• Among various riputes of sugarcane production, although fertilizers contribute maximum to the increase in yield but these cannot help to maintain and enhance soil organic matter content which is ultimate key to sustainability.
• Organic matter maintains porous soil structure, provides superior water holding capacity and allows oxygen to penetrate for use by soil microbes that break down manure, crop residues and other organic matter.
• Infact, earlier to the introduction of chemical fertilizers in cane cultivation the fertility of fields used to be sustained not only by animal and plant wastes, but also by certain practices of mixed cropping, crop rotation etc.
• These practices have in fact been followed for centuries in India but have been rapidly given up in recent years due to input-intensive agriculture.
• There is no doubt that sugarcane crop needs fertilizers. A crop of 125 tonnes per hectare removes 83 kg nitrogen, 37.2kg phosphorus and 168 kg potassuim per hectare from soil.
• The tendency to supply all these nutrients through chemical fertilizers, however, has to be avoided as these have deleterius effect on soil productivity on long-term basis.
• However, to sustains sugarcane production under intensive cultivation as practiced in the hot climate of India, organic matter content of soil must be maintained either by recycling organic wastes, use of farm yard manure, green manuring, growing legumes in crop sequences and as companion crops.

• Deficiency of Nitrozen leads to:
  i.   paleness of foliage.
  ii.   early leaf senescence
  iii.  thinner and shorter stalk
  iv.   longer but thinner roots

• Excess Nitrozen leads to:
  i.    harmful to crop
  ii.   prolongs vegetative growth
  iii.  delays maturity and ripening
  iv.  increases reducing sugar content in juice
  v.   lowering juice quality
  vi.  increases soluble N in juice affecting clarification
  vii. susceptible to lodging, pest and disease incidence

• Uptake depends on presence of soluble and plant absorbable form.
• P- requirement is relatively less than N and K.
• Necessary for formation of proteins and thus for yield build up.
• Important for cell division leads to crop growth
• Stimulates root growth
• Necessary for plant metabolism and photo synthesis
• Required for adequate tillering
• Interacts with N and thus enhance ripening.
• Deficiency of P leads to:
i.   reduced tillering
ii.  delays in canopy development, excess weed growth
iii.  affects stalk elongation.
iv.  less production of secondary and tertiary stalks
v.   leaves grow closely
vi.  leaf colour appears green violet
vii. for proper clarifiction while processing 300-400 ppm of phosphorus viii.  in cane juice is necessary.

Excess P is wasted due to fixation in soil

• Requirement of K is greater than N and P.
• Required for carbon assimilation, photo synthesis translocation of carbohydrates
• Involved in various enzymatic activities
• important for sugar synthesis and translocation to the storage organs.
• develops resistance to sugarcane against pest, disease and lodging.
• Maintains cell turgidity under moisture stress conditions.
• Balances the effect of N and P
• Excess availability of K leads to "Luxury consumption".

• NPK requirements depends on variety, soil type, irrigation level etc. The requirements of nutrients not only met by the application of manures and fertilizers but also fertility status.

• Dosage of nutrient to be supplied will be determined based on crop requirement contribution from the soil and organic manures applied, likely losses of applied nutrients by means of leaching, volatililization, fixation etc.

• Timing is based on crop need at different growth phases, and best use of applied nutrient with less wastage.
• Nitrogen requirement is maximum at tillering and early grand growth phase viz., within the first six months. upto tillering the nitrogen need is much limited and hence application at planting may not be required in most cases.
• If at all N needed from the beginning by the crop 10% of the total dose can be applied at planting by placing near the sett.
• Between 3-4 months age (tillering phase) high amount of N uptake is observed and hence, the first application of nitrogen should be at the start of tillering viz., at 45 days of planting.
• In case of short duration, early maturing varieties first application of N can be given at 30 days age of the crop.
• Beginning of the grand growth period viz the end of tillering phase the N-requirement is very high and this can be met by applying N between 90-120 days period for Eksali crop.

• Late application or N beyond 120 days (Eksalicrop) will have adverse effect on juice quality because of continued vegetative growth, late tillering, reduce 5% of Juice, increased soluble nitrogen in juice, water shoot formation etc.
• Farmers should realise that late application of N will do more harm than good.
• Most of the late applied N goes to late tillers and water shoot formation besides becoming susceptible to pests and diseases.
• The time of N application however, can be extended to six months in case of adsali crop.
• Small quantities of N along with P and K can be applied late for recovery of crops suffered due to flood and water logging. This should be done only when there is sufficient time between harvest and the time of application.
• Fertilizer application should invariably followed by irrigation and excess irrigation should be avoided to avoid leaching losses.

• Apply phosphorus in the furrow bottom and mix slightly with soil before planting.
• Nitrogen and potassium fertilizers are given in split doses, applied in bands on either side of the cane row.
• Cover the fertilizer with soil immediately after placement to reduce volatilization losses. This is also achieved by partial earthing after first top dressing and full earthing up after second top dressing.

• Zinc deficiency is another important micronutrient problem in soils where paddy is grown in rotation. To overcome zinc deficiency 0.5% ZnSo4 , spray can be done.
• Zinc spray can also be done along with ferrous sulphate spray. Ferrous sulphate and zinc sulphate together can be applied to soil at 25kg each per hectare.

• Foliar nutrition of urea (1 to 2.5%) and potassium (2.5%) under moisture stress is a useful practice to improve yield and quality.
• Foliar application of DAP formed to be useful to improve yield and quality.
• Good foliage wetting is necessary. 'Teepol' can be used as a wetting agent.
• Sprayings done preferably in the morning hours.
• A boom sprayer may be used in a grown up crop.

@Varies with Fe/Mn ratio, Critical level can be below 10ppm if Fe/Mn remain>1 (Source : Schmehl and Humbert, 1964)