Industrial technologies for harvesting alfalfa seeds and stems

Abstract

In the last decade, there has been a trend towards a reduction of the gross yield of alfalfa seeds which are traditional source of obtaining green mass for forage production with high content of plant protein and the accumulation of nitrogen in the soil. The reason hindering seed production is the loss of alfalfa seeds during harvesting which is 2-4 times higher than the permissible agrotechnical requirements, and sometimes amounts to 30-50% of the biological yield. Direct and two-stage harvesting of alfalfa with combines does not allow for the complete collection of high-quality seeds and stem and leaf mass which is characterized by high nutritional properties. The technology with the collection of small seed heaps and the industrial technology with handling the entire biological harvest in a highly mechanized thrashing floor are discussed. A field machine for collecting not winnowed small seed heap reduces seed losses in the field, collects better alfalfa seeds by 8% regarding germination and by 16% regarding vigor than in alfalfa seeds obtained from combines. The key straw rack of the field machine allows alfalfa seed screening in the field. The operations of the industrial technology for harvesting the entire biological harvest of alfalfa seeds and the technical systems used and their performance indices are discussed. The design of a field machine for complete collection of the biological harvest and a technological line of machines for separating seeds from the harvested mass which includes a dispenser, a separator, a stationary harvester and a pneumatic conveyor for transporting leaf and stem mass to storage sites are presented. The performance indices of the machines and equipment included in the production line which operates stably at a feed rate of 3 to 4 kg s are presented. The seeds separated by the separator and stationary combine harvester are supplied to the post-harvest seed handling line. After bringing the seeds to marketable condition, they are packed into bags using a robotic packer.