Development of an Alternative, Reaper/Flail Based Harvesting System for No-Till Farming

Abstract

A harvesting system is introduced that combines existing technologies in a unique way to simplify harvesting equipment, lower production costs and improve grain quality consistency. The harvesting system is comprised of three machines – one to gather the crop and prepare the residue for no-till seeding, a second to thresh and clean the crop and a third to separate the grain by density/quality. The crop-gathering machine consists of a power unit equipped with a stripper header to harvest the crop and a flail to chop the standing residue into small pieces. A prototype harvester was fabricated to determine the system design criteria and performance characteristics in terms of machine power requirements and bulk density of the material harvested. Trials were conducted in three wheat fields that ranged in yield from 3.3 to 5.4 t/ha. Flail power requirements ranged from 3 to 11 kW/m depending on harvesting speed and concentration of biomass. Flail power requirements were linearly correlated with biomass feed rate (t/h) with an R2 of 0.87. Stripper header power requirements ranged from 2.0 kW/m to 2.7 kW/m, only slightly higher than the no-load power requirement of 1.9 kW/m. Total harvester power requirements for harvesting, conveying and flailing ranged from 5.7 kW/m to 13.5 kW/m depending on travel spend, wheat yield and quantity of straw chopped. Total machine power requirements for a harvester with a 7.3 m header would be about 175kW, including 75 kW for propulsion, losses and reserve. The chaff yield in the grain/chaff mixture (graff) harvested ranged from 1.6 to 2.5 t/ha. With chaff valued at $23/t, collecting 2 t/h of chaff would increase farm revenues by $46/ha. Realistic graff densities of awned wheat were less 1/13 that of clean grain and efficient material handling systems would need to be developed. Awnless wheat had graff densities that were 1/4 that of clean grain and therefore could be handled with commercially available equipment.