Causes of Low Sugarcane Yields in Sindh

Dr. Ali Muhammad Khushk & Salahuddin Junejo

In Pakistan sugarcane is grown over about 10314 thousand hectares, its average yield about 53.12 tons per hectare and production 12529 thousand hectares with 8.70% recovery, is much lower that the world average of 60 tons/ha, where as the potential is between 150-250 tons per hectare. Pakistan ranks fourth in area and production among the leading sugarcane producing countries of the world. There are several reasons for low cane yield and recovery. But the main reason of low yields is cultivation of old varieties by the growers in the country. Besides sugar production, sugarcane produces various valuable products like alcohol, ethanol, bagasse, press mud, wax and tops and trash used as feed for animals. In Sindh, about 214 thousand hectares of sugarcane was cultivated and harvested 12529 thousand tons during the year 2006-07. The average yield was recorded 58 tons ha. The highest cane yield 58 tons/ha was produced by Sindh followed by Punjab (52) and NWFP (45) tons /ha. The recovery % was recorded i.e: 9.14, 8.54% and 8.53 from Sindh, NWFP and Punjab respectively.

The southern part of Sindh province is most suitable for sugarcane cultivation and may be called the Cuba of Sindh. It has got the potential of becoming the center of Pakistan Sugar Industry. The southern part is located in 24.5North, most suitable for sugarcane cultivation owing to its longer growing season, frost free area, mild winter and higher atmospheric humidity. The favourable coastal climate and well drained alluvial soils are natural gift for high cane and sugar yields. The area of this region (lower Sindh) has a high yield is low around 50-65 t.ha.

Despite an increase in area under cultivation, timely rain, judicious use of fertilizers, improved cultural practices and better management, sugar crisis is still looming large in the country. The average cane yield at the rate of 53 ton per hectare is far below the existing potential of the country’s crop. From our in-depth discussion with sugarcane growers and key information, the following causes of low sugarcane production are identified as below.

The causes of low yields are as under

1. Conventional production practices.
2. Lack of suitable high yielding varieties.
3. Imbalance use of fertilizer.
4. Water scarcity.
5. Poor irrigation system.
6. Water logging and salinity.
7. Chocked drains.
8. Poor agronomic status of soil.
9. Poor management of ratoon crop.
10. Lack of plant protection.

To achieve the high yield of sugarcane up to 110 t/ha and 11.0 sugar recovery %, can be achieved. It has been reported that high yielding variety contributes about 20-25%, while good cultural practices contributes 75-80%. Thus could be possible with the development of high cane yield and sugar varieties, improved production technology and proper plant protection measures as under.

Land Preparation

Land preparation is an important operation in sugarcane cultivation. Sugarcane is a deep-rooted and exhaustive crop which will flourish well if planted on well prepared soil. Crop penetrating up to 90cm inside soil, tillage practices can help in development of better root system and optimal growth of the crop. Proper land preparation is very essential for good establishment and growth of the crop. It needs deep plowing up to 20-30 cm with the help of chisel plough, not any soil turning, use of sub soiler after every there years, 2-3 subsequent disc harrows and 2-3 cultivators are enough to achieve good pulverized seed bed. It is very important to level the land with the laser leveler in a precise way of even distribution of water for irrigation purpose. Open the furrows with the help of tractor drawn ridger at distance of 90 cms in the East – West direction.

Variety

Improved and high yielding of sugar varieties are one of the major sources through which cane and sugar yield per unit area cane be increased. Varieties should be cultivated according to the areas.

Seed Rate and Planting Season

Selection of quality seed is important for high yields. 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.

To prevent the seed setts being attacked by fungal diseases and also to improve germination, the seed setts are dipped into 0.5 percent solution of Agallol (3%) or 0.25 percent solution of Aretan (6%) or Tafasam (6%) before planting. Aretan along with gamma BHC is also recommended. Aretan improves germination and keeps off fungal attack while gamma BHC keeps away the termites and shoot borers.

To maximize 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 percent 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 top achieving optimum plant population for high production. Generally for medium to thin varieties high seed rate is used than tick 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 neighboring country. To get optimum plant population the following practices may be followed for seed selection and planting.

• The seed of plant crop of 6-8 months should be used for better germination.
• Healthy and disease free cane should be used.
• The seed from ratoon crop and commercial crop should not be used.
• Optimum seed rate should be 100-110 mds / acre for thick variety and 80-90 mds/ acre for thin variety or 20,000 three budded sets, 15,000 four budded and 12,000 five sets i.e. 60,000 budded / hectare should be planted. The sets should be placed on ¼ over lapping the furrows,
• For better germination 1/3 bottom neither portion of cane seed should not be used.

In Sindh sugarcane crop can be planted in spring and autumn season, but in lower Sindh, sugarcane plantation should be done during autumn season (Sep. – Nov.) to obtain high cane yield.

Planting Method

Sugarcane crop can be planted by the wet method or dry method. Wet planting method is mostly done in low to medium fertile soil. In this method the furrows are thoroughly irrigated and treated setts are placed 3.5 cm deep insuring that all the eye buds face upwards. In the highly fertile soil dry, method of planting can be adopted. The setts are placed in dry furrows at specified distance and covered with soil and then a field is irrigated.

Fertilizer

Sugarcane is a heavy feeder and will respond to adequate doses of fertilizer. Fertilizer requirements for various varieties and soil types differ from each other. According to soil types, climate and availability of water, the timings of application of fertilizer is also differ, the dose NPK fertilizer for lower Sindh is NPK (225-112-168kg/ha) recommended by ARI, Tandojam. 1/3 N and full dose of P and K should be applied as basal dose at planting time and remaining dose of the nitrogen will be applied into 2 splits at the time of 1^st earthing up (February – March) and 2^nd earthing (April – May) or before the month of June. Quality of sugarcane is very much affected by carelessness of balanced nutrition and in timely application to sugarcane crop which greatly impairs in productivity of sugarcane. In addition micronutrients i.e. Boron, Zink, and Manganese have assessed to increase the yield and improve the quality of sugarcane.

Organic Matter

Against the minimum required level of 1.0% soils of Sindh have organic matter contents of about 0.4% or even low. Due to low organic matter land productivity is depleting and can not expect for good yields. Therefore, the application of F.Y.M is essential, in the absence of manures the organic matter in soil can be increased by:

• Growing of green manuring crop i.e. Susbania, Leguminous crop and barseem etc.
• Application of press mud.
• Incorporating sugarcane trash in inter row spaces of cane.

Irrigation

The irrigation is the most important aspect of sugarcane next to fertilization. Sugarcane crop required 89-90 acre inches about 20-25 irrigations for whole season. Use of irrigation at proper intervals will ensure optimum production. Water requirements vary with the climate, type of soil and planting season. Framers should take care of irrigation in sugarcane particularly during the summer and should adjust irrigation requirements according to available water at far level.

Weeding

There is need of integrated practice 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. Weed control is necessary that there seed formation and sprayed, should be properly checked in time. The germination of cane takes about 45 days and weeds grow vigorously during the period, weeding operation is thus necessary for better development of the crop, besides manual eradicating weeds, many herbicides (per emergence and post emergence) are also available in the market should be applied. All broad and narrow leave weeds will get killed by these. Control of weeds resulting increasing the tiller.

interculturing

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 wee control. In sugarcane intercropping of onion. Potato etc. is done for getting high economic return at early stages pf cane crop. Inter-crop species should be restorative, not heavy feeder, with shallow root system and of short duration. Interculturing should be done twice during Feb-April with tractor drawn implements, plowing with bullocks, spade or using herbicides i.e. Gesapax or any other weeidicide available in market.

Earthing up

Two earthing ups should be done; first earthing up should be done in March-April and second earthing up should be done in May-June.

Control of Insect, Pest and Diseases

Effective plant protection measures are very essential in plant crop as well as in ratoon crop. The Top borer, Stem borer, Root borer, Gurdaspur borer, Mealy bug, Mice and Termites are the common insect of sugarcane in various areas, the smut is the common disease should be controlled by chemically are biologically measurers identified and decided by the experts working for their control at proper time. 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 form the field and should either be buried or burnt.

Harvesting

Harvesting should be done when the crop is fully ripened. 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. Of 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. 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.

Sugarcane is ready for harvest in about 12-14 months after planting. Early maturity variety and ratoon crop should be harvested first. Harvest should be done as possible close to the surface. The cane should immediately be delivered fresh to the mill otherwise weight and sucrose losses occurs. Indent should be arranged before load purpose.

Ratoon Management

In Sindh, about 20-25% area under sugarcane is remained as ratoon crop. Rationing offers many advantages in the economy of the growers. It saves the cost on procurement and preparation of seed, land preparation. The yields of ratoon crop in Sindh are very poor since, moist of the rations are neglected or subjected to miss management. The productivity of ratoon cane be enhance to the level of plant crop are even better. Proper cultural practices and efficient crop management is needed for better growth and obtained optimum yield as follow.

• Harvesting should be done as close to the ground as possible.
• Trash should be burnt immediately after harvesting or spread in inter row spaces to control the weeds.
• Plowing between the rows immediately.
• Fill in the gaps by planting sets directly or transplanting per germinated plants in polythene bags to maintain the plant population.
• Early fertilization of ratoon crop is essential to obtain high yield.
• Effective weed control through interculturing, mechanically and chemically is essential.

The crop harvested during February-March gives good ratoon crop.