The BrLLETiN 



41 



soil a considerable aiiiount of pliosplioric acid wlicii liheral amounts 

 of manure, cotton-seed meal and soy-bean meal, and ground bone are 

 used alone or in such materials as tankage or fish scrap. 



Wliei'e large amounts of organic matter are being turned back into 

 the soil, in many cases it may be profitable to use finely ground phos- 

 phate rock at the time the material is being turned in. The organic 

 matter in rotting will tend to bring into available form some of the phos- 

 phoric acid contained in this phosphatic material. Again, a plan that 

 in many cases would a^^pear to be practical would be to add finely ground 

 phosphate rock to manure in stables as the manure is being formed, using 

 the rock at the rate of 1 to 2 pounds per day broadcast over the manure, 

 twice per week. 



Fig. 12. — The kind of pigs that can be iirofiuced in this county 



Potash — With soils of this county, as well as wilh Piedmont soils 

 generally, the least important constituent to be added of the main plant- 

 food constituents at the present time has been found to be potash. As a 

 matter of fact, from the standpoint of potential plant-food it would 

 appear beyond doubt that potash is far less important than is phosphoric 

 acid and nitrogen to be applied. Xone of the soils contain less than 

 0.13 per cent, while the Cecil Fine Sandy Loam and Cecil Coarse Sandy 

 Loam contain over 4 per cent and the Durham Coarse Sandy Loam al- 

 most 3.7 per cent potash. Speaking generally, the soils of the county 

 contain enough potash in them for the growth of maximum crops for 

 a number of years to come, but it is not present at the present time, 

 apparently, in large amounts in soluble form. It is generally, with the 

 soils of this county as well as most other Piedmont counties, more of 

 a problem of making the supply present available than of increasing it 

 by the addition of fertilizing materials supplying this constituent. Par- 



