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65 Cards in this Set

  • Front
  • Back

Two key properties of soil

1. Texture

2. Structure


Relative proportion of sand, silt and clay particles in soil.

Mineral particles in order from largest size to smallest size.

Largest: Sand

Medium: Silt

Smallest: Clay

How does high amounts of sand make soil feel?


How does a high amount of silt make soil feel?


How does a high amount of clay make soil feel?

Velvet when dry, sticky when wet

In a soil sample (like from the assignment), what particle will be suspended to the bottom? How about the top?

Sand on the bottom, clay on the top

What tool is used to identify the type of soil based on percent composition of particles?

Texture Triangle

Lester soil was proposed in 1939 in what county?

McLeod (near Lester Prairie, MN)

When was the soil established (Lester reading)

1945 in Dakota County

Lester soils are ___ ___ and formed in loamy glacial till on ground moraines.

Lester soils are well drained and formed in loamy glacial till on ground moraines.

Lester soils have properties developed from grassland and forest environments and are primarily used for ____, ____ and ____ production.

Lester soils have properties developed from both grassland and forest environments and are primarily used for forage, corn and soybean production.

What is the state soil?

Lester (passed in 1987, official on April 28, 2012)

Soils high in sand have great ___ and aeration so roots are exposed to air in the soil and don't rot.

Soils high in sand have great drainage and aeration so roots are exposed to air in the soil and don't rot.

True or False: Sandy soils are good at holding moisture during dry spells and hold nutrients well.

FALSE: Sand soils don't hold moisture well when it is dry outside and they do not hold moisture well.

True or False: Nutrients and moisture hang on to a soil best when the soil particles have lots of surface area, and sand has the least surface area (relative to particle volume) of the three types of particle.


True or False: Roots penetrate easily in a dry clay soil.


Clay soils tend to be what?


Clay holds water so much that what occurs?

It can be hard for the plant to water itself

Silt has ___ properties between sand and clay.

Silt has intermediate properties between sand and clay.

True or False: All soil textures have good and bad points.


Potatoes and peanuts are grown in what type of soil to make harvesting easier?

Sandy soil

Loam soils are used for what types of crops?

Corn, wheat and soybeans

True or False: It is tough to modify soil so you just have to make do (you can't really add clay for instance...)



The way in which the soil particles and other materials like organic matter in the soil bind together in clumps.


Clumps of soil

True or False: Pure sand does not clump together into aggregates.



When sand, silt, clay and organic matter interact to form small aggregates

Large holes in aggregates allow for what?

Spaces for water and gases to pass


Holes available for gas exchange. They are important because if soil becomes water-clogged, they can die.

Organic matter is like glue in what way?

It builds aggregates by stickle soil particles together.

Good Tilth

Soil with granular aggregation that favors plant growth by holding water and nutrients while still allowing for drainage and gas exchange - does not form clumps and breaks apart into crumbly moist chunks

2 ways to improve soil structure

1. Increase organic matter

2. Reduce compaction

Increasing organic matter improves and stabilizes what?

Soil aggregation

Reducing compaction does what?

Maintains macro- and micro-pores in soil to promote drainage, moisture retention and gas exchange

Tillage exposes ___ ___ to oxygen, which breaks down organic matter through oxidation. As organic matter is lost, so is the glue that causes aggregation.

Tillage exposes ORGANIC MATTER to oxygen, which breaks down organic matter through oxidation. As organic matter is lost, so is the glue that causes aggregation.

True or False: Tractors compact soil and reduces porosity.


Soil Organic Matter

Carbon-based material in the soil that was originally a living organism (plant, animal or microbe)


Sticky substance that helps bind soil particles together. Humus created from the decomposition of former living materials.

Humus can absorb __ times its weight in water, so it is important in improving light (sandy) soils.

Humus can absorb 6 times its weight in water, so it is important in improving light (sandy) soils.

True or False: Organic matter is negatively charged so it holds positively charged cations like calcium.


True or False: Decomposing organic matter makes nutrients such as nitrogen available to plants.


4 types of organic matter


Raw organic matter

Green manure

Incorporating crop residues


Leaves, weeds, manure, grasses and other organic materials. Builds soil structure and retains moisture and nutrients.

Raw organic matter

Uncomposted organic material that is tilled into the soil. Slow working, but arguably provides more nutrients because nutrients aren't released into the atmosphere like in compost.

Green manure

Growing a crop with the sole purpose of tilling the crop into the land to increase organic matter. Helps improve moisture holding capacity. Great benefits for legumes.

Incorportating crop residues

Incorporating plant material into soil after harvest.


Using bare minimum tillage or leaving residue at the top of the soil. This minimizes erosion.

If you add too much organic matter that has too much carbon and not enough nitrogen, what happens?

You can harm growth and deplete the soil of nitrogen. That's why using manure (chicken manure especially) is a safe bet.

USDA standards for organic production in the USA

1. Description of practices

2. List of each substance used in production

3. Identification of monitoring techniques used to verify that the organic plan is implemented

4. Describe management practices and physical barriers

Organic crops can only be grown on what type of land?

Certified organic land with defined boundaries and buffer zones.

In organic farming tillage must minimize what while improving the soil?


How are crop nutrients and soil fertility managed in organic farming?


Plant and animal materials are used to improve what in organic farming?

Soil organic matter.

Raw animal manure can be applied to what in organic farming?

Land used for crops not intended for consumption OR it must be in the soil not less than 120 days prior to harvest (90 for some crops that don't come in contact with soil)

In organic farming, what must the compost carbon:nitrogen ration be between.

25:1 and 40:1

In organic farming, the pile of manure must be between what temperatures for 15 days while being turned 5 times?

131 to 170 degrees F

GMO crops are not allowed in what?


Container gardening is not desirable because why?

The plants are too compact and there is poor drainage. Instead, use soil-less mix or an organic mix to increase aeration-porosity.

What type of gardening is better than container gardening for the purposes of porosity?

Raised bed

Fertilizer Analysis

The 3-number NPK series on fertilizer bags

What does N-P-K represent?

The % nitrogen, phosphorous and potassium in fertilizer

10-15-10 fertilizer has what percent of each nutrient? What is the rest of the fertilizer made of?

10% N

15% P

10% K

The rest is "filler" (sand or gravel usually)

In MN, what nutrient is typically absent in fertilizer? Why?

Phosphorous because legislation limits it to prevent algae after run off.

In MN, what nutrient is typically valued the most? In other words, we try to get the best deal on which nutrient?