Basics of Fertilizers

Here you will learn about how fertilizers are broadly categorized. There will be a brief description of each category of inorganic and organic fertilizer - the categorization of inorganic fertilizers based on their nutrients, their physical form and on their solubility properties and examples of each. Also about the three different types of organics - the manures, biofertilizers and biostimulants with examples

This lecture teaches about all nutrients that a plant needs and the important concept of Liebig's barrel of minimum. It also teaches about the chemicals forms in which the plants can take up nutrients and how each nutrient has diverse roles within the plant. This is a fundamental requisite for understanding fertilizer requirements and why yields become limited even though large quantities of macronutrient fertilizers are frequently added.

This lecture you will learn about how plants can take up even insoluble nutrients from the soil. It is important to understand this mechanism because it determines which types of chemicals function as fertilizers and which ones cannot. You will learn about how nutrient availability can be affected by soil factors such as its pH. You will also learn about the basic principles of foliar fertilization

This lecture is all about understanding what happens to fertilizers after they are added to soil. Why is the entire amount not available for plants? Each nutrient undergoes different types of transformation reactions because of which a part of it or even a major fraction becomes non-available.  Some are lost to ground water or the atmosphere causing pollution. some remain in the soil but become so firmly bound to soil components that they are no longer plant available. These are some important concepts for understanding the fate of added fertilizer. Concepts such as Fertilizer Use Efficiency (FUE) including both Recovery Efficiency and Partial Factor Productivity (PFP) are explained. Finally you will also learn about fertilizer response curves and the concept of optimum versus maximum yields.

This lecture discusses all the popular nitrogenous fertilizers - urea, ammonium sulfate, calcium ammonium nitrate and ammonia. For each fertilizer you will learn about how they are produced, their properties and how they are applied. You will also learn about transformation of nitrogen fertilizers in the soil, leading to their leaching and volatilization losses.

You will learn about the various types pf phosphatic fertilizers that are popularly used. These include - DAP, MAP, TSP, SSP and other liquid types. You will also learn in brief about how they are produced and the best methods for applying phosphates to plants. Finally, you will also learn about the fate of phosphate fertilizers when added to soil. This explains why phosphates can cause water pollution and also why only a small fraction of added phosphate is used by the plant.

This lecture broadly follows the same structure a the previous two. Firstly you will learn about the various types of potash fertilizers that are available- MOP, SOP, potassium nitrate, langbeinite and some others. You will also learn how they are produced and how best to apply them. As before, you will learn about the transformations that occur when potassium fertilizers are added to soil and how it could cause low utilization of potassium. Finally there is a description of some popular terms - the differences between straight, mixed and complex fertilizers.

Secondary nutrients - calcium, magnesium and sulfur - are very important for the plant, yet are quite neglected. In this lecture you will learn about different types of secondary nutrient fertilizers like lime, dolomite, sulfur bentonite etc. Unlike the macronutrients, the secondary nutrient products are required to be chosen based on soil pH. You will then be able to chose the correct type of Ca / Mg / S fertilizer depending on your soil acidity or alkalinity. You will also understand the transformations that the secondary nutrients undergo in soil.

Here you will learn about the popular cationic micronutrient fertilizers of zinc, iron, manganese, copper & nickel and the anionics, boron, molybdenum and chlorine. This will help you understand how best to use them - as basal application to soil or as foliar spray. You will also learn about why only a small fraction of added micronutrients are utilized by the plant.

In this section you will learn about newer fertilizer materials that have reduced environmental footprint. Firstly, there is a brief outline on the basic principles of such SCRF (slow and controlled release) fertilizers. Then you will learn about the differences between slow release and controlled release fertilizers. The polymeric nitrogen fertilizers, coated fertilizers and biological control of nutrient losses are discussed. This includes, urea formaldehydes, IBDU, CDU, sulfur coated (SCU) and other coated materials. For each type you will will be able to understand how nutrient is ultimately released for plant uptake from an overview of the release mechanisms which are very simply explained. You will also be able to understand the concepts of stabilized nitrogen products and enhanced efficiency fertilizers (EEF). Finally you will also learn about about the latest concept of smart fertilizers and how these could help in high efficiency fertilization without impacting the environment.

Here you will learn about the different types of organic materials that you can add to improve crop health. Solid and liquid manures like compost, sea weed liquid manures, etc have their advantages and also some drawbacks if one considers them as replacement for conventional fertilizers. You will gain a broad knowledge of the various biofertilizers  and their functions.  Finally you will also be able to have some understanding of biostimulants like humic acids.

This section explains about how fertilizer doses are estimated. This will give you a basic understanding of the process though you will not be able to conduct these experiments yourself. From either soil testing information or field trial data you will get a dosage recommendation. One then needs to convert these dosages to actual weights of fertilizers required. These calculations are critical and you learn how to do them. Basic equations are also provided that you can use for different situations - such as with straight fertilizers or complex fertilizers. General fertilizer recommendations for different types of soils and crops are also listed to help you understand what to expect in a particular type of soil.