400 THE MONTHLY BULLETIN. 



twenty pounds of sulphate of potash to the acre, no nitrogen being 

 added. 



Plowing then takes place Avith a fourteen inch moleboard plow, turn- 

 ing the furrow slice well over and running nine to ten inches deep. The 

 soil is then worked down with the disk and acme harrows ready for the 

 planting of the summer vegetable crops. 



Now follows the second part of the experiment from which we get 

 the results of the nitrogen added by the various legumes. 



Vegetables, such as corn, potatoes or sorghum, are planted in plats 

 running the opposite direction from those previously occupied by the 

 covercrops. Thus each covercrop plat has growing upon it during 

 the summer the same sized plat of each vegetable used. During the 

 growth of these vegetables, nitrate of soda in amounts varying from 

 two hundred and seventy pounds to one thousand and eighty pounds 

 per acre is applied in three applications to every second non-legume 

 plat. Uniform cultivation and irrigation are given all plats. 



Upon the maturity of the vegetable crops, accurate determinations 

 are made of the number of plants per plat and the total yield of each 

 plat in pounds and ounces. 



From these figures we get the yields in pounds per acre of each of 

 the seventeen plats and can easily compute the increases resulting from 

 the various treatments of the soil. 



Yields. 



The following are the average annual yields in tons per acre of 

 green tops produced by the various legumes and barley in their order. 

 These averages cover the Avork of five years with these exceptions, the 

 averages of Melilotus clover and the vetch, Vicia ervilia, cover but the 

 last four years work ; while the purple vetch was grown for the first 

 time this past winter. 



TABLE I. 



Purple vetch {Viciu (iftrupiirpiirca) ISJ tous. 



Tangier peas 34 tons. 



Melilotus clover (Melilofns indica ) 1 12f tons. 



Fenugreek 12i tons. 



Common vetch {Vicia sativa) 12 tons. 



Lentils 12 tons. 



Burr clover 12 tons. 



Barley and rye (average) 12 tons. 



Bitter vetch (Vicia ervilia) Hi tons. 



Canadian field peas 9 tons. 



The total cost of growing these legumes, including cost of seed, cost 

 of sowing, and two extra irrigations, averages about $8.00 per acre. 

 This expense is practically covered by the saving due to the cessation 

 of cultivation for the period of five to six months that the land is occu- 

 pied by the covercrop. Thus we arrive at the time for plowing in early 

 March without having gone to any additional expense in handling the 

 orchard and have groAvn on the land a large amount of valuable organic 

 material. 



