Basic Understanding of Fertilizers

The fundamentals of Fertilizers must know by the Farmers:    

The very basic information about the fertilizer to identify its nutrients composition. With the name of every fertilizer there are three numbers with proportion sign like 0:0:0, in this format first number reflects the value of Nitrogen (Denoted by N) content in percentage (%), Second number reflects the value of Phosphorus (Denoted by P) content in percentage (%), Third number reflects the value of Potassium (Denoted by K) content in percentage (%).

Moreover, it is also called NPK ratio mentioned with proportion sign between each two values.

Furthermore, the characteristics of the fertilizers like PH, Salt index value, active ingredients is vital to know for best fertilizers plan for crops. 

Behavior of Fertilizers in the Soil:

Fertilizer is an expensive component of the agriculture production; optimized use of the fertilizer makes it possible the maximum crop yield from minimum application of the fertilizer.

To practice the optimized use of the fertilizers for crops is possible only if the crop supervisor has the knowledge of the following concepts.

Fertilizer behavior in soil is based on the active elements desired by the crop, forms of the elements available in fertilizers and possible chemical reactions in the root zone.

To determine the possible chemical reactions of fertilizers in the soil, farm staff must have the knowledge of the physical properties of soil and chemical analysis report is also required.

Knowing the status of the soil and complete chemical information of the fertilizer make the crop production staff able to plan an optimized fertilizer plan for the crop. By which we can get more yield against per unit application of fertilizer.

Fertilizers to Soil Relationship.

Salt Index

The fertilizers contain salts during the manufacturing parallel to the active nutrients for plants, in other words, can be described as the property of fertilizers due to which it induces the salts concentration in the soil solution. On the basis of the above phenomena, scientists describe the salt “index as a numeric ratio of the increase in osmotic pressure produced by a selected fertilizer product compared to that produced by the same weight of sodium nitrate (NaNO3), where sodium nitrate is assigned a relative value of 100.”

The problem occurs when salt concentration becomes higher in soil, the reverse osmosis starts and water start releasing from seed/seedling to the soil, that phenomena is deadly for the new seedlings established. The same phenomena are the reason that make agriculture impossible in saline soils.

Salt effect occurs when fertilizer is placed near the seed and seedling, the desiccation (dryness/ removal of water) may start depending upon the following factors:

The adverse effects of salt index to crop can be minimized by adopting the best practices of fertilizer application to crops.     

By considering the following factors adverse effect of salt index can be managed:

Moisture content of soil

Type of fertilizer applied

Rate of fertilizer applied

Proximity (Location w.r.t the Seed placement)

PH Values of the Fertilizers

The PH values of the fertilizer solutions are given in the table, but it cannot affect the soil by the values. There are some further chemical reactions depending upon the soil conditions like Moisture content, Chemicals available in the soil, Temperature, habitats, and plant species.

Detail behavior of fertilizer towards the PH value will be discussed in some independent blogs.  

Fertilizer Name	PH of the Fertilizer Solution
Urea (46:0:0)	3.6
DAP (46:18:0)	7.5 - 8
Nitro-Phos (22:20:0)	3.5
Nitro-Phos (20:20:0)	3.5
Nitro-Phos (18:18:0)	3.5
Ammonium-Sulphate	5-6
Calcium Ammonium Nitrate	7
Zaekeez NPK - 8:23:18	5.88
Zaekeez NPK - 17:17:17	5.88
Zaekeez NPK - 12:12:12	5.88

  

 

 

 

 

 

 

 

 

 

 

 

 

Fertilizer Constituents:

Urea:

Urea mostly available in granular form and has 46 percent of Nitrogen content. When applied to the soil Urea normally undergoes the three chemical reactions before the time crop utilizes the nitrogen.

 As urea is applied to the crop residue and enzymes in the soil convert it to ammonia, after that ammonia reacts with (H) hydrogen ion and converted to ammonium. Plant can also use that form of nitrogen. If soil moisture is too low then ammonium uptake by plant persistence for a longer period, it may cause ammonium toxicity in plants.

 In the third step, the microorganisms in the soil convert that ammonium to nitrate. The nitrate is soluble in water and can be lost with groundwater deep peculation.

If conditions like soil moisture and temperature are favorable, then ammonia will take only 2 to 4 days to convert to ammonium. Low temperature up to the freezing point slows the process but don’t stop the conversion.  During the cold temperatures at a slower conversion rate may increase the leaching losses.  

If urea is broadcast to the surface of the soil, the formed ammonia will be volatized and escaped to the atmosphere. This phenomenon occurs when soil moisture is low and temperature is high. Furthermore, with these conditions, if soil PH is higher than the 7, the greatest losses will be there.

On the other hand, if urea is applied within the soil surface (under the soil surface) the conversion of ammonia to ammonium will be rapid and not volatized nor move with water.  

 

constituent’s percent basis

PH of the Fertilizer Solution	Fertilizer Name	Nitrogen (%)	Phosphorus (%)	Potassium (%)	Calcium (%)	Sulfur (%)	Magnesium (%)
3.6	Urea (46:0:0)	46
7.5 - 8	DAP  (46:18:0)	46	18
3.5	Nitro-Phos (22:20:0)	22	20		10
3.5	Nitro-Phos (20:20:0)	20	20
3.5	Nitro-Phos (18:18:0)	18	18
5-6	Ammonium-Sulphate	21				24
7	Calcium Ammonium Nitrate	26		0.9	0.4	10	0.05
5.88	Zaekeez NPK - 8:23:18	8	23	18
5.88	Zaekeez NPK - 17:17:17	17	17	17
5.88	Zaekeez NPK - 12:12:12	12	12	12
	MOP 0:0:60	0	0	60
	SOP 0:0:50:18	0	0	50		18
1 - To <2	Engro SSP + Zinc		16-20		18-21	11-12
	TSP
	Zabardast Urea
	Power Potash	13		44

Fertilizers