NCSU's Agronomy Department
College-Day Recruitment Flyer
This is a flyer from the NCSU's Agronomy Department. Agronomy is the study of plants and soils and their environment. People who study agronomy are agronomists. Agronomists are scientists who look for ways to raise more food on the same amount of soil and also work to improve the quality of seed and the nutritional value of crops. What if there is a big population one day and there is not enough soil to make food with so agronomist will try to find a way to grow more food with that amount of soil.
Weathering
Weathering is the breaking down of rocks, soils and minerals.
Chemical weathering is when rocks are broken down by chemical reaction.
- Water- dissolves rock, also most important cause.
- Oxygen- combined with water and iron and it makes rust and the process is called oxidation.
- Carbon Dioxide- CO2 with rainwater and it makes carbonic acid and it weathers softer rock.
- Living Organisms- roots of plants make a weak acid and dissolves rocks that are around the plant.
- Acid Rain- it causes rock to weather very rapidly.
Mechanical weathering is the physical breakdown of rock by environmental factors.
- Release Of Pressure- causes top layer of rock to crack and flake off
- Freezing and Thawing- water freezes causing the crack to get bigger.
- Animal Actions- animal digs, this loosens the soil and breaks apart the rock.
- Plant Root Growth- roots grow in cracks in the rock breaking them, apart
- Abrasion-Sand in wind, water, ice or gravity can wear away rock.
Soil Composition/Texture/Horizons
- Soil Composition is an important aspect of nutrition management
- Basic components are minerals, organic, matter, water and air.
- Soil is very complex and dynamic.
- Soil can change on a daily basis depending on numerous factors some are water supply, cultivation practices and soil type.
- Inorganic parts of soil are made of different amounts of different size particles and affects characteristics of soil.
- If spaces are large enough and well connected water can go through easily
- Light soils drain water
- Soils that have more clay are heavier and the clay particles have small spaces so they hold water.
- A soil that has a mixture of grain sizes are called loam.
- Soil horizons are different layers of soil with depth
- weathering occurs most on top layer or top soil is most exposed to weather and is where fresh water is in contact with soil.
- Each layer lower is weathered just a little bit less than the one above.
Soil Formation
What affects soil formation?
1. Parent Material
1. Parent Material
- Soils form in parent material that is bedrock weathered in place.
- Also classified based on mode of transportation -Ice -Water -Gravity -Wind -Lake -Oceans -In Place
- Doesn't form overnight
- Soil formation can take thousands and even millions of years.
- Time is an important factor in soil formation.
- Newly exposed surface will have little soil and old surfaces will have deeper soils.
- Two important climate components are temperature and precipitation.
- Determine how quickly weathering will be and what kind of organic material will be on and inside the soils.
- Moisture determines chemical and biological reactions that will occur as soils are formed.
- Warmer climate with more rainfall means -more vegetative cover - more animal cover -more runoff -more water erosion
- Refers to the landscape position and the slopes it has.
- Steep, long slopes are going to have water going down faster and maybe bring up the surfaces of slopes.
- Effect is poor soil on the slopes and better soils at the bottom of soil.
- Slopes may be exposed to more sunlight, which may dry out soil moisture and it will be less fertile.
- Source and richness of organic matter is down to the living things that live in and on the soils.
- Plants provide lots of vegetative residue that are added to soils.
- Roots hold soils and protect from wind and water erosion.
- Shelters soils from sun and other environmental conditions.
- Worms break down organic matter and aid decomposition.
- Animal droppings, dead insects and animals result in more decaying organic matter.
- Microorganisms help with mineral and nutrient cycling and chemical reactions.
Remote Sensing
Remote sensing is the scanning of objects of areas from a aircraft or satellites to obtain information about the place.
It is used for checking how much soil there is left and how much is gone from before.
It is used for checking how much soil there is left and how much is gone from before.
Why Is Soil Important?
- Soil is a vital part of the natural environment
- Influences the distribution of plant species and provides a habitat for a wide range of organisms
- Controls flow of water and chemical substances between atmosphere and Earth.
- Acts a source and store for gases in the atmosphere
- Reflect natural processes
- Record human activities in past and present
- Part of our cultural heritage.
- Supports plant and animal life.
- Develops Rock.
- Position in landscape and climate it experiences form a complex natural system.
- Plant crops, make gardens, provide grazing land, create dams, build road beds and layering material at land fills.
Misuses Of Soil and Negative Consequences
- People waste it and don't know how important it is
- Farmers put something on there fields to get the pests out of the crops and it goes down to the hill and ruins the soil.
- Putting different kind of plants in the same place will make the soil not fertile anymore.
Soil Stewardship and Advances in Agronomy
1.
- Manage more by disturbing soil less
- Keep a living root growing throughout the year
- Keep the soil covered as much as possible
2.
- Use tools to check the soil and see how much soil is left on earth and how much soil the world has lost.