The Bulletin, 



87 



111 the investigations of soil of North Carolina one of tlu; important factors 

 wliic-li we are consiilering is the relation of the different fertilizer cojistitueiits 

 to the various soil tyjies. The deticiencies of the individual soils have never 

 received any direct study until very recent years. The results already ob- 

 tained show beyond a possibility of a doiibt that for the permanent increase 

 of our crop yields the soil should be considered as the basis for determining 

 the fertilizer application. 



There are a great many distinct soils in North Carolina. Already nearly 

 a hundred separate types have been found. The chemical composition in 

 some types shows as large amounts of plant food as are contained in the black 

 prairie soils of the Western Stales; while others have not enough total plant 

 food in the surface soil for the production of a dozen maximum corn crops. 

 The Porter's black loam, for instance, found in the mountains of the State, con- 

 tains on an average o.UUO jiouuds of nitrogen, 3,000 pounds of jihosplioric acid, 

 and 30.000 pounds of potash in the surface 7 inches of an acre ; while the Nor- 

 folk sand contains in the same strata 400, 500, and 2,000 pounds respectively. 

 The fornuu' soil is well supplied with three of the important plant-food ele- 

 ments, while the latter is deficient in every one. Other types may be well 

 supplied with one element, hut very deficient in the other two. Such is the 

 case with many of our agricultural soils of the piedmont and mountain sec- 

 tions. The red clay and clay loams of granitic formation found in the pied- 

 mont are generally well supplied with potash, but deficient in both nitrogen 

 and phosphoric acid. The black soils of the coast region, on the other hand, 

 are well supplied with nitrogen, frequently deficient in phosphoric acid, and in 

 the southeastern part of the State also poorly supplied wnth potash. 



In the following table are given the results of plat experiments on an im- 

 portant soil type in each of the mountain, piedmont, and coastal ijlain sec- 

 tions of the State : 



Fertilizer Treat- 

 ment. 



Blanttre Field. 



Porter's Clay. 



Chas. Baldwin's Farm. 



Gastonia Field. 



Cecil Sandy Loam. 



C. M. Faire's Farm. 



GoLDSBORO Field. 



Norfolk Sandy Loam. 



J. E,. Hooks' Farm. 



No fertilizer 



Lime.- 



Nitrogen 



Phosphoric acid - 39.0 15.5 



Potash. 19.7 —3.8 



Nitrogen, phos. acid 55.0 31.5 



Nitrogen, potash 28.7 5.2 



Phosphoric acid, potash! 40.1 16.6 



Nitrogen, phosphoric 



acid, pota.sh ' 52.7 29.2 



Lime, nitrogen, phos- 

 phoric acid, potash. J 59.8 36.3 [ 23.2 23.2 46.9 17.9 



The same fertilizing materials were used on each of these three soils. The 

 rate of application is based on the amounts of the various constituents removed 

 by a maximum yield of the crop to be grown. Cowpeas were sown broadcast 

 in the corn on all fields in 1910 and turned under in the fall before the small 

 grain was seeded. Consequently the treatment for the small grain in each 

 case is the same as for the corn, plus nitrogen secured from the atmosphere 



