Plant Nutrient Analysis
For plants to grow and prosper, they need multiple nutrients from the soil and water. Each plant has different needs - K is particularly important for coffee plants, while S is critical for soybeans. By pairing FTIR with XRF, we can analyze a suite of essential and beneficial nutrients in plants.

Essential Nutrients

Nitrogen (N)
Plants absorb N typically as Nitrite, but sometimes as ammonia. Nitrogen is a requirement for amino acids; the viability of all plants hinges on nitrogen availability (85% of the N in a plant is bound in protein). Nitrogen deficiency thus prevents protein synthesis, and constricts the growth of the plant. The leaves are the first area affected, as the plant will redirect growth to fruits and roots. Leaves provide a relatively easy way to identify nitrogen deficiency - they will turn pale green or even yellow.

Magnesium (Mg)
The core process of plants is photosynthesis, photosynthesis depends on chlorophyll, and chlorophyll is made, in part, with magnesium. Deficiency in magnesium is tied to the inability of plants to grow and generate energy.

Phosphorous (P)
Phosphorous has been popularized as the limiting nutrient of life - need for it drove world exploration in the 19th century as people looked for guano. Plants absorb orthophosphate from the soil to use as an internal binding site for multiple molecules. P is also the key energy driver in both plants and animals, phosphorylation is how energy is stored at the molecular level. The increasing availability of P is perhaps the biggest factor in food productivity in the 20th century, though it has also become a significant ecological problem as phosphorous runoff into rivers, lakes, and seas has created dead zones of ocean productivity.

Sulfur (S)
Sulfur is not critical for all plants, but it is essential for humans. Sulfur is used in the amino acid methionine, which is the protein that makes plants like soybeans sufficient for human dietary needs. Most plants do not have enough methionine for humans to receive all 8 essential amino acids. If phosphorous is the limiting nutrient for plants, then sulfur is the limiting nutrient for humans. This is not to say it isn't essential in plants, like phosphorous it is critical for the growth of plant tissue, and is absorbed primarily as a sulfate.

Potassium (K)
Without potassium, plants simply will not grow. It serves multiple critical roles, including binding to enzymes, protein synthesis, ion transport, and mediating CO2 respiration in the stomata. Potassium is frequently available in soils, but it is not always in the cation form that is necessary for plant absorption.

Calcium (Ca)
Calcium ions (Ca2+) are key to maintaining conductivity in nutrient transport, and is the key structural nutrient for plant cell wall growth. The skins of apples and potatoes are stabilized based on Ca availability.


Chlorine (Cl)
Absorbed as a negative ion, Cl helps move positively charged nutrients like K and Ca transport through cell tissue. Cl is also needed for optimal enzyme synthesis. With K, Cl helps mediate stomatal closure, thus playing a key role in plant respiration.

Manganese (Mn)
Manganese is not always a micronutrient, for some plants such as rice, pea, cabbage, and tea plants, it is essential to growth. It's key roles are in activating enzymes and in the reduction-oxidization reactions ancillary to photosynthesis. It is also key to generating O2, the waste product of photosynthesis.

Iron (Fe)
Electrons readily attach to Fe, making its role in electron transport important in plants. This role helps assist with enzyme and protein synthesis, as well as reduce free radicals from harming essential processes in the plant such as photosynthesis.

Nickel (Ni)
This element is not traditionally an essential nutrient, but recent studies have shown that it is critical to core metabolic processes in plants. It tends to be essential in organisms that are symbiotic to plants, like rhizobia bacteria.

Copper (Cu)
In the roots, Cu can assist with transport of other nutrients. It itself does not travel far in the plant. It tends to be a multiplier for other nutrients - for example there is limited benefit to N without sufficient Cu, and Mn requires its presence.

Zinc (Zn)
One of the challenges of micronutrients is that they interfere with each other - Zn can interfere with Cu uptake, and vice-versa. In some enzymes, zinc is a component, and it also is included in some amino acid ligands. It is also a factor in the hydration of CO2, which is a critical step in photosynthesis.

Molybdenum (Mo)
While Mo is only needed in very small concentrations, it is generally essential to nitrogen fixation and sulfur metabolism. It's aggregate effect is quite large when considered in the global nitrogen cycle, as well as long-term viability of nitrogen-fixating crops such as legumes.

Beneficial Nutrients

Sodium (Na)
Sodium is often toxic, as it can be substituted for K. While normally destructive, there are situations when K is unavailable that Na can become functional and even assist growth.

Aluminum (Al)
While micronutrients tend to be common in mg/kg levels in soils, the average concentration of Al in soil is 7%, so it is commonly available. Al helps with the uptake of P, as well as some growth stimulation. It is also toxic to many potential pathogens for plants.

Silicon (Si)
Phytoliths are Si minerals which are used to form structural support in the exterior of the plant. In some cases, like bamboo, it is critical to its structural integrity. Silicon in its bioavailable form is toxic to potential pathogens. It is also associated with root growth.

Vanadium (V)
While always toxic in high quantities, in low concentrations it may help with growth in the context of other nutrient availability.

Cobalt (Co)
Cobalt tends to be more important for fungi and bacteria that are symbiotic (or at least helpful) to plants, rather than the plants themselves. It is also essential for animals. It's positive charge (Co2+) assists with multiple functions.

Selenium (Se)
More often than not, Se is toxic to plants. It is absorbed as a negatively charged ion, and thus interferes with the update of P and S. In some cases, it can be used to regulate the use of S in plants.