Sustainable agriculture

Key points

• Sustainable agriculture is a collection of practices that help fulfill society’s crop needs while also protecting the environment and maintaining economic viability for farmers.
• One important part of sustainable agriculture is soil conservation. The goal of soil conservation is to prevent erosion, or the loss of fertile topsoil as a result of water, wind, or human activity. Agricultural methods of soil conservation are listed below.
  • Contour plowing is a method of planting crops in rows that run parallel to a slope’s topographic contour lines. Contoured rows help slow runoff and hold topsoil in place.
  • Wind breaks refer to lines of trees and shrubs planted at the edges of agricultural fields. The trees and shrubs break the force of the wind, preventing soil from blowing away.
  • Perennial crops are those that live for multiple years. Planting perennial crops results in less soil disturbance than planting annual crops, which die after one year and must be replanted.
  • Terracing is a technique used to farm hilly or mountainous areas. This method involves growing crops on terraces, which are flat strips of land built into a hillside. Water flows gradually from terrace to terrace, reducing overall water loss and soil erosion.
  • No-till agriculture is a practice that involves planting seeds without first turning over top soils. Crop residues are left in the field from season to season, and the top layer of soil is left undisturbed. This practice helps maintain soil structure and promotes water infiltration.
  • Strip cropping is a crop rotation system in which strips of erosion-susceptible and erosion-resistant plants are grown in an alternating pattern. This system helps stabilize the soil and maintain soil fertility.
• Soil fertility is the ability of a soil to sustain plant growth. Erosion can deplete soils of essential plant nutrients. So, strategies for preventing erosion can also help maintain soil fertility. Other sustainable methods for promoting soil fertility are described below.
  • Crop rotation is the practice of changing the type of crop grown in a field, usually season by season. Crops are rotated to balance out nutrient demands on the soil, reducing the need for added fertilizer. For example, crops that demand a lot of nitrogen (e.g., corn) can be rotated with crops that restore soil nitrogen via nitrogen fixation (e.g. legumes).
  • Green manure is a crop grown specifically to be mixed into topsoil while still green. As the green plant material decomposes, nutrients are released into the soil.
  • Limestone is a type of rock composed primarily of calcium carbonate. Limestone can be mixed into acidic soils to increase the soils' pH. Making soils less acidic can help increase the nutrient availability of the soil.