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Mixed fertilizersFor over hundred years the mixed fertilizers are in use besides straight fertilizers. Many fertilizer mixtures are made available now and this account for a major portion of the consumption of N, P and K. Present day statistics show that numerous grades of fertilizers mixtures are manufactured and the fertilizer mixing industry is beingconsidered as one of the major agro- industry.The following are some of the common term frequently used in the mixed fertilizer industry.
Fertilizer : The substance which is used for the supply of plant nutrients
Mixed fertilizer : A mixture of more than one straight fertilizer which can supply more than one plant nutrient element
Complete fertilizer : A single fertilizer material containing the entire three major plant nutrients viz, N, P and K
Fertilizer grade : This refers to the minimum guarantee with regard to the nutrientcontent of the fertilizer mixture in terms of N, P and K.
Fertilizer formula : This related to the quantitative expression of the analysis of the different ingredients included in the mixed fertilizer in terms of N, P and K.
Fertilizer ratio : This indicates the relative percentage of N, P2O5 and K2O in the manure mixture.
Acidic fertilizer : Fertilizer capable of increasing the acidity of the soil by continued applications.
Basic fertilizer : Fertilizers which increase the pH and the soil on continued use by leaving a basic residue in the soil.
Neutral fertilizer : Materials which are neither increasing nor decreasing the pH of the soil
Filler : It is called as the ‘make-weight’ material added to the fertilizer mixtures. Filler materials are inert materials like sand, saw dust etc, are added to make up the difference between weight of ingredients added to supply the plant nutrients in a tonne and the final weight viz., 1,000 kg.
Advantages
All the three major plant nutrients are made available in one and the same material. There is saving of time and labour. The residual effects will not be there. The fertilizer mixtures are usually prepared taking into account the acidic or alkaline nature of the ingredients, and other chemical reactions. Hence, some of the residual effects like acidity will not be there. Usually mixed fertilizer are prepared to suit a group of crops and soils.
Disadvantages Specific needs of crops and deficiency of individual nutrient elements cannot be satisfied by using mixed fertilizers as efficiently as in the case of straight fertilizers.
The use of mixed fertilizer in such cases of specific needs will be a waste as other nutrients are also added to the soil.
Unit cost of the various nutrients contained in the mixed fertilizer will always be higher when compared to the unity cost of nutrients contained in the straight fertilizers.
Improper mixing and storage of fertilizers can result in large nutrient losses. \
Some important aspects to consider in fertilizer mixing and storage include the following:
• Urea should not be mixed with ammonium calcium nitrate (CAN), KCl, SSP or TSP.
• Urea can be mixed with most other fertilizers but fertilizer mixtures containing urea should be applied immediately after mixing. Do not store fertilizer mixtures containing urea.
• Ammonium phosphates and super phosphates should not be mixed with lime, slag, rock phosphate or CAN.
• Potassium chloride and sulfate of potash can be mixed with most fertilizers, but mixtures of these fertilizers with urea and calcium ammonium nitrate should not be stored.
• CAN should not be mixed with basic slag but can be mixed with urea, single superphosphate, and ammonium phosphates immediately prior to application. Do not store fertilizers in damp or dirty places. Make sure that bags of fertilizer in the store do not absorb moisture from leaky roofs or water seepage through walls and floors.
Preparation of mixed fertilizers
Many kinds of materials are used in the manufacture of fertilizer mixtures. The materials are found to be highly varying in their properties. However, only a limited number of materials are being used like (NH4)2SO4, CO(NH2)2, Super phosphate, ammonium phosphate, muriate of potash, limestone, gypsum and some fillers.
The manufacture of fertilizer mixtures usually involves the weighing andproportioning of ingredients that are used, sieving and sizing of the various ingredients, mixing the different materials and packing. All the above operations are done both mechanically and by hand operation. Different kinds of machineries are being used.
• Urea should not be mixed with ammonium calcium nitrate (CAN), KCl, SSP or TSP.
• Urea can be mixed with most other fertilizers but fertilizer mixtures containing urea should be applied immediately after mixing. Do not store fertilizer mixtures containing urea.
• Ammonium phosphates and super phosphates should not be mixed with lime, slag, rock phosphate or CAN.
• Potassium chloride and sulfate of potash can be mixed with most fertilizers, but mixtures of these fertilizers with urea and calcium ammonium nitrate should not be stored.
• CAN should not be mixed with basic slag but can be mixed with urea, single superphosphate, and ammonium phosphates immediately prior to application. Do not store fertilizers in damp or dirty places. Make sure that bags of fertilizer in the store do not absorb moisture from leaky roofs or water seepage through walls and floors.
Preparation of mixed fertilizers
Many kinds of materials are used in the manufacture of fertilizer mixtures. The materials are found to be highly varying in their properties. However, only a limited number of materials are being used like (NH4)2SO4, CO(NH2)2, Super phosphate, ammonium phosphate, muriate of potash, limestone, gypsum and some fillers.
The manufacture of fertilizer mixtures usually involves the weighing andproportioning of ingredients that are used, sieving and sizing of the various ingredients, mixing the different materials and packing. All the above operations are done both mechanically and by hand operation. Different kinds of machineries are being used.