Prune Orchard Investments in a Better Market Year

Franz Niederholzer, UCCE Farm Advisor, Colusa and Sutter/Yuba Counties

Prune prices to California growers are influenced by world production volume that can change, dramatically, from year to year. For example, in 2013 world prune volume declined by 47,000 tons (17%) when production in France, Chile and California was reduced by bad weather. In 2014, Argentina was hit with unfavorable weather leading to a further 4% (7,000 tons) reduction in world market volume despite production increases in California, Chile, and France. Coincident with these changes in world prune volume, CDFA reports show an increase in average price to growers from $1330/ton (2012) to $2470/ton (2014). In 2015, world prune volume increased by 40,000 tons (18%) over 2014 levels and average prices to California growers decreased to roughly $2000/ton and have hovered at or below that price since then as world production has not experience dramatic swings.

The 2021 prune crop in California appears to be in a good position in the world market due to a solid crop at home and bad weather in major prune exporting countries (Chile, Argentina and France) which reduced world production volume by around 50,000 tons from expected levels. While rising labor and shipping costs may dampen possible price increases, now might be a time for growers to consider investments in practices and/or equipment that can help improve or sustain future production. If history is any indication, world production may rebound quickly.

Pruning. Good pruners are hard to find and the cost of pruning is very high. However, if part of an orchard could be cleaned up with some detailed pruning (best) or even just a few big cuts made for light and deadwood removal (OK) better production and orchard health could be sustained. In particular, cutting out cytospora infected large wood with a small, trained crew using “chain saws on a pole” could be especially valuable. If not cut out, this damaging disease will continue to grow and reduce yield in infected trees and be a source of infection to other trees. A free Pocket Pruner’s Guide to Cutting out Cytospora is available on-line and in this newsletter to help pruners recognize when the disease has been completely removed from a branch. If all the disease isn’t cut out, the job isn’t done. Spraying the orchard with Topsin®-M fungicide after pruning or cutting is another investment in long-term orchard health as damaging diseases and wood rots enter the tree through those cuts if not protected ahead of rain.

Irrigation. The 2022 season may be especially challenging if decent to excellent levels of rain (and snow) don’t fall. A thorough checkup of your well, pump and irrigation system may be in order, especially if system testing has been deferred. A pump test will identify possible major problems such as substantial pressure reductions or water flow rates. Learn how to monitor standing and pumping groundwater levels to track changes in groundwater conditions. Check the Well Completion Report for your well. This site will provide information regarding the well conditions at completion of drilling, submitted by the driller as required by regulation. Find out how deep your pump bowls are relative to the pumping water depth. Bowl depth information may have been moved since the well was first completed, so check maintenance/repair records. Thoroughly check filters, pressure gauges, screens and lines to make sure there are no plugs or leaks. Finally, there is no better tool to check orchard water status than a pressure chamber. For a-time investment of around $1500-4500, you will have the means of knowing your trees water status and how your irrigation program is working at any point time.

PotassiumThis essential nutrient is expensive and growers may have been shaving application rates to help make ends meet. A full maintenance rate of 400-500 lbs. of potassium sulfate (SOP) per acre should help reload the “potassium bank” in the orchard root zone this winter. (This assumes that enough rain will fall to dissolve the material and move it into the soil.) Winter irrigation may be needed (to manage salts, ease orchard water stress, and/or incorporate fertilizer) if adequate rainfall doesn’t occur, so make sure the fertilizer is applied ahead of that irrigation water. The argument for fall application of dry material is that it is less expensive than in-season options (see next paragraph) and can be applied in a relative down-time.

Potassium may also be applied during the growing season as foliar potassium nitrate sprays and/or by injecting liquid potassium through the drip or micro-sprinkler system. However, these materials are usually more expensive per unit of applied potassium than dry SOP applied in the fall. They are effective if enough potassium is applied to meet crop needs. The advantage of these injected or sprayed materials is that crop load, and therefor potassium need, can be checked before expensive potassium is applied.

Best wishes for a good, restful, and WET end of 2021!


Leave a Reply

Your email address will not be published. Required fields are marked *