Ultisol

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Ultisol
Red Clay Soil
Ultisol.jpg
A Ultisol profile
Used in USDA soil taxonomy
Key process weathering
Climate tropical, humid subtropical, oceanic

Ultisol, commonly known as red clay soil, is one of twelve soil orders in the United States Department of Agriculture soil taxonomy. The word "Ultisol" is derived from "ultimate", because Ultisols were seen as the ultimate product of continuous weathering of minerals in a humid, temperate climate without new soil formation via glaciation. They are defined as mineral soils which contain no calcareous (calcium carbonate containing) material anywhere within the soil, have less than 10% weatherable minerals in the extreme top layer of soil, and have less than 35% base saturation throughout the soil. Ultisols occur in humid temperate or tropical regions. While the term is usually applied to the red clay soils of the Southern United States, Ultisols are also found in regions of Africa, Asia, Australia and South America.

Contents

In the World Reference Base for Soil Resources (WRB), most Ultisols are known as Acrisols and Alisols. Some belong to the Retisols or to the Nitisols. Aquults are typically Stagnosols or Planosols. Humults may be Umbrisols. [1]

Introduction

Ultisols vary in color from purplish-red, to a bright reddish-orange, to pale yellowish-orange and (in cooler areas such as Pennsylvania) even some subdued yellowish-brown or grayish-brown tones. They are typically quite acidic, often having a pH of less than 5. The red and yellow colors result from the accumulation of iron oxide (rust), which is highly insoluble in water. Major nutrients, such as calcium and potassium, are typically deficient in Ultisols, [2] which means they generally cannot be used for sedentary agriculture without the aid of lime and other fertilizers, such as superphosphate. They can be easily exhausted, and require more careful management than Alfisols or Mollisols. However, they can be cultivated over a relatively wide range of moisture conditions. Where the organic matter content is high, as in Humults like the Olympic series, the soil is relatively fertile.

Ultisols can have a variety of clay minerals, but in many cases the dominant mineral is kaolinite. This clay has good bearing capacity and no shrink–swell property. Consequently, well-drained kaolinitic Ultisols such as the Cecil series are suitable for urban development.

Ultisols are the dominant soils in the Southern United States (where the Cecil series is most famous), southeastern China, Southeast Asia, and some other subtropical and tropical areas. Their northern limit (except fossil soils) is very sharply defined in North America by the limits of maximum glaciation during the Pleistocene, because Ultisols typically take hundreds of thousands of years to form—far longer than the length of an interglacial period today.

The oldest fossil Ultisols are known from the Carboniferous period when forests first developed. Though known from far north of their present range as recently as the Miocene, Ultisols are surprisingly rare as fossils overall, since they would have been expected to be very common in the warm Mesozoic and Tertiary paleoclimates.

Gardening in Ultisol

The lack of organic matter in Ultisol makes it difficult for plants to grow without proper care and considerations. Soil amendments are generally required each year in order to sustain flourishing plant life in regions with primarily Ultisol soil. [3] The use of soil tests, coupled with the corresponding provisions, can alleviate issues of nutrition and irrigation that can result from non porous Ultisol. [4] Soil tests help indicate the pH, and red clay soil typically has a low pH. [5] The addition of lime is used to help to increase the pH in soil and can help increase the pH in Ultisol as well. [6]

Mulch can be used to help improve Ultisol Mulch J1.jpg
Mulch can be used to help improve Ultisol

Possible solutions

Generally, gardeners aim to have 45% mineral, 5% organic matter and 50% pore space in their soil. [7] The composition of Ultisol in North Carolina, for reference, is approximately 16% pore space, 2% organic matter and 82% mineral. [8] The use of mulch is widespread in the Piedmont region of the United States as a solution to the high temperatures and saturation of the soil. [9] The addition of mulch helps to make the soil more porous. [10]

Adding manure and compost can help boost the amount of organic material present in the soil, which in turn helps add essential nutrients. Specifically, adding a 2- to 3-inch layer of compost and manure should be mixed into the soil to match a shovel's depth. [11] The addition of organic material also helps to improve the drainage, while decreasing the overall weight of the soil. [12]

A garden planted in a raised bed Raised bed (30827889786).jpg
A garden planted in a raised bed

However, microorganisms in the soil consume the same nutrients that plants use to grow so certain nutrients will remain unavailable to plants until the microorganisms completely break down the organic material and release nutrients. [13] Living organisms within the soil use, and subsequently convert, organic material into usable humus. [14] To avoid the delay presented by this process, adding manure in the fall is advisable. [15]

Some gardeners who live in areas with large amounts of red clay soil use raised beds or Hügelkultur to avoid having to amend the soil. [16] By using raised beds, gardeners avoid having to deal with Ultisols altogether.

Planting in Ultisol

Plants found native to regions with high amounts of Ultisol can thrive. Generally, these species adapt to poorly drained, damp soils. [17] The Missouri Botanical Garden recommends tickweed, spotted jewelweed, mealycup sage, Camassia , spring starflower, ostrich fern, sideoats grama, Bouteloua curtipendula , and prairie dropseed. [18]

Suborders

See also

Related Research Articles

<span class="mw-page-title-main">Compost</span> Mixture used to improve soil fertility

Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers. The benefits of compost include providing nutrients to crops as fertilizer, acting as a soil conditioner, increasing the humus or humic acid contents of the soil, and introducing beneficial microbes that help to suppress pathogens in the soil and reduce soil-borne diseases.

<span class="mw-page-title-main">Hydroponics</span> Growing plants without soil using nutrients in water

Hydroponics is a type of horticulture and a subset of hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions in an artificial environment. Terrestrial or aquatic plants may grow freely with their roots exposed to the nutritious liquid or the roots may be mechanically supported by an inert medium such as perlite, gravel, or other substrates.

<span class="mw-page-title-main">Fertilizer</span> Substance added to soil to enhance plant growth

A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods.

No-dig gardening is a non-cultivation method used by some organic gardeners.

<span class="mw-page-title-main">Physiological plant disorder</span>

Physiological plant disorders are caused by non-pathological conditions such as poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, and affect the functioning of the plant system. Physiological disorders are distinguished from plant diseases caused by pathogens, such as a virus or fungus. While the symptoms of physiological disorders may appear disease-like, they can usually be prevented by altering environmental conditions. However, once a plant shows symptoms of a physiological disorder, it is likely that that season's growth or yield will be reduced.

<span class="mw-page-title-main">Vermicompost</span> Product of the composting process using various species of worms

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<span class="mw-page-title-main">Green manure</span> Organic material left on an agricultural field to be used as a mulch or soil amendment

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<span class="mw-page-title-main">Soil test</span> Analysis of soil

A soil test is a laboratory or in-situ analysis to determine the chemical, physical or biological characteristics of a soil. Possibly the most widely conducted soil tests are those performed to estimate the plant-available concentrations of nutrients in order to provide fertilizer recommendations in agriculture. In geotechnical engineering, soil tests can be used to determine the current physical state of the soil, the seepage properties, the shear strength and the deformation properties of the soil. Other soil tests may be used in geochemical or ecological investigations.

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<span class="mw-page-title-main">Potting soil</span> Medium in which to grow plants

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<span class="mw-page-title-main">Red soil</span> Soil type

Red soil is a type of soil that typically develops in warm, temperate, and humid climates and comprises approximately 13% of Earth's soils. It contains thin organic and organic-mineral layers of highly leached soil resting on a red layer of alluvium. Red soils contain large amounts of clay and are generally derived from the weathering of ancient crystalline and metamorphic rock. They are named after their rich red color, varying from reddish brown to reddish yellow due to their high iron content. Red soil can be good or poor growing soil depending on how it is managed. It is usually low in nutrients and humus and can be difficult to cultivate due to its low water holding capacity; however, the fertility of these soils can be optimized with liming and other farming techniques.

<span class="mw-page-title-main">Agricultural pollution</span> Type of pollution caused by agriculture

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<span class="mw-page-title-main">Manure</span> Organic matter, mostly derived from animal feces, which can be used as fertilizer

Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nutrients, such as nitrogen, that are utilised by bacteria, fungi and other organisms in the soil. Higher organisms then feed on the fungi and bacteria in a chain of life that comprises the soil food web.

French intensive gardening also known as raised bed, wide bed, or French market gardening is a method of gardening in which plants are grown within a smaller space and with higher yields than other traditional gardening methods. The main principles for success are often listed as soil improvement, raised beds, close spacing, companion planting, succession planting and crop rotation. Originating in France, the practice is very popular among urban gardeners and small for profit farming operations.

<span class="mw-page-title-main">Soil aggregate stability</span> Property of soil

Soil aggregate stability is a measure of the ability of soil aggregates—soil particles that bind together—to resist breaking apart when exposed to external forces such as water erosion and wind erosion, shrinking and swelling processes, and tillage. Soil aggregate stability is a measure of soil structure and can be affected by soil management.

References

  1. IUSS Working Group WRB (2015). "World Reference Base for Soil Resources 2014, Update 2015" (PDF). World Soil Resources Reports 106, FAO, Rome.
  2. Vitousek, P. M.; Sanford, R. L. (1986). "Nutrient Cycling in Moist Tropical Forest". Annual Review of Ecology and Systematics. 17: 137–167. ISSN   0066-4162.
  3. "Tips on gardening for Georgia newcomers" . Retrieved 2018-04-10.
  4. "Tips on gardening for Georgia newcomers" . Retrieved 2018-04-10.
  5. "Dealing With Red Clay". www4.ncsu.edu. Retrieved 2018-04-14.
  6. "Dealing With Red Clay". www4.ncsu.edu. Retrieved 2018-04-14.
  7. "Dealing With Red Clay". www4.ncsu.edu. Retrieved 2018-04-14.
  8. "Dealing With Red Clay". www4.ncsu.edu. Retrieved 2018-04-14.
  9. "Tips on gardening for Georgia newcomers" . Retrieved 2018-04-10.
  10. "Improving Clay Soil – Garden.org". garden.org. Retrieved 2018-04-14.
  11. "Improving Clay Soil – Garden.org". garden.org. Retrieved 2018-04-14.
  12. "Improving Clay Soil – Garden.org". garden.org. Retrieved 2018-04-14.
  13. "How to improve clay soil | Oregon State University Extension Service | Gardening". extension.oregonstate.edu. 28 February 2003. Retrieved 2018-04-14.
  14. "How to improve clay soil | Oregon State University Extension Service | Gardening". extension.oregonstate.edu. 28 February 2003. Retrieved 2018-04-14.
  15. "How to improve clay soil | Oregon State University Extension Service | Gardening". extension.oregonstate.edu. 28 February 2003. Retrieved 2018-04-14.
  16. Kemper, William. "Best Plants for Problem Clay Soils: Annuals, Bulbs, Needled Evergreens, Ornamental Grasses" (PDF). Missouri Botanical Gardens.
  17. Kemper, William. "Best Plants for Problem Clay Soils: Annuals, Bulbs, Needled Evergreens, Ornamental Grasses" (PDF).
  18. Kemper, William. "Best Plants for Problem Clay Soils: Annuals, Bulbs, Needled Evergreens, Ornamental Grasses" (PDF).