Compost in a Garden, Farm, or Rangeland

Benefits of Compost in Croplands and Gardens

• Helps with soil increasing aggregation, building soil capacity to hold more air, moisture, and nutrients, and reducing the potential for erosion

• Contains all essential plant nutrients and releases them slowly, over months or years, unlike synthetic fertilizers

• Brings diverse life to soil, including bacteria, fungi, insects, and worms

Note: Depending on your feedstocks and composting process, a high rate of manure and compost application can cause salt accumulation and therefore have negative effects on crop production. If in doubt, it’s best to test your compost before heavy applications.

Potting Mix Blend

On page 12, we discussed why plants cannot be planted directly into 100 percent compost. Now let’s look at how to make a soil blend from your compost for raised garden beds or large pots. Commonly, planting mixes contain topsoil (largely clay/sand in New Mexico and light brown in color); something to encourage drainage, such as pumice, perlite, or vermiculite; something fluffy for porosity and moisture regulation, such as coconut coir or peat moss (peat moss is not recommended due to the damaging harvesting methods used, but we mention it here since it is common in commercial soil blends); and then of course the compost. You can begin with one part each in your blend as a base, and experiment with different ratios and ingredients to find what best suits your situation. Batches can be made in any size, from a wheelbarrow to a several cubic yards!

The next time you work on raised beds, add potted plants to your porch, or set up a row of vegetables, trying mixing up different ratios of compost, coconut coir or peat moss, pumice or vermiculite, and sand/clay from elsewhere on your property. Be sure to write down what the ratios were and how the plants did, and evaluate what worked best for your plants!

Compost Application to Rangeland

Usually amendments are used in farm settings, but over the past decade researchers have been exploring application of compost to rangelands as a way to potentially increase forage production, soil carbon storage, and water retention. Several researchers and organizations are currently researching how compost applications can affect forage production and soil health in arid and semiarid rangelands in the Southwest.

• Shovel, rake, bucket and wheelbarrow: This low cost, low tech, time-consuming method gives you lots of control over spacing and depth.

• Manure spreader: There are a variety of sizes available that can be pulled by hand or behind a riding lawnmower or tractor. Cost will vary depending on the size and model.

• Blower services or blower trucks can be used to distribute compost across extensive croplands and broader landscapes. This method is more costly and technically complicated than the other two, but it can be used to cover a large area.

Soil Remediation Application – Disturbed Sites

There has been some research on using compost for roadside stabilization, mine reclamation, and other remediation activities. This work is outside the scope of this manual.