

**4 « 



The method consisted of weekly appHcations of the fertiHzers at various 

 rates upon isolated sections in the benches, beginning about October i 

 and continuing until about May i or until injury became serious. 



Effects of Overfeeding on Condition of Plants. — The rapidity with 

 which the sections of carnations became affected followed in a general 

 way the solubility of the fertilizer used.* The solubilities** of the pure 

 substances in water per hundred parts at o° are given in Table I. 



Table I. — Solubilities of Pure vSalts in Water at o°. (Parts per ioo.) 



NaNO, (NH4)2S04 NaCl KCl K2SO4 



72.9 7I-0 35-7 28.5 8.5 



Na2HP04.i2H20 CaH4(P04)2.H20 CaHP04 CaS04.2H20 



6.3 4 (15°) 0.028 0.241 



Commercial acid phosphate consists of about equal parts of mono-calcium 

 phosphate and calcium sulfate. Reversion to monohydrogen phosphate 

 in presence of bases in the soil would further decrease the low solubility 

 of the acid phosphate and by double decomposition with calcium, iron 

 and other bases in the soil render the sodium phosphate first applied less 

 soluble, as pointed out by Cameron and Bell.'^ 



Dried blood, giving soluble products at a rate depending upon the 

 rapidity with which bacterial decomposition proceeds, could not be 

 rated as having a known solubility without a study of the bacteriological 

 activity of the soil mixture. Tests with litmus paper showed that the 

 surface of the soil, neutral at the beginning of the experiment, became 

 acid seven or eight days after the addition of the dried blood. Soil to 

 which ammonium sulfate was applied became acid as quickly also. 



Single applications of ammonium sulfate and sodium chloride at the 

 rate of 12.5 kg. per loo sq. ft. made on December 3, 19 13, produced marked 

 injury within a week's time. Equal amounts of potassium sulfate, at 

 this time, followed by further applications at intervals of one or two 

 weeks, at the rate of 1.25 kg. per 100 sq. ft., produced no signs of injury 

 until about January 15, when a lack of turgidity became noticeable, fol- 

 lowed by a gradual stunting of growth, with the more pronounced signs 

 appearing only after the middle of March. Signs of injury in sections 

 treated in the same manner with sodium phosphate became evident even 

 more slowly, while acid phosphate produced no apparent injury even in 

 the largest applications. 



* The impurities in the ammonium sulfate, potassium sulfate (in this case 1.26% 

 of chloride as sodium chloride) and disodium phosphate are not sufficient to interfere 

 with the use of the solubilities of the pure substances as a rough measure of the solu- 

 bilities of the fertilizers themselves. 



** Van Nostrand — Chemical Annual, 19 10. 



