CONNECTICUT VALLEY ONION INDUSTRY 45 



4. Varieties: ^^'hat \arietie.s of onions are best suited to the Connecti- 

 cut Valley? Do varieties run true to name? Can desirable varieties be 

 maintained under Valley conditions? What are the best sources of seeds 

 and sets? 



Since the experiments have rug only one year, and since tlie attack of 

 mildew coming August 8 practically ruined most of the crop, only progress 

 and incomplete results can be reported. It can be stated: 



(1) That timothy, red and crimson clovers can be grown as cover crops 

 in onions, if seeded immediately after the last shove hoeing and not later 

 than July 26. These crops made considerable growth before the ground 

 froze. Biennial sweet clover made poor growth as a cover crop. 



(2) Moderate applications of lime, equivalent to one ton ground lime- 

 stone, gave small increases in yields of onions. Large applications, up to 

 seven tons per acre, showed no additional advantage. 



(3) Complete fertilizers rather high in phosphoric acid and fairly high 

 in potash gave the best results. Rate of application was 2500 pounds per 

 acre. That fertilizer having the ratio of 1:3:2 for ammonia, phosphoric 

 acid and potash gave the best yield. The fertilizer had the grade of 

 •i-l 2-8. 



(4) Concentrated complete fertilizers carrying a total of 32 per cent 

 l)lant food can be used for onions. The 8-16-8 grade was used. 



(5) No advantage was gained by the application of fertilizers at dif- 

 ferent times throughout the growing season instead of all at the begin 

 ning. 



(6) Source of seed is an important consideration in the selection of 

 seed stock. This was strikinglj^ brought out by the diffe.-ence in resistance 

 of certain stocks to the attack of the mildew. 



In considering this brief report of progress of this second group of field 

 experiments with onions it should be l)orne in mind that on some points 

 tlie results are not conclusive but merely indicative. Further, the land on 

 which the plots are located had received very little cultivation for a num- 

 ber of years. It is probable that several years will be required to put it 

 into a condition that is representative of our typical onion land. 



The earlier group of field experiments had for their main objective in- 

 formation as to the kind of fertilizer materials required to grow a good 

 onion crop. This objective was the one common to many field experiments 

 conducted throughout the country during the period of early development 

 of agricultural experiment stations. It was not known at the time the 

 experiments started, whether one needed to feed the onion a single or a 

 mixed ration of fertilizers; or which if any one of the plant food nutrients 

 is the most important; whether lime is necessary for onions; etc. Some of 

 these and other questions of plant feeding were answered by the earlier 

 experiments. 



The results are summarized as follows: 



(1) On Connecticut Valley soils that have been cropped for a number 

 of years, onions cannot be successfully grown unless a complete fertilizer, 

 or one carrying ammonia, phosphoric acid and potash, at least, is used. 

 There is still unanswered the question as to the necessity of sulfur, but 

 since it is ordinarily present in a complete fertilizer the question is not 

 at present very important. 



(2) Fertilizers carrying ammonia entirely in the form of certain chemi- 

 cals were found to be as good as those carrying ammonia in organic form 



