158 Bulletin 130. 



was easily disintegrated and fined, thus bringing into a more 

 av^ailable condition its mineral fertilizing elements. By the fre- 

 quent tillage given to the plats not only was nitrification pro- 

 moted, but the mineral elements were partly liberated and made 

 more available for the plant's use. 



In a soil analyzing about one-half of the average in fertility, 

 enough plant- food was liberated and made available by means of 

 tillage alone to insure a vigorous plant growth. This partially 

 explains why the application of chemical fertilizers on plats 6 and 

 7 and 29 and 50 failed to give any marked beneficial result. It is 

 probable that had there been more moisture in the soil better 

 results would have been shown from the fertilized plats, but under 

 the existing conditions the fertilizer was applied at a loss 

 as far as any effect was evident on the yield of pota- 

 toes. True, the fertilizers applied may be of some benefit to 

 future crops, but the farmer can scarcely afford to purchase high- 

 grade chemicals and apply them to his soil except for their imme- 

 diate benefit to the succeeding crop, as it is well known that they 

 become less readily available for the plant's use after having been 

 in the soil for a considerable time. While this is true of the min- 

 eral fertilizers, it is more especially true of the nitrogenous, for if 

 the most readily available form of nitrogen is applied, as in 

 nitrate of soda, that portion of the nitrogen which is not made 

 use of quickly by growing plants may be largely lost to the soil, 

 being carried away by the drainage water. 



Shall the attempt be made, not only in potato culture, 

 but with all farm crops, to substitute fertilizers for 

 tillage ? With potatoes at 25 cents per bushel and fertilizers 

 at $25 per ton, is it good policy to purchase plant-food before an 

 earnest effort has been made to utilize that vast store which nature 

 has provided ? If the effort has been made and the soil fails to 

 respond satisfactorily, then it is not only justifiable, but it may 

 be a wise policy to supplement the stores of the soil with addi- 

 tional readily available plant-food. The low average yield of the 

 state is not so much due to lack of plant-food as to deficiency of 

 moisture. It has been estimated by Professor King* that for 



*The Soil, p. 155. 



