Understanding Green Manure: Types, Benefits, and Drawbacks

Green Manure



In the vast and intricate world of agriculture, green manure stands out as a timeless and sustainable practice that has shaped the foundation of healthy soils for centuries. Often overshadowed by its commercial alternatives, this organic method of enriching the soil is a testament to nature’s innate wisdom. Through a deliberate cycle of planting, growing, and incorporating specific crops, green manure aims to enhance soil fertility, structure, and overall health. In this piece we will uncover the nuances of green manure, explore its types, the clear benefits they bring to gardens and fields, as well as the potential disadvantages that practitioners should be aware of.


How Green Manure Works

When it comes to green manure, one might envision vibrant fields teeming with life, and rightly so. Green manure refers to specific crops grown primarily to be incorporated back into the soil. As they decompose, these plants play a pivotal role in enriching the ground beneath.


A fundamental aspect of green manure’s effectiveness lies in soil enrichment. As these chosen crops decay, they generously release essential nutrients, like nitrogen, back into the earth. This process not only supplies the soil with vital nutrients but also boosts its overall fertility, paving the way for healthier and more abundant future harvests. Through this cyclical and natural method, green manure stands as a testament to agriculture’s potential to work hand in hand with nature.


Pros & Cons of Green Manure

The practice of using green manure in agriculture has been a cornerstone for organic farmers and those keen on sustainable practices. By understanding the green manure advantages and disadvantages, growers can make more informed decisions about their soil management strategies.


Here are some of the main advantages of green manure:


  • As green manure crops decompose, they release nutrients, particularly nitrogen, enriching the soil and reducing the need for synthetic fertilizers.
  • Green manure improves soil structure, making it more porous and enhancing its water retention capacity. This leads to better root growth and overall plant health.
  • Certain green manure crops can outcompete weeds, thereby reducing their growth and eliminating the need for chemical herbicides.
  • Some green manure plants deter pests or disrupt the lifecycle of soil-borne diseases, offering a natural method of pest control.
  • The root systems of green manure crops help bind the soil, preventing erosion by wind or water.
  • Green manure crops play a role in capturing carbon from the atmosphere, thus aiding in tackling climate change.


Despite the undeniable benefits, there are also some disadvantages linked to green manure:


  • Incorporating green manure requires plowing or digging it into the soil, which can be labor-intensive and might not be feasible for all growers.
  • If not managed properly, some green manure crops might harbor diseases that could affect subsequent crops.
  • Growing green manure crops requires a portion of the growing season, which might delay or reduce the time available for growing main cash crops.
  • Green manure plants, like all vegetation, require water. In areas with water scarcity, this might present a challenge.
  • Choosing the wrong type of green manure crop for a specific soil or climate can reduce its effectiveness or even harm subsequent crops.


Green Manure Types

Depending on the soil’s needs and the intended outcome, farmers can choose from a variety of green manure crops. At the forefront of this agricultural strategy are two primary categories: legumes and nonlegumes.


Legumes have a symbiotic relationship with bacteria known as Rhizobium. These bacteria inhabit the root nodules of leguminous plants, allowing them to perform the unique act of atmospheric nitrogen fixation. This means that legumes, such as clover, vetch, and field peas, can pull nitrogen from the air and convert it into a form that subsequent plants can use, enriching the soil and reducing the need for synthetic nitrogen fertilizers. Beyond this, their extensive root systems work wonders in enhancing soil structure, making it more porous and fertile.


Although nonlegumes might not offer nitrogen fixation abilities, they compensate with a range of other benefits. Crops like rye, buckwheat, and mustard contribute significantly to the organic matter of the soil. Their growth, often dense and rapid, acts as a natural barrier against invasive weeds, while their deep roots hold the soil firm, reducing erosion. Furthermore, certain crops, like mustard, have biofumigation properties that help in controlling soil-borne pests and diseases.


To decide which type of green manure crop to plant and when, growers can use modern technology. For example, EOSDA Crop Monitoring software offers a set of features useful for this purpose.


EOSDA Crop Monitoring & Green Manure

EOSDA Crop Monitoring platform is a precision agriculture tool designed for comprehensive farmland management based on satellite data. It serves as a unified solution, offering a diverse range of data, from crop health and weather conditions to crop rotation, field activities, soil moisture, elevation, and more, all centralized for easy access.


Utilizing software tools like EOSDA Crop Monitoring can help pinpoint the optimal moment to incorporate a green manure cover crop into the soil. The platform supports the complete cultivation process, whether dealing with cash crops or green manure. By inputting data such as the crop’s name, sowing date, and maturity, the software facilitates the tracking of plant growth stages. This enables farmers to determine the most opportune time to incorporate the green manure, ideally before the onset of flowering, seed production, or when the stems are still tender and easily decomposable.


If a cover crop doesn’t sufficiently address the soil’s fertilizer needs, additional interventions might be necessary. That is when the Zoning feature allows for the implementation of the Variable Rate Application (VRA) method for soil fertilization. This method ensures precision, preventing over-fertilization and potential soil and water pollution, ultimately conserving resources and costs.


As the agricultural world moves towards greater harmony with nature, green manure underscores the notion that time-tested solutions often offer the most sustainable paths forward. Backed up by the possibilities of modern technology, this practice can be even more effectively planned and executed.