specific weight of the rice straw bale, rice straw loss in the field,
and the labor involved in all related operations.
The collection capacity of
the machines was calculated based on the length of collection time
corresponding to their alloted area converted to tons of straw per
hour (h t−1). The weight of straw in the working area was obtained
based on the number of bales made and the average weight of each
bale. However, for the machine that only gathers loose rice straw,
the weight of straw was assumed the same as the average weight
of straw gathered by the self-propelled balers based on our in-situ
observations. The specific weight of the straw bale (kg m−3) was
calculated based on the volume of the bale (except those that were
collected by the gathering machine).