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Plant Nutrients

Plants use inorganic minerals for nutrition. Twenty chemical elements are known to be necessary or beneficial to a plant's growth and survival.

Carbon (C), Hydrogen (H) and Oxygen (O) are supplied by air and water.

The mineral nutrients which come from the soil are dissolved in water and absorbed through a plant's roots. There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many farmers and gardeners use fertilizers to add the nutrients to the soil. 

  Mineral Nutrients
1- Macronutrients:
This can be divided into two main groups:

Primary Nutrients: Nitrogen (N), Phosphorous (P) and Potassium (K).

Secondary Nutrients: Calcium (Ca), Magnesium (Mg) and Sulfur (S).

 
2- Micronutrients: 
This can be divided into:

Essential Mineral Elements: Those elements essential for plant growths which are needed in only very small quantities. These elements are sometimes called minor elements or trace elements.

 Boron (B), Copper (Cu), Iron (Fe), Chloride (Cl), Manganese (Mn), Molybdenum (Mo), Zinc (Zn), Sodium (Na) and Nickel (Ni).
Beneficial Mineral Elements: Those elements which have not been deemed essential for all plants but may be essential for some.

Cobalt (Co) and Silicon (Si).

Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants.
   

 Macronutrients
Nitrogen (N)
Nitrogen is a part of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy.
Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis. 
Helps plants with rapid growth, increasing seed and fruit production and improving the quality of leaf and forage crops. 
Nitrogen often comes from fertilizer application and from the air (legumes get their N from the atmosphere, water or rainfall contributes very little nitrogen)
 
Phosphorus (P)
Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis. 
Involved in the formation of all oils, sugars, starches, etc.
Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress.
Effects rapid growth.
Encourages blooming and root growth.
Phosphorus often comes from fertilizer, bone meal, and super-phosphate. 
 
Potassium (K)
Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium. 
Helps in the building of protein, photosynthesis, fruit quality and reduction of diseases.
Potassium is supplied to plants by soil minerals, organic materials, and fertilizer.
 
Calcium (Ca)
Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant.
Necessary for cell growth and division.
Sources of calcium are dolomitic lime, gypsum, and super-phosphate.
 
Magnesium (Mg)
Magnesium is part of the chlorophyll in all green plants and essential for photosynthesis. It also helps activate many plant enzymes needed for growth.
Essential for seeds germination, fruit and nuts formation.
Soil minerals, organic material, fertilizers, and dolomitic limestone are sources of magnesium for plants.
 
Sulfur (S)
Essential plant food for production of protein.
Promotes activity and development of enzymes and vitamins.
Helps in chlorophyll formation.
Imparts flavor to many vegetables.
Improves root growth and seed production.
Helps with vigorous plant growth and resistance to cold.
Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels. 

Micronutrients
Boron (B)
Helps in the use of nutrients and regulates other nutrients.
Necessary for cell wall formation.
Aids production of sugar and carbohydrates. 
Essential for seed and fruit development, flowering, pollen germination, cell division water relationships and movement of hormones. 
Sources of boron are organic matter and borax.
 

Copper (Cu)
Important for reproductive growth.
Aids in root metabolism and helps in the utilization of proteins. 
 

Chloride (Cl)
Aids plant metabolism. 
Chloride is found in the soil.
Iron (Fe)
Essential for formation of chlorophyll.
Necessary for many enzyme functions.
Essential for the young growing parts of the plants.
Sources of iron are the soil, iron sulfate, iron chelate.
 
Manganese (Mn) 
Functions with enzyme systems involved in breakdown of carbohydrates, and nitrogen metabolism. 
Soil is a source of manganese.
 

Molybdenum (Mo) 
Helps in the use of nitrogen (It’s a structural component of the enzyme that reduce Nitrate to Ammonia).
Soil is a source of molybdenum.
 
Zinc (Zn)
Essential for the transformation of carbohydrates.
Regulates consumption of sugars.
Part of the enzyme systems which regulate plant growth.
Sources of zinc are soil, zinc oxide, zinc sulfate, zinc chelate.
 
Nickel (Ni)
Essential for seed germination.
Required for the enzyme urease to break down urea to liberate Nitrogen into useable form.
Requires for iron absorption.
 
Silicon (Si)
Compound of cell wall.
Increase cell wall strength.
Enhance plant heat and drought tolerance.
Reduce population of Aphids and sucking insects.
 
Sodium (Na)
Involved in osmotic and ionic balance in the plant.
 
Cobalt (Co)
Required for Nitrogen fixation and root nodules.
   
 

Many Factors Influence Nutrient Uptake for Plants:
Soil:
  In general, most plants grow by absorbing nutrients from the soil. Their ability to do this depends on the nature of the soil. Depending on its location, a soil contains some combination of sand, silt, clay, and organic matter. The makeup of a soil (soil texture) and its acidity (pH) determine the extent to which nutrients are available to plants.
   
Soil Texture:
 

(The amount of sand, silt, clay, and organic matter in the soil) 

Soil texture affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. This condition is called leaching. When nutrients leach into the soil, they are not available for plants to use. 

 
Soil pH:

(A measure of the acidity or alkalinity of the soil)

Soil pH is one of the most important soil properties that affect the availability of nutrients:
Macronutrients tend to be less available in soils with low pH.
Micronutrients tend to be less available in soils with high pH.
The range of pH for most of the crops is 5.5-6.2 or slightly acidic. In this pH range, nutrients are more readily available to plants, and microbial populations in the soil increase. Microbes convert nitrogen and sulfur to forms that plants can use.  
   
CEC:
 

(Cation Exchange Capacity)

CEC refers to the ability of the growing media to hold exchange mineral elements within its structures.

Peatmoss and other growing media all have some level of cation exchange capacity.

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