How to improve soil fertility using green manure in organic farming is a question we take seriously, when our cost to produce a high yielding crop is considered.
Put simply, utilizing green manure can be a very effective way for organic farmers to increase crop yields. Using it as an organic fertilizer has multiple benefits and can prove very efficient when implemented the right way. So, how do we best use green manure? What are some of the best sources of green manure?
These are all questions we’ve been working on trying to answer ourselves, first hand over the past two decades we’ve spent in organic farming. In this article, we’re going to crack open the lid on some of the best ways to utilize green manure in your organic rotation, as well as some things to consider avoiding.
Why should I trust you guys?
We’re Crop Fertility Services. We’ve been farming organically for the past two decades here in Minnesota, we employ a full time organic agronomist, and we’ve learned a thing or two about not producing the yield we wanted (hopefully, we’ve fixed that) along the way.
Let’s jump into this.
The Definition of Green Manure
Green manure is a living plant. In order to maximize the results of a green manure crop, true cover crops should not be used. The reason we call it “green manure”, is because we let the crop grow, before incorporating it into the soil to unlock it’s fertilizing benefits.
Is green manure a cover crop?
While technically, anything you grow simply to till into the soil can be referred to as green manure, cover crops are not the best suited for use as such. In the case of the organic row crop farmer, we see cover crops being used in row as a method of organic weed control rather than their ability to add nutrients to the soil.
Cover crops are typically made up of a wide combination of small seeded crops designed to help build healthier soils through: nitrogen fixation and nutrient sequestering.
Can you grow corn using only green manure?
Technically, yes. However, to get the maximum yield of corn, you will likely need to add additional NPK sources. Green manure is best thought of as a supplement to other fertility options. You can’t live on Flintstone vitamins, and neither can your crop.
It’s better to utilize a source of additional fertilizer, like chicken manure pellets, when growing crops such as corn that require large quantities of available Nitrogen.
Green Manure Examples
Corn Stover and stalks, terminated cover crops, bean/small grain stubble, terminated alfalfa/grazing grasses.
Green Manure Advantages
Green manure advantages include: supplementing other forms of fertilizers, cover crops also “hold” nitrogen into the soil instead of letting them potentially leech out. By incorporating corn stover and stalks, you can also take advantage of different cultivators and more specifically tine weeders.