Vertisol at the playground. 8-foot baby used for scale. See the shrink/swell cracks? |
For example, I proudly (and digruntled-ly, given its issues with construction and amateur gardening) live on the state soil of Texas, the Houston Black clay, a Fine, montmorillonitic, thermic Udic Haplustert. The "ert" in Haplustert means it is a vertisol- a shrink-swell clay (we've discussed the joys of this before).
Ultisol Analysis!
Anyways, my friend and fellow soil-o-phile over at the Bipartisan Victory Garden lives in Florida, and on the (drum roll please) Millhopper-Urban land complex, 0 to 5 percent slopes! Ooooooh! What does this mean for her? Let us consult the WSS, shall we?
This series is a Loamy, siliceous, semiactive, hyperthermic Grossarenic Paleudult. The "ults" in Paleudults means it belongs in the soil order Ultisol. Booooohhhhh. Very sad. Why? Ultisols are naturally low-nutrient soils. Not only are there not many nutrients, it has a low cation exchange capacity (!), which means even if you add nutrients, the soil will have a hard time storing them. However, there is a lot of good news. Especially considering the woman on this soil- she can pay attention, and this soil responds well to good management. Here is the good news-
- these soils are formed in areas with long growing seasons and plenty of water (this is where the "ud" in Paleudult comes from: humidity),
- the silicate clays in ultisols are usually not sticky (unlike my lovely smectite vertisol, sigh), meaning they are pretty workable,
- with lime (to counteract the soil's acidity) and proper fertilization (and compost, mayhaps?), this soil competes with the breadbasket mollisols and alfisols we all pine after ;-) HOWEVER, liming an ultisol to >6.5 pH can reduce phosphorus and micronutrient availability. Why? Not sure yet. It has something to do with precipitation of Ca or Mg phosphates.
Más definiciones:
Hyperthermic: >22 degrees Celsius average annual temperature
Thermic: 15-22 degrees Celsius average annual temperature
Ultisol: soils with low base saturation (<35%) and an argillic or kandic horizon (translocated silicate clay) or fragipan. Base saturation decreases with depth (reference).
Vertisol: Soil with 30% or more clay and that shrinks when dry (and cracks) and swells when wet.
You're on fire. Don't stop.
ReplyDeleteI'm Lewisville soils and urban land. I think. I'm around next weekend and this week after work if you want to come by and see the dirt. Let me know what works best for you. We could even have a cookout and drinks on the deck. I am loving this weather!
ReplyDeleteCool. When is after work for you?
ReplyDelete