without leaving any uncut material. Cutting height was between 1 /2 and 

 1 inch. Also, the 7 -foot bar put more live seed in the windrow, which is 

 perhaps a more accurate indication of a bar's capabilities. 



Of the swath dividers tested, the rolling colter (supported separately 

 from the tractor, and positioned and weighted to cut through the crop just 

 ahead of the outer end of the mowing bar) was the only one that divided a 

 swath of green subclover consistently. 



HARVESTING CROPS THAT SHATTER FREE SEED 



Birdsfoot trefoil is a good example of this type of crop. Its seed 

 cannot be harvested efficiently by the methods discussed because (1) 

 suction reclaimers are not, as yet, refined enough to pick up free seed 

 efficiently, and (2) even though the crop is mowed early and windrowed 

 in the usual way, shatter or germination losses may still be excessive. 

 Research, however, has worked out other ways of harvesting the seed of 

 free -seed shattering crops, like birdsfoot trefoil. 



The preferred method is to delay harvest until field shatter approaches 

 10 percent, then mow, form the swaths into loose, rectangular bales, and 

 subsequently combine the bales. Harvesting birdsfoot trefoil in this manner, 

 as opposed to conventional methods, increases field germination and re- 

 duces combine -germination losses. It also keeps shatter loss at a minimum. 

 Overall gains in live seed yields have amounted to about 23 percent. 



Another method of harvesting free -seed shattering crops (still in 

 the experimental stage) utilizes tined bars that are mounted on the mower 

 cutterbar and that rolls the material as it is cut in a continuous windrow 

 onto wide plastic or paper sheets. The sheets are laid down as the tractor 

 moves forward from a roll connected to the tractor by chains on each end 

 of a shaft inserted through the roll. The sheets catch and hold the shattered 

 seed. 



After the crop is cured, combining the crop and rewinding the sheets 

 go on simultaneously. The rewinding attachment connects to the combine 

 pickup and consists of a wooden reel and an auxiliary wheel that is driven 

 by a 3 -inch belt that is controlled by a spring -loaded slip clutch. The 

 action of the clutch is not severe enough to tear the sheets, but it has 

 enough force to keep slack out of the rewinding sheets and to allow the 

 operator to stop the cornbine without tearing the sheets. As the sheets 

 rewind, they help carry the material with the shattered seed into the 

 combine. The practicality of this method depends on the longevity of the 

 sheets. If they can be used for several years, the seed saved (up to 32 

 percent in Oregon trials in birdsfoot trefoil) might offset the extra har- 

 vesting expense. 



In 1959 tests, seed saved on black plastic did not lose any germi- 

 nation even though the temperature of the black plastic (1540F.) was from 

 20° to 54° higher than the temperature of clear plastic and paper used 

 in similar tests. These 1959 results did not confirm the results of previous 

 years. 



