FOOD FOR PLANTS 123 



Crops No. lbs. Nitrogen Phos. Acid Potash 



Potatoes (Sweet) 10,000 24.00 8.00 37.00 



Tomatoes 40,000 64.00 20.00 108.00 



Lettuce aver, crop 41.00 17.00 71.00 



Cantaloupes (est.) aver, crop 57.00 16.00 100.00 



Barley 2,500 44.00 20.50 13.50 



Corn 2,000 37.40 14.00 8.00 



Oats 1,200 24.72 9.84 7.44 



Rice 3,500 37.80 6.30 3.15 



Sorghum 2,500 37.00 20.25 10.50 



Wheat (Spring) 1,200 28.32 8.40 4.68 



Sugar Beets 40,000 173.40 116.16 387.44 



Cotton (total crop) 1 bale 64.35 22.37 51.33 



EXPLANATION 



This table does not include all the elements or plant foods, required by 

 various crops, such as lim-e, soda, sulphur, etc., which are just as impor- 

 tant, even though required in some cases in lesser amounts. Whereas we 

 have searched practically all sources of available information, zve have 

 been unable to secure complete or authentic information on the quantities 

 of plant foods required by plants other than Nitrogen, Phosphoric Acid 

 and Potash. Inco)nplcte figures shozv that as a general rule lime is required 

 in quantities similar to potash, and soda similar to phosphoric acid. 



With regard to fruits, the crop only has been considered, as no complete 

 information is available on the quantities of plant food required by the 

 leaves and it'ood, but it is known that they require as much, ij not more, 

 plant food than the crop. The leaves and wood require more nitrogen in 

 proportion to other elements than taken out by the crop. 



The above figures are based upon the finding of the University of 

 California Agricultural Extension Service, Myers "Food for Plants," for 

 Cotton — Alabama Experiment Station. 



Green Manure. 



The growing of legume cover crops is one of the 

 most economical forms of supplying the necessary 

 organic matter. Nitrogen is also supplied by 

 legumes in two ways : First, through the Nitrogen 

 constituent in its roughage which is plowed under; 

 second, through the Nitrogen formed in nodules on 

 its roots. 



According to "Feeds & Feeding" by Henry the 

 average Nitrogen content in the green roughage of 



