1、Frontiers

Legume crops, such as common bean, cowpea, soybean, lablab, and groundnut, are important hosts for rhizobia to perform BNF.

2、Top Nitrogen

Nitrogen-fixing plants form symbiotic relationships with specific bacteria, primarily Rhizobium species, which colonize root nodules and carry out the nitrogen fixation process.

3、52 Nitrogen

Discover the amazing world of nitrogen-fixing plants! Learn how these incredible organisms enrich the soil and support healthy ecosystems.

4、11 Nitrogen

Gardening enthusiast Emily Estep walks you through 11 nitrogen-fixing plants that will improve your garden soil with minimal effort. Earth’s atmosphere is made mostly of nitrogen (N), but this crucial nutrient isn’t automatically available in a form that plants can digest.

Plants of the POP Learning Orchard: Herbaceous Nitrogen Fixers

These bacteria form root nodules on the plant roots, within which bacteria can convert nitrogen into ammonia. This symbiosis mostly occurs with plants in the legume family, but not exclusively.

31.3A: Nitrogen Fixation

Both the plants and the bacteria benefit from the process of nitrogen fixation; the plant obtains the nitrogen it needs to synthesize proteins, while the bacteria obtain carbon from the plant and a secure environment to inhabit within the plant roots.

Patterns and Mechanisms of Legume Responses to Nitrogen

Nitrogen (N), while the most abundant element in the atmosphere, is an essential soil nutrient that limits plant growth. Leguminous plants naturally possess the ability to fix atmospheric nitrogen through symbiotic relationships with rhizobia in their root nodules.

Nitrogen

Legumes are known as the best nitrogen-fixing plants. These soil improvers collect nitrogen on their roots and restore it to the soil. Some legumes are better at fixing nitrogen than others.

How do plants fix nitrogen?

An incredible 48% of protein in the human diet comes from plants grown using artificial nitrogen fertiliser, but production and application of these fertilisers is unsustainable.

Nitrogen Fixation in Plant Growth

In this way, nitrogen-fixing plants like legumes, such as soybeans and clover, can harness these microbial partners to enrich the soil with nitrogen compounds, improving their own growth and benefitting neighboring plants in the process.

In agricultural production, nitrogen-fixing plants play a critical role as organic fertilizers. They effectively improve soil nitrogen levels and promote plant growth. Below is an overview of several nitrogen-fixing plants suitable for root irrigation, along with their characteristics:

1. Alfalfa (Medicago sativa)

• Root System: Alfalfa has a well-developed root system capable of absorbing water and nutrients from deep soil layers. Its roots not only fix atmospheric nitrogen but also release nitrogen by decomposing soil organic matter.
• Nitrogen Fixation Capacity: As one of the most widely grown forage crops globally, alfalfa exhibits strong nitrogen-fixing abilities. Under optimal conditions, it can fix over 20 tons of nitrogen per hectare annually. Additionally, it thrives in diverse climates and soil types due to its stress resistance and adaptability.
• Uses: Alfalfa is primarily used as livestock feed (fresh, dried hay, or silage). It also contains nutritional components like vitamins and minerals, lending it medicinal value.

2. Clover (Trifolium repens)

• Root System: Clover develops dense, deep roots that enhance nitrogen fixation. Its root exudates promote the dissolution and accumulation of phosphorus in the soil.
• Nitrogen Fixation Capacity: Clover fixes approximately 15 tons of nitrogen per hectare annually. It also resists pests and diseases, reducing the need for pesticides.
• Uses: Primarily used as green manure, clover improves soil organic matter and structure when incorporated into the soil. Its ornamental appeal also makes it popular in landscaping.

3. Black Medick (Medicago lupulina)

• Root System: Black medick has shallow roots concentrated in topsoil, yet it remains effective at nitrogen fixation. Its root exudates aid in phosphorus mobilization.
• Nitrogen Fixation Capacity: While weaker than alfalfa, it still fixes around 10 tons of nitrogen per hectare annually. It also resists pests and diseases.
• Uses: Similar to clover, black medick serves as green manure to enrich soil structure and organic content. Its flowers add aesthetic value to gardens.

4. Legumes (Fabaceae)

• Root System: Legumes typically have deep, nutrient-seeking roots that secrete organic acids to solubilize soil phosphorus.
• Nitrogen Fixation Capacity: Legumes are highly efficient, fixing over 20 tons of nitrogen per hectare annually. They also resist pests and diseases.
• Uses: Widely used as green manure, legumes rapidly boost soil organic matter and fertility. Many species also serve ornamental purposes in landscaping.

Alfalfa, clover, black medick, and legumes are all effective nitrogen-fixing plants for root irrigation. They not only provide nitrogen but also enhance soil structure, fertility, and biodiversity. When selecting plants, factors such as soil conditions, climate, and crop requirements should be considered.