No. 4.] KEEPING UP FERTILITY. 81 



able forms ; for this Agawam " plain " land will not produce 

 even one good crop of corn without manure or fertilizer. 

 We also know that our crops cannot " lick the platter 

 clean," or, in other words, that in order that they may obtain 

 what tliey need there must be much more than they will take 

 up at hand. 



It does, however, impress me strongly that, since there 

 exist, even in the poorest soils, such enormous stores of 

 inert plant food, it does behoove us as farmers to so manage 

 our lands as to favor in all possible ways its conversion into 

 available forms. You have doubtless all heard or read of 

 the famous Englishman, Jethro Tull, who by thorough and 

 frequent working of the soil to a good depth raised better 

 crops of wheat for many successive years upon the same 

 land without manure than his neighbors did with it. Tull 

 followed laborious and painstaking methods of hand work 

 with the spade, — methods clearly not adapted to present 

 economical conditions ; but whatever the method followed, 

 work upon the soil costs, and it becomes, therefore, an im- 

 portant question to decide as to how far it will pay to 

 attempt to substitute tillage for manures, — a question, how- 

 ever, which must be left to individual determination. Thor- 

 ough drainage, fall ploughing, complete aeration and pulver- 

 ization of the soil before and during the growing season are, 

 however, means of keeping up fertility which often receive 

 too little attention. 



DiFFEREXCE BETWEEN NiTROGEX AND PHOSPHORIC AciD 



AND Potash. 



Before taking up the question of the selection and appli- 

 cation of manures and fertilizers with a view to increasinof or 

 keeping up the fertility of our soils, it is important to under- 

 stand the wide difierence in the extent to which soils are 

 capable of retaining nitrogen on the one hand, and phos- 

 phoric acid and potash on the other. We are indebted 

 largely to the careful and long-continued study of the drain- 

 age waters of the experimental acres at Rothamstead for the 

 knowledge that soils have very little capacity to hold the 

 former in its soluble compounds, such as nitric acid and 



