ORGANIC MATTER AND NITROGEN 



2OI 



products. Mature work animals excrete practically as much 

 nitrogen as they consume. These facts certainly emphasize the 

 importance of saving all liquid manure and the danger of loss 

 of nitrogen in that form. 



In a series of digestion experiments (not yet published) con- 

 ducted by the Illinois Experiment Station, with six milk cows, dur- 

 ing a period of 15 days, the average daily consumption of food per 

 cow was 19.67 pounds of dry matter contained in a ration of clover 

 hay, corn silage, and mixed concentrates, including corn, oats, 

 wheat bran, gluten meal, and linseed meal. The total dry matter 

 recovered in the dung and urine amounted to 8.1 1 pounds, or 41.23 

 per cent. (With heavy feeding the digestibility is appreciably 

 less than with lighter feeding.) 



Of the nitrogen consumed, 80.32 per cent was recovered in the 

 dung and urine, and 20.12 per cent in the milk, indicating a slight 

 loss from the animal bodies. 



Of the phosphorus consumed, 73.34 per cent was recovered in the 

 manures and 22.28 per cent in the milk, only 4.38 per cent being 

 retained by the animals. 



Of the potassium taken in the food, 76.02 per cent was recovered 

 in the manures and 13.69 per cent in the milk, the balance, 10.29 

 per cent, probably having been largely excreted through the skin. 

 The experiments were conducted the last half of June. (Consider- 

 able amounts of commercial potassium salts were once regularly 

 obtained from the washing of sheep wool.) Table 30 shows these 

 results in more detail for ready comparison: 



TABLE 30. PLANT FOOD RECOVERED FROM FOOD CONSUMED BY MILK Cows 

 Illinois Experiments: Average of 90 Days 



As an average of the best three cows, the plant food not recovered 

 in the total solid and liquid manures was 25.03 per cent of the 



