ANNUAL REPORT, 1929 33.3 



The Value of Cover Crops for Onions. (J. P. Jones and M. E. Snell). 

 The work on this project was begun in 1925. The plan has been to seed 

 several cover crops on different plots at the last shove-hoeing and by 

 comparison witii adjacent plots without cover crops determine the effect 

 on yield and quality of onions. Four j'ears' records are now available. 

 Considering the average effect on yield, red clover and rye appear to have 

 been injurious, while crimson clover, timothy and redtop have been with- 

 out effect. In 1928 and 1929 crimson clover and redtop increased the yield 

 by 19 and 14 per cent respectively, but this was offset by decreased yields in 

 the two previous years. A more consistent positive response is necessary 

 before any of the cover crops thus far tested can be recommended as 

 having a favorable influence on the yield and quality of onions. 



Sulfate versus Muriate of Potash for Onions. (J. P. Jones and M. E. 

 Snell). To answer the question frequently raised by growers as to the 

 relative merits of sulfate and muriate as sources of potash for onions, 

 the Station has conducted a comparative test of these two materials during 

 the past four years. Summarizing the results for the entire period of the 

 experiment, sulfate of potash gave an average yield of 137 bags per 

 acre, while muriate gave 136 bags. In 1929, the year in which the onions 

 were least affected by troubles such as blast, 242 bags per acre were 

 obtained with sulfate of potash as contrasted with 250 bags with muriate, 

 an insignificant difference. From the standpoint of growth of onions, 

 it appears to make little difference which of these two forms of potash 

 is used. In case of planning to grow tobacco on the land in the near 

 future, it is perhaps best to fertilize with sulfate of potash to avoid any 

 harmful effect on the burn of the tobacco frequently attributed to the 

 chlorine carried by muriate of potash. 



Lime in Relation to Onion Growth. (J. P. Jones and M. E. Snell). 

 The experiments conducted during the past five years have shown lime 

 to be almost indispensable in the successful growth of onions on acid soils. 

 This has been demonstrated both on the Experiment Station farm and on 

 several farms in the Connecticut Valley. The average of four years' 

 results on the Experiment Station farm showed an increase of about 70 

 per cent in yield of No. 1 onions. Two tons of lime per acre have been 

 about as effective as higher applications. In the last two years there 

 has been a decline in the percentage response to lime. For instance, in 

 1926 and 1927 an increase of 87 and 96 per cent, respectively, was record- 

 ed for two tons of lime per acre, while in 1928 and 1929 the increase 

 was only 51 and 33 per cent. Since the application was made five years 

 ago, these results might indicate an exhaustion of the lime. On the other 

 hand, this same trend is evident on the plots which received seven tons 

 of lime per acre, and it scarcely seems possible that lime should be lacking 

 with so large an initial application, even at the end of five years. The 

 difference is believed to be due to a variation in seasons. In 1928 the 

 blast hit the onions quite early, before the bottoms had begun to show 

 appreciably. The tops were killed rapidly, and the injury seemed to be 

 equally severe on limed and unlimed plots. The limed plots produce 

 bulbs earlier and hence have an advantage when the blast occurs some 

 time after bulbs have begun to form, as was the case in 1927; but in 1928, 

 with the blast appearing just about at the beginning of bulb formation, 



