20 



week of almost continuous rain, beginning August 16, this leaf 

 disease spread so rapidly that the leaves died in large areas 

 over the field, and a large percentage of the plants dropped 

 every leaf. The appearance of the affected plants seemed to 

 justify the local name of " black rast" for the disease which, 

 although not carefully observed in its early stages, was ap- 

 parently the same as the disease described by Prof. G. F. At- 

 kinson in Bulletin No. 41 of this Station as " yellow leaf 

 blight," or « mosaic disease." 



August 21 an estimate was made of the percentage of 

 seriously diseased plants on each plot. At that date the plot 

 receiving 240 pound per acre of acid phosphate, and the plot 

 supplied with both acid phosphate and cottonseed meal, had 

 been most injured. Next in extent of injury were the unfer- 

 tilized plots. 



The plots least injured were Nos. 4 and 6, the one treated 

 with kainit alone, the other with kainit and cottonseed meal. 

 The next healthiest plots were Nos. 1 and 7, the former being 

 the cottonseed meal plot, the latter the cottonseed meal and 

 acid phosphate plot. 



The results on plot 10 are considered unreliable, because 

 a part of this plot consisted of a strip of land which in the 

 preceding year had received treatment different from the bal- 

 ance of the field, and because the growth of plants and the 

 prevalence of leaf disease were so different on the two portions 

 of this plot. 



The following table gives the yield of seed cotton per 

 acre ; the calculated* increase ; the value of the increase at 2 

 cents per pound of seed cotton (5:^ cents per pound for lint 

 and $7.50 per ton for seed) ; the actual cost of fertilizers deliv- 

 ered in Auburn in carload lots ; and the " profit from fertil- 

 izers," or difference between value of increase and cost of fer- 

 tilizers : 



*Increase of plots 4-7 inclusive is calculated by giving to the figures 

 for each unfertilized plot a weight inversely proportional to its distance 

 from each in turn of the fertilized plots. 



