Tips for Increasing Nitrogen Efficiency in Organic Crops

With the increasing cost of organic nitrogen inputs and regulatory restrictions on nitrogen applications in agriculture, it is important to maximize all sources of nitrogen to minimize cost, environmental impact and regulatory headaches. Here is a summary of important strategies to increase nitrogen efficiency:

• Test soil, crop, and water to determine nitrogen status before adding nitrogen, of any source.

• Use legume cover crops: Inoculate legume seeds at planting with fresh, living Rhizobium of the correct species. Plant immediately. Irrigate as needed to aid establishment and inoculation. Completely incorporate legumes into the soil at full bloom with the addition of cellulose digesting microbes from compost, compost tea or lactobacillus cultures. Shred cover finely, incorporate immediately and follow initial incorporation within one week with another pass to aerate the soil and speed decomposition, and nitrogen release to subsequent crops.

• Apply only low C:N ratio aerobic compost, manure or nitrogen fertilizer. Use materials with 15:1 or lower C:N to maximize nitrogen availability. The finer the particle size, the quicker and more efficient the release to the plant.

• Incorporate compost, manures and nitrogen fertilizers in the top 3-6”, not deeper, to maximize aerobic digestion of the materials. Leaving inputs on the surface slows nitrogen release to plants, reduces microbial activity, and loses nitrogen and carbon to the atmosphere.

• Cultivate to increase oxygen, microbial activity and nitrogen release rate. Additional oxygen stimulates aerobic carbon digesting bacteria to speed release, and improve efficiency, of applied nitrogen rich materials.

• Avoid over-irrigation, as it leaches nitrogen as nitrate or nitrate below the root zone and into the groundwater. Maintain optimum moisture in top 6 inches for maximum aerobic nitrogen release.

• If additional nitrogen is needed, fertigate with microbially active liquid nitrogen fertilizers, compost tea or lactobacillus culture.

• Quickest plant response and maximum efficiency of applied nitrogen occurs when using foliar feeding of digested nitrogen rich inputs.

• Test soil, plant and water to determine nitrogen status before adding nitrogen of any source.

Amigo Bob Cantisano, of Organic Ag Advisors, is the most experienced organic farming consultant in the U.S. He is available for cost effective, proven, practical organic farming advice via phone, email or on site, worldwide. For further information: 530-292-3619,

This post was written by Amigo Bob Cantisano.