IN YOUR ORCHARD
In May, young trees planted in January and February should be showing active shoot growth. Some of this growth may occur where the trunk will eventually be shaken during harvest and should be removed. Trunk dominance can be lost in the first growing season due to water-sprouts or suckers. For this reason, they should be removed during the spring. In removing unwanted growth, one wants to establish the approximate height of the first primary scaffolds and to maintain tree trunk dominance. The first scaffold should be about 30 inches from the ground level, thus, any shoots developing below this height should be rubbed or cut off as early as possible, with care taken to avoid sunburn of the bark. This initial suckering will leave about six to ten inches above the first primary where seven or more shoots will hopefully emerge that will be considered for a primary scaffold after their first growing season in your orchard. The distribution of these shoots should be around and up and down the tree trunk. All duplicate shoot or “twins” should be eliminated. It is also important to keep the trunk straight. This will prevent shaker injury at harvest and wound canker infections. One can keep the trunk straight by driving a grape stake on the prevailing wind side of the tree and by tying the upper portion of the trunk to the stakes. May is also the time to decide on an approach to mite management. Many growers and PCAs prefer a preventative calendar program by applying a product in May (Agri-Mek or generic abamectin) and then following up with a second miticide at hull split with their NOW spray. The main disadvantage with this strategy is that two sprays are used when one spray could have been sufficient, and that a biological control program with predators never had a chance. Another approach is to base treatment decisions on pest density. The recommendation is to do presence/absence sampling and avoid spraying until about 50% of the leaves have mites present on them (in the case that beneficials are found) or until about 25% of the leaves have mites (if there are no beneficials). See the pest management guidelines for spider mites in almond at our UC IPM website www.ipm.ucdavis.edu. Following this IPM approach will often result in not needing to spray until
Orchard grinding
as 70 tons per acre of old wood chips. In orchards where high rates of wood chips were applied, we have noticed weed suppression and reduced tree growth in the second- generation trees, even after fumigating. We realized that we were not applying enough N to counter the N that was tied up with all the carbon from the wood chips. There is so much carbon in the soil that your N to carbon ratio may be out of balance. In a new trial, we applied a quarter ounce of nitrogen at planting time when we watered our bare root trees, and we continued to add a quarter ounce of N per irrigation for the first month. We observed tremendous growth and only ended up applying 46.6 lbs. of N per acre (five ounces of N per tree). With these results we believe that early N applications are very important, starting at planting time, after whole orchard recycling, and we are recommending approximately 50 lbs. of N per acre (roughly five ounces of N per tree, one ounce of N per month over the season). Of course, this rate will vary depending on the amount of carbon that was added to each individual orchard during recycling. Remember not to add more than one ounce of actual N per first leaf tree at any one time, but you can add multiple ounces over the course of the season. Another advantage of using granular fertilizer applications early in the season, is that some growers have applied too much water too early in the season in order to deliver the desired amount of N and have experienced Phytophthora Root and Crown Rot infections.
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ALMOND FACTS
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