Fertilizer Mixtures: Principles, Types and Advantages

After reading this article you will learn about Fertilizer Mixtures:- 1. Principles of Mixing Fertilizers 2. Materials Used in Fertilizer Mixtures 3. Types of Fertilizer Mixtures 4. Advantages 5. Disadvantages.

Principles of Mixing Fertilizers:

The compatibility of various fertilizers for mixing depends upon the various reactions that take place. Most fertilizers could be mixed together without any adverse effects, while some fertilizers react with one another.

Some of the changes brought about by injudicious mixing (incompatibility) of fertilizers are indicated below:

1. Loss of nitrogen from injudicious fertilizer mixtures:

Basic compounds liberate ammonia gas from ammonium salts and organic nitrogenous manures, and lead to loss of nitrogen. Quick lime, slaked lime, potassium carbonate, basic slag and cynamide, which are basic in nature, should not therefore, be mixed with ammonical fertilizers and organic manures.

2. Lumps formation in incompatible mixtures. Superphosphate is likely to form lumps when mixed with other fertilizers and kept over for some time. It reacts with nitrates and liberates nitric acid and makes the mixture sticky and inconvenient for handling.

3. Unavailability of phosphate in wrong mixtures. Substances like slaked lime react with superphosphate on mixing and soluble mono-calcic phosphate is reverted to di-calcic and tri-calcic forms (which are insoluble and unavailable to plants).

Materials Used in Fertilizer Mixtures:

The following types of materials are used in making the mixture:

1. Natrients:

Supplier of plant nutrients (fertilizers).

2. Conditioner:

They help in maintaining a good physical condition of the mixture. They can be powdered tobacco stalks, paddy husk powder, etc.

3. Neutralizer:

They are used to neutralize the residual acidity of certain fertilizers in mixture e.g. ammonium sulphate. Mostly dolomite, limestone are used for this purpose.

4. Filler:

They are sand, soil, powdered coal, ash etc.

Types of Fertilizer Mixtures:

(i) Open Chain Fertilizer Mixture:

The producers write the percentage of available nutrients from those mixtures, thus, it facilitates the farmers to select the right type of grade for his crop and soil.

(ii) Closed Chain Formula Fertilizer Mixtures:

These mixtures do not indicate their grade (% of available nutrients) and type of fertilizers mixed together. Thus, the farmers cannot choose a correct mixtures for their use in production of crops.

Fertilizer Mixtures Available in the Market:

1. Sufla (15 : 15 : 15)

2. Sufla (20 : 20 : 20)

3. Lakshmi (12 : 12 : 12)

4. Lakshmi (8 : 8 : 8)

5. IFFCCO-1 (10 : 26 : 26)

6. IFFCCO-2 (12 : 32 : 16).

Grade:

Grade of mixed fertilizers 5-5-10 (fertilizer ratio of 1 : 1 : 2), means that 100 kg of the mixed fertilizer of this grade will contain 5 kg of N, 5 kg P₂O₅ and 10 kg K₂O. The source of N, P and K are urea (46% N), single superphosphate (16% P₂O₅), muriate of potash (60% K₂O), respectively.

For this grade, 10.9 kg urea, 31.3 kg superphosphate and 16.7 kg muriate of potash will be used. The total weight of fertilizer ingredients will be 58.9 kg. To this fertilizer mixture, 41.1 kg of inert material will have to be added to make up 100 kg bag of mixed fertilizer. The inert material is usually soil, coal, ash, sand etc. known as filler. A filler is a weight make up material added to fertilizer ingredients to produce a mixture of desired grade.

Balance Fertilization:

Plants contain 90 or more elements, only 16 of which are currently known to be essential. The elements essential for plant growth are carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulphur, calcium, iron, magnesium, boron, manganese, copper, zinc, molybdenum and chlorine. On practical point of view, generally application of nitrogenous, phosphatic and potassic fertilizers are considered as balanced fertilisation.

Unbalanced fertilization has led to decrease in the yield of crops and also deteriorate the physical condition of the soil. The growing of crops by using only nitrogen fertilizer have depleted the reserve of available phosphoric acid, potash, and other nutrients in the soil. The result is that subsequent additions of nitrogen fertilizer do not result in increased yields because some other essential elements such as phosphorus and potash are now a limiting factor.

Balanced application of fertilizers enhances the efficiency of nutrients. For example, the efficiency of a nutrient like nitrogen is greatly enhanced when it is used in conjunction with phosphorus. For instance, when a dose of 30 kg of nitrogen was applied in the field, only 14 to 30% of nitrogen is utilized by the crops.

On the other hand, when 3 kg of nitrogen was applied along with 30 kg of phosphoric acid, the recovery of added nitrogen varied from 23 to 50%. This clearly shows that phosphoric acid contributed to the better utilization of the nitrogen. Just as phosphoric acid helps in the better utilization of nitrogen, potash also helps in the better assimilation of nitrogen and phosphoric acid.

Balanced fertilizer application, particularly, phosphorus and potash makes plants more drought resistant and winter hardy. Balance fertilization impart plant vigour and resistance to certain diseases. A certain balance among the various nutrients is essential for the greatest efficiency in the use of fertilizer is to be obtained.

Advantages of Fertilizer Mixtures:

The advantages of fertilizer mixtures are summarized as follows:

1. The farmer is supplied a balanced fertilizer mixture that is adopted for each soil and each crop.

2. Time and labour costs are saved since all of the fertilizer materials are applied at one time.

3. Fertilizer mixtures can be prepared in a manner to correct residual acidity of certain nitrogen fertilizers.

4. Fertilizer mixtures in balanced form help in maintaining good physical condition of soil.

5. One nutrient increases the availability of other nutrient.

6. Balance fertilizer mixtures provide tolerance against drought, cold, pests and diseases.

Disadvantages of Fertilizer Mixtures:

The arguments against using fertilizer mixtures that are usually put forward are:

1. The unit cost of plant nutrients, in mixtures is higher than that of purchasing the same materials separately.

2. The improper mixtures may not be suitable for all soils.

3. The purchase and use of correct formulation of fertilizer mixture requires relatively greater knowledge. Lack of proper knowledge about the proper mixture for a specific soil type and for a particular crop may result in improper use.

4. When mixed fertilizers are used, single nutrient fertilizer may still be necessary at a specific plant growth stage. For example, nitrogen in split application (top dressing), i.e., at 2 or 3 stages of plant growth. Therefore, farmers have to purchase nitrogenous fertilizers for split application (top dressing), apart from mixed fertilizers.