All of the New England states and most of New York were once covered by huge expanses of snow and ice, like Antarctica today. These glaciations have had great effect on the soils we find in the Northeast. We know of four glaciations (in chronological order): the Nebraskan, the Kansas, the Illinoisan, and the Wisconsin glaciations. When large amounts of snow and ice accumulated the ice started to move due to gravity. At the bottom of the ice, rock was picked up. This rock would scrape along the bottom of the ice, be pushed into it, and grind up the rock below. At the end of the ice age, the ice melted and dumped everything in it in-situ, as well as caused massive runoff that caused erosion and sedimentation.

The five factors that determine soil formation are:

1. Parent Material
2. Climate
3. Relief
4. Biota
5. Time

The influence of forest vegetation is clearly seen in soils of the Northeast. Forest soils typically do not have high contents of organic matter, probably due to the limited turnover of the root systems of trees. This contrasts sharply with the prairie soils with high organic matter prevalent in the Midwest which developed under perennial grass vegetation. Further, some tree species, especially coniferous ones, release significant amounts of organic acids from their leaves upon decomposition. These acids can dissolve organic matter, aluminum and iron oxides and wash these down into the soil profile. This leaves a leached layer (gray or white) near the soil surface, under a dark organic surface layer. The organic acids and aluminum and/or iron oxides will be deposited below the leached ('E') horizon forming a dark and sometimes orange colored layer.  These soils are most common in sandy soils, especially in the outwash plains common in the Northeast.

1. Sand, silt, and clay; coarse fragments.
• Sand = 2.0-0.05 mm diameter particles
• Silt = 0.05-0.002 mm diameter
• Clay = <0.002 mm diameter
• Coarse fragments = > 2 mm diameter
2. Understand and use the textural triangle.

The textural triangle helps determine the soil textural classification of a soil based on its fine-earth fraction (particles <2mm, that is sand, silt and clay). On the bottom, find the percent sand, on the left hand, percent clay, and on the right hand, percent silt. As an example, a soil has 15% sand, 60% silt, and 25% clay – this soil would be classified as a silt loam (Figure from Soil Survey).

image source: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet29.pdf

A soil is in the liquid state when it acts as a viscous liquid when jarred.  A soil is in the plastic state when it can be molded in different shapes. A soil is friable when moist soil crumbles into aggregates when crushed with only light pressure. A soil is loose when it has no consistency at all, typical of dry, structureless sand. A soil is hard when it can only be crushed with difficulty between crumb and forefinger, typical of dry, structureless clay soils. The liquid limit is the limit between the plastic and liquid state. The plastic limit is the limit between the friable and plastic state.

To assess conditions for tillage and traffic, perform a "ball test" by grabbing a fistful of field soil in your hand and mold it – if you can form a ball the soil is in the plastic state and highly sensitive to soil compaction by traffic and tillage. In contrast, if the ball breaks into smaller pieces, the soil is in the friable state and resists compaction and can be tilled.

"Wet ball" test method

Photo courtesy of NRCS

http://photogallery.nrcs.usda.gov

 To determine the soil type:

1. Select the soil survey of your County.
2. Go to the Index to Map Sheets and select the map of your location.
3. On the map, find your location. You will see a Soil Series Symbol.
4. Go to the Soil Legend and determine what this symbol stands for.

Soil structure is defined as 'the arrangement of primary soil particles into groupings called aggregates or peds' (Brady and Weil, 1996). Soil structure determines properties such as total porosity, air-filled and water-filled porosity, pore-size distribution, soil tilth, and aggregate stability. A soil with a well-developed structure will have larger total porosity and greater air-filled porosity and therefore will be better drained and provide a better environment for root growth than the same soil with poor structure. The soil will also absorb water better. This water will be filtered by the soil before it is released to groundwater instead of running off. Runoff causes soil erosion and carries nutrients, organic matter, and pesticides to surface water, causing an environmental threat.

Organic matter largely determines the quality of a soil for crop production. Typical mineral agricultural soils have organic matter contents of 1-6%. Organic matter consists of three distinctly different parts: living organisms, fresh residues, and well-decomposed residues (i.e., the living, the dead and the very dead organic matter).

Living organic matter is composed of roots, fungi, bacteria, viruses, protozoa, algae, insects, earthworms, and large animals. The living portion represents about 15% of the total soil organic matter. Living organisms play an important role in determining soil quality. Roots stimulate soil aggregation and create pores in the soil. Most other soil organisms live off the 'dead organic matter' and create 'very dead organic matter'. Earthworms completely modify the soil architecture by their burrowing action, and mix soil with organic matter in their intestines which forms stable aggregates upon excretion. Micro-organisms such as fungi contribute to soil structural stability through their hyphae which function as nets around primary soil particles and micro-aggregates. Bacteria produce sticky organic substances that stimulate aggregation. In the process, the living organisms recycle large quantities of nutrients and convert them to forms that are available or unavailable to plants.

Humus is the end product of the decomposition of 'dead organic matter'. Humus is not food for organisms, but it's very small (colloidal) size and chemical properties make it an important soil component. Humus has cation and anion exchange capacity, and thus holds on to some essential plant nutrients, storing them for slow release to plants. Humus can also 'neutralize' certain harmful chemicals, making them unavailable to plants. Humus improves drainage and hence reduces compaction of clay soils, and it improves water retention in sandy soils.

Soil is an integral part of agriculture and in management of resources including water and nutrients.  Soil is classified by the method of formation, particle size, texture, structure, and organic matter.

Links

• Cornell University Nutrient Management Spear Program: NYS Soil Test Summaries. http://nmsp.cals.cornell.edu/publications/soilsummary.html

• USDA NRCS Regional Boundaries, State Offices, Centers. http://www.nrcs.usda.gov/about/organization/regions.html and http://offices.sc.egov.usda.gov/locator/app
• USDA NRCS Web Soil Survey: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx