PRESENTATION SIGNIFICANT IMPACTS OF CHANGES IN AGRONOMIC PRACTICES ON SUSTAINABLE PRODUCTION OF SUGARCANE ON THE NORTH COAST OF KWAZULU-NATAL CONTEXT

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1 PRESENTATION SIGNIFICANT IMPACTS OF CHANGES IN AGRONOMIC PRACTICES ON SUSTAINABLE PRODUCTION OF SUGARCANE ON THE NORTH COAST OF KWAZULU-NATAL CONTEXT A PRESENTATION TO THE SOUTH AFRICAN SUGAR INDUSTRY AGRONOMISTS ASSOCIATION AT THE ANNUAL GENERAL MEETING, KWA-SHUKELA, OCTOBER 2004 THEME AGRONOMIC PRACTICES FOR PROFITABLE SUGARCANE PRODUCTION Presented by John. P. Boyce ; M. Sc. Agric ( Natal ), M.B.L. ( UNISA ) P.O. Box 1246, Maidstone Village, MAIDSTONE 4380

2 SIGNIFICANT IMPACTS OF CHANGES IN AGRONOMIC PRACTICES ON SUSTAINABLE PRODUCTION OF SUGARCANE ON THE NORTH COAST OF KWAZULU-NATAL 2. INTRODUCTION The profitability of sugarcane production is dependent on many factors. This article is focused on those historical changes in agronomic practices which, from the author s perspective, had significant impacts on the sustainability of sugarcane production on the North Coast of Kwazulu-Natal. This perspective covers the period 1965 to 2004 and is mainly restricted to those impacts experienced by large Millercum-planter ( MCP ) operations. The preference for the concept of sustainable production, provides for the impacts of any changes in agronomic practices against the criterion of sustainability, rather than against the profitability of sugarcane production. This approach provides more direct relationships for the purposes of any evaluation, because many external factors, unrelated to agronomic priorities, are then excluded. The purpose of this article is to present an historic perspective of significant impacts of changes in agronomic practices over the past 39 years, and to identify and evaluate opportunities which could contribute towards sustainable sugarcane production. The significant changes in agronomic practices chosen for this article involve land preparation and stool eradication, weed control, age at harvest and control of Eldana borer and environmental management practices. 3. DEFINITION OF SUSTAINABLE SUGARCANE PRODUCTION Peter Prince in 2003 stated that If sustainability of sugarcane production is our desired goal, then Sustainable Development ( SD ) provides the strategies required to reach that destination ( 11.3 ). SD is defined as development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. This conceptual measure of business legitimacy for sugarcane production is based on economic, environmental, social and community interests. The criteria for SD of sugarcane production therefore, involve changes in agronomic practices which contribute towards the destination of sustainability. There is a need for development of modern agronomic practices to comply with new standards or criteria for sustainable development ( i.e. SD ) of sugarcane production. The significant changes in agronomic practices selected for this article will be evaluated against this fundamental benchmark or criterion. 4. LAND PREPARATION & STOOL ERADICATION 4.1 Significant change Manual and mechanised methods of soil preparation ( now referred to as maximum tillage ), were used prior to the 1970 s to create suitable soil tilth for germination of the new crop and to destroy the old crop. This process was accepted at that time, although the method often involved exposure of bare land to potentially severe and irreversible losses of soil. In the early 1970 s the chemical called Roundup ( Glyphosate ) was registered for cane stool eradication and the first applications to cane proved highly effective. Expansion of the areas treated involved providing extra application resources, including tractors, water tankers and knapsacks. This

3 change enabled the new practice, called minimum tillage, to replace the maximum tillage method during the period October to February each season. 4.2 Significant impacts The article by Allan Stead in The Link in 2002 entitled Minimum Tillage ; Best for Land Preparation provides an ideal evaluation of major changes in this agronomic practice ( 11.8 ). Chipping ( hand preparation ) & Ploughing & harrowing costs were R1360 and R1314 per hectare respectively, compared with R392 for the cost of minimum tillage. Stead concluded that there must be very few instances that warrant the use of maximum tillage. 4.3 Evaluation Against the criterion of SD, Stead stated that there is no doubt that chemical eradication of the old crop at replant stage is cheaper by far, it reduces potential soil loss by between 9 and 24 times the loss for minimum tillage, and it reduces negative impacts of soil erosion on siltation of rivers, dams and estuaries ( 11.7 ). However, effective chemical stool eradication with Roundup is often restricted by adverse growing conditions, affecting both the rate of ratooning of the old crop for efficient application of Roundup and the effectiveness of the kill of the old crop. Slow ratooning of the old crop, usually due to dry conditions, will delay the replanting programme. Consequential premature application of Roundup to the old crop will jeopardise the percentage kill and promote regrowth of volunteers. On some large Estates, the annual replanting programmes are subject to limited labour and machine resources, which are allocated across the main planting season from August to the end of January. There is a tendency to apply Roundup as early as mid-august and this premature action often leads to excessive volunteer growth, which may result in transfer of Ratoon Stunting Disease ( RSD ) to the new crop. Testing old crops for RSD and delaying planting operations when RSD is present, can prevent transfer to the new crop. Another tendency is premature furrowing between the old cane rows and planting the new crop almost immediately after application of Roundup to the old crop. These adverse circumstances can be aggravated by poor soil tilth in heavy soil types, when good germination cannot be easily achieved under dry conditions. These sub-optimal situations for minimum tillage could be addressed more closely by Agronomists. Although natural restrictions cannot be eliminated, new compensating agronomic strategies could well be developed in due course. For example, irrigation or water planting applications, different rates of Roundup chemical, methods of application of Roundup to old ratoons and mechanical stool pruning operations, could well be changed to facilitate timely completion of planting programmes whilst meeting quality standards. 5. WEED CONTROL 5.1 Significant changes Manual and mechanical methods of weed control were dominant in the 1970 s, when available herbicides were limited mainly to MCPA, 2,4-D amine & ester, Diuron, Gesapax and Paraquat. The absence of effective pre-emergence herbicides to control grasses ( Panicum & Sorghum ) and watergrasses ( Cyperus esculentis/yellow & Cyperus rotundus/purple ) resulted in loss of control and serious competition. These setbacks were aggravated when excessive hand-weeding caused shortages of resources. The incidence of damage to young crops due to excessive application of chemicals was also prevalent e.g eruption of nodes and stunting. In addition, the expansion of cane burning increased the workload of weed control due to the loss of the traditional trash layer. The advent of Lasso ( Alachlor ) in the early 1970 s provided pre-emergence control of both grasses and yellow watergrass. Subsequent introductions of Velpar ( Hexazinone ), Sencor ( Metribuzin ), Falcon ( Metolachlor ) and Har-i-cane ( Acetochlor ) all added strength and variety to the choice of available herbicides for weed control. Post-emergence herbicide treatments were improved significantly when MSMA ( Monosodium Methanearsenate ) was available to control Rottboellia grass and when Servian ( Halosulfuron ) gave control of purple watergrass ( 11.6 ).

4 5.2 Significant impacts These changes produced better weed control and major reductions of resources per hectare cultivated ( replant and ratoon areas ). For example, budget standards for labour used on hand-weeding in the 1970 s were as high as units per hectare, whereas by 2004 the same labour standards were as low as units per hectare. The increased usage of herbicides required extra resources, including tractors, tankers and knapsacks. Furthermore, these changes compensated for the extra weed control challenges introduced by increased cane burning and the loss of the traditional trash layer. 5.3 Evaluation Against the criterion of SD, and taking into account wage escalations and inflation, there is no doubt that these changes in agronomic practices for weed control contributed significantly, both in terms of prevention of yield losses from competition and production costs per hectare cultivated. Without these changes, sugarcane production would have been seriously reduced, together with profitabilty. Weed control is significantly improved when the crop competes directly with any weeds by way of canopy development. Any improvement of canopy development will contribute to weed control. It follows that normal weed control operations can be supplemented by integration with other agronomic practices. As examples, row spacings were reduced in the late 1970 s from 1.2 metres to metres to provide earlier canopy development, the control of nematodes with Temik ( Aldicarb ) on the weak coastal sands improved crop growth and the application of remedial topdressings of nitrogen and potassium fertilisers eliminated deficient yellow areas. This approach to weed control could be useful to Agronomists to enhance SD of sugarcane production. The advent of mechanisation of infield cane loading with Funky Bell loaders in the late 1970 s tended to increase cane burning and the loss of the trash layer for natural weed control, and soil and water conservation. The benefits of cane burning were reflected in improved productivity of cane cutters and the better payloads for infield transport, cane transhipment and cane haulage to the mill, where the benefits of reduced extraneous matter were also evident. However, the benefits of pre-trashing of stalks and green cane harvesting were demonstrated to Agronomists at a SASTA field day, as reported by Meyer in 2003 ( 11.5 ). This new approach will reinstate natural control of weeds by the trash layer and will reduce dependence on herbicides. It may also contribute to the effective control of Cynodon grass which is a growing hazard not adequately controlled with current weed control strategies. 6. AGE AT HARVEST AND CONTROL OF ELDANA BORER 6.1 Significant changes The evidence of Eldana Borer on the North Coast became significant in The predominance of the variety NCo 376, a high age at harvest for carry-over cane, soil moisture stress, excessive applied nitrogen and other complex factors were all causes of this situation. Various changes in agronomic practices were soon adopted to minimise the impacts of Eldana on cane yield and quality. The most effective strategy to control Eldana was to reduce the age at harvest. Whereas 65% of the area under cane harvested each season was the standard for setting the average age at harvest in the 1970 s, the percentage area harvested was soon increased to 80-90% of the area under cane. The variety N 12 tended to be used to replace NCo 376 because of its greater resistance to Eldana. 6.2 Significant impacts The damage to yield and quality of cane by Eldana was only partially offset by changes in agronomic practices adopted as control measures. The net outcome was that costs increased materially as a result of increased areas to be ratooned and revenue declined materially due to poor cane quality and in extreme cases, by reduced cane yields. Carl Bezuidenhoud recently estimated that in the absence of Eldana, optimal economic results would be achieved when less than 60% of the area under cane was harvested annually ( 11.5 ).

5 The sub-optimal performance of the variety N 12 when harvested too early was a major cause of losses in revenue and increased costs of production. The absence of a better variety than N 12 meant that Eldana had caught producers in a strategic trap until such time as better varieties could be substituted. 6.3 Evaluation Against the criterion of SD, it is clear that changes in agronomic practices to control eldana have moderated the adverse effects, but that the negative impacts of Eldana still outway the benefits of new agronomic practices. Eldana is still exerting significant adverse effects on the sustainability of sugarcane production on the North Coast of Kwazulu-Natal. A comprehensive research programme has been ongoing at SASRI to find solutions to this problem. The question is whether or not, and to what extent, Agronomists could contribute to this situation by changing current agronomic practices? The advent of registration of the insecticide Fastac ( Alpha-Cypermethrin ) for use against Eldana in carry-over crops has provided a new opportunity to integrate this treatment with existing control measures. The inclusion of Fastac applications will contribute to the reduction of Eldana damage recorded on harvesting carry-over cane at the start of each new season. Significant changes in current agronomic practices are being developed, which will enhance the impact of Fastac. A Grower, Rusty Tedder, who farms in the Felixton Mill area, has demonstrated a Clean Green Cane programme which has significantly improved his cane yield and quality. According to Meyer ( 11.5 ), he has introduced manual pre-trashing with cane knives before harvest, combined with Green Cane harvesting and the usual treatments to control Eldana. An Umhlali Grower, Mike Jeffrey, has developed an effective trash rake which is used by cane cutters to improve their trashing and still achieve 3.5 tons/man/day cut and stacked in good cane ( 11.9 ). Finally, cane burning could be reduced materially if a suitable self-trashing variety could be developed. The strategic imperative to develop self-trashing varieties has not yet been accepted by Agronomists. In addition, there has been no deliberate effort to simultaneously increase the average age at harvest, together with the application of Fastac to carry-over crops and all other treatments to control Eldana. The simultaneous integration of all treatments could well provide significant impacts on Eldana control, cane yield and cane quality. The impact of integrated agronomic practices to control Eldana could be significant, and there would be other benefits for stakeholders in respect of economic, social, environmental and community interests (11.5 ). For example, cane burning would be minimised without detriment to the productivity of cane cutting, infield transport, cane transhipment, cane haulage to the mill and to milling of this cane. Desktop economic evaluations have been conducted to measure the potential of these changes in agronomic practices. Although the results will eventually be tested in practice, there is strong evidence that both Growers and Millers could gain significant benefits. 7. ENVIRONMENTAL MANAGEMENT 7.1 Significant changes The traditional agronomic practices for sugarcane production in the 1970 s involved soil conservation layouts, cane extraction networks and crop management on the basis of economic priorities. The purpose was to ensure that the rate of soil loss did not exceed the rate of soil formation, whilst farming within sustainable economic limits. Land use planning standards were set to balance the needs of cane production and protection of natural resources. The advent of minimum tillage significantly reduced exposure of soil to severe erosion in plant cane fields, and expansion of the area treated with Roundup has decreased soil erosion to a minimum. However, the corresponding increase in cane burning at harvest for ratoon fields tended to increase the risk of soil erosion. Horizontal farm layouts aimed at the introduction of strip-cropping have contributed to reduction of soil erosion. Progressive withdrawal of cane production from wetland areas adjacent to water courses and rivers, combined with planting of trees, has also reduced soil erosion and consequent siltation of rivers, dams and estuaries. Significant progress has also been evident in respect of other aspects of environmental management. As examples, the regulation of cane burning adjacent to residential, industrial and tourist venues, to avoid cane smut deposits and smoke hazards, and the control of invader plants, biodiversity and cane spillage, have all received attention throughout the sugar industry.

6 7.2 Significant impacts Sugarcane is a perennial crop which normally remains in situ for 6-15 years. Restriction of exposure to soil erosion to the short periods of incomplete canopy between crops, implies that this crop is much less susceptible than most other crops, especially when cane is trashed at harvest and the trash layer protects ratoon crops. Plant cane fields subjected to maximum tillage and heavy rainfall may lose large amounts of topsoil, but this hazard has been reduced materially as a result of the expansion of minimum tillage. These changes in agronomic practices have almost eliminated the soil erosion hazard in plant cane fields at the replant stage. 7.3 Evaluation Against the criterion of SD, significant progress has been made towards the sustainability of natural resources used for sugarcane production and towards minimising the impacts on other stakeholders. However, the excessive damage and losses of soil experienced in the momentous 1987 floods could well occur again, in the face of up to 90% of the annual current area harvested being subject to cane burning at harvest. At that time it was acknowledged that if old-fashioned trashing of cane at harvest had been the custom in 1987, very much less damage would have occurred. The integration of Green Cane harvesting with all measures to control Eldana Borer, could provide the stimulus for the reinstatement of the trash layer to ratoon crops as a significant contribution to environmental management of sugarcane production. The Manual of Standards and Guidelines for Conservation and Environmental Management in the South African Sugar Industry was distributed in July 2002 ( 11.7 ). This event represented a major milestone towards a new era and a paradigm shift in Environmental Management. The manual addresses the implications of new legislation and provides reasonable standards for the management of natural resources. However, implementation towards legal compliance requires the introduction of audited impacts of current farming operations and a system of certification to bring all sugarcane production up to the required standards. Agronomists would be wise to adopt this approach. Unfortunately, there is currently no formal Canefield Management Certification system available in South Africa to facilitate the certification process. The Forestry industry has a Forest Management Certification programme which is operated under the auspices of the international Forest Stewardship Council ( FSC ), an NGO based in Mexico ( 11.4 ). The FSC does not conduct audits for forest certification programmes, but rather accredits certification organisations to do so on its behalf ( e.g. SGS, which now has an office in South Africa ). However, there is a Management System Certification process applicable in South Africa called the ISO Environmental Management System. The SA Bureau of Standards ( SABS ) is a member of the ISO federation involved in standardisation to facilitate the international exchange of goods and services. The ISO standard does not establish absolute requirements and rather establishes commitment to comply with legislation, and with continual improvement towards legal compliance. There is current uncertainty as to which method of certification should be adopted in the sugar industry. Nevertheless, the required changes in agronomic practices to achieve legal compliance will surely be given serious attention by Agronomists. Certification will ensure implementation of the manual for the benefit of environmental management in the sugar industry. 8. INTEGRATION OF ALTERNATIVE AGRONOMIC PRACTICES Alexander ( 1985 ) stated that the economic sustainability of international sugar production was under severe threat ( 11.1 ). There was still time from 1985 for developing nations producing sugarcane to adapt agronomic practices for a future sugar crop, a domestic energy crop and a multiple-products commodity. In other words, the sugarcane plant is not only capable of producing sugar, but is also a better producer of renewable biomass than any other plant when managed to maximise solar energy conversion to biomass ( 11.1 ). The agronomic practices associated with high-yield biomass production will differ significantly from those currently used for sugar production. Agronomists would do well to consider the opportunities which are inevitably coming on stream. The costs of nonrenewable fossil fuels are expected to escalate exponentially with increasing demands in relation to the

7 rate of supplies and to residual supplies of fossil fuels, with the consequence that renewable sources of energy would be economically attractive by the year CONCLUSION This process of reviewing the impacts of significant changes in agronomic practices on the sustainability sugarcane production has served to highlight particular changes in practices and to identify certain opportunities for Agronomists. Some opportunities can be listed as follows :- 9.1 Improve the effectiveness of minimum tillage operations. 9.2 Re-instate the trash layer for better, safer and healthier weed control operations. 9.3 Increase age at harvest to improve Clean Green Cane production in the face of integrated control of Eldana. 9.4 Minimise cane burning and promote implementation of environmental management practices to meet certification standards. 9.5 Anticipate opportunities to change agronomic practices for multi-purpose high-energy biomass production of sugarcane. Since change is inevitable for survival and prosperity, there will be many new and significant changes in future agronomic practices for sustainable sugarcane production. According to Charles Darwin, it is not the strongest that survive, nor the most intelligent, but the most responsive to desirable change. 10. ACKNOWLEDGEMENTS The author wishes to thank SASRI and the Chairman of SASIAA, Michiel Smit for assistance with the preparation and presentation of this article. 11. REFERENCES 11.1 Alexander, A.G : The Energy Cane Alternative ; Sugar Series Volume 6. Published by Elsevier Science Publishing Company Inc., New York, USA Bezuidenhout, C. N., Singels, A., and Hellman, D : Whole farm harvesting strategy optimisation using the CANEGROW model : A case study for irrigated and rainfed sugarcane. Proc. S. Afr. Technol. Ass. 76: Prince, P.A : Sustainable Development Towards Sustainability. Unpublished Powerpoint presentation to Senior Management of Tongaat-Hulett Sugar Limited at an Environment Forum Forestry South Africa 2002 : Environmental Guidelines for Commercial Forestry Plantations in South Africa. Second edition Meyer, E : Green Cane Harvesting is the future. The Link, Volume 12, Number 3: South African Sugar Association Experiment Station : Herbicide Guide, July South African Sugar Association Experiment Station : Manual of Standards and Guidelines for Conservation & Environmental Management in the South African sugar industry. 1 st edition Stead, A : Minimum Tillage ; Best for Land Preparation. The Link, Volume 11, Number 1; Stranack, R : Trashing. The Link, Volume 13, Number 1; 9.

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