THE CULTURE OF SET ONIONS 3 



Some difficulty may be experienced from using tractors in preparing onion 

 land. With a tractor, as the soil is worked following fertilizer application, the 

 fitting harrow tends to concentrate the fertilizer in the two trenches left by the 

 rear wheels, occasionally resulting in some injury to the crop. The possibility 

 of trouble can be reduced to a minimum if lightweight tractors are used for the 

 final fitting operation and if repeated working of the soil after fertilization is 

 avoided. 



Cover Crops 



Anyone who has witnessed dust storms in the Connecticut Valley during the 

 winter and early spring months will agree that winter cover crops should be 

 grown more extensively than they are. While cover crops will not eliminate all 

 blowing of the soil, particularly in the spring, the use of good sod-forming cover 

 crops will markedly reduce wind erosion. The difficulty is that the onion crop 

 is one of those for which an entirely' practical system of cover cropping has not 

 yet been worked out. Because of their earlier maturity, set onions can be fol- 

 lowed with a cover crop more satisfactorily than seed onions; but difficulties of a 

 practical nature still exist in disposing of a winter cover in the spring. 



If suitable cover crops are to be fully effective in curtailing wind and water 

 erosion and in accomplishing all the other beneficial effects ascribed to them, 

 they should remain on the land over the winter. But such a practice requires 

 spring plowing, and, as has already been explained, spring plowing for onions 

 tends to delay planting and is not generally favored. It has been suggested that 

 this objection be met by plowing in the late summer after the onions have been 

 harvested and seeding with a non-winter-hardy cover crop such as oats or barley. 

 The following spring the winterkilled remains could be taken care of with a 

 thorough discing in the process of seed bed preparation. The practicability of 

 .such a plan will depend upon whether or not a cover which is heavy enough to be 

 effective can be disposed of in this way so that it will not interfere with the 

 planting and cultivation of the onions which follow. 



If the cover crop is plowed under in the late fall, there is no interference with 

 spring planting but some of its effectiveness is. lost. Nevertheless, such a practice 

 is a great improvement over no protection whatsoever, and in recent years many 

 growers have sown cover crops on onion land and have handled them in this 

 manner. Results from trials carried on in 1941 with different cover crops indicate 

 that some are more valuable than others. Oats, domestic or common rj'e grass, 

 Italian rye grass, field brome grass, and buckwheat were all seeded on August 12 

 following the harvesting of a crop of set onions. Excellent growth was made on 

 all plots both with and without additional fertilization. On October 21 all plots 

 were plowed. Dry matter yields of the tops of the different crops used are shown 

 in the following table. 



Table 1. — Dry Matter Yields of Cover Crops Following Set Onions 



Type of Cover Crop 



Yield of Dry Matter (Lb. per Acre) 



150 1b. 



No Nitrogen Calcium Cyanamid 



Oats 2900 



Domestic Rye Grass 2975 



Italian Rye Grass. - -- 3125 



Field Brome Grass {Bromus nrvensis) 2250 



Buckwheat --- 1810 



3480 

 3050 

 3340 

 2030 



