284 



bore a rich green foliage. The yellow color of the plants in 

 plat i was evenly distributed over the leaf, there being no in- 

 dication of the mosaic arrangement so characteristic of the 

 disease. In September the plants were matured, and only a few 

 showed any sign of the disease. The yellow color of the 

 plants was due to the acid phosphate and kainit ripening the 

 plants prematurely (acid phosphate being known to produce 

 this effect), along with a suffused yellowing of the plants. 



" Early in August the plants in plats 2 and 3 were badly 

 a ected, the leaves showing the checkered appearance of the 

 disease, and were an easy prey for such fungi as 3Iacrosj)or- 

 ium nigncantium and Cercospora f/ossypina, resulting in their 

 curling up, drying and falling off". 



"In a field of cotton of 3 or 4 acres near the scene of the 

 above experiment the plants in May and June were very prom- 

 ising, but in August the disease had appeared to such an 

 extent that the yield fell off at least one-half of what would 

 have ordinarily been expected. The fertilizer used in this 

 case was stable manure, cotton seed and acid phosphate. 



"■ These experiments seem to show what has for some time 

 been held by a number of intelligent planters who have ex- 

 psrimeflted with kainit as a fertilizer. It has been quite fre- 

 quently noted that with quite large applications of kainit 

 ttiere was no appreciable increase in the yield of cotton. 

 This occurs in those seasons when the rains are quite fre- 

 quent, not long continued, and keep the soil moist and the 

 plant in normal growth. On the other hand, during dry sea- 

 sons as well as seasons of drought followed by long-continued 

 rains, kainit has a perceptible, sometimes a remarkable in- 

 fluence in increasing the yield. This, with the well-known 

 effect of such salts in changing the physical condition of the 

 soil, leads to the belief that the increased yield and the 

 comparative freedom from disease result from the action of 

 the kainit in binding more firmly together the soil particles, 

 so that it is more retentive of moisture or more able to draw 

 it up from below.* Salt and wood ashes are known to pro- 

 duce much the same results in the soil.f Rolling the land is 

 frequently resorted to in order to produce the same effect. 

 Iq the cultivation of cotton the more progressive planters 

 are careful to prepare the land well before planting, and then 

 to cultivate only the surface soil afterwards, in some cases 

 scraping the surface of the soil with a " sweep" to a depth of 

 only a few inches. This leaves the underlying soil undis- 



*A.labama CollP^e Sta. Bui. 36. 



tSee article on climatology and soils, p. 160. 



