Green Manure Crops and the Benefits
- 11 December 2015
Green manure crops will offer a huge range of benefits to your soil and future crops. They are grown exclusively for the benefits and not for harvest or grazing. They are commonly used to improve the soil, for organic matter, nutrients or to control weeds.
Rather than harvest or graze the crop, the green manure is left on the soil surface or worked into the soil. Green manures incorporated into a rotation add significant benefits but they are a low cost addition.
Green manures are not a few trends as they have been used for centuries but they have been replaced by the advent of chemical fertilisers. What we now understand is that the benefits of a green manure crop far outweigh the nutrients that they add back into the soil.
They also feed the soil which feeds the plant rather than the other way around. In feeding the soil a green manure crop feeds all the soil organisms and improves the fertility of the soil. A biologically fertile soil grows healthy plants that able to resist disease and fight pests in addition a healthy soil has more drought resistance.
By growing green manures you provide soil microbes with a boost as well as food and an environment they can thrive in. These microbes will convert the nutrients in the green manure into available nutrients for crops. By stimulating these soil organisms and proving a food source, they also convert the unavailable nutrients in the soil into available nutrients. By improving the biological activity in the soil you will also improve the general soil conditions.
The Benefits of a Green Manure Crop
The purpose of a green manure crop varies depending on each situation but some of the benefits they offer are:
- Increasing organic matter and soil humus
- Increased Nitrogen fixation
- Protection of the soil surface
- Prevention of erosion
- Maintaining or improving soil structure
- Reduced susceptibility to leaching
- Access to unavailable nutrients from lower soil profile
- Provide readily available nutrients to the next crop
These green manure crops should be tilled in, mowed down almost to the ground, or smothered by organic mulches before they go to seed. The no-tilling option is the best way to ensure that you get the largest benefit out of the crop and the least amount of damage to the soil biota. Excessive tilling, or tilling too deep, can kill off beneficial fungi in the soil and create soil texture problems and some soil fertility issues. Using EM in conjunction with your green manure crop will also speed up the breakdown process and also the biological activity. This will ensure that you get the most out of your crop and provide the best environment for the next crop in your rotation. EM should be applied once the crop has incorporated with the soil.
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