David Doll2 CommentsAugust 1, 2022Nutrient

Using Mid-Summer Leaf Samples to Guide Fertility Programs, Part 1

By this time, mid-July leaf tissue sample results should be available. These tissue results are critical for any nutrient management plan. They should be taken annually to determine if the nutrient program is adequate for the orchard, and the values should be used to tune the orchard´s nutrient program. Research has shown that once an orchard reaches sufficiency of a specific nutrient, increasing it further will not improve yields. This has been demonstrated several times, both within nitrogen and potassium. Second-guessing and adding more fertilizer beyond sufficient levels to address existing yield problems will not improve the situation. This fact is relatively unpopular as it is easier to add more fertilizer than it is to fix the problems that limit orchard production, or assure oneself during a period of second guessing.  More on that can be found here (slide 17) and here (slide 20), and this article will focus on nitrogen The typical nitrogen program often budgets for 20% of the nitrogen to be applied during the post-harvest period. Mid-summer leaf samples should be used to determine if the post-harvest fertility plan should be changed. Within nitrogen, leaf tissue samples that exceed 2.5% can reduce or even eliminate the need for postharvest nitrogen applications. This is based on: Many orchards with leaf levels above 2.5% often have high residual nitrogen within the soil that will meet post-harvest needs, The reduced transpiration rates of the postharvest period reduce uptake of nitrogen, There is significant canopy loss from the harvest process, reducing nitrogen uptake, Nitrogen remobilization back into perennial tissues is happening earlier than previously thought – probably sometime between hull-split and harvest (or maybe even earlier!). Additionally, a long-term study in Arbuckle found that postharvest nitrogen applications did not improve yields in a reasonably high producing almond orchard. Nitrogen levels within

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David Doll0 commentsApril 25, 2022General

Re-evaluating operational costs for a difficult year

2022 will be a difficult year. Increased input costs, including water, fuel, and fertilizer, and decrease crop pricing will impact the operational expenses and crop revenues significantly. Many operations will struggle to maintain cash flows through the year. Operational costs should be closely evaluated to determine if savings are possible. Some expenses may be reduced on a short-term basis until pricing improves. Others may be eliminated from the current and future budgets due to more efficient management. A list of things to consider in helping reduce costs for the coming year include: Balance nitrogen rates. Typically, nitrogen budgets utilize a nitrogen use efficiency factor of 70%. By integrating more frequent, smaller applications of nitrogen, it is possible to assume a much higher utilization ratio – maybe closer to 85-90%. This could reduce nitrogen needs by 15-30 lbs/acre without impacting tree performance. Mid-summer leaf samples can provide feedback to this process (target range 2.2-2.5%). Test groundwater and accounting for nitrogen content. Groundwater in many parts of the San Joaquin Valley contains nitrate-nitrogen. If groundwater is used to irrigate orchard and it contains nitrate, make sure to account for the nitrogen and reduce the nitrogen budget. Balance potassium applications with any compost usage. The amounts of potassium and phosphorus within compost contribute to the nutrient budget of the orchard. Testing compost and accounting for moisture percentage should provide an estimate of the nutrients applied. This can reduce the need for fertilizers containing potassium and phosphorus (as well as many micronutrients). Review annual soil samples to determine if certain nutrients are not needed to be applied. It is common to see very high phosphorus amounts within CA soil samples and additional P may not be needed. Additionally, many loamy to clay containing soils contain potassium reserves. If the amount of potassium is high

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David Doll4 CommentsMarch 6, 2022General

Considerations for March 2022

March is a month full of surprises. Weather can be highly variable, with rain, risk of frost, and heat waves all being possible. Below are some points to consider as the season progresses. Ongoing frost concerns. Frost conditions can occur through the end of March. Maintain a watchful eye on the weather conditions to reduce the risk of any frost event. Critical temperatures after petal fall are around 28F (-2.2C), and temperatures at or below 28F for an extended period will cause crop loss. Micro-irrigation can increase orchard temperature by a few degrees, with higher flows of water providing a greater warming effect. More on frost mitigation can be found here. With irrigation occurring during multiple frost events, it is common to see trees push slow and with pale green growth. This is due to saturated rootzones that lead to loss of fine feeder roots and low micronutrient uptake. Soil irrigation levels should be monitored, and irrigation withheld until stored soil moisture begins to drop. Furthermore, nitrogen applications should not occur during the period of frost risk as running water for extended periods of time will leach nitrogen out of the rootzone. Crop losses from frost are hard to define in early March. Frost affected flowers will have blackened tissue inside the ovary, or flowers may appear blighted and remain on the tree. Trees will slightly compensate for loss of flowers with a slight increase in fruit set percentage of the remaining flowers as well as greater nut size. Therefore, in areas of minimal damage, the impacts might not be observed. In areas with losses greater than 10%, yield reductions should be expected. If frost damage is suspected, it is important to contact any insurance company as soon as possible and trim the early season fertilizer applications until a better

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David Doll6 CommentsFebruary 5, 2022Diseases

2022 Bloom Considerations

Weather is always a consideration when almonds begin to flower. Flowers are one of the most susceptible parts of plants to disease, and environmental conditions that favor disease could lead to crop loss. These conditions include periods of rain and warm temperatures. Protecting these flowers through the conditions is therefore important to maintaining yields and tree health. The forecast at the time of writing for the next few weeks is suggesting dry weather. If dry, warm weather persists, the risk of disease is very low and a different fungicide program should be considered. In this situation, early fungicide treatments can be withheld without too much risk. This is not just due to the dry conditions, but also the warmer temperatures increase the rate in which the tree progresses through bloom. Treatments within this scenario may skip the early and full bloom stages, and focus on an application timed to the petal fall of Nonpareil. If the weather forecast changes and rain is predicted, the plan should change. Rainy conditions over 59F/15C favor brown rot and other spring diseases. If wet, mild conditions persist for over 24 hours, a spray is warranted. This spray should be made prior to the rain event for best coverage. If utilizing FRAC 3, 11, newer 7 fungicides, and 9, this window can extend to 24-48 hours after the rain. Re-application should occur within 10-14 days depending on the frequency and amount of rain received. Fungicides should be applied 30-45 minutes before to provide enough time for them to dry. Although earlier stages of flowering may not require fungicide treatment, an application at petal fall should be considered. This stage of the flower/fruit development is very sensitive to diseases due to the dying flower petals, and amount of dead plant material aggregating within the fruiting clusters.

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David Doll2 CommentsJanuary 29, 2022Diseases

Bloom Sprays: Spray Rig Strategy

Spraying trees during bloom and in the early spring is different than spraying in the summer. This is due to the reduced canopy which allows easier movement of the droplets. Rig speed, therefore, can be increased to help cover the orchard more quickly. Speeds from 3-3.5 mph (4.5-5.5 km/hr) are more common during this period. This contrasts with hull-split sprays which are typically done between 2.0-2.5 mph (3.2-4 km/hr). Many operations have considered every-other-row spray applications during bloom. Although not ideal, this strategy works reasonably well in lower density, small canopied, or young orchards. As the trees increase in size, however, the amount of wood within the canopy increases. This reduces the distribution of spray droplets through the tree, reducing protection on the unsprayed side. Spray rig speed must be moderate (~2.75-3.00 mph) and volume should be high (80-110 gpa, 750-1000 liters/ha) if using this strategy to improve canopy penetration by the droplet. I use this strategy for younger blocks when rain risk is high but uncertain– a spray is made to “side A”, with a follow-up spray made 7 days later to “side B.”  I typically follow up these two “half sprays” with a full spray using a different fungicide chemistry 7 days after the completion of the “B-side.” I only use this strategy for years 3 and 4 (up to 40% canopy coverage). In densely planted orchards, rig speed should be reduced (Figure 1). Increased tree density increases the amount of wood that blocks the distribution of droplets. To compensate, slower speeds must be utilized to improve air displacement and droplet movement. This would also be needed in orchards that have tall trees and have a lot of vertical wood growth. Every-other-row spraying should not be considered in these orchards due to the lack of coverage on the

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