Secrets to successful almond production

Secrets to successful almond production

By Brady Colburn, Horticulturist, Agri Technovation California 

California is the world’s largest almond growing region with over 1.3 million acres producing overall, and an average yield of just under 2,200 pounds per acre (USDA NASS, 2022).

Most growers begin to harvest at the third or fourth leaf and see a profitable return come years seven or eight. As of late, however, multiple industry factors have growers reevaluating their methods to find the best way to increase long-term returns while keeping their operations profitable. Factors such as new varieties, water and labour shortages, as well as a diminishing nut price, have forced growers to find the most efficient ways to spend their capital. Although there is no easy fix to the complicated challenges facing almond growers, there are many principles that can still assist growers to be successful in almond production despite the challenges. This article discusses factors pertaining to almond production, in particular the grower’s return on investment, as well as guidance on those factors that need to be considered before making management decisions on the farm.

Thoughts to ponder

The bearing almond acreage in California has increased consecutively year after year for the past twenty years and is set to continue to do so. An era of strong returns, low-cost comparisons to other crops, and availability of land and water all made almonds a profitable crop to grow. Prices fluctuated from R7.8 per kg back in 2002, to R28.11 per kg in 2014, and have since dropped to the current R12.86 per kg (USDA NASS, 2022). This recent drop in price has caused cash flow concerns for many involved in the industry. The best approach for growers to combat diminishing returns and lower prices is to produce more nuts per acre.

Some growers believe that to achieve better results (higher yields) they need to increase their input costs. While increasing the amount of fertilizer and other inputs could certainly contribute to an increase in the number of nuts produced per acre, there are better, more methodical methods available to growers to increase the return on investment, and it starts before the orchard is planted. Growers need to focus their attention on their pre-planting and day-to-day activities to obtain higher yields. The most important factor to consider in determining profitability on a farm is the growing condition. What is in the soil? What is in the water? What type and size of irrigation and fertigation system are needed? Are there limiting layers that need to be addressed? All these questions need to be asked and answered before planting an orchard. Site selection and preparation will ultimately determine the variety and rootstock combination to be selected, the most appropriate irrigation system and system capacity, as well as the yield threshold for the block. Expecting to yield a crop larger than what a site is capable of producing will most definitely adversely affect the time needed for a return on investment to been received. Time spent on determining and evaluating the most suitable site for production is an investment worth making, and will contribute greatly to achieving budgets and receiving a return sooner rather than later. To achieve higher yields does not necessarily mean that the grower must spend more money.

What it does mean is that investing time and capital in the planning and preparation stage of production will always determine the success of the orchard.

Site and plant selection

Almonds are grown on a large variety of soils up and down California’s central valley. It is a fairly hardy crop that can tolerate hot summers and drought conditions moderately well compared to other crops. In older cultivars, two varieties of almonds are required for proper pollination, but new selections utilise self-fertile genetics to allow for a single variety per block. They prefer loamier, well-drained soils but are planted on a wide array of soil in California. Almonds can grow well in the 6.0-7.5 pH range, but can easily have micronutrient limitations. These deficiencies are generally seen in high pH or high phosphorus soils. High boron can also be an issue with almonds and should be avoided if excessively present in the soil or the water supply. Sites with these types of soils do not necessarily have to be avoided, but with regard to future production, it must be considered that high or low pH limitations will require higher production costs year after year to obtain the same yield.

From a nutritional perspective, growers should consider making amendment applications to increase soil uniformity. Soils naturally vary quite substantially and by addressing problems in an orchard with amendments, young trees will have a much better opportunity to grow and accumulate biomass, which is key to getting higher yields in early production. Each growing day where a tree is limited in its growth potential is an opportunity lost for the grower. The more suitable the growing environment, the more likely the plant will grow to its fullest potential. It is very important to do a soil classification prior to planting, to identify the areas where waterlogging may occur due to different soil textures, hardpan, or low spots. Knowing the location of these areas in advance, enables the grower to select a more appropriate rootstock for the conditions. New hybrid rootstocks are available that are resistant to root rot diseases and nematodes, and also have other specific characteristics that make them favourable for certain growing environments. By planning ahead and planting rootstock according to the soil classification maps, growers are better able to manage their orchards and achieve improved results without having to spend extra money each year. Bloom overlap is also a crucial factor for site selection. It is important to plant varieties with known overlap to ensure full pollination and the highest yields. A site that does not receive enough chilling hours for uniform pollination should not be considered for planting.

New varieties

California nurseries are always working on developing new genetics to introduce to the market, and almonds are no different. Some of these new introductions, such as Independence from Zaiger Genetics and Shasta from Burchell Nursery, have had a major impact in California as they are self-fertile.

This means that growers can harvest in a single shake and no longer have to worry about monitoring two varieties within the same block. But with these advances, new growing techniques need to be implemented in order to optimise the benefits. Independence and Shasta are both strong-growing varieties and produce a heavy crop early in their production. Independence has a mostly upright structure and produces a well-developed tree. The vigour in the tree may however cause breakage issues in the early production years. Shasta grows vigourously and produces large amounts of fruiting wood early on. This variety also has breakage issues but for different reasons than those associated with Independence. The structure of both these varieties is the highest priority in years one through four. The structure is the base for the rest of the tree’s (and therefore the orchard’s) producing life and early cropping could result in continuous problems. Many growers prefer to crop the orchard in year three because the trees grow vigorously and have by then set a harvestable crop. Such cropping leads to the creation of two simultaneous areas of nutrient demand in the tree: in the crop and in new growth, resulting in problems during the following year when the tree sets its first “true crop”. Many orchards cropped in year three end up having tree structure issues in the form of branch breakage. This could have a major impact on orchard productivity and trees may become more vulnerable to pathogenic risks. The very small harvest normally achieved in year three (generally 113 – 227 kilograms per 4046 m2) generally does not warrant cropping the trees. Instead, it is more appropriate to keep building tree structure for the first harvest in year four, especially for the newer, more vigorous varieties. Effective vigour control of these new varieties and subsequent additional yield can be achieved through proper pruning. Growers must observe the orchard as it develops in years two and three. In year two, the establishment of the scaffold at the proper crotch angle for maximum support is most important. This can be done by tying the future scaffold limbs in an upward fashion as well as proper cuts that remove all branches that are not at a 30 – 45 degree angle. There should be four to five scaffolds per tree, all growing in their own distinct direction to avoid competition. In year three, topping can be done in spring or fall, depending on tree development, to eliminate fruiting wood on long structures. This forces new shoot growth from inside the tree canopy and condenses the weight of the crop closer to the scaffold, giving it more support and leading to less breakage. The timing is determined by tree growth. If trees become excessively lengthy in the current season’s shoot growth before the end of the spring growth period, it would be advisable to top these in the spring. If the new growth is not excessive and branches are not growing in a way that is unsupportive of fruit, then this cut can be pushed out to the fall. This will cause a similar effect to the spring pruning but will keep the new shoots shorter in length and give more support to the nuts that develop the following year. Regardless of timing, it is extremely important to monitor the strength and development of the canopy. To avoid continual problems in the future, make sure to spend the time to develop the tree for the long term, not only for each year’s crop.

Growth

Something often overlooked in California when developing an almond orchard is the true (actually determined) requirements of juvenile plants while growing. There may be growers that question whether any returns can be generated by investing in proper fertilizer programs for non-producing trees. At first glance, this line of thought seems sensible as there is no crop to harvest and trees, therefore, are not in high nutrient demand. Also, there is no revenue – not a single dollar spent will deliver a return for that financial year. However, the importance of monitoring tree health in the first three years of non-bearing production is and remains crucial for long-term success. All growers should therefore implement a tissue sampling program and develop a fertiliser schedule that addresses the needs indicated through sampling. This approach will also eliminate or minimise any spending on nutrients or products that are not required. For example, nitrogen is often overapplied to young trees, resulting in weak, excessive growth. Through tissue sampling, growers will have the insight to direct their spending towards the correct solutions and quantities. In California specifically, where almonds are grown on heavy clay or high pH soils, micronutrient availability is a major concern. Most orchards in California exhibit zinc and iron deficiencies. These elements are crucial to plant development and can have a major impact on yield as plant processes are limited. It is therefore very important to collect tissue samples multiple times a year to determine any deficiencies, and secondly, to visually check trees. Also, some micronutrients may not show as a deficiency on analysis, but symptoms of deficiency may still be visible on the plant. For example, a zinc deficiency is known to cause “little leaf” on almonds where the buds do not push well, resulting in leaves that are about 1/3 of the normal leaf size. This is because of zinc’s association with auxin production and auxin’s role in leaf size and cell expansion. However, when sampled, these leaves don’t always indicate a zinc deficiency. This is because the plant’s need for additional zinc has already passed, therefore, the opportunity to generate larger leaves (addressing the deficiency) has already gone, resulting in energy levels that are lower than what they could have been. The little leaf condition will however be visually noticeable on the trees. A combined approach is therefore recommended: Tissue samples should be taken as described and orchards should also be visually checked to ensure that the results from the testing are representative of what is observed in the field.

Conclusion

Overall, almonds are a simple crop when compared to other complex crops that are produced in the world. The success of an orchard is completely dependent on the preparation done prior to development to ensure that the planting area is most suitable to receive the plantings. Choosing the right rootstock and taking sufficient time to plan the orchard lay-out, will also assist in minimising future problems. Return on investment can be achieved sooner than later, but requires growers to monitor the development of the structure of their trees to ensure long-term success. By foregoing a crop in year three, growers can by year 4 be sure to have trees strong enough to provide the energy needed for a full crop that can support the weight of the crop without major breakage. Nutrition should be monitored constantly to allow for optimal growth and to prevent 1) nutrient deficiencies and 2) wasted expenditure on products/nutrition that is not required.

Reference: USDA NASS. Sacramento, CA, 2022 April, 28. 2021 Almond Acreage Report.