The cropping schedule of rice in the Muda area requires the rapid performance of a sequence of farm operations stretching from harvesting of the off-season crop to transplanting of the main seasn crop. However, the acute labor shortage in the area makes the rapid performance of these operations difficult. The mechanization of harvesting would be an essential step to the stabilization of double cropping of rice.
Two methods for the hardening of a paddy field in the rainy season to facilitate the operation of harvesters were tested. The drainage of surface water from the experimental fields was difficult because of the unevenness of their surface. Moreover, based on laboratory tests and the analysis of long term rainfall data it was evident that the hardening of a paddy field by drying in the rainy season was not possible due to the limited number of continuous fine days.
It was, however, possible to maintain the soil hardness required for the operation of a medium-sized combine harvester even under inundated field conditions by hardening the field soil through a prolonged dry season fallow and by using a low-ground-contact-pressure tractor equipped wiht a shallow-plowing tiller.