LOSSES OF MOISTURE AND PLANT FOOD BY PERCOLATION. 



29 



orated or percolated. This assumption is, of course, not true, but the 

 table emphasizes the high percentage evaporation during the summer 

 months, which are probably really higher than the figures given. 



TABLE NO. 11. 



Percentages Evaporated and Percolated (estimated). 



EFFECT OF SULPHATE OF POTASH AND MANURE ON PERCOLATION. 



Table No. 12 compares the percolation from the soils which received 

 sulphate of potash, and manure, with the zero pot. None of these soils 

 were cultivated, except to the extent necessary to work in the manure 

 when it was applied. 



Sulphate of potash caused an average increase of percolation with 

 the sandy soils. This increase occurred with two of the four soils of 

 the group; with the Miller fine sandy loam, there was a decided de- 

 crease. On the other hand, the sulphate of potash caused a decided de- 

 crease in percolation with the loam and clay soils, amounting on an 

 average to 3.20 inches, and occurring with all the soils of the group. 

 This is perhaps due to the saline material causing the surface soil to 

 run together, decreasing the penetration of water, and causing it to re- 

 main near the surface to undergo evaporation. The Houston black 

 clay, particularly, showed a great decrease in 'percolation, due to the 

 presence of the sulphate of potash. 



The quantity of sulphate of potash used in 1911 was equal to an 

 annual application of 68 pounds potash (K 2 0). In 1912, three times 

 this quantity was added to the Norfolk sand,' Orangeburg fine sandy 

 loarn, Houston loam and Houston black clay, and five times as much to 

 the Yazoo clay. Miller fine sandy loam, Crawford clay and Lufkin fine 

 sandy loam, but there is no evidence that the increased application 

 caused an increased evaporation during the year 1912 over that of 1911. 

 According to these results, application of soluble salts to the heavy soils 

 may result in no increased loss of moisture. 



the application of the manure resulted in a decreased loss ot water 

 by evaporation from the sandy soils especially. With the clay soils, ti 

 manure applied October 15 caused a decreased loss of water, while 

 that applied March 15 increased the loss. With almost all the soils, 



