BeCrop Test Results: Nutrition (Major Nutrients)

Learn more about the nutrition section

The last section of the BeCrop Test report discusses how the soil microbiome affects nutrient availability to crops. In this article, we will focus on major nutrients (NPK) and Carbon (C) and show you how each of the indices is affected.

Major Nutrients

In this report section, you can see the nutritional status based on the potential microbial mobilization of certain compounds, divided into major and minor nutrients.

How do we classify the Pathways according to their impact on Plant Nutrition?

1. Pathways that directly benefit plant nutrition (nutrient supply):

These pathways directly generate nutrients that plants can use for their nutrition:

• Carbon Fixation
• Inorganic Nitrogen Release
• Inorganic Phosphorus Solubilization
  
  

2. Pathways that take up nutrients from the soil (nutrient competition): 

These microbial pathways compete for compounds that plants would also use for their growth. Although these microbial pathways can immobilize nutrients and thus reduce nutrient availability to crops in the short term, they also help reduce the loss of nutrients from the soil in the long term.

• Aerobic Respiration
• Inorganic Nitrogen Consumption
• Inorganic Phosphorus Consumption
• Potassium Consumption 

Carbon

Carbon is the basis of biological soil fertility. It is the main compound in organic matter and an essential source of food for beneficial soil microbes. The presence of organic carbon improves soil health and fertility, increasing crop yields and reducing soil degradation. A low value indicates potential for Carbon Loss from the soil, while high values indicate potential for Carbon Sequestration.

 

Carbon Fixation: the conversion process of inorganic carbon to organic compounds by living microorganisms. Autotrophic (lithotrophic) microorganisms utilize the conversion of CO2, carbonates, or other single-carbon compounds (e.g. Methane) into organic forms (carbohydrate) for anabolism (Sylvia et al. 1999). Examples of these organisms are algae, cyanobacteria, nitrifying bacteria, methanotrophs (bacteria and archaea that use CH4 as an energy source), as well as methane, hydrogen, iron, and sulfur-oxidizing bacteria. This metabolic pathway yields far less energy than heterotrophs, but they can use energy sources that most other organisms cannot, so this can make them more competitive in certain environments (e.g. low organic carbon). This measurement is linked to “Methanogenesis.” 

 

Aerobic Respiration: the conversion process of inorganic carbon to organic compounds by living microorganisms.

Fermentation: the process in which cells gain energy from organic compounds in non-oxygenated conditions, releasing CO2. The process where microbes use a carbon compound (usually pyruvate) for both electron acceptor and donor and typically occurs in an anaerobic environment. 

Methanogenesis: methane (CH4) by microbes, contributing to the degradation of organic matter. Use of CO2 for anabolism that results in the byproduct methane (CH4). Typically archaea (different domain than bacteria distinguished by a different type of cell wall) are responsible for this process. The typical soil conditions for methanogenesis are anoxic (lacking oxygen) microsites in soil or in flooded soils (Serrano-Silva et al. 2014). Wetlands are major sources (flooded rice fields being a primary source). A few researchers have reported methanogenesis in aerobic (oxic) environments. The thought is that this process is possibly abiotic, but recent research has found an organism Candidatus Methanothrix paradoxum (an archaea) may be responsible in oxic wetland soils (Angle et al. 2017).

Organic Matter Release: the process in which soil microorganisms decompose vegetal debris, releasing diverse mineral nutrients. It is related to soil humification. One aspect to keep in mind is the OM release. Is this from new carbon inputs (e.g. crop biomass, cover crops) or is this stored carbon that is being released due to management practices (i.e. tillage breakdown of aggregates where protected carbon inputs are now being accessed by microbes and metabolized releasing CO2). Looking at active vs. passive organic matter is important as changes to these pools can influence total organic matter pools (Brady and Weil 2017). These can also be thought of as structural (a resistant carbon pool) and a metabolic (easily decomposed carbon pool). This metabolic pool is typically where one will see changes to carbon first. The structural component is typically lost and gained over a much longer time scale.

Carbon Cycle explanation

 

Nitrogen

Nitrogen is a major component of plant DNA, proteins, and chlorophyll, playing a fundamental role in crop yield. The mineralization of organic to inorganic nitrogen by microorganisms supplies N in readily available forms (nitrate and ammonia) for plants.

LOW values indicate low nitrogen mobilization potential by microbes.

 

Inorganic Nitrogen Release: mineralization, or the microbial transformation of organic nitrogen compounds into inorganic nitrogen compounds that serve as plant Nutrients.

Nitrogen Consumption: immobilization, or the microbial transformation of inorganic nitrogen compounds to organic forms, which are not readily accessible for uptake by plants.

Nitrogen Cycle:  the process in which soil microorganisms decompose vegetal debris, releasing diverse mineral nutrients. It is related to soil humification.

 

Source: https://kids.frontiersin.org/articles/10.3389/frym.2019.00041

 

Phosphorus

Phosphorus is a fundamental nutrient required in the regulation of protein synthesis and plant growth. It enhances the development of roots, while its deficiency leads to stunted growth, dark purple color of leaves, and inhibition of flowering. Low values indicate that the microbial processes that make phosphorus available for plants are low.

LOW values indicate that the microbial processes that make potassium available for plants are low.

 

Inorganic Phosphorus Solubilization: certain soil microorganisms are capable of dissolving insoluble phosphorus from minerals and rocks. They convert insoluble phosphorus in the soil into a form that plants can access, improving their growth and yield. Major portions of conventional phosphorus fertilizers applied to fields end up locked in this insoluble form, so higher levels of phosphorus solubilizing microbes can improve phosphorus fertilizer use efficiency.

Inorganic Phosphorus Consumption: both plants and microbes require phosphorus to support their metabolic functions. High values indicate high competition/immobilization of phosphorus by soil microbes.

Organic Phosphorus Assimilation: Organic phosphorus may represent from 15% to 80% of the total content of this element in the soil. During the phosphorus mineralization process assessed by this index, organic phosphorus is converted by microbes from the organic form that is not readily available to the plant, to inorganic forms that can be more easily uptaken by the plant.

 

Potassium

Potassium is a regulator of metabolic activities, especially those involved in producing proteins and sugars and regulating crop evapotranspiration. When bioavailable potassium is deficient it causes leaf curl and sensitivity to droughts.

LOW values indicate that the microbial processes that make potassium available for plants are low.

 

Potassium Solubilization: certain soil microorganisms are capable of dissolving insoluble potassium from minerals and rocks. They convert insoluble potassium in the soil into a form that plants can access, improving their growth and yield.

Potassium Consumption: both plants and microbes require potassium for their functioning. High values indicate a high potential for microbes to compete with the plant by assimilating this nutrient.

 

Frequent questions related to BeCrop Reports 

Here are some of the FAQs; remember that you can read all of them by clicking here 📚.

How long does it take to receive results? 

Result delivery takes approximately 3 weeks. Lead times vary depending on the sample quality, number of samples, location, and shipping times.

How are scores calculated in reports?

The ratings on BeCrop reports reflects how each sample compares to the BMK database of soil samples. The score is compared across samples in the database from only that specific crop type. This allows us to provide more accurate and relevant conclusions. 

What is functionality data and how do I use it?

Functionality data describes the specific roles that microbes play in the soil. It describes the ecological roles through which microbes support plant growth, boost yield, and promote nutrient retention in the soil, among many other benefits. 

Do you provide any resources for result interpretation?

Yes, we offer our BeCrop Guide, which is a document providing layman definitions and basic guidelines for interpretation of the BeCrop report. Our agronomy staff is also available for a short virtual consultation call to review sample results and address any technical questions. Our BeCrop Advisor Program and online webinars, case studies, and blog articles also provide additional opportunities to learn how to interpret and leverage BeCrop results in agronomic practice. 

What are the practical applications of the results?

BeCrop Tests serve a wide variety of practical applications. They can be used to identify and address problems involving soilborne pathogens, microbial nutrient mobilization, and crop stress tolerance. BeCrop Tests can also inform soil health focused management practices, evaluate biological agriculture inputs, and identify areas of potential improvement to bolster yield and reduce input costs. 

What does the F/B ratio tell us about? How can this index be interpreted?

Bacteria, which have a lower C:N ratio than fungi, need food rich in nitrogen (e.g. green manure, legume residues). A fertilizer with a low C:N ratio, therefore, favors the bacterial community in a soil, whereas a substrate with a relatively high C:N ratio enables growth of the fungal population.

Due to their structure and C:N ratio between 7:1 and 25:1, fungi need a greater amount of carbon to grow and reproduce and will therefore 'collect' the required amount of carbon available for this from the soil organic matter. Bacteria, however, have a lower C:N ratio (between 5:1 and 7:1) and a higher nitrogen requirement and take more nitrogen from the soil for their own requirements.

What type of correlation exists between BeCrop indexes and performance metrics like germination rate, root growth, nutrient use efficiency, etc?

It would be imprecise to give an answer for specific nutrient results to predict germination rates or rates of growth for a specific crop as there are many other external factors that can affect this, like location and soil type, etc, but our technology can serve as an informative tool to predict yield or other rates if used in a trial manner, as can be seen in this study: https://journals.asm.org/doi/10.1128/mSphere.00130-21