Scope and Importance of Straw management machinery
The conventional Combine harvesters leaves considerable amount of long straw and stubbles in the field. Farmers usually burn them in-situ to avoid field operational problems for next crop. It has been estimated that one ton of straw on burning release 3 kg particulate matter, 60 kg CO, 1460 kg CO2, 199 kg ash and 2 kg SO2. The burning of left over straw not only leads to environmental pollution but also causes a considerable economic loss of precious biomass widely used as a cattle feed. This problem can be solved either by incorporation of straw into the soil for decomposition or straw retrieval for use as a cattle feed. The retrieval of straw from combine harvested rice-wheat fields is done either by straw reaper or straw baler.
A straw reaper essentially consists of four main units viz., stubble cutting and collecting unit, feeding unit, straw bruising unit and "BHUSA" blowing unit. Serrated saw type cylinder is mostly used in the straw combines for bruising. Serrated knives are attached on the bars at specific spacing and the bars arranged parallel to drum axis. Straw combine is pulled by tractor (45 hp) with an attached trolley. As soon as this trolley is filled with straw, it is unloaded near the dumping site normally located centrally or in the corner of the field.
Main features of straw reaper
Saving of time, money and labor
Fine straw (Bhusa) can be obtained as bi product
Small farmers welcome the work to be get done by custom hiring
Straw recovery is 50 per cent
The straw split was 92.36% and length of bhusa was 2.0 to 2.5 cm.
There was an additional grain recovery of 35-60 kg/ha. .depending upon crop and field conditions
Straw combine is very economical. it is used extensively by the farmers as the cost of wheat fine straw has risen and usage of combine has increased.