Comparison of harvesting systems

Method

Description

Advantages

Disadvantages

1. Manual reaping and threshing

• Cutting, stacking, bundling, handling and piling by hand
• Threshing by beating
• Cleaning by winnowing

• Efficient
• Most effective in lodged crop
• Winnowing/cleaning necessary
• Less weather dependent

• High labor cost· Skill dependent
• Susceptible to grain damage

2. Manual reaping and threshing by machine

• Cutting and stacking by hand
• Threshing by machine
• Cleaning by machine or by hand

• More effective in wet season harvest-wet crop conditions
• Higher capacity than manual
• Lower labor requirements
• Less dependent on field size

• Higher capital cost
• Dependency on the availability of contractor

3. Reaping and threshing by machine

4. Stripper harvesting and threshing by machine

• Reaping by machine
• Threshing by machine
• Cleaning by machine or hand

• Higher capacity than manual
• Lower labor requirements
• Less dependent on field size

• Higher capital cost
• Dependency on the availability of contractor

5. Combine harvesting

Standard Combine-harvester

• Harvesting, threshing, and crop cleaning are done mechanically
• Cutter-bar cuts crop, while conveying system feeds crop into the threshing and cleaning systems
• Threshing drum tip speed ranges from 20 to 25 m/s

• High throughput; timeliness
• Produces Clean grain
• Spread straw back in the field
• Multi-crop ability (often used for wheat)

• Higher Cost
• More straw left behind in the field
• Less effective in partially lodged crop
• Can not be used for Basmati rice

Combine-harvester with stripper-header

• Same as above except a stripper header is used instead of a cutterbar

• Highest throughput
• Less power required for subsequent threshing and cleaning operations
• Can start threshing earlier in the day

• High Cost
• Not suited for small, muddy Asian fields
• Problems in lodged crop

Head-Feed Combine

• Cutterbar cuts crop, conveying system "holds" on to the straw and feeds only the panicles into the thresher
• Threshing drum tip speed 15 m/s

• High mobility
• Can operate in small fields
• Less power required for threshing/cleaning · Ideal for hard-to-thresh varieties
• Straw cutting/chopping is easier

• High Cost
• Low throughput
• Pick-up reel not suited for indica and other high-shattering varieties
• Complex machine

Axial Flow combine

• Similar to Conventional combine harvester, except an axial flow type thresher is used.

• High Throughput
• Axial-flow threshing system ideal for tropical conditions
• Works with Basmati rice