64 The Bulletin 



The results thus far secured on this field, as a whole, show that nitro- 

 gen and phosphoric acid are the chief plant food deficiencies of this 

 soil. The use of potash alone, too, has shown good gains in oat-and- 

 vetch hay and in seed cotton per acre, the total increased yields of all 

 three of the crops from the plat receiving potash alone heing a little in 

 excess of the value of the total yields from the plat which received a 

 nitrogen application alone. However, potash, when added to an appli- 

 cation of phosphoric acid and nitrogen, only increased the yields of the 

 crops to the value of 9.5 per cent. On a whole, the potash applications 

 do not show up as marked increases in yields of the different crops over 

 the unfertilized plat as do the different applications of nitrogen and 

 phosphoric acid. 



Although the use of phos^jhoric acid alone had practically no influence 

 upon yields, yet when this constituent was added to an application of 

 nitrogen, the yields per acre of all the crops were more than double in 

 value of those secured from an application of nitrogen alone. Potash 

 added to a nitrogen application increased the yields per aci-e to the 

 value of 47 per cent over nitrogen used alone. The average gains per 

 acre were for the different constituents alone and in combinations: for 

 nitrogen 9.3 bushels of corn and 580 pounds of stover, 4,795 pounds of 

 air dried oat-and-vetch hay, and 65 pounds of seed cotton per acre; 

 for phosphoric acid, 7.4 bushels of corn and 370 pounds of stover, 1,595 

 pounds of oat-and-vetch hay, and 85 pounds of seed cotton; for potash, 

 2.2 bushels of corn and 270 pounds of stover, 1,685 pounds of oat-and- 

 vetch hay, and 345 pounds of seed cotton; and for lime, 1.8 bushels of 

 corn and 210 pounds of stover, 640 pounds of oat-and-vetch hay, and 55 

 pounds of seed cotton. Lime when used alone gave its best results with 

 all the crops. The increases in corn and in oat-and-vetch hay were 

 good, but a decrease of 190 pounds per acre resulted in the yield of seed 

 cotton. 



The most marked increases from the different applications were ob- 

 tained with the oat-and-vetch hay. 



The results on this field would seem to justify the assumption that, if 

 large crops are to be produced on this land permanently, additions of 

 carriers of nitrogen and of phosphoric acid will have to be made. The 

 results, too, indicate that at the present time the use of potash in avail- 

 able form will increase the yields of oat-and-vetch hay, seed cotton and 

 possibly other crops. Although additions of potash have given fairly 

 good increases in yields, the soil is well supplied with this constituent, 

 there being enough present in the surface 6^^ inches of this type of soil 

 on an average for about 128 one hundred bushel corn crops. The 

 potash is evidently in a form not easily assimilated by the plant roots. 

 The assumption above with reference to the nitrogen and phosphoric 

 acid requirements of this type of soil is in accord with the chemical 

 analysis. Seventeen one-hundred bushel crops of corn would require 

 an amount of phosphoric acid equal to the total present in the top Q% 

 inches, while five such crops would more than use up all the nitrogen. 



TREATMENT AND RESULTS ON GASTONIA FIELD. 



The type of soil on which this field is located is Cecil sandy loam, 

 which is exceptionally uniform throughout. This is one of the most 



