This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)(Learn how and when to remove this template message)
Ratooning is the agricultural practice of harvesting a monocot crop by cutting most of the above-ground portion but leaving the roots and the growing shoot apices intact so as to allow the plants to recover and produce a fresh crop in the next season. This practice is widely used in the cultivation of crops such as rice, sugarcane, banana, and pineapple. Ratoon crops cannot be perennially renewed, and may be harvested only for a few seasons, as a decline in yield tends to occur due to increased crowding, damage by pests and diseases, and a decline in soil fertility.
The word "ratoon" probably owes its origin either from the Latin words retonsus, meaning "to cut down" or retono, which means "to thunder back" or "resound". In Spanish, the close words retoño (retoñar) mean "sprout" ("to sprout").
Ratooning is an ancient method of propagation in sugarcane in which subterranean buds on the stubble (the part of cane left underground after harvesting) give rise to a new crop stand, which is usually referred to as the 'ratoon' or the 'stubble crop' as opposed to 'plant crop', which is raised from seeds or seedlings. Ratooning reduces the cost of cultivation by dispensing with additional seed material and some cultural practices such as land preparation and preparatory irrigation (palewa). It also results in early ripening of canes by at least a month or so, thus it adds to the effective crushing period. Sugarcane has a tremendous ratooning potential, and the oldest cultivated ratoon, being ratooned since 1757, in East China, in Fujian Province, stands to its testimony. The number of ratoons in sugarcane production cycles varies throughout the world, i.e., from one plant crop in Indonesia and some parts of China, one plant crop and a ratoon crop in India, Fiji and some parts of China, to six or more successive ratoons in Mauritius, Cuba, Venezuela, clayey soils of Zimbabwe, some parts of Puerto Rico, etc. The later is also referred to as multiple ratooning. A decline in cane yield in successive ratoon crops, the ratoon decline, on the order of 20%, had been reported from many sugarcane-growing areas in India; the decline is more (up to 40% ) in subtropical India. Causes for this decline are: poor ratoon management, inherited differences in potential (ratoon) productivity, increasing incidence of diseases (like smut, grassy shoot disease, and red rot) which result in stands with gaps (studies conducted in India have shown that a gap over 10% significantly affects productivity of a ratoon crop), relatively less efficient enzyme systems (particularly nitrate reductase activity, in vivo and prevalence of low temperatures during harvest, especially for early-ripening varieties and ratoon crop(s) in subtropical India which affects sprouting of stubble buds, etc. Insect pests also assume importance in a ratoon crop as: stubble acts as a 'carry-over' of the inocula of pests both for coming up ratoon and for the neighbouring sugarcane crop(s), improperly looked-after crop gets infested by a number of insect pests, emerging sprouts of a ratoon crop favour rapid development and multiplication of some of the insect pests, and insect associated with stubble affect sprouting causing gaps which ultimately affect productivity of the ratoon crop, per se.
In Indian context, in subtropical India, ratoon initiated during spring (March) resulted in higher number of millable canes, cane yield and sucrose % juice in comparison to ratoon crops initiated either in winter (January) or summer (May). In peninsular India, however, as the sugarcane crop does not suffer extremes of weather conditions during summer and winters, differences in time of planting and harvest do not significantly influence the yield of succeeding ratoon crop[5,6 ].
Such a decline could be effectively prevented by proper ratoon management. Need for the latter stems from the famous Kalai (Aligarh, India) experiments conducted during 1939-1949. A good example of ratoon management and multiple ratooning is from Hoshalli village ( in district Shimoga, Karnataka, India) where good yields of sugarcane ratoon crop (125-134 t/ha) were harvested year after year since 1968 without much loss in cane yield and quality. The crux for such a success was trash mulching, application of lime and irrigation after harvest of the crop every year. Ratooning has now become so much important in sugarcane production system that ratooning ability has become one of the important selection criteria for release of sugarcane varieties for commercial cultivation.
Besides sugarcane, ratooning is also practiced commercially in many other crops like banana, pineapple, pigeon pea, sorghum, rice, cotton, ramie, mint, etc.. Rice is grown as a monocarpic annual plant. However, in tropical areas it can survice as a perennial, producing a ratoon crop, and may survive for up to 30 years. The earliest record for ratooning, in a crop plant, could be traced back to the Vedic period in India, wherein, in Atharvaveda, there is mention that the farmers cultivating barley (yava) used to cut barley plants many a times ( 20/125/2, Richa or Shloka No. 5755).
Ratooning is most often used with crops which are known to give a steady yield for three years under most conditions. For example, the woody desert shrub guayule, an alternative source of natural rubber, is first harvested at two years, then ratooned annually in spring with a final crop that includes both tops and roots.
Assessment of ratooning ability
Yield of ratoon crop is a function of yield potential and its ratooning ability. The latter, by and large, envisages the extent of multiple ratooning and their relative yield performance as compared to corresponding plant crop In India sugarcane varieties cultivated prior to introduction of Co varieties were not rationed because of their susceptibility to insect-pests and diseases. Incorporation of S. spontaneum genome into modern sugarcane varieties has contributed to ratooning ability[15,16]. The latter has been assessed by dry matter production of above ground parts at periodic harvests (at 4 months intervals), the ratio of performance ( of NMC and/ or cane weight) of ratoon crop vs. plant crop. Characters like higher plant cane yield, stalk population and sprouting of stubble buds are useful in selecting good ratooners. Ratoon x environment interaction were high in varieties with poor ratooning ability and inherited differences in potential productivity appear to be responsible for ratoon decline. In Jamaica to calculate decline in ratoon productivity a Ratoon Performance Index (RPI) is used.
In India, the second major sugarcane growing country, among the sugarcane varieties released and notified from 2000 to 2015 for commercial cultivation Co 85004, Co 2001-13, Co 2001-15 Co 0218, Co 0403, Co 86249, Co 0237, CoPk 05191 are good ratooners and CoPant 90223, CoS 95255, CoS 94270, CoSe 92423 have been rated to be the excellent ratooners.
Growth and development of ratoon crop vis-à-vis plant crop
Buds on the lower half of the stubble give rise to most of the shoots in a ratoon. Initially, emerging shoots, for their development, depend on the nutrients stored in the stubble and for water supply on the roots attached to the stubble. Using S we have seen that these roots remain active up to 106 days after harvest though relatively less efficient in nutrient uptake, possibly due to suberization and ageing. The new root system (shoot roots from the developing shoots) develop in 6–8 weeks after harvest subject to soil and weather conditions. Ghosh et al. observed on per unit root weight basis, development of shoot was relatively more in the settlings raised from stubble buds as compared to the one from top cane buds.
Experiment at Kalai (Aligarh, in sub-tropical India) indicated that the maximum number of tillers were attained by July and maximum number of canes (NMC) increased gradually in the subsequent ratoons and it was also associated with increased tiller mortality. In response to manuring, NMC gradually increased in succeeding ratoons. The average cane weight (ACW) is relatively lesser in ratoon crops and it gradually decreased in subsequent ratoons. Manuring also increased ACW by 62-75%. Interaction to space is relatively more pronounced in a ratoon crop as compared to its corresponding plant crop and perhaps due to this ratoon crops can tolerate a gap of 10% without any appreciable reduction in cane yield. Since optimal temperatures for tillering is 33.3-34.4 [o]C, winter-harvest of crop adversely affects tillering in an upcoming ratoon. If ratoon is initiated in April, tillering is profuse but mortality is high with poor growth of shoots. With successive ratooning, arrowing (flowering) increases.
Why a ratoon crop ripens earlier than its corresponding plant crop
A ratoon crop ripens earlier, in general, by at least one to one and a half months or so due to: early development of shoots, maintenance of relatively lesser N content in index tissues and rapid run-out of N during grand growth phase and relatively higher inorganic non-sugars in its juice.
Poor ratoon crops due to low temperature harvest
In subtropical India, in crops which are harvested from November to mid-January, due to prevalence of low temperatures result in poor sprouting of stubble buds and the succeeding ratoon crop is invariably poor. Buds located on the stubble remain dormant and sprout only when favourable temperatures are available in February. This could be managed by either foliar application of growth regulators before harvest of plant crop or giving some treatments to the stubble of the freshly harvested crop. In the former, among various treatments used application of Ethrel + urea was more effective. Among the later, treatments like (a) stubble protection by spreading polyethylene cover, loosening soil around stubble and trash mulching and irrigation and irrigation at 10–15 days interval[35 ], (b) maintaining optimal clump population by gap filling using dug-out stubble, pre-germinated settlings, sprouts from clumps in the growing ratoon crop[5,6], (c) improving cultural conditions by intercropping with suitable varieties of guar, cow pea, moong and potato[5,6] and (d) application of growth regulating substances to the stubble of freshly harvested cane like Cycocel[36,37] help to sustain ratoon productivity under such conditions.
Need for ratoon management
Need for ratoon management stems from its being an integral component of sugarcane production system, contributing to over half the cane acreage (it may increase when multiple ratooning is practiced); and as compared to corresponding plant crop, a ratoon crop has superficial roots, early shoot growth has to depend upon relatively less efficient root system (roots on the stubble), relatively less efficient enzyme system (especially the NRA), is infested/ infected more by insect-pests and diseases, ripens early and suffers ratoon decline.
The ICAR-Indian Institute of Sugarcane Research, Lucknow has identified certain technologies for ratoon management like dismantling of ridges, stubble shaving and off-barring at initiation of ratoon; gap filling when there is more than 45 cm distance (gap) between clumps; paired-row system of planting (120p x30) to reduce gaps and optimize plant population; trash mulching in alternate rows so as to conserve soil moisture, manage weeds and maintain soil organic carbon, etc. They have also designed and developed a tractor operated two-row Ratoon Management Device (RMD) to perform field operations for ratoon cultivation such as stubble shaving, deep tilling, off-barring, application of manure, fertilizers, bio-agents, etc., and finally earthing-up in a single pass to manage ratoon crop (0.35-0.4 ha/h) so as to improve its productivity. It also saves 60% on the cost of cultivation.
Studies on ratooning ability, overcoming ratoon decline, and early ripening of ratoons will be desirable in times to come.
The main benefits of ratooning are that the crop matures earlier ( by one and half month or so) in the season and also decrease the cost of field preparation, preparatory irrigation as well as seed cane used for planting. By early maturing may increase the effective crushing duration of sugar mill adding to sugar production. At some places ratooning sugarcane (for short duration ratoon crops) has also been utilized to provide quality fodder for cattle.
Multiple ratooning of sugarcane, with proper management including plant protection, may be utilized for maintaining purity of new improved varieties as well as genetically modified (GM) plants, for a longer period of time.
Being endowed with high rates of CO2 fixation, enormous capacity for storage of soluble compounds, metabolic transformation systems and containment of its genes, ensured by its vegetative propagation make sugarcane a desirable plant for its use as a bio-industry for synthesis of value–added products (molecular farming). Using biotechnological tools, the latter has been accomplished for the synthesis of p-hydroxy benzoic acid[39,40], sorbitol, isomaltulose; and in this endeavour, vast ratooning potential could be more helpful in containing desirable genes in such GM plants for sufficiently longer rather more faithfully.
1. Winburne J N 1962. A Dictionary of Agricultural and Allied Terminology, Michigan State University Press, East Lansing, Michigan (USA).
2. Sang T 1980. The world's cultivated ratoon. International Sugar 82:146.
3. Smith D 1978 Cane Sugar World, Palmer Publications, New York, Pp 240.
4. Rai R K, A K Shrivastava, A K Ghosh & S P Shukla 1989 Indian J. Plant Physiology 32(4): 320-324.
5. Shrivastava A K, Ghosh A K & V P Agnihotri 1982 Sugar Cane Ratoons, Oxford & IBH Publishing Co. Pvt. Ltd, New Delhi, Pp 182.
6. Shrivastava A K, Prasad S R & B L Srivastava 2000. Chapter 10, Sugarcane ratoons and their management, in 50 Years of Sugarcane Research in India, (eds. Shahi, H N, A K Shrivastava & O K Sinha), ICAR- Indian Institute of Sugarcane Research, Lucknow, India, pp. 175–196.
7. Anonymous 1952. Final Report, Sugarcane Ratooning Scheme at Kalai (Aligarh, Uttar Pradesh), India (January 1939 to March 1949), Pp. 76.
8. Anonymous 1992. Sugar Crops Newsletter 2(2):16.
9. Plucknett et al. 1970. Advances in Agronomy 22:285-330.
10. International Rice Research Institute, Manila, Philippines The Rice Plant and How it Grows, Retrieved may 4, 2014.
11. Pt. Shri Ram Dharma Acharya 2002 Atharvaveda Samhita, Part 2, Published by Bramhvarchas, Shantikunj, Haridwar, U.P. (now in Uttara Khand), India, Pp. 399.
11. "Britannica: Ratooning". Britannica Online Encyclopedia. Retrieved 2009-01-19.
13. "Evaluating New Guayule Varieties for Low-Allergenic Rubber Production, George et al. (2005) p.viii. Retrieved 2017-09-05.
14. Anonymous 1983 70 Years of Sugarcane Research (1912-1981), U.P. Council of Sugarcane Research, Shahjahanpur, India, Pp. 59.
15.Ethiarajan A S 1981 Proc. National Seminar on Ratoon Management, IISR, Lucknow in collaboration with STAI and ASTI, March 14–15, Vol. I: 75-81.
16. Ethiarajan A S 1982 Research & Development Workers Meeting, Sugarcane Breeding Institute, Coimbatore, Trichy, India.
17. Kapur R, S R Bhat & B K Tripathi 1985 Indian Sugar 35(8):1-4.
18. Sundara B 1996 Proc Annl. Conv. S T A I 58: Ag. 3-Ag.12.
19. Tripathi B K, S S Gill, G P Misra & S Lal 1982 Indian Sugar 32: 577-580.
20. Potty N.N., S Kurien & K C Chandy 1987 Proc. Annl. Conv. STAI 50: Ag. 33-Ag. 39.
21. Shaw M E A 1989 Sugar Y Azucar 84(7): 19, 22-23, 26.
22. Sinha O K, Rajesh Kumar, S K Chaudhary & A. Zubair 2016 Forty five Years of AICRP on Sugarcane, All Indian Co-ordinated Research Project on Sugarcane, ICAR- Indian Institute of Sugarcane Research, Lucknow, India, Pp. 77.
23. Shrivastava A K, R L Yadav, K Singh & N K Kacker 1981 Proc. National Seminar on Ratoon Management, IISR, Lucknow in collaboration with STAI and ASTI, March 14–15, Vol. I:82-91.
24. Ghosh A K, K Singa, A K Shrivastava & Y R Saxena 1988 Indian J. Plant Physiology 31(1): 11-15.
25.Tandon R K & G N Misra 1955 Proc. Bienn. Conf. Sugarcane Res. & Dev. Workers 2(2): 380-388.
26. Prasad S R, R K Sharma & M Alam 1981 Proc. National Seminar on Ratoon Management, IISR, Lucknow in collaboration with STAI and ASTI, March 14–15, Vol. I: 72-74.
27. Mathur R N & I M Haider 1940 Proc. International Soc. Sugar Cane Technol. 9 : 11-26.
14. Parthasarthy S V & E J Rao 1954 Proc. Annl. Conv. STAI 23 (Pt I): 29-34.
28. Parthasarathy S V & E J Rao 1954. Proc. Annl. Conv. STAI 50: Ag.29-Ag.34.
29. Panje R R 1965 How to Improve the Sugar Content of Cane Tech. Bull. No.1, Indian Institute of Sugarcane Research, Lucknow, India, Pp. 19.
30. Mohan Rao N V, G Rama Rao & E J Rao 1956 Proc. International Soc. Sugar Cane Technol. 9: 233-254.
31.Shrivastava A K, K Singh & Y R Saxena 1985 Production Physiology of Sugarcane Cultivar Co 1148, Tech. Bull. No. 15, IISR, Lucknow, India, Pp. 128.
32. Gupta A P & B Prasad 1971 Proc. Joint Conv. STAI, DSTAI & SISSTA, Poona, India 4:91-98.
33. Sharma H K, O Singh & R S Kanwar 1987 Proc. Annl. Conv. STAI 50: Ag.81-Ag.86.
34. Kanwar R S & H Kaur 1977 Proc. International Soc. Sugar Cane Technol. 16: 1325-1331.
35.Panwar B S, R S Verma & S N L Srivastava 1989 Coop. Sugar 20(6): 409-410.
36. Peng S Y and L T Twu 1970 Taiwan Sugar 25: 8-17.
37. Chauhan R S, R S Verma & K C Pathak 1984 Coop. Sugar 16(3):135-138.
38. http://iisr.nic.in/research/technologies.htm, 15.09.2017.
39. McQualter R B, B F Chong, K Meyer, D E Van Dyk, M G O'Shea, N J Walton, PV Viitanen & S M Brumbley 2005 Plant Biotechnology J. 3(1):29-41.
40. Brumbley, S M, M P Purnell, L A Petrasovits, L K Nielsen & P H Twine 2007 International Sugar J. 109(1297):5-6,8-10,12,14-15.
41. Wu L & R G Birch 2007 Plant Biotechnology J. 5:109-117.