Your source for orchard news & information in the Sacramento Valley
Research findings in a Red Bluff, CA walnut orchard have seriously challenged the conventional wisdom that walnut growers should start irrigation early in the spring to save deep soil moisture ‘in the bank’ for use later in the season. Read this post to learn more. Continue reading
One of the motivations for making good water management decisions early in the growing season is to reduce risk of root and crown diseases that can eventually kill almond, walnut, prune, and other tree species. Early season water management influences the environment where roots grow by affecting soil temperature and aeration and can be pivotal in how much tree decline actually occurs. Continue reading
Fall and winter orchard management considerations range from irrigation and plant nutrition to weed, pest and disease management. Continue reading
When prices are lean walnut farming is tough business. Farm advisors are not economists or financial advisors. However, farm advisors can be useful in providing best practices for economically sustainable production. Two key economic decisions growers face are when to replant individual trees and when to remove and replant entire orchards. Continue reading
This tutorial consists of three videos. We explore how managed levels of crop stress can benefit some crops when employed properly by reducing risk of disease, aiding crop maturity, and optimizing water and energy inputs. We discuss how soil moisture … Continue reading
Infections by Rhizopus stolonifera and Aspergillus niger occur after hull split because these are wound pathogens that require an opening to enter and infect the hull. The best, current approach to managing Rhizopus hull rot management includes three parts. The first two steps help to manage the environment, with respect to the disease triangle, while the latter seeks to control the pathogen. Continue reading
Researchers have historically been unable to pin down a cause for leafing failure because it was a rare event, only being reported periodically in the last couple decades. The problem was noted periodically before 2000, but most recent reports were made by farm advisors of leafing failure symptoms in 2000, 2006, 2010, 2017, 2018, and 2020. Continue reading
A key role of roots is the uptake of water and nutrients. Roots do not function well when exposed to too much water and will stop growing and eventually die in stagnant and/or saturated soil conditions. We consider how a better understanding of root biology can inform best irrigation practices. Continue reading
A single yellowing walnut tree in an otherwise healthy orchard has been a frequent sighting when driving along the roadways of the Sacramento Valley this summer. These yellowing trees have also been common this summer. The most likely cause of this yellowing and tree collapse was waterlogging induced root death. Continue reading
This calculator estimates the maximum weekly hours of irrigation need based upon weekly estimates of crop ET and the hourly water application rate of your system. The maximum weekly hours of irrigation may not be needed because in-season rainfall or soil … Continue reading
During about the second or third week in June, many Howard walnut trees experienced nut drop of perhaps as many as 100 nuts per tree, with many trees losing no more than 60 nuts per tree. These nuts were full size with the shell beginning to harden. Cutting open an immediately dropped nut, you could see darkening of the inside watery kernel material. Several possible causes are explored in this article. Continue reading
Originally posted July 2018; Updated July 2019. Franz Niederholzer, UCCE Farm Advisor, Colusa and Sutter/Yuba Counties & Allan Fulton, UCCE Water Resources Advisor, Tehama, Glenn and Colusa Counties Hull rot can be a heartbreaker, appearing suddenly at harvest in orchards where … Continue reading
Elizabeth Fichtner, UCCE Farm Advisor, Tulare County; Carlos Cristosto, CE Specialist, Postharvest Physiology; Bruce Lampinen, CE Specialist, Plant Sciences The overall value of a walnut crop is based on yield and nut quality. Commodity prices are depressed, improving nut quality … Continue reading
A sudden autumn freeze event last November is the likely cause of widespread dieback observed in both young and mature orchards in the Sacramento and northern San Joaquin Valleys this spring. Following reports in April of walnut orchards not leafing out, our initial diagnosis was freeze damage. We advisors, specialists, and faculty agree that this initial diagnosis has been further supported after examining additional orchards and weather station sites. Continue reading
From the northern San Joaquin Valley to the northern Sacramento Valley, walnut growers are reporting a widespread and alarming issue of walnut trees not leafing out this spring. The initial hypothesis from researchers is that we are seeing frost damage from mid-November, however the symptoms on mature blocks are both more unusual and more severe than autumn freeze events in recent memory. Continue reading