A recent website just posted hopes to make research papers available to the general public. Many times these papers are locked away in archives or libraries and are hard to access. This website wants to change that. It is sponsored by various group0s, including USDA, University of Missouri, industry, Resource Conservative Districts and other entitites. It's a small data base at this point, but hopes to build over time. check it out:
There's a lot of distracting stuff at the site, but the guts are at
Other good ag websites are the USDA's National Ag Library:
USDA's ATTRA which is loaded with basic and detailed farming information:
USDA's Farming Information Center
It's a new year, READ ON!!!!
From the UC Weed Science Blog
A repost and link today to a recent Weed Science Society of America press release entitled: "About Weed Seeds and Their Longevity" Click the link to go to the full article.
An excerpt from the press release and links to the free download:
Did you know some weed seeds can lie dormant in the soil for more than a century and then sprout when conditions are right? A new factsheet available for free download from the Weed Science Society of America (WSSA) dives into the topic of weed seed longevity, as well as how weed seeds travel, when and why they germinate, and ways they can be eliminated.
“Understanding weed seeds and their lifespan is critical for both farmers and backyard gardeners alike,” says WSSA member Greta Gramig, Ph.D., associate professor of weed science at North Dakota State University. “Seeds can remain viable in the soil for extended periods of time. That means if even a single weed is allowed to go to seed, you may be battling the aftermath for years to come.”
Here are just a few of the many facts about weed seeds that are covered in the new WSSA fact sheet:
- Moth mullein seeds buried by a researcher in 1879 were still able to germinate more than 130 years later.
- Weed seeds can easily be spread and transported far from their original location. Some have found their way into the earth's planetary boundary.
- Earthworms are known to collect weed seeds and move them into their burrows.
- Weed seeds that remain dormant in the soil will often germinate in response to changes in temperature, moisture, oxygen or light.
- Carabid beetles are voracious eaters and can consume large quantities of weed seeds that drop to the soil.
In addition to its fact sheet on weed seeds, WSSA offers a variety of other free fact sheets and educational materials online, including infographics and presentations on herbicide resistant weeds and their management./span>
Calcareous soils have often more than 15% CaCO3 in the soil that may occur in various forms (powdery, nodules, crusts etc…). They are relatively widespread in the drier areas of the earth. California is notable for its young soils, that is, soils that have a relatively high level of nutrients because low rainfall means that natural productivity has not been leached out. The potential productivity of calcareous soils is high where adequate water and nutrients can be supplied. Water is the most limiting input to making California soils productive.
The high pH associated with these soils, though, is not the level of calcium present. It is the carbonate in the soil or the bicarbonate associated with the waters found in those soils which controls the pH. The high pH then controls the availability of iron, zinc, manganese and copper. These nutrients need to be added as foliars or soil applied, or better yet, the soil pH needs to be dropped to around 7 to make these nutrients available.
Recently someone asked if replacing the calcium with potassium would change the pH. No, it won't. The carbonate needs to be removed. Calling it a calcareous soil confuses people about what caused the high pH. The carbonate or bicarbonate needs to be removed with acidification, it turning it into CO2 gas. This is done with urea sulfuric acid or sulfuric or sulfurous acid. There are actually magnesium dominated soils in the San Luis Obispo area that have high pHs due to carbonates. They are carbonateceous.
I am frequently asked if I can recommend a book on Soils. And yes, I can. It is Soils: An Introduction by Michael Singer and Donald Munns. The sixth edition recently came out so there's a lot of older used copies floating around on the wed for under $10. This book takes a different tack on describing soils. Instead of tacking the tack of a chapter on Nitrogen another on Calcium etc., it weaves a story of how all the parts are related.
It is more than just the confusion about the effects of phosphonates, but also how to spell the words associated with the P atom. Phosphorus with an ending in “us” is the element we know as P, while Phosphorous with a “ous” ending is the adjective of P. So an acid containing Phosphorous acid is written H3PO3 while phosphoric acid is H3PO4. These are both strong acids and can hurt and cause damage if splashed on the skin. When either is reacted with calcium or potassium hydroxide, a salt is formed which is less dangerous to users, but as with any chemical can be misused.
The salt formed from Phosphorous acid is called calcium phosphite or calcium phosphonate depending on what naming system is used to describe it. Whereas when these bases are reacted with phosphoric acid, the result is calcium or potassium phosphate. These salts are relatively benign in contact with skin. Labels on containers often call phosphorous acid, “soil applied” whereas the phosphite forms are called “leaf applied”. The “soil applied” when applied to a leaf can cause damage, whereas, the leaf applied is much less likely to cause damage to both plant and applicator. It can be applied to the soil, as well. It's much safer to use the leaf applied in either application technique.
The phosphites are often registered as fertilizers, but they have little nutrient effect. Most of their effect is to boost the plant's immunity to Phytophthoras and pythiums. This is called fungistasis and the material is called a fungistat. They don't act as a fungicide when normally applied to kill these organisms.
So you can see there is a lot of confusion in the phosphorous world. Knowing the proper spelling, pronunciation and use is note only good grammar, it makes good farming.
To read more, see:
There are few documented cases of phosphorus (P) deficiency in tree crops in California.