Green Manuring

Over the next few posts, I will slowly describe the Organic principles that I have always believed in and the approach that we have taken to start on the quest for Organic Certification.

Organic farming can be described as farming sustainably without the addition of artificial chemicals, farming in a manner that respects the environment, and having a whole farm approach that treats it as a living and growing organism.

At the heart of this process is the soil;

From the outset we have used green manuring to improve the soil, and to prepare the soil for the plantings, given our soil was a little acidic, and had low organic material I set out to improve the ground using cover crops and re-mineralisation

Below is a brief description of these processes

Green Manure / Cover Crop

Green manure crops play a valuable role in agriculture, and especially organic farming practices because of the many benefits they provide to the soil, the ease of addition and to the cropping system.

Green manures are crops grown specifically to improve soil condition and nutrition. They can be used instead of heavy chemical fertilisers and inorganic farming practices, chemical fertilisers supply nutrients but no organic matter. Suppression of weeds and soil-borne diseases are additional benefits of particular green manures.

Instead of being harvested, green manure crops are incorporated back into the soil, usually while they are still lush and green and before they go to seed. At this stage of growth the plants have a relatively high nitrogen and moisture content, and provide an ideal food source for soil microbes and other organisms like earthworms. Under favorable conditions these organisms decompose the green manure reasonably quickly. During this process, organic matter and nutrients are released into the soil where they become available for use by other organisms including crop plants.

Some benefits of green manures

Organic materials:
Organic matter is provided by root growth and mechanical mulching. Soil organisms then decompose this organic matter into humus and other organic compounds. Improving the organic matter level and biological activity of soil is one of the fundamental objectives of organic agriculture, and green manure cropping helps growers achieve this

Weed control and Erosion
Weeds are suppressed by the competition that dense, green manure crops exert for water, light and nutrients. Soil improvement is also achieved by decreased erosion from heavy rains. Soil compaction can also be prevented with the use of a green cover crop.

Nitrogen Fixing
Soil nitrogen levels are increased by leguminous green manures through their association with nitrogen-fixing Rhizobium bacteria. The Rhizobia can take nitrogen (N2) from the air and convert it to the form plants normally obtain from the soil. This process is called nitrogen fixation. When leguminous plants decompose, the nitrogen is released for use by other crops.

Biological tillage
Biological tillage (cultivation) is the term used to describe plants loosening the soil as their roots grow and as they dry out the soil and it cracks. This can help in soil improvement by breaking down the hardpan in heavily compacted soils.

Below are some images of Oats and Dunn Peas that are a winter cover crops that we have used.