Post on 24-Dec-2015
transcript
Outline
• General sugarcane information• Sugarcane production
– Planting– Harvest
• Weed management– Factors that influence management– Chemical – Mechanical – Cultural
FL Sugar• Approximately
400,000 acres of sugarcane
• Grown by FL Crystals, US Sugar, and Sugar Cane Growers Cooperative of FL
Sugarcane Biology
• Sugarcane is a giant perennial grass (Poaceae)
• Tribe: Adropogoneae• Commercial clones are typically
hybrids of Saccharum officinarum L. and a combination of S. barberi, S. robustum, S. sinese, and spontaneum
Growing Season
• Planted September to December • Grows for approximately one year
between harvests• Harvest season runs from October
through March• Cane that will be replanted
(successively) is harvested first
Sugarcane Growth
• Grows rapidly in the summer period of warm temperatures and high rainfall
• Matures, ripens, and is easily harvested during the cool, dry winters
• The lake provides a winter warming effect
Soils
• About 90% is grown About 90% is grown on muck soils on muck soils
• ~ 70 to 90% ~ 70 to 90% organic matter and organic matter and do not require N do not require N fertilizerfertilizer
• Remainder is grown Remainder is grown on sand soils (1-3% on sand soils (1-3% OM)OM)
Sugarcane Harvest
• Most sugarcane in FL is burned prior to harvest to remove leaf material
• Yields range from 20 to over 100 tons/acre
• Yields typically decrease with each ratoon crop
• The average is around 45 tons/acre
Green Cane Harvest
• As the population of S. FL grows, air quality becomes a larger issue
• Many sugarcane producing countries are phasing out burning
• The impact of GCH on the FL production system is unknown
• GCH results in a heavy residue layer (5-15 tons/acre)
Weed Management Overview
• Most growers utilize an integrated approach (primarily chemical and mechanical)
• Sugarcane is relatively competitive and somewhat forgiving
• South FL environment is ideal for many tropical and sub-tropical weed species
Factors that influence weed management
• Virtually a monoculture crop• Row spacing • Crop age • Minor use crop • High organic matter soils• Corporate mentality (sugarcane
prices) and tradition
Monoculture• Crop rotation is a valuable tool for
weed management• The majority sugarcane is replanted
every 3 years• Only a small percentage of the fields
are rotated to vegetables or left fallow
Row spacing
• Sugarcane is planted on 5 ft rows• Although a competitive crop, grows
slowly at temperatures below 70 F• Results in bare ground following
planting and harvest until ~March• Cultivars vary in their canopy
architecture
Crop Age
• Yields typically decrease each year• Influences the crop value and the
amount growers are willing to spend for weed control
• Additionally, some growers do not apply herbicides to plant cane
• Weed pressure typically increases
Minor use crop
• Although a major crop in south Florida, sugarcane is a minor use crop in the US and worldwide
• Consequently, there are a limited number of registered herbicides
• Little incentive for new product research in current ag chemical industry climate
Muck Soils
• High organic matter (70-90%) has considerable effect on duration of weed control with PRE herbicides
• Despite high use rates, control can last less than 4-6 weeks
• High rates increase likelihood of crop injury
• Results in a reluctance to use PRE herbicides
Corporate Mentality and Tradition
• Weed control decisions are often made by accountants
• Results in a fixed budget and plan for weed control
• Goal is often quantity of acres treated rather than quality
• Traditional reliance and overuse of on tillage
Application timing
Envoke + Asulox applied to 4-5 inch tall crabgrass and fall panicum
applied 13 days later applied 20 days later
Chemical Weed Control
• Both PRE and POST herbicides are used
• PRE treatments are typically POST to the crop
• Most herbicide applications are banded over the row
• Mainly older chemistries• Short residual with PRE herbicides
PRE herbicides
• Atrazine is the backbone of most weed control programs– Used both PRE and POST– Applied at 3-4 lbs per acre, and 1 to 2
times per season– Typically last 3-5 weeks
• Heavy reliance on triazine herbicides
POST Herbicides
• Asulam is used extensively for grass weed control
• Because of cost it is often applied late to insure only 1 application before canopy closure
• Trifloxysulfuron, halosulfuron for nutsedge control
• 2,4-D for broadleaf weed control
Mechanical Weed Control
• Varies depending on plant cane or ratoon cane
• Plant cane-scratchers are used over the top of the cane and tines are removed as the can gets larger
• Ratoon cane-disk cultivators are used for weed control in row middles
Cultural Weed Control
• Selection of cultivars that have quick canopy closure
• Seed cane from clean fields• Control of weeds on field borders and
ditch banks