It is necessary to adapt the cultivation practices to maintain cane yield under wide row spacing on par with the conventional 90 cm row spacing. Based on the experiments conducted at Sugarcane Breeding Institute, Coimbatore agro techniques for wide row sugarcane have been standardized. High yield levels have been achieved by selection of varieties, manipulation of plant population and planting pattern and by judicious manuring. The studies conducted on fertilizer and irrigation requirements of sugarcane under wide rows and normal rows indicated that these do not change between the two situations as the yields obtained are comparable.
Varietal selection plays a pivotal role in the success of wide row spacing. Significant variety x spacing interactions and differences in the response of sugarcane varieties to row spacing have been reported. Among the varietal characters, high tillering capacity, synchrony in tillering, fan shaped growth pattern, non-lodging nature, higher cane number and higher single cane weight are important for wide rows. In an experiment at Coimbatore with three varieties, variety x spacing interaction was found significant for stalk population, cane yield, and CCS yield.
The variety Co 91010 recorded similar cane yield at 90 cm, 120 cm, and 150 cm (dual rows) row spacings, whereas in the other two varieties (Co 94005 and Co 94008) the cane yield was the highest at 90 cm row spacing and decreased with increase in row spacing. The sugarcane variety Co 86032 performs well over a range of row spacings including 150 cm wide rows.
A seed rate of 75,000 two budded setts/ha, which works out to 6.75 setts per meter length of the row, is being adopted for Sugarcane under the normal row spacing of 90 cm. It has been well established that tiller mortality is substantially lower and a higher percentage of shoots survive to become millable canes under wide rows. Increase in the average weight of cane at wide row spacing has also been observed in several experiments.
Hence, it may not be necessary to increase the seed rate to 11.25 setts per meter row to maintain the seed rate of 75,000 setts per hectare. In an experiment conducted at Sugarcane Breeding Institute cane yield in the sugarcane variety Co 86032 under wide row spacing (150 cm row spacing and 60,000 setts/ha) and normal row spacing (90 cm row spacing and 75,000 setts/ha was almost the same, 119.1 t/ha under wide row and 119.8 t/ha under normal row.
Among the different methods of sett placement, ‘dual row planting’ has been found to be superior. In this method, broad furrows are formed at a spacing of 150 cm, and in the middle of the furrows, sugarcane setts are planted in two rows adopting a spacing of 25 – 30 cm between them. In a comparative study of two different methods of wide row planting, the dual row system gave higher cane yield compared to the single row system and normal 90 cm row spacing.
Ridges and furrows
Ridges and furrows are formed in a finely prepared field using tractor or bullock drawn implements. The depth of the furrow should be around 25 cm, and for obtaining proper depth, tractor drawn implements are preferable. Convenient furrow length depending upon the slope of the land must be followed. The furrow bottom should be loosened to a depth of about 10 cm to facilitate placement and covering of the setts. This system is adopted under highly intensive irrigated Sugarcane cultivation. It facilitates easy irrigation and good soil aeration. At the time of earthing up, the ridges are converted into furrows, and the soil from the ridges is placed along the cane rows to provide solid support to the plant.
Trench planting is practiced in heavy clay soils, where clod formation is frequent. In this system, ‘U’ shaped furrows or trenches of about 25 – 30 cm depth are formed manually using a spade or by using machinery. Trench planting helps to conserve and provide adequate subsoil moisture which facilitates good germination and cane growth. This also prevents lodging. In areas where there is early drought and late waterlogging condition, deep trenches of 30 – 40 cm depth and 60 cm width have been found to perform better. In this system, as the cane grows, the trench is filled with soil in stages during manuring. In the initial stages, the germinating cane crop gets adequate soil moisture from the subsoil, and a good crop stand is established. During later stages, the trenches serve as drainage channels. The deep trench system has also been reported to ensure better ratoon performance.
Pit method of planting
In this system, circular pits of 90 cm diameter are dug out to a depth of about 45 cm with a gap of 60 cm between two adjacent pits, i.e., the distance from the centre of one pit to the next pit is 150 cm. At this spacing, about 4000 pits could be formed per hectare. The pits are refilled with top soil and FYM / compost mixture to a depth of 15 cm. About 20 setts are planted in each pit in a radial fashion and covered with soil to a depth of about 5 cm. This system requires a large amount of manual labour for making the pits and hence was not very popular.
In recent years, tractor drawn machinery for making pits has been developed by Indian Institute of Sugarcane Research (IISR), Lucknow, Tamil Nadu Agricultural University (TNAU), Coimbatore and other organizations. As the cost of pit making has been greatly reduced with tractor drawn machinery, the pit system is increasingly becoming popular. In the pit method of planting, tillering is often suppressed, and the growth of mother shoots is very vigorous. This results in thicker and taller canes and single cane weight is substantially increased. The number of millable canes is also usually higher in this system resulting in very high yields especially under the subtropical conditions.
Many authors have reported very high cane yields, as high as 184.4 t/ha with the pit system of planting, which was 100 % more than the yield obtained in the normal flatbed planting. The pit method is frequently adopted with drip irrigation. The pit system of planting has several other advantages like better ratoon performance and has also been found useful in saline soil, and saline water irrigated conditions. However, this is not suitable for machine harvesting.
Planting sugarcane in FIRB
About 3.0 lakh ha of sugarcane area in India is under wheat – Sugarcane – sugarcane ratoon – wheat system. A drastic reduction in sugarcane yield is a common feature when sugarcane is planted late (summer) after the harvest of the wheat crop. To improve sugarcane productivity in wheat – Sugarcane sequential system, the overlapping cropping under Furrow Irrigated Raised Bed (FIRB) system with wheat sowing on raised beds and Sugarcane planting in furrows has been developed at Indian Institute of Sugarcane Research, Lucknow.
In this system three rows of wheat are sown on each raised bed (48/50 cm top width) at optimum sowing time in November at 17 cm row spacing, keeping the seed rate of 75-80 kg/ha through a tractor drew Raised Bed Maker-cum-Fertilizer Seed Drill. Immediately after sowing of wheat, irrigation to the height of 3/4th of the furrow is given for proper germination of wheat. Subsequent irrigations are applied in the furrows. Germination, tillering and growth of wheat are better due to better soil tilth on the raised beds. Sugarcane is planted in furrows (32/30 cm top width and 22 cm depth) in the month of February (optimum time of Sugarcane planting in sub – tropical India) in the standing wheat crop. In this system, sugarcane planting is advanced to 50-60 days which otherwise is done in late April/May in wheat – Sugarcane sequential system.
Sugarcane planting coincides with irrigation at boot leaf stage in wheat. Irrigation is given in furrows preferably in the evening and sugarcane setts are planted next day and pressed into the soil manually when the soil is in muddy condition (wet planting). The technology has been evaluated in sandy loam soil successfully. In order to chisel the furrow, a wheel hoe has also been designed to loosen the soil before irrigation for better placement of setts. After wheat harvest, the furrows are used for irrigating sugarcane till earthing up operation. To make the technology operationally feasible and cost effective, IISR has developed a tractor drawn Raised Bed Maker-cum-Fertilizer Seed Drill. The equipment can be operated by any 35 HP tractor The first and foremost benefit of the FIRB technology is that sugarcane is planted at the optimum time i.e. in the month of February.
Otherwise, it is delayed by nearly 2 months to April end /May in wheat – Sugarcane sequential system and thus system produces 35 per cent higher cane yield without a reduction in wheat yield. The system increases water use efficiency by saving irrigation water as it is applied only in the furrows requiring less volume of water in wheat, which works out to be 20% water saving as compared to the flat method. The technology reduces production cost and increases the margin of profit especially for small and marginal farmers with limited resources.
- Sugarcane Breeding Institute