Maximize Almond Profits in Record Crop Years

Mario Viveros

UCCE Farm Advisor, Kern County

Deciduous Tree Fruits and Nuts

December 1999

Maximize Almond Profits in Record Crop Years

It is not a secret - almond plantings have been increasing for the past ten years. During this period, growers in Kern County planted 55,000 acres; Merced and Stanislaus Counties planted 29,795 and 29,164 acres respectively. These three counties have contributed about 114,000 acres to the 501,115 total state acreage. The increase in almond acreage has the potential to produce record almond crops. The crop for the 1999 season has been forecast to be 860 million pounds. This has triggered a 22% set-aside by the Almond Board of California and a market price less than a dollar per pound. This is not good news for some almond growers. If a grower produces 2,000 pounds per acre, he can only sell 1,560 pounds due to the set-aside. If he sells at $1.00 per pound, he will be at the break-even point since the cost of production is around $1400 to $1600 per acre. Large crops can therefore reduce growers' profit margin. Growers can increase production and/or decrease cost of production to minimize the erosion of profits. The ideal goal to accomplish is to decrease cost without sacrificing production.

Almond growers need to examine each orchard cultural practice and determine their need and value. There are cultural practices that cannot be eliminated but there are others that can be skipped every other year. There are some that can be modified and others that can be eliminated because they serve no purpose.

Dormant sprays are important for the control of San Jose Scale and peach twig borer. Spraying is necessary if these pests are creating problems. If San Jose Scale is not a problem, the dormant spray is not necessary and peach twig borers can be controlled during their emergence with Bt sprays.
Pruning for light management is necessary as light must penetrate the center of the tree canopy as well as between tree canopies. Pruning is not necessary if the trees are open in the middle and there is light between them. Pruning is also done to control tree height. If almond trees have been pruned for height control consistently, the pruning can be skipped one year and not lose control of the tree height. Supplemental pollen has been very popular in the past five years. This practice has been valuable when variety and pollenizer do not bloom at the same time. However, there may not be much value when both pollenizer and variety overlap in bloom.

Bloom and foliar diseases can sometimes be a problem in Kern County. Most of them are driven by free moisture from rain, fog or heavy dew. The best way to control them is with preventive fungicide sprays applied at the proper bloom and foliage development. If we were to have accurate weather forecasts, our sprays would be based on rain events. Furthermore, one can monitor for Shothole disease and/or use historical orchard disease pressure to decide on a fungicide spray. Scab is one disease that does not require moisture to spread. If scab is present in the orchard this year, spraying the orchard will need to be two to five weeks after petal fall next year.

Nitrogen fertilization practices have made great improvements due to the use of low volume irrigation systems. There are orchards that only use 100 units of nitrogen. Twenty units are applied post harvest and 80 units are applied post bloom. In orchards with less efficient irrigation systems, one can cut the amount of nitrogen to 100 units for one year and not seriously affect tree production in the following year.

Foliar nutrient sprays need to be considered very carefully. It is known that almonds will respond to zinc, boron, copper and potassium. If almond trees are deficient in these elements, one can use the single salts (zinc sulfate or zinc chelate, solubor, copper sulfate or copper chelate and potassium nitrate to correct the deficiencies. This approach will correct the deficiency in question without using expensive mixed nutrient sprays.

Irrigation is the most important cultural practice in almond production. It should be the last cultural practice to be modified or eliminated. If one must eliminate irrigation, cut in half those applied early in the season (post bloom to May). Almond trees need to be watered well in June and July for mite control management. Post-harvest irrigations are the most important irrigations of the season and should not be eliminated since they determine next year's crop.

When prices are low, and the grower needs to protect his profit margin, he must examine every cultural practice. This will help him decide whether or not to keep, modify or eliminate a given cultural practice from his program. There are no questions about future record almond crops that will drive the price down. However, growers can survive low prices by cutting unnecessary costs and maintaining good production.

Almond Tree Pruning

Almond harvest was unusually slow this year due to the cool and humid weather. The next cultural practice in an almond orchard is pruning which is not weather dependent but requires skill and knowledge of tree growth and development.

Books define pruning as the art and science of removing unwanted limbs from a tree. Since books don't elaborate on it, I can offer the following interpretation. The art of pruning is the ability to create an eye- pleasing tree canopy utilizing the natural growth habit of the tree. The science of pruning is the ability to utilize research-based information to create an everlasting productive canopy. Some people may not see the relationship between the art and the science in pruning, however, both interrelate with each other in the principals of pruning. Let's discuss some of the pruning principles which are used in almonds.

Tree Balance. A well-balanced tree is symmetrical, pleasing to eye, tolerant to wind damage and productive for many years. A well-balanced tree is made up of a perpendicular trunk and three or four well-placed scaffolds around the trunk of the tree. The grower can balance a tree with pruning cuts. Two common causes for an unbalanced tree are the prevailing wind and sunlight on the south side of the canopy. If the prevailing wind is pushing the canopy into the center of the tree, prune limbs from the inside of the canopy. This will allow outside limbs to develop into the wind. If the canopy is leaning toward the south due to the action of the sun, thin out limbs from the south and outside of the canopy. This will allow limbs from the south to grow upright.

Stiffening Cuts. These are heading cuts by which one-third of a limb or a shoot is removed by the pruner. This cut is done when the limb or the shoot is too limber. This cut is especially beneficial to stiffen main limbs during the training of young trees. Keep in mind that during the training years, you want the tree to grow upright toward the sky. Also, stiffening cuts will result into a strong canopy where future crops will be born.

Light Management. The main principal of pruning is light management. In young trees we want light to cascade down to the main scaffolds. This will stimulate the creation of fruiting positions on secondary shoot growth. In older trees, it will maintain productive wood in the lower half of the tree. Light penetration through the canopy is achieved by thinning cuts. Crossing-over and parallel limbs should be eliminated. Keep in mind that two parallel or two crossing-over limbs are occupying the same space. The inside of the tree should be kept reasonably open by eliminating water sprouts and limbs growing through the center. A common mistake is to eliminate the lower limbs and leave the upper problem limbs. This will not only eliminate productive limbs but also will force the tree to grow higher into the sky. This may not be desirable for mature trees. You can evaluate your pruning by the amount of sunlight you see cascading down the tree or by the amount of sky you see through the tree's canopy.

Crop Management. In the past, I have stated that pruning can be used to reduce alternate bearing in almonds - prune heavy in a light crop year and prune light in a heavy crop year. Experience has taught me that this principle may not be applicable to all orchards. If a grower has problems with yields, he needs to evaluate other cultural practices that might be more limiting than pruning. One cultural practice that limits yields is post harvest water stress. If a grower has this problem, he needs to overcome it before he considers pruning.

Tree Size Control. The best method to control tree size is with a big crop. Nut set effectively reduces vegetative growth, therefore reducing tree height. One can increase nut set by tipping (heading cuts) horizontally growing limbs. This type of pruning cut will stiffen horizontal branches, promote fruiting position behind the cut, and reduce the vegetative response to a pruning cut.
Tree size control in mature trees can be achieved with tower pruners. This machines reduces tree height by selectively cutting back the tallest branches. The reduction of tree height has significantly reduced navel orangeworm reject levels. Topping and hedging for tree size control has been successful in young almond trees (fifth- and sixth-leaf trees) but they have not been successful in ten- to twelve-year-old orchards. The yield reduction in older orchards makes this practice unacceptable.
Pruning is a very popular orchard activity among almond growers. Growers tend to prune because the neighbor is pruning and not because the trees need any pruning. Before you prune your trees, examine the reason for pruning and what you want to accomplish from this expensive cultural practice.

Zinc in Almonds

Zinc is an essential element which is required in small amounts by plants. There is evidence that fruit trees use less than two ounces of zinc per acre. However, when this supply is reduced below adequate levels, the result is dramatic zinc deficiency symptoms.

· Role of Zinc: Mineral elements not only have distinct roles in plants such as electrochemical and structural but also catalytic ones. This is the case of zinc. It has been found to be an enzyme activator for the synthesis of trytophan--a chemical compound from which auxin (indole-acetic acid) is formed in plants. Auxin is a plant hormone essential for cell enlargement in stems and leaves. A reduction of zinc will result in auxin deficiency and, subsequently, in a failure of young shoots and leaves to expand normally during their growth.

Zinc is also an essential part of certain enzymes such as alcohol dehydrogenase, lactic acid dehydrogenase and others. In addition, its inter-venal chlorosis symptoms suggest that zinc somehow participates in chlorophyll formation.

· Symptoms: Zinc deficiency symptoms are so dramatic that terms like "little leaf" and "rosetting" have been used to describe them. "Little leaf" as the name implies, refers to small, narrow and pointed leaves. "Rosetting" refers to the failure of internodes to elongate, causing the leaves of several nodes to lie telescoped together in a plane--rosette-fashion.
These characteristic features occur at the tips of new growth and usually are accompanied by a chlorosis which may resemble that of iron deficiency. However, it is readily distinguished by the short internodes at the shoot tips and by small, narrow and pointed leaves. In the summer, one can frequently find normal size leaves that are bent sharply upward on either side from their midribs.

· Determination of Zinc Sprays: Zinc sprays should be based on leaf analysis as well as on zinc deficiency symptoms. It has been found that the correlation between leaf analysis levels and zinc deficiency symptoms isn't a very good one. On border line cases, one may or may not see zinc deficiency symptoms on the leaves. Furthermore, in almonds, deficiency symptoms are not clear unless the shortage is rather severe. A poor set of nuts will occur before one can see deficiency symptoms on the tree.

The above information has led growers to make zinc applications a yearly practice. However, other growers have used leaf analysis levels as a guide for zinc sprays. If the zinc level is 18 ppm or less, a zinc application is in order and a zinc application will be required as long as zinc deficiency symptoms are present.

· Zinc Sprays: There are three different times during the year when zinc sprays can be applied to almond trees: at the beginning of normal leaf fall, during the dormant season and during the spring.
The fall application is commonly done at the end of October to the end of November. Zinc sulfate (36 percent Zn) is used at the rate of 10 pounds per 100 gallons of water. This spray will cause some leaf injury but no damage will be done to the trees.

The dormant application, as the name implies, is done during the dormant seasons-- when no leaves are present. At this time, the rate is 10 to 15 pounds of ZnSO4 (36 percent Zn) in 100 gallons of water. Warning: do not spray zinc sulfate at the same time as
oil sprays; apply it two or more weeks after the oil spray.

The spring application is done when leaves have nearly attained full size. At this time, basic ZnSO4, or zinc oxide (both at 5 lbs. per 100 gallons of water) are effective foliar sprays. Another effective zinc compound is zinc chelate. Please use table rates.