FERTILIZERS FOR VEGETABLES 



233 



time when the tubers were forming, it might start the trouble 

 with the scab. In that case, the same treatment would an- 

 swer, the application of chemical manure in place of or along 

 with those substances. 



Question: A better way would be perhaps to put the 

 manure on the preceding crop? 



Professor Van Slyke: Yes. To go back, I am very 

 much interested in that condition of things in Bermuda. In 

 putting on the organic matter, you get little or no leaching. 

 With chemical fertilizers on that sandy soil, there would be 

 great liability of large loss, and I would suggest that in 

 further work only a part, five or six hundred pounds, be put 

 in the soil at the start and the other be used as a surface ap- 

 plication. 



Mr. Wortley: I have arranged to repeat those experi- 

 ments entirely and to have duplicate ones. 



Professor Van Slyke : The soil must leach. The nitrate 

 would be the first thing to go out. 



Mr. Wortley : I used tankage and nitrate of soda. 



Professor Van Slyke: That certainly would not go out 

 that early in the season. 



Does Nitrate Improve Soil? 



Mr. Russell: Will sodium nitrate in any way deplete 

 the natural fertility of the soil? 



Professor Van Slyke : It will in this way : If you have 

 in the soil already considerable amounts of potash and phos- 

 phoric acid and you put on large amounts of nitrogen with- 

 out putting on phosphoric acid and potassium compounds, 

 the nitrogen of the nitrate of soda will promote the growth 

 of the crops and they will use up the potash and phosphoric 

 acid there is in the soil ; and if you go on putting on nitrate of 

 soda without putting on phosphoric acid and potash, the re- 

 sult will be depletion of the latter. Nitrate of soda has a 

 very marked effect in liberating potash in the soil. In your 

 clay soils where you are growing anything that needs potash, 

 if you use the nitrate of soda, you do not need to use in the 



