Green Manure: And Its Benefits

Manure is used as fertilizer in agriculture to help grow crops and flowers. They add nutrients, organic matter, and minerals to soil fertility. Today, you will find manure in the form of animal manure, compost, or green manure. Since the focus here is on green manure, what exactly is green manure?

Green manure refers to specific plants or crop varieties grown and turned into the soil, helping it improve its overall quality. These cover crops or plants are grown and then uprooted or sown and left on the field to wither, providing mulch for soil cover and nutrients for enhancing soil fertility.

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The cover crop could be left whole or cut and then plowed or left on the ground for some time before tilling the soil. The cover crops can also be planted after harvest or as part of crop rotation during the growing season.

In addition to improving the soil’s quality, it keeps the rich topsoil from being washed away during rainy seasons. Green manure is associated with organic farming and is vital to sustainable annual cropping systems. Read below to learn more about the topic.

What is Green Manure?

Green manure is also known as a cover crop. It is primarily plant debris that has already wilted or been uprooted and then place them into the soil. You can use it afterward as mulch for soil improvement. The green undecomposed substance is another name for green manure.

You can sow green manures after collecting the herbs n the fall. During the growing season, you can also plant your green manures as a part of your crop rotation. You can use green manure as your cover crop. The reason being as can prevent the rich topsoil from being washed away. Planting such plants will help them grow throughout the fall and winter seasons.

In the early spring, gardeners or farmers turn or till the green manure crop into the ground. They do this when the soil is dry enough not to compress while you are working with it but is still too cold to plant in. You should avoid walking on or attempting to deal with moist dirt.

Suppose the soil in your farm or garden is thick, such as clay. In such a scenario, you should incorporate green manure late in the fall so that it can break down during the winter.

All you need to do is choose the right plant to be buried in your garden’s soil after the growing season. Even in the off-season, you can plant green manures when your veggies and herbs are not growing. Remember that these plants are an excellent and organic approach to sustaining the fertility of your soil over time.

Green Manure: How Should it be Planted?

Remember that you should plant green manure just before it starts to rain. Throughout the germination process, the seed must not become dry at all.

You can spread or broadcast the seeds evenly by hand for a little herb garden. Before spreading, you can mix the seeds with sand or dirt to give you greater control over where they go. Rake the dirt after you have dispersed the seeds. It will ensure that they are suitably covered for germination. In the absence of rain, sprinkle water sparingly.

Green Manure: Types

1 Legume

Do you know that these are roots-equipped plants that cooperate with soil microbes? They help to fix nitrogen from the air – a process commonly known as nitrogen fixation. An additional aid to the procedure is an inoculant or treatment media, making the legumes more effective.

Applying inoculant, usually sold in powder form at garden centers, can dramatically raise yields. Lettuce, soybeans, alfalfa, peas, beans, lupins, and clover are common legume green manures.

2 Non-legumes

Non-legume plants are generally used as cover crops. They also serve as green manures. They extensively add organic matter to the soil, which helps improve its fertility. At the same time, they consist typically of rye, chicory, phacelia, turnips, oats, barley, mustard, and buckwheat, among others.

Green Manure: Uses

You can also classify green manure crops based on their purposes.

Cover crops: Do you know you can sow these crops to cover soils and prevent erosion? They generally include vetch, Sirius peas, oats, clovers, winter rye, and lentils.

Break crops: They are crops that interrupt the lifecycle of diseases or pests and include mustard, alfalfa, brassica, and rye.

Nitrogen-fixing crops: They are leguminous crops you can plant to enrich soils of available nitrogen. Some examples include beans, peas, vetches, clovers, soybeans, lupins, and alfalfa.

Nutrient conserving crops: As you can see, the name is self-explanatory. They minimize nutrient leaching and, at the same time, add more nutrients to the soil. They often include ryegrass, oil radish, buckwheat, and red clover.

Smother crops: These are crops generally grown to outcompete weeds in growth. These plants include winter rye, buckwheat, oil radish, and sweet yellow clover.

Green Manure: Benefits

Leaching and erosion prevention

Green manure, also known as cover crops, shields the soil from harsh weather conditions like heavy rainfall and intense sunlight by providing physical coverage. The plants protect the soil from erosion by forming a protective barrier. At the same time, their roots help anchor soil particles in place.

Furthermore, green manure minimizes nutrient runoff by absorbing nutrients into their bodies, which are later buried in the soil. This approach is beneficial as it ensures the preservation of soil quality by preventing nutrient loss. Moreover, the process also reduces erosion, thereby promoting sustainable agriculture practices.

Getting rid of weeds

Green manure is a popular choice among farmers due to its ability to control weeds. You can achieve this through a combination of factors, including disrupting the growth patterns. It also affects the life cycle of weed plants. At the same time, it helps to compete with them for essential resources such as nutrients, water, and space.

Moreover, some species of green manure have the unique ability to release chemicals from their roots. These chemicals can hinder the growth of weeds and prevent their seeds from germinating in the soil. This is known as the allelopathic effect, which is another way green manure helps keep weeds in check.

Providing the soil with nutrients and organic matter

The use of green manure results in the presence of high amounts of essential plant nutrients. Using leguminous green manures such as clover and vetch can extract nitrogen from the atmosphere. At the same time, it can incorporate into the soil. Nitrogen is a vital component that promotes the healthy growth of subsequent crops.

Providing pollinator habitat

Several commonly cultivated green manures offer a source of essential nutrients for bees and other pollinators through their flower nectar and pollen. For example, pollinators such as butterflies and bees are attracted to the blooms of yellow mustard.

These insects are also attracted to the yellow, blue, or white lupin and the white, pink, and red clover. These plants provide a valuable food source for pollinators. Moreover, they also contribute to their overall health and well-being.

Enhancing the structure of the soil

The use of green manure in soil significantly enhances its structure by introducing organic matter. This organic material helps to create soil aggregates by binding soil granules together. As a result, the clusters of more extensive, enhanced particles facilitate the development of pores.

At the same time, it also enables adequate soil aeration, nutrient distribution, and water retention. Incorporating green manure into the soil can lead to improved soil quality. It will also promote better plant growth and overall soil health.

Green Manure: Drawbacks

Harbors snails and slugs

Do you know that snails and slugs find the ideal env for breeding in a green manure crop? They also multiply and may eventually impact some of your products, including vegetables.

Time intensive

After thinning and rotating their green manure crops, farmers and gardeners should allow a minimum of one month before planting a new crop. This is because some green manure plants are allelopathic – which means they release naturally toxic compounds into the soil that inhibit the growth of new plants.

These harmful substances get enough time to break down if you wait for a sufficient period. As a result, they minimize the risk of crop failure or reduced yields due to allelopathic effects.

Water utilization

Similar to other crops, green manure crops require water for their growth. Green manure crops may consume all available moisture in areas where water is scarce, which would otherwise have been conserved during fallow periods.

However, in regions with sufficient water, these crops consume less water than mature crops. Hence, the water needs are quite similar to other crops. Hence you should consider it while planning crop rotation and irrigation schedules.

Costs of establishment

The cost of growing crops for green manure should not exceed that of other crops, nor should it outweigh the benefits to the soil and nitrogen levels. Farmers and gardeners may incur losses if the cost of producing green manure crops surpasses their potential advantages.

It will cost more to prepare the land than they could earn from selling marketable products. Therefore, it is essential to carefully consider the economic viability of cultivating green manure crops. At the same time, you should also ensure that the associated costs are reasonable and justifiable.

Limits on rotation

An additional crop in the cycle is a green manure crop. If you plant immediately after harvesting your main crop, your land would not get enough time to recover. Additionally, to reduce disease issues, you may need to limit the land you utilize to produce other legume crops.