EXTENSION COURSE IN SOILS. 



61 



EXERCISES, LESSON VHI. 



Materials required. — A pint of muck or peat; two wide-mouthed pickle bottles; 

 three or four ounces of ammonium carbonate; two pieces of woolen cloth for strainers; 

 two glass tumblers. 



1. Why barnyard water is colored. — Every farmer and farm boy has observed the 

 peculiar color of barnyard water and has detected strong ammonia odors in the horse 

 stable. The one condition is closely related to the other in this way: The nitrogen 

 of an animal body is excreted through the urine. The principal nitrogenous sub- 

 stance in urine is urea. Urea is acted upon by fermenting organisms producing the 

 compound ammonium carbonate which, with moisture, has the ability to dissolve 

 organic matter. This accounts in a large degree for the brownish color of barnyard 

 water. This solvent action may be observed as follows: 



Place a handful of peat or muck in each of two wide-mouthed pickle bottles. Add 

 about half a cup of ammonium -carbonate solution to one, and a like amount of water 

 to the other. Shake each for a few minutes, let stand about 20 minutes, then shake 

 again for a few seconds. Run the liquid contents of each bottle through woolen cloth 

 into glass tumblers and note color of liquids. Explain results. 



PROBLEMS. 



1. A ton of good average barnyard manure contains about 0.5 per cent nitrogen, 

 0.1 per cent phosphorus, and 0.4 per cent potassiiun. How many pounds of each of 

 the elements are contained in 1 ton? 



2. When nitrogen is worth 18| cents per pound, phosphorus 10 cents, and potassium 

 6 cents per pound, what is the value of the plant food contained in 1 ton of good 

 manure? 



3. A farmer applied 30 tons of good manure per acre to his tobacco land. About 

 how many poiinds of each of the fertilizing elements did he apply per acre in the 

 manure? What may be considered the total value of the plant food applied? 



4. How many pounds of each of the three fertilizing elements are applied when 



8 tons of manure are applied per acre? What is the value of these fertilizing elements? 



Under average good conditions about 40 per cent of the nitrogen is lost in the feed- 

 ing transaction and production and handling of manure, about 20 per cent of the 

 phosphorus, and about 5 per cent of the potassium (straw for bedding). 



5. A 40-bushel barley crop removes from the soil about 48 pounds of nitrogen, 



9 pounds of phosphorus, and 30 pounds of potassium. If 10 acres of such barley were 

 fed and all the manure produced from this crop were returned to the same field, would 

 there be a loss or gain, and how much of nitrogen, phosphorus, and potassium as 

 compared with that contained in the soil before the crop was planted? 



6. The amount of plant food removed per acre by corn, oats, and alfalfa is as follows : 



Amount of plant food removed from the soil by different crops. 



Crop. 



Yield per 

 acre. 



Pounds per acre removed from soil. 



Nitrogen. 



Phos- 

 phorus. 



Potas- 

 sium. 



Corn, bushels 

 Oats, bushels 

 Alfalfa, tons.. 



85 



50 



200 



79 



37.5 



95.5 



How much plant food would be lost in feeding 7 acres of corn averaging 65 bushels 

 of shelled corn per acre, and 10 acres of oats, averaging 50 bushels per acre? (All 

 straw used for bedding.) 



