About 1,000kg per 10 a field of long mat rush stems, "Nagai", has been almost yearly yielded in Matsue's farm field, where is located at the northern part compared to Okayama and Kumamoto of the main mat rush cultivation centre in Japan. Then, the mat rush growth of farmer's field in Matsue was surveyed and the several experiments were investigated.
The tip cutting, "Sakigari", was generally carried out at the middle of May, in farmer's field of Matsue and it was closely related to increase the long stem yield at the iniddle July.
But the tip cutting decreased the long stem yield, when Stem Surface Area （SAI）was below 10, and the number of stems above 45cm was also below 2,000 per m^2 at the middle of May.
New buds which were emerged at the last May to the early June in Matsue, have been elongated to the long stems above 105cm at the middle July. The emergence of new buds was prevented below 30% of the relative light intensity, and 10 to 30% of the relative light intensities promoted the elongation of new buds.