No. 6. DEPARTMENT OF AGRICULTURE. 442 



taining this element. Sow broadcast 8 lbs. nitrate of soda on the 

 wheat and corn plots, leaving a plot each for wheat and corn unfer- 

 tilized. Slioiild both corn and wheat re»i)ond favorably to the ap- 

 plication of nitrogen, then the soil is in need uf available nitrogen. 

 Should the wheat alone respond and the corn not. then the soil is not 

 in great need of nitrogen, but does n(i( coulaiii nun li in a\ailable 

 form. 



To test the soil whether it is defiicienl in phosi)horic a<id. nsc the 

 same method as above, and apply 1(5 lbs. acid phosphate. Sow one 

 plot with barley and the other with turnips. If both cro])s show- 

 marked benefit then the aoW is in need of available ])hosi)horic acid. 

 If only the turnips respond then the soil contains a sufficient amount 

 of phosphoric acid. To determine whether a soil is deficient in 

 potash, proceed in the same way as before with the plots, and use 

 potatoes and oats. If there is a decided increase of yield in both 

 cases the soil is in need of available potash. If the potatoes alone 

 respond and there is very little difference in the oat crop, indicates 

 that the potash is not in the most available form, but that it is not 

 deficient, especially is this the case if there is no increase in the oat 

 crop. The importance of these field trials is obvious to any one, 

 for in this way the farmer can analyze his own soil, and can discover 

 in two seasons its fertilizer deficiency', whereas if whole fields were 

 taken for the trials, at least six to eight years would have been re- 

 quired, and during all this time the soil would not have received the 

 proper fertilizer, and unnecessary and expensive plant food would 

 have been provided. *These trials will help us to answer the ques- 

 tion, does the use of fertilizers pay? What quantities to use? How 

 and when and for what crops to use it? They also give us some 

 idea of the feeding capacities of our agricultural crops, and in this 

 way help us to establish a rotation by means of which we can secure 

 the best results for our soils, and get the largest yields for labor and 

 fertilizer expended. 



ROTATIONS. 



1. In a rotation, a shallow and deep rooting crop should follow 

 each other ,so that the demand for plant food is shifted. 



2. Crops that produce humus and crops that consume humus should 

 alternate or if possible be raised together. 



3. Crops should be rotated so that the fertilizing materials left by 

 the preceding crop are in the best condition for the succeeding one. 



4. The weak feeding crop if it is a desirable one should be put in 

 the rotation when the fertilizing substances are in the most avail- 

 able form. 



• These trial experiments are similar to those given In Snyder's Chen?J.«t?y Qf Spi!? ^jjj 

 fevtiUr.er with a few additions of other experiments. (Author.) 



