APES 3.6 - Sustainable Agriculture

Lesson 3.6

SUSTAINABLE/REGENERATIVE FARMING

Sustainable Agriculture

Issues that should be addressed by sustainable farming practices:

• Topsoil Erosion
• Degenerating Topsoil
• Depletion of Freshwater Aquifers
• Contamination of Surface Waters
• Pesticide Treadmill
• Biodiversity loss
• Deforestation

Irrigation Issues

Sustainable irrigation must balance the issues of water loss through evaporation and excessive runoff. Runoff is also capable to carrying away valuable topsoil and bringing chemicals (fertilizers, pesticides) into nearby waterways.

No-Till Farming

In no-till farming, farmers do not till their fields before planting. Instead, they use specialized equipment to create a channel that is just spacious enough for seeds to be planted, minimizing soil disturbance.No-till farming can:

• minimize wind and water erosion
• protect soil from high temperatures and moisture loss
• organic matter from previous crops enriches the untilled soil

Contour Plowing & Terracing

Soil erosion can occur more severely on sloped land. In order to combat this, contour plowing, (where the rows of crops follow the contours of the land) is used. This can also:

• improve water infiltration
• minimize fertilizer loss
• improve quality of local waterways

In areas with greater slopes, terrace farming can accomplish the same things. It involves cutting flat strips into the slope.

Rotational Grazing

In rotational grazing, livestock are penned in a portion of the total land, allowed to graze, then later moved to another area.

• This allows plants in non-grazing areas more time to regrow. This stores more organic material in the soil as they can photosynthesize more.
• Healthier plants also have stronger root system that hold topsoil in place.

Mixed farming (where a farmer is both growing crops and raising livestock) is not done widely in modern agriculture, but it is a highly valuable technique.

• Animal manure acts as a natural fertilizer, preventing the need for synthetic fertilizers.

Strip Cropping & Crop Rotation

Crop rotation involves changing the type of crop that is grown on a piece of land from year to year. Farmers can use this technique to capitalize on the benefits of certain plants. For example, they could rotate:

• a plant that promotes nitrogen fixation by supporting N-fixing bacteria on its roots
• a plant that outcompetes weeds
• a plant that is effective at holding topsoil in place with roots, or covering the soil with its foliage
• a plant that can earn high profits

In strip cropping, farmers grow several different types of crops at the same time, in strips. The benefits are similar.

Agroforestry

One of the most destructive agricultural techniques is slash-and-burn agriculture, where forested land is logged, then the remaining brush is burned away to clear space for farm land. This brings all the consequences of deforestation, coupled with the destruction of modern agriculture. It has been known to completely shift local climate. In contrast, agroforestry preserves the trees in an area, since crops are planted among them.