5.15 - Sustainable Agriculture

Question 1

Soil Conservation

Answer 1

• Agricultural techniques that minimize erosion
  (US is losing topsoil to erosion 10x faster than it forms)

Prevents loss of:
- Nutrients in topsoil
- Soil moisture
- Decomposers in topsoil
- Organic matter that traps
soil moisture

Question 2

Types of Soil Convervation

Answer 2

• Contour plowing
• Terracing
• perennial crops
• Windbreaks
• no till
• Strip Cropping

Question 3

Contour plowing

Answer 3

• Plowing parallel to natural slopes of the land instead of down slopes prevents water runoff & soil erosion
• Forms mini terraces that catch water running off, conserving soil & water

Question 4

Terracing

Answer 4

• Cutting flat “platforms” of soil into a steep slope
• Flatness of terraces catches water & prevents it from becoming runoff and eroding soil

Question 5

Perennial Crops

Answer 5

• Crops that live year round and are harvested numerous times
• Longer, more established roots & prevention of bare soil between harvest

Question 6

Windbreaks

Answer 6

• Using trees or other plants to block the force of the wind from eroding topsoil
• Can be used as a source of firewood, fruit (income)
• Can provide habitat for pollinators & other species

Question 7

No Till

Answer 7

• Leaving leftover crop remains in soil instead of tilling under
• Adds org. matter to soil (nutrients, soil cover, moisture)
• Prevents erosion from loosened soil

Question 8

Strip Cropping

Answer 8

• Another name for intercropping
• Alternating rows of dense crops (hay, wheat) with rows of less dense crops (corn, soy, cotton) to prevent runoff from eroding soil from less dense rows of crops

Question 9

Improving Soil Fertility: Crop Rotation

Answer 9

• Methods of restoring nutrient levels in the soil (N, P, Ca, Mg)

Crop Rotation:
- Replanting same crops continuously depletes soil of the same nutrients
- Crop rotation can allow soil to recover from nitrogen-demanding crops like corn
- Peas/beans (legumes) have nitrogen fixing bacteria in their root nodules that can return nitrogen to the soil

Question 10

Improving Soil Fertility: Green Manure

Answer 10

• Green manure is leftover plant matter from a cover crop - a crop planted in the offseason, between harvest & replanting of main crop
• Cover crop roots stabilize soil limiting topsoil erosion
• Remains of cover crops (green manure) left on field breakdown to release nutrients into the soil

Question 11

Improving Soil Fertility: Limestone

Answer 11

• Limestone releases calcium carbonate (base) which neutralizes acidic soil
• Acidic soil has high H+ ion concentration, which displaces + charge nutrients from soil (leeching them out)
• Acidic soil also makes toxic metals (aluminum) more soluble in soil
  ***Calcium is a needed plant nutrient as well

Question 12

Rotational Grazing

Answer 12

• Regular rotation of livestock to different pastures to prevent overgrazing
• Overgrazing can kill plants, compact soil, and lead to erosion of topsoil
• Rotational grazing can actually promote pasture growth at faster than normal rate
• Clips grass back to length where growth is fastest & encourages deeper root growth