- (Public Value) UCANR: Promoting economic prosperity in California
- Author: Ben Faber
Old crop, new crop. What's up there in the trees? Are they big enough to sell? Is there a good set for next year? These are questions every avocado grower has every year, and often all year long. What is up there in the trees is confounded by what is called the "Avocado Illusion".
And boy was I reminded of the issue the other day when harvesting a GEM planting density trial. You don't see GEMs, you feel them, sense them being somewhere near your hand. There's a mass that's different from all the leaves near your hand, and you reach for it with your clipper and by golly you got a live one. But how many have you missed? You really need to search.
In a Science Magazine Letters to the Editor in Dec 1990, Paul Sandorff commented on a book written by Maurice Hershenson called The Moon Illusion. In the book Hershenson described the illusion of why the moon seemed so much larger when it was on the horizon than when it rose to its zenith on the same night. http://science.sciencemag.org/content/250/4988/1646.1
Sandorff said that this illusion applied to avocados since it was so hard to gauge the size of avocados when they were in the tops of the tree canopy. It is the surrounding environment that puts a context to size according to this theory of illusion.
Hershenson added to this observation in the March 1991 Science letters section with the comment that the leaves surrounding the fruit changes our depth perception and so changes our idea of the fruit size.
A further addendum to the avocado illusion theory is that since the fruit are the same color as the leaves (they are both dark green and the fruit unlike most other fruit continues to photosynthesize), it is hard to actually make out the fruit. You can be looking right at the fruit and not see it, confusing it with a leaf.
This illusion makes for difficult fruit estimation. To compensate for this illusion, I will eye the canopy in quadrants, counting the number of fruit, then arbitrarily doubling that total number. It usually gives a pretty close number to the real number of fruit that are in the tree.
By the way, with all the low down fruit in the skirt and with the wet winter, there were a heck of a lot of snails in the canopy dining on fruit.
Photo:
Can you count the number of fruit in this Hass canopy?
Photo: a mess of GEM fruit revealed hiding in the skirt.
- Author: Ben Faber
So rain is great………as long as it doesn't cause problems like increased iron chlorosis, root rot, snails, erosion, too many weeds, etc., etc., etc, And now we are seeing more anthracnose. This disease is not normally much of a problem in dry California. Colletotrichum gloeosporioides, the causal fungus of the disease, is widespread in avocado and citrus groves. We see it frequently on small stems and branches, but It is normally of little importance on fruit because unusually large numbers of spores are required to produce damaging infections.
Disease on stems
Disease on leaves
Low humidity and no rain during much of the growing season limit disease development in California. With extended foggy or rainy conditions and mild winter temperatures, and where many dead leaves and twigs and mummified fruit accumulate in trees, the fungus can produce enough spores to cause a disease problem. Spores spread in splashing water and can cause infection anytime from fruit set to harvest. Once infected fruit starts to ripen, temperatures of 75°F and above will accelerate anthracnose development, while temperatures below 59°F retard disease development.
Disease on fruit - black speckles
Fuerte, Rincon, and Wurtz scion cultivars are more susceptible to anthracnose than Hass. Healthy trees often recover from foliar infections and defoliation once conditions become dry. Anthracnose becomes a postharvest problem after the grove has been excessively wet for extended periods. Poor growing practices and mishandling of fruit during or after harvest greatly increase the potential for significant fruit loss.
Anthracnose is controlled primarily with good cultural practices in the grove and proper preharvest and postharvest fruit handling.
- Prune out dead limbs and twigs where fungi sporulate. If many dead leaves are entwined in the canopy, knock them out of the tree.
- Prune low limbs to at least a foot off the ground to reduce humidity within canopies by improving air circulation.
- Prune and harvest only during dry conditions and minimize fruit contamination and injury.
More at UC IPM
https://ipm.ucanr.edu/agriculture/avocado/anthracnose/#gsc.tab=0
We do like the rain, so keep it up.
- Author: Ben Faber
The ratio of N applied to N removed is a key metric in the Central Valley Irrigated Lands Regulatory Program (CVILRP). Growers report applied N and yield to agricultural water quality coalitions. The coalitions in turn convert yield to N removed from fields and report various statistics to the Central Valley Regional Water Quality Control Board. Nitrogen accumulated into perennial plant tissues may also be counted as “removed”. For these calculations, reliable values of N concentrations in the harvested parts and perennial tissues of crops are needed. It's important to know the amounts of N removed by various crops in order to have a better estimate of how to manage N to avoid ground water contamination.
For a report released in 2016, Geissler and team mined the scientific literature for data on N concentrations in harvested crop parts with an emphasis on California data (Geisseler, 2016). For many commodities, a robust dataset of recent samples from California was not available. With financial support from the California Department of Food and Agriculture – Fertilizer Research and Education Program (CDFA- FREP) and the help of the Kings River Watershed Coalition, John Dickey, Ken Miller, and their team at the Southern San Joaquin Valley Management Practices Evaluation Program, a large number of samples were collected and then processed in the author's nutrient management lab at UC Davis. The present report is the second update of the 2016 report, the first being released in March 2021, and includes results for kiwis, lemons, mandarins, oranges, nectarines, and grain sorghum. In addition, recently published data for cotton and N in perennial parts of cherry and citrus trees were included.
This sort of reporting will soon be required in all the Water Quality Control Board Regions. Understanding how much nitrogen to apply is important not only for insuring water quality, but also for tree growth, health and insect and disease management. An expanded list for coastal crops will soon be made available by Richard Smith, Andre Biscaro and Michael Cahn.
You can read the more detailed discussion of the Geissler report HERE.
In the tables presented here "VC Acreage" represents the acreage of a given crop in Ventura County and "N Coefficient" is the amount of that crop removal represented in the different units in the following column. There are different estimates for different crops largely because of varietal differences, soil types and climatic conditions of different growing areas. The values are not exact, but approximations to give growers a better understanding of what a crop would use and therefore how much N to apply.
- Author: Ben Faber
State and County Profiles are now available. USDA's National Agricultural Statistics Service (NASS) released the profiles Mar. 27, 2024. These 2-page summaries include farms and farmland, value of sales, producer demographics, top crops, internet access and more from every state and county in the nation.
NASS released the much-anticipated ag census at nass.usda.gov/AgCensus and in Quick Stats on Feb. 13, 2024. Ag census data spans millions of data points about America's farms and ranches and the people who operate them. The once-every-five-years Census of Agriculture remains the only source of uniform, comprehensive, and impartial agriculture data down to the county level. Follow @usda_nass for the latest data highlights and news updates.
Census of Agriculture
2022 State and County Profiles
/h4>/h3>- Author: Ben Faber
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The California Department of Food and Agriculture (CDFA) has allocated $5 million of the Healthy Soils Block Grant Program to the California Citrus Quality Council (CCQC) in collaboration with California Farm Bureau (CAFB) and Xerces Society. The California Farm Bureau through its 501(c)(3) science and research nonprofit, the California Bountiful Foundation, will oversee all administrative functions, and financial functions, of this project including reporting and on-farm project verifications. The Xerces Society will provide technical expertise in pollinating plants for hedgerows and other similar management practices.
This grant program supports citrus growers in adopting conservation management practices that improve soil health and sequester carbon. Citrus growers will receive on demand assistance at no cost through the implementation and verification process of their on-farm projects. The program will fund 20-45 on-farm projects over three years, focusing on practices like planting pollinator hedgerows, cover crops, compost application, mulching, whole orchard recycling, and windbreak establishment. Funding for each on-farm project may receive up to $200,000, depending on the project's size and the number of practices implemented.
Enroll Now for the Healthy Soils Block Grant Program
Begin your application by clicking the "Enroll Now" button to submit your online application form.
We can only process applications in English. For Spanish-speaking growers needing assistance with filling out the application in English, please contact Ana Resendiz at aresendiz@ucanr.edu or call (442) 265-7709. View the application in Spanish: here
Got questions? Contact Margaret Honig, Administrative Lead, at (916) 561-5504 or email at mhonig@cfbf.com
Why Citrus Growers?
The citrus sector in California contributes approximately $2 billion annually to the economy and plays a crucial role in job creation and supports agriculture and environmental sustainability efforts. This grant program will help citrus growers in reducing costs associated with conservation management practices, offering insights into effective pest and disease management while protecting pollinators. Citrus growers involved in this program will make meaningful contributions towards pollinator protection, environmental stewardship, climate change resilience, and meet sustainable demands by consumers for citrus production.
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