Sugarcane being a giant crop producing huge quantity of biomass generally demands higher amounts of nutrient elements. A large number of research experiments have clearly demonstrated that for producing higher cane and sugar yields on a sustainable basis application of adequate amounts of fertilizer nutrients viz., N, P and K is essential.

At the same time the cost of chemical fertilizers have increased and there is a need to improve fertilizer use efficiency for more benefits. The best answer to this challenge is "Fertigation", where both water and fertilizers are delivered to crop simultaneously through a drip irrigation system. Fertigation ensures that essential nutrients are supplied precisely at the area of most intensive root activity according to the specific requirements of sugarcane crop and type of soil resulting in higher cane yields and sugar recovery.

Fertigation Offers Several Distinct Advantages in Comparison to Conventional Application Methods:

• Distribution of plant nutrients more evenly throughout the wetted root zone resulting in increased nutrient availability & uptake contributing to higher crop growth rates and cane yields
• Supply of nutrients incrementally according to the crop developmental phases throughout the season to meet the actual nutritional requirements of the crop
• Careful regulation and monitoring the supply of nutrients
• Application of nutrients to the soil when crop or soil conditions would otherwise prohibit entry into the field with conventional equipment
• Minimal nutrient losses through consumption by weeds, leaching and runoff
• No damage to the crop by root pruning, breakage of leaves, or bending of leaves, as occurs with conventional fertilizer application methods/equipment
• Less energy is expended in application of the fertilizer
• Usually less labour & equipment are required for application of the fertilizer and to supervise the application
• Soil compaction is avoided because heavy equipment never enters the field
• No salt injury to foliage
• Allows raising of crop on marginal lands, where accurate control of water and nutrient ion in the plant's root environment is critical
  

Nutrient Uptake by Sugarcane

 Absorption of macronutrients by the variety CB41 - 76 (Malavolta, 1982)

fig. shows the accumulation of macronutrients by the variety CB 41-76 under Brazilian conditions. Several works have indicated that there is a close relationship between increase in stalk production and accumulation of N and K, which suggests that these two elements "go together" in the nutrition and fertilization of the sugarcane plant. The maximum rate of uptake of macronutrients by plant cane and first ratoon in the period of higher growth rate is given in

Table 11.

Table 11. Maximum Rate of Uptake of Nutrients by Plant Cane and Ratoon Cane (Malavolta, 1994)

Element	Plant cane	Firfst ratoon
	kg ha-1 day-1
Nitrogen	0.59	0.73
Phosphorus	0.08	0.11
Potassium	0.71	0.95
Calcium	0.45	0.33
Magnesium	0.24	0.26
Sulphur	0.16	0.31

Generally speaking, the content of the macro and micronutrients in the plant obeys the following decreasing order:

K»gt; N»gt; P»gt;Ca»gt;S»gt;Mg»gt;Cl»gt;Fe»gt;Zn»gt;Mn»gt;Cu»gt;B»gt;Mo

Further most of the published data on the mineral requirements of sugarcane refer only to the above ground parts, which are stalks and leaves. Table 12 is an attempt to show the quantities of macro and micronutrients contained in the entire plant cane.

Table 12. Quantity of Macro and Micronutrients in the Below Ground and Aerial Parts of Plant Cane

Element	Roots	Millable stalks	Leaves	Total
	Kg/ha
Nitrogen	8	83	77	168
Phosphorus	1	15	8	24
Potassium	4	109	105	218
Calcium	2	30	45	77
Magnesium	1	29	18	48
Sulphur	2	25	22	49
Chlorides	--	--	1	1
Silicon	--	98	150	248
	g/ha
Boron	34	214	144	392
Copper	13	201	105	711
Iron	4900	3800	7900	16600
Mangnese	84	1170	1981