THE GARDEN PRIMER 



not perhaps enter into the beginner's gardening, but 

 who can tell what moment the beginner, inspired by 

 success and other things, is going to branch out and 

 become a real scientific agriculturist who wants to 

 know everything? And then besides, who can know 

 too much, even though he be but a beginner? 



It is only recently, comparatively, that investi- 

 gators have been led to beheve that plants give off 

 certain organic substances during the processes of 

 growth which, accumulating in the soil, are harmful 

 to the successive growth of plants of the same kind. 

 This may be the reason, or one of the reasons, why 

 the benefits of crop rotation are so marked: the soil 

 is freed from the toxic matter emanating from one 

 species in the three or four years during which other 

 crops are grown upon it. Sometimes — not often to 

 be sure, but sometimes — poor and sterile soil may be 

 poor and sterile because thus poisoned. 



But this is , a big subject, and such a condition 

 Mnll hardly occur in any excepting a very extensive 

 garden. So one need not go into the matter at 

 first. However, remember it if later experience ever 

 brings you the baffling problem of a soil that con- 

 sistently and obstinately produces only failure under 

 every kind of manipulation. There are such — soils 

 that will not >ield nourishment enough to sustain 

 plant life — but happily they are being studied and 

 experimented on until the reasons for their sulkiness 

 stand small chance of remaining secret much longer. 

 And every State Agricultural Experiment Station is 



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