248 Missouri Agricultural Report. 



for potassium, the value of these elements is $2.76 in a ton of 

 wheat straw, $5.40 in timothy hay, $8.40 in clover hay and $9.42 

 in a ton of alfalfa hay. 



The following facts may well be kept in mind : 



1. In grain crops about two-thirds of the nitrogen, three- 

 fourths of the phosphorus and one-fourth of the posassium re- 

 required for the crop will be contained in the grain, while about 

 one-third of the nitrogen, one-fourth of the phosphorus and three- 

 fourths of the potassium required for the crop will be found in the 

 straw of stalks. 



2. In nitrogen and phosphorus clover and other legume crops 

 are about as rich as grains, nearly twice as rich as timothy or red 

 top, and more than twice as rich as straw or stalks. 



From these facts it becomes very plain that the quality of 

 richness of manure must depend very largely upon the kind of feed 

 used. 



The plant food in a ton of maunre varies greatly with the ex- 

 posure it has suffered under the weather conditions. 



If ordinary fresh farm manure contains 10 pounds of nitro- 

 gen, 2 pounds of phosphorus and 10 pounds of potassium per ton 

 of manure with a dry matter basis of 25 per cent (and 75 per cent 

 water) , the manure that will result from holding such fresh -ma- 

 nure until it becomes more or less rotted will vary greatly in com- 

 position, depending upon the conditions to which it is subjected. 

 If the fresh manure is exposed for a few weeks to the leaching of 

 heavy rains, half of the nitrogen and potassium may be leached 

 out, while smaller losses of phosphorus and dry matter occur, so 

 that a ton of the resulting manure, in which the urine (which usu- 

 ally contains about half of the nitrogen and potassium) has been 

 replaced by rain water, may contain only 6 pounds of nitrogen, 2 

 pounds of phosphorous and 6 pounds of potassium. The differ- 

 ence of 4 pounds each of nitrogen and potassium does not repre- 

 sent the total loss, because if the pile contained 10 tons of fresh 

 manure, there will be left perhaps only 8 tons of the leached ma- 

 nure, even with the same percentages of dry matter and water. 



If, however, the pile of manure suffers less from leaching but 

 more from fermentation and heating for several months, the loss of 

 dry matter or total weight will be great and the loss of nitrogen con- 

 siderable, while the loss of phosphorus and potassium will be less. 

 Thus, after six months of such conditions, the 10 tons of manure, 

 with 100 pounds of nitrogen, 20 pounds of phosphorus and 100 

 pounds of potassium, may be reduced to 5 tons of manure, contain- 



