52 MISC. PUBLICATION 4 3 4, U. S. DEPARTMENT OF AGRICULTURE 



Tests for available nutrients are useful only as aids in determining 

 probable soil deficiency and should be supplemented, if possible, by 

 actual field tests of various fertilizers. 



For nurseries in the prairie-plains region, the use of soiling crops with 

 application of animal manures will usually be the most feasible method 

 of maintaining productivity, even though it may be necessary in many 

 cases to supplement this by the use of commercial fertilizers, especially 

 superphosphates . 



ANIMAL MANURES 



Although animal manures do not run as high as commercial fertilizers 

 in percent of different plant nutrients, they have a higher value in soil 

 building, maintaining the soils in good tilth and increasing their ability 

 to absorb and retain moisture. In the process of decomposition in 

 which phosphorus and other elements are dissolved and converted 

 into available plant nutrients, the bacteria present not only aid in the 

 decomposition of the manure itself, but also attack the soil material. 

 If added in liberal amounts the manure often takes care of most soil- 

 nutrient deficiency. 



It is advisable to allow animal manures to be rotted thoroughly 

 before applying them to the soil. Fresh manure, especially that which 

 contains a high percentage of horse excrement, has an injurious effect 

 on many plants, commonly known as burning. Moreover, it has a 

 higher percentage of viable weed seeds than well-rotted material. To 

 some extent, the burning effect can be controlled by maintaining soil 

 moisture at a fairly high level by means of irrigation. 



Van Slyke (39, pp. 218-226) gives analyses of the various animal 

 manures as shown in table 13. He gives the following values per ton 

 as averages for the various animal manures when mixed with the usual 

 amount of straw used as bedding or litter: Hen, $3.55; sheep, $2.75; 

 steer, $2.45; horse, $2.40; cow, $2.00; pig, $1.95. These values are 

 based on the following assumed prices per pound: Nitrogen, 12 cents; 

 phosphoric acid, 5 cents; potash, 4)4 cents. 



Table 13. — Percentage of plant-food constituents in fresh animal excrements 1 



Kind of animal and excrement 



Water 



Nitrogen 



Phos- 

 phoric 

 acid 



Potash 



Horse: 



Solid (80 percent) - - 



Liquid (20 percent) _ 



Mixed 



Cow: 



Solid (70 percent) _ _ 



Liquid (30 percent) . 



Mixed 



Pig: 



Solid (60 percent) . . 



Liquid (40 percent) . 



Mixed 



Sheep: 



Solid (67 percent) . . 



Liquid (33 percent) . 



Mixed 



Hen (mixed) 



i From Van Slyke (39) 

 2 Trace. 



Percent 

 75 

 90 

 78 



85 

 92 



Percent Percent 



0.55 , 0.30 



1. 35 (2) 



.70 .25 



.40 

 1.00 



.55 



.40 

 .50 



.75 

 1.35 



.95 

 1.00 



20 



( 2 ) 



Percent 

 0.40 

 1.25 

 .55 



.10 

 1.35 

 .45 



.40 

 .45 

 .40 



.45 

 2.10 

 1.00 



.40 



