Posts Tagged: soils
Many states have a designated state bird, flower, fossil, mineral, etc. In California, the state bird is the California Valley Quail, the state flower is the Golden Poppy, the state fossil is the Sabertoothed Cat, and the state mineral is Native Gold. The state rock is Serpentine which contains chrysolite asbestos which is a carcinogen. It's a beautiful rock, though.
The state soil is the San Joaquin series. The series concept is that a given soil has certain properties like pH, depth, color, texture, etc. that distinguishes it from other “soils” or series. So wherever this soil is found it is given the same name. San Joaquin series is a soil that is found primarily along the foothills of the Sierras in the Central Valley. The name comes from where it is first described, in this case, San Joaquin, but it is found in other places. Yolo series is named after a soil on the campus at UC Davis in Yolo county, but it is also found in San Diego county, and in other states.
A description of the state soil can be found at the link below, as well as the state soils in other states:
Soils can be highly variable depending on the context in which they are found. Going to flat old Kansas which is actually flatter than a pancake (http://www.usu.edu/geo/geomorph/kansas.html), the variability from spot to spot across miles can be minimal. But going to a place like Ventura, Santa Barbara, San Luis Obispo Counties of the Sierra foothills, you can't step on the same soil twice. That's because of the terrain and landforms. Where there is natural erosion (yes, it doesn't take humans to cause erosion) or accelerated erosion (this is where humans have often changed the landscape with roads, houses, removing ground cover) soil gets moved around and deposited in different positions and over time forms different soils with different properties. On large tracts of land that have not been altered much, such as avocado orchards, the naturally formed soils can be seen. In a housing tract where soil has been moved around to level and compact housing pads, it is often hard to find a natural soil because it is so highly disturbed. The soil can have been moved from one end of a 100 acres tract to the other with big equipment. It's all one big homogenous mix down to several feet at times depending on the slope.
In many cases, it is still possible to see the natural soils and knowing their series classification, it's possible to learn some of the properties and some of the problems that will be encountered when working with them. Knowing the pH prior to working it means that it could be adjusted before planting. It's a whole lot easier to adjust before planting than when the plants are in the ground.
You can see the soils in your area by going to the USDA-NRCS (Natural Resources Conservation Service) website - https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm - and typing in the area code to find the soil at a given site. It probably isn't the state soil series, but it's your soil series.
For a great text on understanding soils, check out Soils: An Introduction by Michael Singer and Don Munns.
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.
Silicon is currently under consideration for elevation to the status of a "plant beneficial substance by the Association of American Plant Food Control Officials (AAPFCO). Silicon has been shown in university and field studies to improve cell wall strength and structural integrity, improve drought and frost resistance, decrease lodging potential and boost the plant's natural pest and disease fighting systems. Silicon has also been shown to improve plant vigor and physiology by improving root mass and density, and increasing above ground plant biomass and crop yields.
Silicon (Si) is the most abundant element (27.2%) present in the earth's crust following oxygen (45.5%). Silicon is known for a number of important chemical and physical properties, i.e. semiconductor property that are used in various scientific and technical applications. In most soils near a neutral pH, the composition is a complex of iron, aluminum, oxygen and silicon. Silicon is one of the most important constituents of dust, which is carried by winds all over the world. Geologists know silicon as the rock quartz and the many silicate materials, such as opal. Formally, silica (SiO2) is a silicic acid (H4SiO4), which is water soluble and stable in highly dilute aqueous solutions. There are many forms that silicon can take in the natural environment, often complexed with water. Plants take up a form of silicic acid and in highly leached, low pH environments, much of the silicon may have been removed over time.
It appears that grains, such as wheat and especially rice have an absolute need of supplemental silicon to improve plant growth. Few non-grass plants have shown this need other than cucurbits apparently. Much of the improvement typically is for improved disease control and improved stature (prevention of lodging).
Many of the studies showing benefits of silicon amendment have occurred in low soil pH environments or in solution culture where it has been possible to create low silicon growing media. Several years ago, potassium silicate was being promoted as a fungistat for controlling Phytophthora root rot in avocado. A number of field and greenhouse trials were tried in California during the early 2000s to assay its effect. For whatever reason, the material showed no effect on the disease. Potassium and calcium silicates are liming materials, raising soil pH. The effect that was noticed in its use in other countries may simply have been a soil pH effect on either the avocado tree, the Phytophthora or both.