Sugarcane plant is a coarse grass which is quite tall about 10-20 feet. A single plant bears many stems in a tuft. It is a rhizomatous, perennial plant with thick solid, aerial stem. The stem colour is variable from white, yellow, black, dark green, purple, and red or violet.
It is jointed and inter nodes are smaller at the base and increase in length, until it terminates in inflorescence. There are present prop or shit roots at the lower nodes to give mechanical strength to the stem on the nodes axial buds are present. Stem contains colored tissues in which many fibro vascular bundles lie. The inflorescence called an arrow or tarsal.
Soil Required for Sugarcane Cultivation:
Sugarcane grows best on the medium heavy soils, but can also be raised on the lighter soil sand heavy clay, provided there is adequate irrigation available in the former type of soils and drainage is good in the latter type of soils. In northern India, it is cultivated largely on the loams and clay loams of the gangetic and other alluviums, whereas in Peninsular India, it is grown on brown or reddish loams, laterites and black cotton soils.
In many places, dark rich clay loams, 120 to 150 cm deep and lying on a previous substratum of murum (disintegrated traprock) are used for this crop. The pH of the soil must be within 6.0-8.0.Sugarcane production is affected by unfavorable soil reaction (pH).The soil should be reclaimed according to acidity, alkalinity and other problems hindering the production of sugarcane.
The main characteristics of the soils suitable for sugarcane cultivation are that it must possess high contents of organic matter and is well drained. Therefore, heavy clay soil with proper drainage or light soils with irrigation facilities are also favorable for this crop.
Atmospheric Condition Required for Sugarcane Cultivation:
Sugarcane grows as well at a temperature of 21° to 26.2°C. A temperature of 20-23.7°C is ideal for good germination. Temperature above 32.2°C and below 18.3°C arrests the growth of the plant.
Sunlight is another key element which influences the yield and quality of cane. Sugarcane loves warmth and sunshine. Sugarcane requires long day for its vegetative growth and short day for its reproductive growth. Day length considerably influences tillering. Short day length decreases number of tillers per plant and ultimately the tonnage.
Day length determines the flowering of the crop. Plant grows under long day conditions produces more dry matter. About 8-10hr of bright sunshine is conducive for yield and sugar output. Shorter days favour tasselling or flowering. Bright sunshine is required the development stages of this crop. Under this condition, sugar content of this crop increases.
The physiological studies show that under good or bright sunshine, stems are thicker, shorter and leaves are broader and greener. Under less sunshine as is the case of cane grown as lower storey in coconut gardens, stems are slender, and taller having thinner and narrower leaves.
Sugarcane does best in tropical and sub-tropical regions having rainfall of 75-100cm per annum. It requires heavy rainfall (150 cm) during its vegetative growth period. It grows well in an area receiving 100-175cm rainfall per annum.
In high rainfall areas (125-200 cm), this crop is grown without irrigation and thrives on the moisture conserved in the soil. Too heavy rainfall and prolong drought affects the crop adversely. Heavy rain lowers the sugar content and dry condition makes the cane fibrous.
High humidities (85 to 90%) are conducive for growth and development. But 45-65% RH is desired for sugar build up in cane stalks. In coastal areas high humidities and high temperature favour good growth and high yields. But sugar recoveries are low.
Atmospheric CO2 Concentration:
Sugarcane benefits from increased atmospheric CO2 concentration. Generally photosynthetic rate increases as CO2 concentration increases from 0.01 to 0.07% but becomes saturated at 0.06%. Varietal differences have also been observed. A strong and positive interaction is found between CO2 and light. With increased sunlight, CO2 fixation is also increased.
Sugarcane experiences frost, which seriously reduces yield and quality. A temperature of -1 to -2 °C kills the plants. Severe cold conditions adversely affect ratoon sprouting and tiller formation. Irrigation just prior to frost and trash/polythene mulching mitigate frost to a great extent.
Effect of Climate on Ripening:
Ripening is influenced by rainfall, humidity, sunshine, night length, altitude, temperature and cultivar. For effective ripening, distinct cooler nights, and dry frost free sunny days are essential. High diurnal variation in temperature is not conducive for sugar accumulation. Ripening and maturity are influenced by the soil moisture.
Better drying-off strategy maximises the sugar output. Cane yield cannot increase after the Readily Available Water (RAW) has been extracted, but sugar yield can increase substantially while the remaining soil water is extracted. A mean dry temperature of 12-14 °C is desirable for proper ripening. At higher temperature during ripening, inversion takes place with considerably reduced sugar recoveries.
Preparation of Land for Sugarcane Cultivation:
The land is brought to fine tilt by ploughing with tractor or power tiller followed by planking after each ploughing. Plough the land thrice length wise and breadth wise and level properly. Prepare furrows 25 cm deep and 75 cm apart for short duration and 90 cm apart for medium duration varieties.
In hills tracts prepare pits in rows along the contour at spacing of 30 cm in the row and 75 cm between the rows. For mid late varieties, an inter row spacing of 75 cm is recommended. Compost or F.Y.M @ 15-20 tonnes per hectare should be applied about 30 days before planting and thoroughly mixed with soil during land preparation. The soil should be made free from stubbles, weeds and clods.
Efficient care and precautions should be taken while selecting the cuttings, treating it with chemicals at the time of planting.
Stem cuttings or sections of the stalks are called “setts” or seed pieces. Each sett contains one or more buds. Sugarcane crop is propagated by stem-cutting. The sugarcane sett should be taken from well matured, erect and healthy crop of not more than 10-12 months of age. The upper-half-portion of the plant bears buds of high viability and is best for raising new crop.
The top portion contains less sucrose and bud remains young and active due to which it germinates well. Cane setts of two or three nodes, bearing 3 or 4 vegetative buds are made from the healthy, free from insect pests and diseases, top portions of the plants after hand peeling. The sugarcane sett having red spot on the cut end should not be used for planting.
The implement used for cutting the sett should be treated with spirit or solution of seed treatment chemical. Generally, three bud setts are used for planting throughout the world, while in some areas two-bud setts are also used. About 35,000 sets is required for one hectare.
Sett Treatment:
Cane-seed-setts are wet and sugary, therefore, while in soil, before sprouting into new plant, these are mostly damaged by insects (termites) and fungus. To avoid these losses, the sets, before planting, are treated before planting by different ways depending upon the condition of planting material.
(i) 1% Fish Oil Rosin Soap Treatment:
The sets are treated with 1 % fish oil rosin shop solution to stop spread of mealy bugs and scale insects.
(ii) 6% Mercurial Fungicide Treatment:
The sets are dipped for 2 to 3 minutes in a solution of 6 % mercurial fungicide like agallol or cerasan @ 500 gm. in 100 liter water. This treatment helps to prevent set borne diseases like smut and to improve germination.
(iii) Hot Water Treatment:
The sets are kept in hot water at 50°C temperature for two hours to control red-rot, grassy shoots and other virus diseases.
(iv) Azotobacter Treatment:
Just before planting sets are dipped in azotobacter inoculant solution which is prepared by mixing 5 kg. azotobacter inoculants in 100 liter water for 2 to 3 minutes. This treatment helps in good germination and save nitrogenous fertilizers.
(v) Lime Water Treatment:
Sets are soaked in lime water solution prepared by dissolving 500 g lime in 200 liter water for 24 hrs to improve germination. This treatment is given only when dry scaled bud sets and staled cane sets are used for planting.
The best time of planting the sugarcane setts for spring crop is the period when the atmospheric temperature records an average of 25°C. Therefore, the time of sowing in Tamil Nadu, Andhra Pradesh, Maharashtra and Karnataka is earlier (i.e. December – January) than the time of sowing in Punjab, Haryana, Uttar Pradesh (February – March).
The crop can be sown round the year. Crop planted before winter season gives less sprouting and tillers due to cold weather, during early sprouting stage. The duration of sugarcane crop in India ranges from 10-18 months. A 12 months crop is most common. Time of planting is governed by weather conditions. Sugarcane requires about 25-320 C temperature for good germination. Spring and autumn plantings are two important planting seasons.
In Northern India spring planting is done in February-March while in Peninsular India it is done in January-February. Spring planted crop is known as suru in Maharashtra and eksali in Gujarat and Andhra Pradesh.
This planting is very popular in Northern India. This planting is done in September-October while in Bihar and Peninsular India it is done in October – November. Autumn planting is also known as pre-seasonal planting in Maharashtra and Gujarat. The pre-seasonal crop matures in 13-15 months and supplies sugarcane in early crushing period.
In Maharashtra and Karnataka, adsali planting is done in July-August and the crop matures in 16-18 months. Because of extended growing season, there is increase in yield as well as sugar recovery. Biggest advantage of adsali is that it passes through only one summer season. In the present scenario, area under adsali planting is declining because of less availability of irrigation water.
Late Planting:
Because of wheat crop is taken on large area in rabi season in Northern and Central India, planting of sugarcane is delayed until harvesting of wheat in March-April. Research data has been proved conclusively that delay in planting causes considerable yield reduction.
Sugarcane crop is sown by various methods, depending upon the field problems.
Common methods of planting are described here:
Flat planting method is mostly common in intensive sugarcane growing areas where soil-moisture is available in plenty. Sets are kept in shallow (8-10 cm) deep furrows at 75 cm apart. On an average, one viable bud per ten centimeter length in each furrow is planted (i.e. one sett/feet). The field is heavily planked. This method of sowing is popular in North India.
Furrow planting method is mostly common under low soil moisture condition. In this method the ridges and furrows are opened with the help of ridge by keeping 120 cm distance between furrows in heavy soil and 105 cm distance in light to medium soil. After sowing irrigation is given immediately. First sets are laid on the top ridges end to end and later planted in furrows by two ways known as wet method and dry method of planting.
a. Wet Method:
This method is followed in light to medium soil. Irrigation is given to the field before planting. Sets are planted by pressing 2.5 to 5 cm deep in furrows with feet or hand. The sets are placed end to end by facing buds on sides.
b. Dry Method:
This method is followed in heavy soil to avoid the pressing as sets deep into the soil. Sets are placed in the furrow end to end by facing eye buds on sides and covered by giving a layer of soil. After completion of planting irrigation is given to the field.
In some coastal areas as well as in other areas where the crop grows very tall and the strong winds during rainy season cause lodging of cane, trench method is adopted to save the crop from lodging. Trenches at a distance of 75-90 cm are dug with the help of ridger or by manual labour. Trenches should be about 20-25 cm deep. After this already prepared mixture of fertilizers (NPK) should be spread uniformly in the trenches and mixed thoroughly in the soil.
The setts are planted end to end in trenches. Gamma BHC 20 EC at the rate of 5 liters in 800-1000 liters of water per hectare is sprayed over planted setts in trenches to control termites and shoot and root borers. Immediately after this, trenches are filled up with loose soil as in case of flat sowing. The tractor-drawn sugarcane planter is a very suitable device for planting cane in trenches.
After sowing, the sugarcane field requires some immediate cares like hoeing and protection from insects and farm animals. The fields are irrigated within a few days after sowing to get required soil conditions for hoeing.
Hoeing assists in the emergence of sprouts and increases the plant population in the field. The new emerging shoots are tender and palatable for animals to eat. Therefore, a number of insects and farm animals are attracted towards it and they require due protection measures.
Sugarcane is a heavy feeder and it occupied the land for about twelve months. Sugarcane depletes large quantity of plant nutrients and makes the soil infertile. In this condition, the growth of the plant as well as yield of sugarcane reduces considerably. So adequate manuring is essential for getting higher yield of sugarcane. The nutrient requirements have been found more important in three stages of growth except ripening phase.
The nutrient requirement of sugarcane varies accordingly to the growing region, variety and fertility status of the soil as follows:
Farmyard manure is added one month before planting at the rate of 10-12 tonnes of well decomposed manure, to improve the soil texture and water holding capacity. Mustard oilcake or Neem cake (Qty.: 300kg/ha), if possible should be applied. Organic manures are good for sugarcane crops the same provides nutrient throughout the growing period of this crop.
Fertilizers are applied based on the recommendation of the soil test. For general purpose 300 kg nitrogen, 80 kg phosphorus, 80 kg potash and 80 kg calcium per hectare are applied. Half dose of nitrogen and full dose of other fertilizers are placed in furrows below or on the side of cane-sets, at the time of sowing as a basal dose.
The rest of the nitrogen is applied in two split doses as topdressing during plant growth period. The application of fertilizer at the early stage of plant growth is advantageous, and increases the sucrose contents in the juice.
Sugarcane needs optimum moisture during all stages of growth. The vegetative growth period of the sugarcane crop can be looked upon in four stages i.e. (i) Sprouting stage, (ii) Formative stage, (iii) Grand growth stage and (iv) Maturity stage.
The water requirement of sugarcane varies from 200- 300 depending upon the soil type and weather conditions, method of planting, timely irrigations result in more juice with high sucrose contents. After the monsoon, mostly 6-7 irrigations are required for successful crop production.
In the case of sugarcane, the maintenance of optimum soil moisture during all stages of growth is one of the essential requisites for obtaining high yields. The crop should, therefore, be grown in areas of well-distributed rainfall or under an assured and adequate irrigation.
In tropical India, depending on the type of the soil, the seasonal conditions, the variety grown, the method of planting and the rate of manuring, the total water requirement of the crop for optimum growth varies from 200 to 300 cm, inclusive of rainfall.
The requirement of an adsali crop is proportionately higher. Where the soil is not retentive of moisture, and where there are no reserves of subsoil moisture, cane requires to be irrigated frequently. In tropical India, usually one or two waterings are given at intervals of three or four days after planting to help the setts to germinate and the seedlings to establish themselves.
Thereafter, in the absence of rains, cane is irrigated every 10 to 12 days during its growing period. In dry areas and in sandy-loams soils, irrigations may be needed at intervals as short as eight days. In deep clay loams, irrigation can be withheld for longer periods, say, up to two or three weeks.
Frequent light irrigations, each 40 to 50 mm, adjusted to suit the growing period of the crop and the prevalent weather conditions, are very useful. Towards the time of harvesting, irrigation frequency is reduced, and just before harvest, irrigation is withheld for about a month.
In Northern India the summer being drier and hotter the crop needs water more frequently than in southern India, but actually, adequate water for frequent irrigation is not available and irrigations are, therefore, usually given at comparatively long intervals. In canal irrigated areas, the frequency of irrigation depends entirely on the running of the canals.
The severity of these conditions is slightly mitigated by the high water-holding capacity of the alluvial loam soil. In the Punjab State because of the lower rainfall, drier climate, and slightly coarser soils, the crop gets 8 to 10 irrigations during summer. In Central and Western Uttar Pradesh three to five irrigations are usually given, and they help the crop to tide over the summer.
In the eastern Gangetic areas, cane subsists almost entirely on subsoil moisture and rainfall, and receives no irrigation at all. In the post-monsoon season the crop receives only one or two irrigations or none at all, however these post monsoon irrigations only help to keep the crop in good condition, for cane does not make growth in winter.
In areas where frost occurs, irrigations are applied to save the crop from them. Sugarcane responds to irrigation in northern India as it does in the south and it is profitable to apply frequent light irrigations to the crop during the hot weather. Where irrigation facilities are scarce in summer, trash-mulching in the interspaces of the cane rows is done for conserving the soil moisture.
As the crop remains in the field for a long period, intercultural operation such as hoeing, weeding, earthing up, wrapping and trashing needs to be done.
i. Hoeing:
Hoeing is done first by a week or so after planting in order to break the surface crust, else light irrigation is followed by the same period in order to help emergence of sprouts.
ii. Weeding:
Weeds are undesirable plants growing within a crop and they compete for resources such as nutrients, water and light. Germination of crop completes in 20-30 days. As area is irrigated, it grows variety of weeds during the period.
Weed poses a serious problem in sugarcane cultivation as its lowers the productivity of land robbing it of available nutrients and moisture. Weeds often serve as host for some virus and vectors and increase the incidence of insects, pests and diseases. Without weed control, crop yields can be significantly reduced. Weed control in sugarcane is done by adopting mechanical method or chemical method.
Fields are given a hoeing with help of kurpi or spade, after a month of sowing and the process is repeated frequently. This method not only removes the weeds but also increases the sprouting and tillers and destroys insects and enhances aeration in the soil. Some growers make best use of this laborious operation by cultivation of second crop in between the sugarcane crop as a mixed crop.
(ii) Chemical Method:
Chemical method is most effective for controlling weed during pre – monsoon period. Weeds can be effectively controlled by the application of herbicides or weedicides. Herbicides are of particular value in keeping down weeds early in the season when weed competition can do the greatest damage to the young growing crop and when no interculture can be performed. Herbicides are applied at different times depending on their mode of action.
iii. Earthing Up:
Soil between the furrows of canes, is taken with the help of spade and applied to the sides of the plants.
This earthing up is advantageous in many ways (i) Acts as hoeing, (ii) Mixes the top dress fertilizers well in the soil, (iii) Support the plant, to save them from lodging, (iv) Help the bud to sprout profusely and (v) Makes watering and drainage easy. This operation is done when the crop is 5 to 5.5 months old and 2 to 3 internodes are visible.
iv. Trashing:
Removal of loosely adhering dried and drying leaves from the sugarcane known as trashing. It is generally done to clean the sugarcane.
v. Propping:
The tying of cane plants to prevent lodging is known as propping. Some canes of two adjacent rows are brought together and tied by sugarcane leaves rope. It also helps in applying irrigation in a better way.
Maturity and Harvesting of Sugarcane:
Cane should be harvested only when it is mature.
Practical tests to judge maturity are- (a) General yellowish colour of whole crop, (b) Cessation of growth, (c) Swelling of eye buds, (d) Metallic sound of cane, (e) Breaking of cane at the nodes and (f) Brix saccharometer reading between 21 and 24.
Irrigation should be held for about 10 to 15 days prior to harvesting. Harvesting should be done with sharp cane cutting knife and very close to ground. The cane should be crushed within 24 hours to get high recovery.