Sugarcane Cultivation: A Comprehensive Guide
Origin and Significance
Sugarcane originated in New Guinea, north of Australia. Today, widespread cultivation spans 77,778 hectares, yielding 3,158,516 tons annually. This production ensures self-sufficiency and enables exports, primarily to the United States. Sugarcane serves various purposes, including energy production, fuel for mobility, and manufacturing paper and veneer.
Climate and Soil Requirements
Temperature
Ideal temperatures for sugarcane cultivation hover around 2°C. Higher temperatures, coupled with adequate nutrition, increase sucrose levels. However, sugarcane cannot withstand cold temperatures, which can lead to crop loss.
Soil
Sugarcane thrives in deep, fresh, organically rich soils with ample nitrogen, phosphorus, and calcium.
Soil Preparation
Thorough soil preparation is crucial for sugarcane, a perennial crop. This process begins with incorporating organic matter (vegetable or animal) and applying fertilizer based on prior soil analysis. Deep plowing, along with proper harrowing and clod breaking, is essential.
Planting
Furrows are opened 1.20 meters apart, 10 to 15 cm deep. Cane pieces with 10 to 12 knots or buds are placed in the furrows and covered. With sufficient moisture, new plants emerge within 15 to 20 days.
Cultural Care
After emergence, regular hilling and weeding are necessary. Hilling provides better anchorage, prevents waterlogging, and secures the plant while aerating the roots.
Pest and Disease Management
Major pests include the sugarcane borer (Diatrea sacharalis) and the minor borer (Helasmupalpus lignoselus). Control measures involve broad-spectrum insecticides and toxic traps placed in cut reeds. Rust diseases, which can cause significant losses, are managed through resistant varieties or regular fungicide applications (e.g., Tilt).
Harvesting
Harvesting should occur when the lower leaves begin to yellow and dry, avoiding both overly green and overly ripe cane to maximize sucrose levels. A saccharimeter can determine optimal ripeness, typically around 12 to 18 degrees Beaumé. Canes are cut at the base with machetes or machines, leaves are removed, and the heads are trimmed. Piles are formed for transport to the mill for grinding.
Yield and Products
Sugarcane yields range from 35 to 130 tons per hectare. Primary products include sucrose for white or brown sugar, molasses (used in rum production), and bagasse. Other uses include agricultural compost, vinasse, waxes, and absorbent fiber.
Environmental Impact
Land
Each ton of harvested sugarcane extracts significant soil nutrients (0.66 kg nitrogen, 4 kg phosphorus, 1.5 kg potassium), potentially depleting soil fertility. Poor irrigation management can also contribute to erosion. The use of fungicides, bactericides, insecticides, and other pesticides poses risks due to their low biodegradability, toxicity, persistence in the environment, potential for aquifer contamination, and disruption of biological control and pollination.
Specific Impacts
- Soil: Excessive fertilizer can alter soil pH and chemistry. Misapplication of ammonium ions creates phytotoxic “duret.” Excess sodium muriate can lead to chemical compaction.
- Air: Chemical spraying releases odors, and pre-harvest burning produces smoke and particulate matter.
- Water: Drainage from plantations connects with rivers, impacting water quality. Underground aquifers are also affected.
- Plantation: Chemical use can have agro-ecological impacts (e.g., eliminating beneficial insects) and environmental-ecological impacts (e.g., wildlife mortality).
- Biotic: The ecological environment remains largely unchanged.
- Socio-economic: Sugarcane cultivation generates employment, improves social welfare, and contributes to infrastructure development.
- Worker Health: Prolonged exposure to herbicides can cause stupor, drowsiness, nausea, vomiting, and seizures. Insecticides can be neurotoxic and carcinogenic.
Mitigation Measures
- Soil: Replenish nutrients through proper fertilization.
- Worker Health: Implement occupational risk prevention and safe pesticide handling practices.
- Plantation: Minimize herbicide use, maximize mechanization and machete use for weed control, and restore soil nutrients through fertilization.
- Water: Optimize water use through canals or other irrigation systems to prevent erosion. Minimize water consumption in processing plants. Construct retention pools for industrial wastewater to remove suspended solids.
- Air: Research alternatives to pre-harvest burning. Implement filters in agro-industries to control emissions.
- Solid Waste: Dispose of waste in designated landfills, not rivers. Bury containers and other waste in deep pits away from water sources.
- Pest and Disease Control: Prioritize biological control methods and consider microbial insecticides.
- Agrochemical Storage and Handling: Ensure proper labeling and calibrate spray pumps.
- Occupational Health: Provide first aid training, conduct regular medical examinations, rotate fumigation workers, and provide protective clothing.
Environmental Management Plan
The primary objective of environmental management is to prevent impacts on worker health and irreversible ecosystem changes caused by agrochemicals.
Other Impacts and Measures
Sugarcane planting contributes to export potential. The industry strives to minimize chemical use through biological pest control. Workers should be trained in first aid and undergo regular medical checkups. Protective gear is essential for those handling chemicals.