Green Manures & Cover Cropping: An Informative Guide

Green manures and cover crops are becoming essential tools in modern farming. They offer a natural way to improve soil health, increase biodiversity, and support sustainable land management.

What Are Green Manures and Cover Crops?

Green manures are crops grown specifically to be incorporated into the soil while still green. Their main job is to add organic matter, restore nutrients, and improve soil structure.

Cover crops are similar but serve a slightly different purpose. They are grown to protect the soil surface between main crops. These crops help reduce erosion, prevent compaction, and limit nutrient loss during fallow periods.

Why Use Them?

Adding green manures or cover crops to your rotation brings many benefits. They improve soil structure, making it more resistant to heavy rain and better at holding moisture during dry spells.

Their roots stimulate soil life, including earthworms, which play a key role in long-term fertility. By keeping the soil covered, these crops also reduce nutrient leaching and suppress weeds—cutting down on the need for herbicides.

Choosing the Right Crops

Different plant types offer different advantages. Here are some common options:

– Legumes like clover, vetch, and lucerne fix nitrogen from the air. They boost soil fertility and attract pollinators.

– Brassicas such as mustard, tillage radish, and kale have deep roots. These help break up compacted soil and recycle nutrients.

– Grasses and cereals like black oats, forage rye, and triticale produce lots of biomass. They protect the soil and improve its structure.

– Fast-growing herbs like phacelia and buckwheat provide quick ground cover. They suppress weeds and support insect life.

How to Establish and Manage Them

Timing is crucial. Most green manures and cover crops are sown right after harvesting the main crop—usually in late summer or early autumn.

Fast-growing species are ideal for late sowings. Hardy types can survive winter and continue protecting the soil until spring.

You can sow them using a drill for even placement or broadcast the seed for a quicker, lower-cost method. Rolling the soil lightly after sowing helps retain moisture and improves seed contact.

The crops can stay in the ground for a few months or an entire season, depending on your goals. When it’s time to terminate them, aim to do so at least three weeks before planting the next crop. This gives the plant material time to break down and reduces the risk of pests or diseases.

Financial Support Available

Because of their environmental benefits, green manures and cover crops may qualify for financial support. For example, the Sustainable Farming Incentive (SFI) offers payments for nitrogen-fixing crops and diverse cover mixes. These schemes help offset costs and promote sustainable practices.

Summary of Common Options