Pakissan.com; How to improve sugar recovery from cane?

DESPITE an increase in area under cultivation, timely rain, judicious use of fertilisers, improved cultural practices and better management, sugar crisis is still looming large in the country.

Apart from low procurement price offered by mill owners, one of the main reasons for the crisis is the poor sugar recovery rate from the crushed cane. Sugar recovery here is hardly eight per cent whereas in many countries it is 12-14 per cent. The average cane yield at the rate of 53 ton per hectare is far below the existing potential of the country’s crop.

Irrespective of policy and economic factors which are beyond farmers’ reach, some important measures to reduce the cost of production and improve cane recovery include improved production practices, nutrient and water management, insects pest management, post-harvest handling together with exploiting the potential of ratoon crop.

Improved production practices: Preparatory tillage is an important operation in sugarcane cultivation. Since sugarcane is a deep-rooted crop penetrating up to 90cm inside soil, tillage practices can help in development of better root system and optimal growth of the crop. For proper growth some farmyard manure and green manure should be added to the soil one month prior to land preparation.

Selection of quality seed is important for high yield. Seeds for varieties of sugarcane with variable sugar contents are available in different parts of the country. Sets or cuttings used for propagation should be fresh and juicy, free from insect pest and disease and 9-10 months old. Eyes buds for seed should be fully developed from planted crop. The seed should be treated with proper fungicides.

Planting time and method: Appropriate planting method and time greatly influence growth, maturity and yield of the crop.

To maximise production, it is necessary to follow planting times without affecting yield from late planting. However, September crop is harvested with higher yield of 25-35 per cent and better sugary recovery due to luxurious vegetative growth compared to February plantation.

Appropriate seed rate with proper row or furrow spacing are the key to achieving optimum plant population for high production. Generally for medium to thin varieties high seed rate is used than thick cane in order to get desired plant population and to facilitate intercultural operations. Recently, spaced transplanting method with single eye set, paired row and wide furrow row method have been introduced in neighbouring country; these should also be tried here.

Nutrient & water management: Water and fertiliser requirements of sugarcane are very high. Framers should take care of irrigations in sugarcane particularly during the summer and should adjust irrigation requirement according to available water at farm level. The crop requires 16-20 irrigations. Drip irrigation saves 40-70 per cent water, improves sugar recovery up to one per cent, increases fertiliser use efficiency, saves electric power in pumping, improves insect and pest control, and reduces labour costs. Although initially installation costs are high, it can be overcome by other advantages.

For proper mineral nutrition of the crop, it is necessary to have knowledge of growth physiology. However, fertilisers’ efficiency can be increased when they are applied through irrigation water as in case of drip irrigation.

Pest management: There is need of integrated practices to control weeds, insects and pests in sugarcane to get high yield. These include intercultural practices for weed control, earthing up, and application of herbicides for proper weed control with the help of technical experts.

Inter-culture: To keep field free from weeds inter-culture of crop is helpful as it provides proper aeration in the effective root zone. Hoeing is done for better aeration water penetrability and weed control. In sugarcane intercropping of onion, potato etc. is done for getting high economic returns at early stages of cane crop. Inter-crop species should be restorative, not heavy feeder, with shallow root system and of short duration.

Ratoon management: For high benefits ratooning is necessary in sugarcane by eliminating the expenses at land preparation, planting material costs and planting expenses. By good irrigation and nutrient management, it is better to get high yield from ratoon crop. Ratooning of cane harvested before February is preferred. The sugar recovery in ratoon crop is also better and it matures earlier than the plant crop.

Cane from the fields to be kept for ratoon should be cut at ground level. Sugarcane planted in two row strips 90 cm apart not only ratoon well but also gave higher yields for each of three planting treatments than three and four-row strip planting systems. Fill the gaps; control the weeds, insect pests and diseases properly. In case of severe attack of any insect, do not keep the crop as ratoon.

For better crop, disease-free, healthy seeds should be used. Preferably disease-resistant varieties treated with fungicide should be planted. Diseased plants should be removed from the field and should either be buried or burnt.

The cane should be harvested after it has attained maturity acquiring maximum weight by adopting right technique avoiding field losses. Harvesting of either immature or over-aged cane with improper method leads to loss of yield, sugar recovery, poor juice quality and problems in milling.

One month prior to harvesting, irrigation should be stopped and the harvested crop should not be left in the field for long. If at all kept in the field for longer period, it should be covered with trash. Different varieties should be harvested according to their period of maturity. The crop harvested during February-March gives good ratoon crop.

Several methods are available to determine the maturity of the crop so that it may be harvested at right time. Many farmers harvest their crop based on its age and appearance. Sometimes farmers harvest the crop even before it attains maturity necessitated by mills demand. Delays in harvesting are also quite common, particularly when there is excess cane area. Harvesting should always be at right time employing right method for better yield.

In many countries including ours even today harvesting is done manually. Among several tools, the cutting blade is usually heavier and facilitates easier and efficient cutting of cane. Manual harvesting requires skilled labour as improper harvest leads to loss of cane and sugar yield, poor juice quality and problems in milling. But the problem is that harvesting labour is becoming scarce and costly.

There is also need to establish more research institutes for the development of crop production and increased recovery from the crushed cane in order to attain autarky in sugar and earn foreign exchange.

Courtesy: The DAWN

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