Straight Vs. Mixed Fertilisers

Introduction

Any commercial chemical which is added in the soil with intention to boost up the yields of the crop, is known as fertiliser. Based upon nutrient content, chemical form fertiliser are classified in different classes like simple, compound or mixed, slow released etc.

Simple or straight fertilisers

Simple or straight fertilisers are designed to supply only one nutrient element. Depending upon the nutrient availability they are further classified as nitrogenous, phosphatic and potassic fertilisers. Ammonium nitrate in the form of 'Nitram', containing 34.5% of nitrogen, is a good example. Some simple fertilisers essentially used to supply one element may fortuitously provide another. For example ground mineral phosphate, essentially a phosphorus source, also contains some calcium. Similarly, ammonium sulphate, although designed to provide available nitrogen, contains rather more sulphur than nitrogen.

Simple Fertilisers

Nitrogen

%N

Urea

45

Ammonium sulphate

21

Prilled ammonium nitrate

34

Ammonium nitrate/calcium carbonate

21-26

Anhydrous ammonia

81

Liquid fertilisers containing ammonium
nitrate, ammonia and urea

20-40

Phosphorus

%P2O5

Superphosphate

18-21

Triple superphosphate

45-47

Ground mineral phosphate

29-33

Basic slag

8-22

Potassium

%k2O

Potassium chloride (muriate of potash)

60

Potassium sulphate

50

Mixed Fertiliser

A mixture of two or more straight fertiliser material is referred to as mixed fertiliser or fertiliser mixture. Mixed fertilisers are physical mixtures of fertiliser materials containing tow or three major plant nutrients. Mixed fertilisers are made by thoroughly mixing the ingredients either mechanically or manually. Depending upon the method of preparation two types of fertiliser mixtures are available

Open formula fertiliser mixtures

Closed formula fertiliser mixtures

Terms used in fertiliser mixtures

Fertiliser grade

Plant nutrient suppliers

Conditioners

Neutralizers

Filler

Advantages

  • Less labour is required to apply a mixture than to apply its various components separately. This is an important factor in areas where farm labour is scarce and expensive.
  • If a proper mixture is used to suit a particular soil type and crop, the used of a fertiliser mixture leads to balanced manuring. This gives higher yield sand more profit to the cultivators.
  • The residual acidity of fertilisers can be effectively controlled by the use of a proper quantity of liming materials in the mixtures.
  • Micronutrients, which are applied in small amounts to soil can be incorporated in fertiliser mixtures. This facilitates uniform soil application of plant nutrients required in small quantities.
  • Mixtures have a better physical condition (granulated) and are more easily applied than many straight fertilisers.


Ag.
Technologies
(Manures
&
Fertilizers)