Sugarcane Production

Sugarcane (Saccharum) or popularly known as “Tubo” here in the Philippines, refers to any of tall perennial grasses of the family Gramineae ( grass family). Native to warm temperate to tropical regions of Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six meters tall.  All sugar cane species interbreed, and the major commercial cultivars are complex hybrids.

Cuba and India together produce a large percentage of the world’s tropical sugar, cane sugar. Cane is harvested by cutting down the plant stalks, which are then pressed several times to extract the juice. The juice is concentrated by evaporation into dark, sticky sugar, often sold locally. Refined sugar, less nourishing as food, is obtained by precipitating out the non-sugar components. Almost pure sucrose , it is the main commercial product. By-products obtained from sugarcane include molasses , rum , alcohol, fuel, livestock feed, and from the stalk residue, paper and wallboard.

The Philippines is also a sugar-producing country, growing it mainly on the islands of Negros, Luzon, Panay and Mindanao. Recently, the Philippine government passed the Biofuel Act of 2006 (or Republic Act 9367) which created a certain market for ethanol investors in the Philippines and paved the way for the development of a new industry: fuel ethanol production. Sugarcane is expected to be the predominant source of feedstock for ethanol production. Commercial production of ethanol from sugarcane will help the country diversify its fuel portfolio and ensure its energy security.

Presently, sugarcane farmers produce an average of only 65 tons of cane/ha potentially yielding only 70 liters (18.5 gallons) or 4550 liters/ha/year (145 gallons/ha/year) of ethanol per metric ton using sugarcane as feedstock. This ratio is very low when compared to the potential cane yields (120 to 150 tons/ha) achieved in Brazil, India, South Africa and other regions growing sugarcane with drip irrigation and fertigation. Therefore, new and innovative sustainable technologies are needed, not only to raise and sustain sugarcane productivity per hectare, but also to enable the consistent supply of feedstock to bio-refineries at lower costs and to meet domestic sugar demands. As both the food and energy industries use scarce and expensive resources such as water and fertilizers, a solution is required to ensure a more competitive position, especially within the global market.

How to grow Sugarcane

Land Preparation

For higher sugarcane yields, providing optimum soil environment is an essential pre-requisite since the crop remains in the field for about 5 to 6 years due to the practice of raising several ratoon crops.

Further intense mechanization involving traffic of heavy machinery from planting to harvesting and transporting to the sugar mill or distillery, can cause the deterioration of soil physical conditions. This translates into soil compaction with a cohort of harmful side effects viz., reduction in storage & movement of air and water, mechanical difficulty for root growth and difficulty in absorption of nutrients from the soil itself and from the fertilizer.

Therefore a through land preparation every time a new crop is planted is absolutely essential to bring the soil to fine tilth for proper germination of the sets and field emergence and root growth.

Tillage is the physical manipulation of the soil with appropriate implements to loosen the surface soil layer.

Objectives of Land Preparation:

• To prepare a seed bed which permits optimal soil water air relations
• Good physical conditions for early root penetration and proliferation
• To incorporate preceding crop residues and organic manures
• To destroy weeds and hibernating pest & disease organisms
• To facilitate proper soil chemical and microbial activity

Tillage operations through tractor drawn implements are most ideal and quick. For initial ploughing use either mold board plough or disc plough. Whenever, soil turning is desired, a mold board plough should be used.

On the other hand when the soil is hard, uneven and composed of crop stubbles, a disc plough is preferable. Ploughing at optimum soil moisture content is very essential to achieve tilth. Too wet soil interrupts movement of machinery and causes destruction of soil structure.

On the other hand too dry soil will not allow tynes to penetrate deep and results in frequent mechanical breakdowns, increased power requirement and cloddy soil surface affecting soil water air relations.

The secondary tillage operations are carried out using disc harrows, tyned harrows or rotavator. The rotavator is a very useful multi purpose implement, which cuts the crop residues, shred them and incorporates in the soil in one pass. Use mechanical methods (subsoiling or chiseling or deep ploughing) or biological means (green manuring between last ratoon harvest and start of a new crop) to destroy the compacted layer and to allow roots to develop normally. Subsoiling was also shown to reduce fuel consumption, working time and facilitate optimum plant population.

Steps in Land Preparation Involve the Following:

• Subsoiling or chiseling to a depth of 50 to 75 cm to break hard compact sub-pan layer
• Ploughing to incorporate previous crop’s crop residues and organic manures
• Discing to break clods
• Land shaping to provide the required gradient for draining excess water during rainy season
• Field layout – Construct ridges & furrows and shape them. Depth of furrows should be 25 cm. The furrow bottom should be loosened to about 10 cm.
• Provide drainage channels, which are deeper than the furrows along the field borders as well as within the field at regular intervals. Drainage channels are particularly important in the high rainfall areas to drain the excess water during rainy season.

Planting Material

Sugarcane is vegetatively propagated for commercial cultivation. Different kinds of planting materials viz., cane setts; settlings and bud chips are used for raising sugarcane crop.

• Cane Setts  –  Stem cuttings or sections of the stalks are called “setts” or seed pieces. Each sett contains one or more buds. Always use fresh, genetically pure, pest and disease free setts as seed material. Generally, three bud setts are used for planting throughout the world, while in some areas two-bud setts are also used.
• Settlings  –  Cane setts with roots and shoots are known as settlings. Settlings can be raised either in nursery beds or in polythene bags. Single node settlings are used as a planting material in spaced transplanting technique of raising sugarcane crop.
• Bud Chips  –  Little portion of stem with one bud is known as bud chip. Bud chips are used to raise settlings in nursery. They were found to produce a good crop when transplanted in main field. The principal advantage of bud chips is substantial saving in seed material. Seed requirement is reduced to less than one ton per ha.

Planting Time

Sugarcane is grown under diverse agro-climatic conditions in the world.  In the Philippines, the best planting time is from October to May.

Germination Irrigation

To get uniform and higher germination (sprouting) percentage of planted setts is quite a technique in drip irrigated cane production. This operation demands full attention of the farmer.

The procedure to be adopted to get best results:

• Prepare the main field to fine tilth
• Lay the drip laterals (driplines) at 15 to 20 cm depth using SDI laying machine and test for their design performance. Under surface drip driplines are spread on the soil surface.
• Plant the treated two or three budded setts at 10-15 cm depth by planting machine adopting recommended planting pattern and spacing.
• After ensuring proper coverage of setts start the irrigation. Continue irrigation until a uniform wet band (not standing water) is formed along the dripline to a depth of not less than 30 to 40 cm.
• Depending upon the soil texture and soil tilth achieved during land preparation it would take about four to six hours.
• Examine the soil frequently at various places in the planting zone i.e, 10 to 15 cm of soil depth, for ascertaining the moisture status. As the days pass on soil moisture content decreases.
• Depending upon the soil texture and the climatic conditions (i.e, evaporative demand of the atmosphere), in about 3 to 5 days the soil moisture content in the planting zone will deplete to a level not congenial for germination process of the cane. When this happens start the second round of irrigation in time so that the bud sprouting process is not interrupted. Continue the second irrigation operation similar to the first round i.e., until uniform wet moisture band is achieved. But this time the irrigation duration will be less may be 50% of the first irrigation cycle (i.e., 2 to 3 hours) to achieve the same level of moisture status and wetting pattern in the soil. However, this needs to be confirmed before terminating the irrigation.
• Normally after 3 to 4 such irrigation cycles an experienced grower can obtain a very high germination percentage and uniformity of growth by adopting the above-described method.
• Poor soil conditions and improper land preparation affect but sprouting, germination and crop emergence.

Weed Management

In sugarcane weeds have been estimated to cause 12 to 72 % reduction in cane yield depending upon the severity of infestation.

The nature of weed problem in sugarcane cultivation is quite different from other field crops because of the following reasons:

• Sugarcane is planted with a relatively wider row spacing
• The sugarcane growth is very slow in the initial stages. It takes about 30 – 45 days to complete germination and another 60-75 days for developing full canopy cover
• The crop is grown under abundant water and nutrient supply conditions
• In ratoon crop very little preparatory tillage is taken up hence weeds that have established in the plant crop tend to flourish well

Major weed flora observed in sugarcane fields are: Sedges- Cyprus rotundus; Grasses-Cynodon dactylon, Sorghum helepense, Panicum spp, Dactylocternium aegyptium, Broad leaved weeds – Chenapodium album, Convolvulus arvensis L., Amaranthus viridis L., Portulaca oleraceae L., Commelina bengalensis L., Trianthema portulacastrum L.

Weeds flora in sugarcane field besides competing for moisture and light also remove about 4 times N and P and 2.5 times of K as compared to crop during the first 50-days period. Weeds also harbour certain diseases and pests that attack sugarcane and thus lead to indirect losses.

Doob grass (Cynodon dactylon), the cogan grass (Imperata cylindrica) are known to play as alternate hosts to ratoon stunting disease of sugarcane. Thus weeds essentially harm young sugarcane sprouts by depriving them of moisture, nutrients and sunlight. Poor growth of cane resulting from weed infestation also affects quality.

Weeds that are present in the furrows i.e., along the cane rows cause more harm than those present in the inter-row spaces during early crop growth sub-periods. Thus the initial 90-120 days period of crop growth is considered as most critical period of weed competition. Therefore the weed management practice adopted should ensure a weed-free field condition for the first 3-4 months period.

Recommended Herbicides

A chemical program for weed control can help Louisiana growers produce maximum yields of sugarcane when combined with sound agronomic practices such as timely cultivation, selection of adapted varieties, proper fertilization, and disease and insect control. Herbicides are expensive, and, unless applied properly and at the correct time, they will not provide maximum control of weeds.

Spray equipment should be in good condition, properly calibrated (several times during a season) and should have vigorous agitation capability (especially important for wettable powders). Herbicides also should be accurately measured or weighed.

Herbicides to control weeds are essential to prevent weed competition and losses in sugarcane production. Sugarcane is most susceptible to weed competition during the first eight to 10 weeks after cane emergence. Unless herbicides are applied immediately after planting, weed seed present in the soil following a fallow program will germinate, producing viable seeds and/or rhizomes.

As a result weeds can quickly re-infest a field, with the benefits of weed control in the fallow period rapidly lost.

Selection of pre-emergence herbicides should be based on soil texture and organic matter content, weed problem and the variety of sugarcane. For best results, apply pre-emergence herbicides im mediately after planting

Fertigation

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 labor & 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

Detrashing

Detrashing refers to removal of unwanted bottom dry and green leaves at regular intervals. Sugarcane stalk bears large number of leaves (30-35) equal to the number of inter-nodes under good management systems.

However, all these leaves are not productive, only top eight to ten leaves are required for optimum photosynthesis. In fact the bottom green leaves are parasitic on the upper productive leaves and drain out the food reserves (photosynthates) which other wise could be used for stalk growth. Therefore, in sugarcane it is important to remove the lower dry and green leaves.

Detrashing should be taken up after the cane formation around 150 days after planting. There after it could be done at bi-monthly interval depending up on the labor availability.

Detrashing helps in:

• Maintaining clean field
• Enhances air movement and enriches Co² with in the crop canopy providing an ideal micro-climate for unrestricted growth of cane
• More food material is made available for stalk growth
• Reduces the problem of infestation of several insect-pests like scales, mealy bug, white flies etc
• Reduces bud sprouting due to accumulation of water inside the sheath in some varieties.
• Bud sprouting is not desirable as it would reduce main stalk growth and affect sugar accumulation
• Facilitates easy entry and movement in the field, particularly to inspect the condition of the crop and drip laterals and thus accordingly plan the fertigation and plant protection schedules
• A clean field minimizes rodents, rats, squirrels in the field which may otherwise cause damage to the crop
• Facilitates easy and economy in harvesting besides clean canes for crushing
• Detrashed trash can be used as a mulch for moisture conservation
• Clean leaves can be used for composting

Propping

The operation of tying the leaves together using the bottom dry and green leaves is known as propping. It is primarily done to check lodging of cane. Usually the trash without removing from the cane is twisted to form a sort of rope and cane stalks are tied together. This is known as trash-twist propping. Propping can be either done for each row or two rows can be brought together and tied.

In India bamboo poles are used and propping is done in certain pockets, but it is too expensive. In areas where cane top growth is heavy and wind velocities are high, propping is very much necessary to prevent lodging. This is because lodging leads to several problems:

• Cane breakage and thus loss of stalk number at harvest and thus loss of cane yield
• Infestation of certain pests and diseases causing microbes through lodged and damaged canes
• Damage by rats and rodents
• Bud sprouting leading to reduced cane quality
• Aerial root formation which also affects cane quality
• Difficulty in inspection of driplines and harvesting

Removal of Water Shoots

Water shoots are the late-formed tillers or side shoots, which are robust and fast growing. They originate mainly due to plentiful supply of water, inadequate earthing-up and late fertigation. These water shoots, as the name indicates, contain lot of water and less sucrose and more of reducing sugars.

Water shoots affects the growth of adjacent stalks. They harbor insect-pests and when they are harvested and sent to mill for crushing, lead to reduced juice quality and affect sugar recoveries. Therefore it is advisable to remove water shoots as and when they arise. The water shoots can be used as cattle feed.

Harvesting Management

Harvesting of sugarcane at a proper time i.e., peak maturity, by adopting right technique is necessary to realize maximum weight of the millable canes (thus sugar) produced with least possible field losses under the given growing environment.

On the other hand harvesting either under-aged or over-aged cane with improper method of harvesting leads to loss in cane yield, sugar recovery, poor juice quality and problems in milling due to extraneous matter.

Therefore, proper harvesting should ensure:

• To harvest the cane at peak maturity (i.e., avoiding cutting of either over-matured or under-matured cane)
• Cutting cane to ground level so that the bottom sugar rich internodes are harvested which add to yield and sugar
• De-topping at appropriate height so that the top immature internodes are eliminated
• Proper cleaning of the cane i.e., removing the extraneous matter such as leaves, trash, roots etc.
• Quick disposal of the harvested cane to factory

1. Manual Harvesting

In many countries even today harvesting is done manually using various types of hand knives or hand axes. Among the several tools the cutting blade is usually heavier and facilitates easier and efficient cutting of cane.

Manual harvesting requires skilled laborer as improper harvest of cane leads to loss of cane & sugar yield, poor juice quality and problems in milling due to extraneous matter. (In the picture: Manual harvesting of sugarcane)

2. Mechanical Harvesting

Harvesting labor is becoming scarce and costly in view of diversion of labor to other remunerative work in industry, construction, business etc. Mill stoppages because of non-availability of canes are not uncommon owing to shortage of harvesting labor. And, most of the new mills are of higher crushing capacity and many are expanding their crushing capacities. Therefore daily requirement of cane is increasing and hence greater demand for harvesting labor.

Added to this most of the present day agricultural laborer are not interested in field operations involving much drudgery. Thus in years to come, the labor position is likely to deteriorate further. Therefore mechanization is inevitable and hence, adoption of mechanical harvesting of cane in future is inevitable.

In countries like Australia, Brazil, USA, South Africa, Taiwan, Thailand etc., where sugarcane cultivation is highly mechanized huge harvesters are employed for cane harvesting. In these countries, sugarcane is grown on large plantation scale in large farms owned by either mills or big farmers. The field capacity of mechanical cane harvesters varies with the size (2.5 to 4 ha per day of 8 hours.

The limitation of mechanical harvesters is use of such machines in small, irregular and fragmented holdings, diversified cropping patterns, limited resource capacity of small & marginal farmers in several countries.

Sources: Encyclopedia.com, netafim.com, sugarcanecrops.com; Photo: Wikipedia.org