Application Fertilizer

1 application

1.1 liquid vs solid
1.2 slow- , controlled-release fertilizers
1.3 foliar application
1.4 chemicals affect nitrogen uptake
1.5 overfertilization

application

fertilizers commonly used growing crops, application rates depending on soil fertility, measured soil test , according particular crop. legumes, example, fix nitrogen atmosphere , not require nitrogen fertilizer.

liquid vs solid

fertilizers applied crops both solids , liquid. 90% of fertilizers applied solids. solid fertilizer typically granulated or powdered. solids available prills, solid globule. liquid fertilizers comprise anhydrous ammonia, aqueous solutions of ammonia, aqueous solutions of ammonium nitrate or urea. these concentrated products may diluted water form concentrated liquid fertilizer (e.g., uan). advantages of liquid fertilizer more rapid effect , easier coverage. addition of fertilizer irrigation water called fertigation .

slow- , controlled-release fertilizers

slow- , controlled-release involve 0.15% (562,000 tons) of fertilizer market (1995). utility stems fact fertilizers subject antagonistic processes. in addition providing nutrition plants, excess fertilizers can poisonous same plant. competitive uptake plants degradation or loss of fertilizer. microbes degrade many fertilizers, e.g., immobilization or oxidation. furthermore, fertilizers lost evaporation or leaching. slow-release fertilizers derivatives of urea, straight fertilizer providing nitrogen. isobutylidenediurea ( ibdu ) , urea-formaldehyde convert in soil free urea, rapidly uptaken plants. ibdu single compound formula (ch3)2chch(nhc(o)nh2)2 whereas urea-formaldehydes consist of mixtures of approximate formula (hoch2nhc(o)nh)nch2.

besides being more efficient in utilization of applied nutrients, slow-release technologies reduce impact on environment , contamination of subsurface water. slow-release fertilizers (various forms including fertilizer spikes, tabs, etc.) reduce problem of burning plants due excess nitrogen. polymer coating of fertilizer ingredients gives tablets , spikes true time-release or staged nutrient release (snr) of fertilizer nutrients.

controlled release fertilizers traditional fertilizers encapsulated in shell degrades @ specified rate. sulfur typical encapsulation material. other coated products use thermoplastics (and ethylene-vinyl acetate , surfactants, etc.) produce diffusion-controlled release of urea or other fertilizers. reactive layer coating can produce thinner, hence cheaper, membrane coatings applying reactive monomers simultaneously soluble particles. multicote process applying layers of low-cost fatty acid salts paraffin topcoat.

foliar application

foliar fertilizers applied directly leaves. method invariably used apply water-soluble straight nitrogen fertilizers , used high value crops such fruits.

fertilizer burn


chemicals affect nitrogen uptake

various chemicals used enhance efficiency of nitrogen-based fertilizers. in way farmers can limit polluting effects of nitrogen run-off. nitrification inhibitors (also known nitrogen stabilizers) suppress conversion of ammonia nitrate, anion more prone leaching. 1-carbamoyl-3-methylpyrazole (cmp), dicyandiamide, , nitrapyrin (2-chloro-6-trichloromethylpyridine) popular. urease inhibitors used slow hydrolytic conversion of urea ammonia, prone evaporation nitrification. conversion of urea ammonia catalyzed enzymes called ureases. popular inhibitor of ureases n-(n-butyl)thiophosphoric triamide (nbpt).

overfertilization

careful fertilization technologies important because excess nutrients can detrimental. fertilizer burn can occur when fertilizer applied, resulting in damage or death of plant. fertilizers vary in tendency burn in accordance salt index.