Nitrogen Fixation – The Biological Way for Improved Soil and Environmental Health.

Biological Nitrogen Fixation

With increasing costs of inputs and a fundamental shift towards recognizing soil health and how it impacts our health, our way of food production is at the cusp of a big leap into the realm of biological systems to help optimize yield and yield quality rather than just increase yield potential and maximizing productivity.

Farmers have a larger responsibility than ever before and must balance productivity as well as sustainability (Herridge et al, 2008).

 For the farming systems to remain productive, profitable as well as sustainable while preserving our ecosystem, there is a need to work with the natural resources and local ecosystems to replenish or effectively recycle the reserves of nutrients which are removed or lost from the soil.

Effective management strategies along with approaches to take advantage of natural soil biology would be a good start (Graham et al, 2000). A good and effective start in this direction would be with biological nitrogen fixation (BNF).

There seems to be a general decline in agricultural dependence on BNF (Wagner, 2011) either because of the extensive use of synthetic inputs or the way soil is handled or both. Ideally about 70% of the agricultural N requirements can be provided through biological route and another 10% to 15% through natural phenomenon such as lightning and combustion.

The growth of all organisms depends on the availability of mineral nutrients including nitrogen, which is required in large amounts as an essential component of proteins, nucleic acids and other cellular constituents.

Although there is an abundant supply of nitrogen in the earth’s atmosphere (almost 79%) in the form of N₂ gas, for most part it is unavailable for use by most organisms because there is a triple bond between the two nitrogen atoms, making the molecule almost hard to be broken down to individual N that can be incorporated by living systems.

This where nitrogen fixation comes in and for nitrogen to be used for growth it must be converted to ammonium (NH₄) or nitrate (NO₃) ions. Microorganisms (part of soil biology and ocean biology) have a central role in almost all aspects of nitrogen availability and thus for life support on earth.

While some microbes (mostly bacteria) – free living or symbiotic can convert N₂ into ammonia by the process termed nitrogen fixation, others bring about transformations of ammonia to nitrate, and of nitrate back to N₂ gas. Also, many bacteria and fungi degrade organic matter thus releasing fixed nitrogen for reuse by other organisms.

Bacteria that fix nitrogen require energy in the form of adenosine triphosphate (ATP) to reduce each mole of nitrogen (Hubbell et al, 2009).

These organisms obtain this energy by oxidizing organic molecules and or through association with plants (Hubbell et al, 2009). Modern industrial production utilizes the Haber-Bosch process to reduce nitrogen through huge supply of energy.

Conventional agriculture has depended upon this process to produce the commercial fertilizer and overuse of these fertilizers in the last 5 decades is showing up its negative side and has caused a huge imbalance in the nitrogen cycle leading to many other negative impacts on global weather patterns to water resources.

Most importantly this has caused the greenhouse effect with higher-than-normal carbon dioxide emissions (Chai et al, 2019).  

Fertilizers have a poor utilization efficiency. Resulting eutrophication and subsequent fertilizer run offs have led to dead zones which will soon catch up with us, areas where little or no aquatic life can be found (Figure 2).

Since the 1960’s, dead zones have increased and presently more than 245,000 square kilometers of coastal regions (Diaz et al, 2008). Taking a step back and adding practices that can help build on soil’s natural ability to fix nitrogen through BNF can have multiple beneficial effects on agriculture as well as human health (Boddey et al, 1997).

This has been one of the primary drivers for Genesis Ag and its allied companies. The big question that we at Genesis Ag are trying to answer and provide sustainable solutions to are.

1. How do we improve BNF?
2. How do we fine tune the product line to incorporate BNF algorithms?
3. How do we understand what our product line is doing to soil biology and BNF?
4. How do we improve and sustain soil’s natural BNF ability while keeping farming profitable?

The need to increase food production to feed the burgeoning population of the while maintaining quality and crop yields and at the same time preserving our valuable resource – soil for future generations is imperative.

BNF has a great potential to contribute to productive and sustainable agricultural systems and Genesis Ag is doing more in terms of research how biologically fixed N, and the increased BNF contributions resulting from research innovations, can be incorporated into sustainable and viable agricultural approaches.

BNF inputs into agricultural systems can be achieved from symbiotic or free living microbial and fungal systems living in association with plant roots.

In an ideal system, we can assume that these N₂-fixing systems will not only cater to their own N requirements but also provide N for the benefit of other crops or forage species. Genesis Ag R & D has been trying to understand this from soil, microbial as well as plant perspective to provide solutions that can optimize soil environments for increasing BNF.

From field observations to direct research as well as extensive literature reviews, we are constantly evolving our product line especially the components and inputs aimed at improving soil ecosystems either through provision of energy components to native beneficial soil biology to addition of acclimatized non-GMO- all natural BNF and PGPR strains or both.

We are also looking at soils from our product line users and other farming lands to come up with customized systems to help reclaim soil health and improve BNF. One of the positive fall outs of this approach is the ability to use available soil phosphates more effectively to also reduce phosphate inputs.  

Our research also indicates that BNF can be more efficient when certain nutrient conditions are met and hence our product line on nutrients side is also designed to address these issues. Our approach is multipronged and is aimed at reducing N inputs to push higher BNF through our product line up and associated practices.

References:

Herridge DF, Peoples MB, Boddey RM. Global inputs of biological nitrogen fixation in agricultural systems. Plant and Soil, Vol 311, 2008.

Graham PH, Vance CP. Nitrogen fixation in perspective: an overview of research and extension needs. Field Crops Research, Vol 65, 2000.

Wagner CS. Biological Nitrogen Fixation. Nature Education Knowledge, Vol 3(10), 2011.

Hubbell DH, Kidder G. Biological Nitrogen Fixation. University of Florida IFAS Extension Publication SL16. 1-4 (2009).

Diaz RJ, Rosenberg R. Spreading dead zones and consequences for marine ecosystems. Science Vol 321, 2008.