19 



Sfftot of Fe^dg oa Fortiliging Congtltuents . 



It has been not«4 above (p. /y) that many ^f^^de possess 

 a very high nitrogen and ush conts^at. It wou-u.d appear that 

 they might cause inju:'y by rmkovinr, either nitrogen or th« 

 mineral elements. On land wh»r© phosphoric acid or 

 potash or nitrogen is highly btfneficiai to crop<», it wouli 

 aesm reason abl« th&it a W6.%d with & high ash find nitrogen 

 content would c-^uk-s injury by removing the d^fici^nt ©lament 

 or tiemento whatever they might be. ?ut in the discussion 

 undsr thia haad, nitros'Sn will receive -the greatest share 

 of att'=»nt.ion, since nitrates cease to form after the soil 

 moisture reaches a certain low ximit, and since the nitrates 

 in the soil show a rjreater variability than the other 

 sssential elements, (©onsidsrable attention will be paid to 

 phosphoric acid, and but little will be givt^n to potash. 

 The potash requirement of soils is not so variable as either 

 phosphoric acid or nitrates, and data is not so available. 



Snyder (Soils and Pertiliaers, 1x5) states, "Nitrifica- 

 tion cannot ta}ta place in a soil deficient in moisture. 

 As m aii ferraentation i)r-oces3«s, so with nitrification, 

 moisture is neesssarj' for the chemical changes to talte 

 place. In « very dry time nitrification is arrested for 

 the ipant of Tpc-ter.** 



Warrenton (Physical properties of Soils, 95) refers 

 to experiments by Schloesing Jr. (Coiapt. rand. OXXV, 824) 



