136 EXPERIMENT STATION RECORD. [Vol.43 



tliiin the corn plant to which three- fourths of the nitrogen was applied late as 

 a side application, and tliat for this I'easoii the cotton plant was able to 

 utilize a larger percentage of the nitrogen in the slowly nitrifying velvet bean 

 meal. 



A comparison of certain raw phosi)hates with acid phosphate for fer- 

 tilizing cotton, T. E. Keitt and A. W. Murray {Georgia Sta. Bui. 131 (1919), 

 pp. 39-.'i.')). — Tests were made on a comparatively poor soil, a similar soil with 

 a. cover crop of oats turned under, and on a very fertile soil to determine the 

 value of different phosphates for fertilizing cotton. The pho;^phates were 

 applied at the rate of 400 lbs. per acre and mixed with dried blood and Nebraska 

 potash so that 800 lbs. of the mixture furnished 3 per cent each of available 

 nitrogen and potash in addition to the available phosphoric acid present in the 

 particular phosphate used. The surface area exposed by the different phos- 

 phates as applied was calculated to determine a possible relation between this 

 factor and the crop yield. The method of calculating the surface area of the 

 phosphate particles is described, and the different experimental results are 

 shown in tables. 



On the soil with the cover crop turned under, Florida soft phosphate proved 

 least eflicient, while Tennessee brown, Florida pebble, and Tennessee blue phos- 

 phates all produced higher increased total yields than those secured with acid 

 phosphate. In every test at the station during the year acid phosphate showed 

 a marked influence on earliness of maturity. The plats receiving Tennessee 

 blue phosphate matured earlier than those treated with the other raw 

 phosphates. 



Florida soft phosphate, which had the smallest surface area, gave the lowest 

 yield, but the results from the other i*aw phosphates were not absolutely in the 

 order of their relative surface area. On the very fertile soil, where phosphorus 

 was not a limiting factor, higher yields were obtained from the Florida pebble 

 and Florida soft phosphates than from the other phosphates tested. On the soil 

 in a medium state of fertility, where phosphorus was distinctly a limiting 

 factor, acid phosphate in every case produced the highest yield to October 1, 

 as well as the Mghest total yield. 



An experiment with nitrogen as a top-dressing on plats treated with acid 

 phosphate, Florida soft phosphate, and Florida pebble phosphate resulted in a 

 marked increase in yield on the plat which had received acid phosphate. 



The results of these experiments are not considered as indicating that 

 Florida soft phosphate possesses any advantage over the other raw phosphates as 

 a source of phosphorus for cotton on Piedmont soils. The experiments, con- 

 ducted for only one year, will be continued to study the residual effects of the 

 different raw phosphates. 



The influence of certain factors on the time of opening of cotton, T. E. 

 Keitt and A. W. Murray (Georgia Sta. Bui. ISO (1919), pp. 21-34, fiff^- 3)-- 

 Tlie experiments reported were conducted to determine the influence of variet; 

 character of soil, quantity and kind of fertilizer, top-dressing, source of phos^ 

 phorus, percentage of potash, and the use of lime to revert soluble phosphates oi 

 the maturity of cotton. 



in a test of 22 varieties of cotton Piedmont Cleveland and Steinheimer Clev< 

 land led in amount picked to October 1, and these two strains with Allen Clev( 

 land and Scott Cleveland were among the five varieties giving the highest yiel( 

 to October 1. The four Cleveland strains mentioned, together with Alabfuni 

 Station Cleveland No. 721 and Georgia Station Cleveland No. 521, led all othei 

 in total yield. 



The fertilizer work was conducted on heavy clay, medium clay, and sandy 

 soil. On the heavy clay soil the largest total yield, the highest yield to October 



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