LET’S GET DIRTY

BY MARIKA ZELDENRUSTEDITS BY SABRINA PARISI

• Soil is the foundation of our basic ecosystem. It filters our water, provides nutrients to our forests and crops, and helps regulate the Earth’s temperature as well as many of the important greenhouse gasses.

• Human use soil as a holding facility for solid waste, filter for wastewater, and foundation for our cities and towns.

• Soil is the basis of our nation’s agroecosystem, which provides us with feed, fiber, food, and fuel.

BASIC SOILS KNOWLEDGE: IMPORTANCE

• Soil forms at different rates in the three kinds of rock: igneous, sedimentary, and metaphoric.

• With time and weathering (temperature changes, erosion by wind and water, etc.), these rocks slowly and continually crumble and disintegrate. This produces the mineral material from which soil forms.

• In the transformation from rock to soil, minerals undergo so many changes that, although still resembling their parent rock, they usually significantly change their composition.

BASIC SOILS KNOWLEDGE: FORMATION

• Water flows across landscape, causing erosion. This is often part of the weathering process, leading to soil formation.

• Water carries off the mineral material from rocks, sorting the particles by size, separating sand, silt, and clay. (Clay is smallest, then silt is bigger, then sand is the largest)

• Centuries of rainwater flowing through soils causes the slow breaking down of minerals.

• When soluble components such as the alkaline ions (Ca, Mg, K) are carried off to the groundwater, soil fertility diminishes and acidity decreases.

• Water is what helps develop the recognizably different A and B soil horizons.

BASIC SOILS KNOWLEDGE: WATER IN SOILS

BASIC SOILS KNOWLEDGE: SOIL HORIZONS• The topsoil, which has the most organic matter and is the

root zone, is called the A horizon. • The next layer is the subsoil, which contains higher

concentrations of clay, is denser, and is called the B horizon.

• The next layer is the parent material--- the altered organic deposit or the weathered bedrock--- called the C horizon.

• The last layer is the bedrock, a layer of solid rock formations below the soil, known as the R horizon.

FRAGIPANS• Fragipans – natural subsurface layers with

higher density than above soil; low in organic matter, very slowly permeable to water, often showing bleached cracks forming polygons.

• Make certain soils hard or not possible to farm because plant roots cannot penetrate it, and water often doesn’t drain properly

• Typically found in glacial till soils and colluvium soils

FRAGIPAN SOIL HORIZON

Fragipans can be seen in the B horizon (white shapes in soil)

BASIC SOILS KNOWLEDGE: SOIL QUALITY

• Soil quality is the capacity of soil to basically do what it’s supposed to--- sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.

• Soil quality indicators include visual (changes in soil color, runoff, weed species, blowing soil…), physical (topsoil depth, density, aggregate stability, infiltration, crusting…) chemical (pH, salinity, organic matter…) and biological indicators.

• There are several causes for soil quality concerns: pesticides, available water capacity, soil biodiversity, sediment deposition on cropland, compaction, and soil erosion.

SOIL HEALTH• Soil Health is defined as the capacity of a soil

to function. • Management practices that improve soil

health increase productivity and profitability immediately and into the future.

• A fully functioning soil produces the maximum amount of products at the least cost.

• Maximizing soil health is essential to maximizing profitability.

Soil pH:

Extremely acid 3.5 – 4.4Very strongly acid 4.5 – 5.0Strongly acid 5.1 – 5.5Moderately acid 5.6 – 6.0Slightly acid 6.1 – 6.5 (6.5 is best for most crops)Neutral 6.6 – 7.3Slightly alkaline 7.4 – 7.8Moderately alkaline 7.9 – 8.4Strongly alkaline 8.5

• Organisms: As soil forms, organic matter (leaves, dead plants, etc.) decomposes, changing the chemistry of the soil. This is also affected by what organisms are currently living in the soil. Fertile soils are those that have enough N, P, K, and other nutrients needed by plants.

• Location: soils at the bottom of a hill will get more water, and soils on the slopes directly facing the sun will be drier. Mineral accumulations, plant nutrients, type of vegetation, vegetation growth, erosion, and water drainage also depend on location.

• Climate: heat, rain, ice, snow, wind, sunshine and other environmental forces break down the parent material and affect how fast or slow soil will form.

• Time: All of these factors depend on time, often hundreds or thousands of years.

BASIC SOILS KNOWLEDGE: FERTILITY

There’s a ton of them and I don’t even know them so just familiarize yourself with this chart.Topographic Map Symbols

UNDERSTANDING MAPS: TOPOGRAPHIC MAP SYMBOLS

Crop Residue Management: farmers will leave crop residue (corn or soybean stalks, small grain straw residue from vegetables, etc.) to prevent erosion. No-till Farming: largely promoted, as it prevents erosion caused by tilling Contour Farming: farming around a hill or slope as near to the contour as it is practical to reduce erosion Contour Strip Cropping: growing crops in strips or bands on or near the contour to reduce soil erosionConservation Buffers: areas or strips of land with permanent vegetation (trees or shrubs) to reduce sediment from runoff and provide wildlife habitatMore Here

LAND USE: CONSERVATION PRACTICES

• U.S. farmers became concerned with “good soil being washed or blown away” even before the American Revolution. George Washington and Thomas Jefferson experimented in ways to prevent erosion.

• Despite the continued efforts of the USDA (United States Department of Agriculture), the dust bowl happened.

• Archaeologists have determined that the demise of many sophisticated civilizations, such as the Mayans of Center America and the Harappan of India, resulted directly from the mismanagement of their soils.

LAND USE: SOILS AND HISTORY

• The practice of repairing and removing damage to the land, air, and water that is caused by pollution

• Most chemicals released in the soil are left by businesses and corporations.

• Bioremediation is a technique where tiny bugs (microbes) live in the soil and eat the contaminated chemicals, digesting them and making the chemical less harmful to the land

Placing a cover or cap over a contaminated land fills is called capping. This system encloses the chemical material in the ground preventing harmful chemical coming in contact with the environment and human beings.

• Chemical oxidation involves drilling wells in polluted land and pumping chemicals known as oxidants (including hydrogen peroxide and potassium permanganate) into the ground, thereby breaking down harmful pollutants.

LAND USE: POLLUTION REMEDIATION

• Wetlands are federally defined as areas that have saturated soils and can support vegetation adapted for life in saturated soil conditions.

• Wetlands contain hydric soils, or soils that are saturated, flooded, or ponded long enough during the growing season to develop anaerobic (lack of free oxygen) conditions.

• They are often recognized as black-colored muck and/or black to dark brown-colored peat. Wetland mineral soils will often have a thick dark organic surface later, and grey subsurface colors.

LAND USE: WETLAND IDENTIFICATION

• More than one third of America’s threated and endangered species live only in wetlands.

• Wetland plants and soils are special; they naturally store and filter nutrients and sediments. They can clean water by filtering, decomposing, and converting.

• They also prevent damage during floods by soaking up floodwaters and slowly releasing it.

• In addition, they help control erosion. Shorelines along rivers, lakes, and streams are protected by wetlands, which hold soil in place, absorb the energy of waves, and buffer strong currents.

LAND USE: WETLAND IMPORTANCE

• Carbon Sequestration is a way to transfer the carbon dioxide from the atmosphere into the soil through crop residue and other organic solids.

• This helps to counteract the emissions from fossil fuel combustion, helping to prevent global warming.

• Global warming affects soils by causing a longer and drier growing season. This causes the organic matter content to decline, as well as decreasing the capacity of water for plants.

• It is often achieved by adding large amounts of biomass to the soil and practicing no-till crop production.

• Soils are also a part of the water and phosphorous cycles.

LAND USE: CARBON SEQUESTRATION

THE END!