Nitrogen fertilizer was applied monthly for a seasonal total of: 170-240 lbs./acre, almonds; 240 lbs./acre, walnuts; and 120 lbs./acre prunes. Foliar zinc sulfate was applied at 30 lbs./acre to all bearing almonds. Potassium sulfate was applied at 400 lbs./acre, almonds; 600 lbs./acre, prunes; and 500 lbs./acre walnuts, via the drip system.

Almond disease pressure was also affected and increased significantly, especially for Blossom Brown Rot which hit most early varieties. Sporadic anthracnose nut infections were also found in the NePlus and Carmel varieties. Fungicide spray applications increased greatly this year.

Mechanical hedging was done in March on the west side of each row in the walnut hedgerow trial. (Alternate sides are hedged year-to-year.) Almonds and prunes received standard dormant pruning annually. Shaker thinning was used in the prunes in May of 1998 to thin the heavy fruit set.

Bloom conditions for 1998 were far more conducive to cross pollination in the Arbuckle area then in many other almond districts. However, bud set and bloom weather varied across different varieties. Crop set was rated as follows: fair for NePlus and Sonora; good for Nonpareil, Mission, Price and other Californias; and very good for Butte, Monterey, Padre and Ruby. Average yields for almonds were 2000 lbs. per acre (range of 1200 - 3200 lbs./ac.). However, production of the prunes and walnuts were both at an all time low with 1.9 dry tons per acre for prunes (63 ctn.) and just under 2 tons per acre for walnuts. Unusually poor sizing conditions prevailed in the northstate for prunes (too cool in spring and too hot in summer), while the walnuts at NSL followed a record setting yield in the previous 1997 season.

Send mail to jlschmierer@ucdavis.edu with questions or comments about this web site.
Copyright © 1999 Colusa County Cooperative Extension, Univ. of California
Last modified: September 01, 2000