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