14 



MASS. EXPERIMENT STATION BULLETIN 318 



bulbs were larger and of better quality when the seed head was removed at an 

 early stage than when it was left on. 



After clipping, the crop was graded according to size. Since the effect of the 

 removal of seed heads was too small to be measured in the case of the bulbs from 

 medium and small sets where but a very small percentage of seed heads was 

 present, the two have been grouped together in the tabulation of the following 

 data. Table 4 gives the yield of bulbs expressed in pounds per acre for the different 

 grades and also the percentage of the different grades in relation to the total 

 yield. This table shows that the removal of the seed heads appreciably raised 

 the yield of onions where large sets were planted. On the plots where seed heads 

 were removed, the weight of bulbs not having seed heads and over 134 inches 

 was increased by 32 per cent, and the weight of bulbs not having seed heads 

 and under 134 inches was decreased by 34 per cent. The percentage gain or loss 

 was much greater when the weight of the poorer grades was included. Where the 

 seed heads were removed, 44 per cent of the weight of the bulbs over 134 inches 

 was produced by the 27.4 per cent not having seed stalks; and where the seed 

 heads were not removed, 52 per cent of the weight of the bulbs over 134 inches 

 was produced by the 26.7 per cent not having seed stalks. If only the bulbs over 

 134 inches and without seed stalks are considered, the large sets on the plots with 

 seed heads removed produced 52 per cent, the large sets on the plots without 

 seed heads removed 39 per cent, and the small sets 52 per cent as many pounds 

 as did the medium sets. 



Table 4. Average yields per acre and percentage of grades. 



Bulbs over 



Size of Plot Treatment Total Bulbs 1}4 inches 



Sets ' 



Pounds Percent Pounds Per cent 



of all of all 



bulbs bulbs 



All Bulbs 



Large f Seed heads removed 33,490 100 32,490 97 



(Seed heads not removed 23,140 100 20,680 89 



Medium Both* 28,195 100 27,565 98 



Small Both* 15,760 100 14,270 91 



Bulbs Having No Seed Stalks 



Large (Seed heads removed 15,000 45 14,310 43 



\ Seed heads not removed 11,840 51 10,800 46 



Medium Both* 28,005 99 27,375 97 



Small Both* 15,760 100 14,270 91 



*Thc effect of seed stalk removal was too small to be measured; hence the two plots wen not 

 kept separate. 



The removal of seed heads is desirable when large sets are used for planting. 

 Even though a greater yield may be obtained, and in a shorter period, from large 

 sets than from medium sets, a greater net income ran usually be expected when 

 medium sets are used, because the crop will be mere uniform and of higher grade, 

 and because the initial cost for sets is less on account of the smaller number of 

 bushels required. 



