No. 4.J CHEMICAL AND FARM MANURES. 175 



of greeu crops. I do not plough in a crop that has a food 

 value. I have o-rown clover to a orreat advantage over what 

 it is commonly grown. 



Mr. Sessions. Your experience has proved that the pot- 

 ash helps out the clover ? 



Professor Brooks. Always. We have been putting pot- 

 ash on four out of fifteen plots. On different plots we have 

 various combinations of fertilizers and ingredients, — lime, 

 phosphate, nitrate of soda, barn-yard manure, etc. We 

 have kept it up year after year, similar manures on similar 

 plots, then planted with clover and sowed back and forth 

 and across the field, so that we would have the same amount 

 of seed on all plots. Where we put the potash there is the 

 clover every time ; where there is no potash there will be no 

 clover. Potash is not the only thing essential. You must 

 make sure that every one of the constituents of plant food 

 is present in abundance. 



Something was said by the speaker this morning concern- 

 ing the relative value of diflerent materials. I want to add 

 one other point. Generalizations, I admit, are dangerous ; 

 conditions alter cases, alter results ; but this generalization 

 I believe is safe. For all those crops that must make most 

 of their growth in the early part of the season you will 

 probably without exception find that nitrate of soda is alto- 

 gether the best source of nitrogen that you can use. The 

 reason is clear to most of you, and that is, that the plants 

 feed upon nitrate nitrogen to the best advantage. It is in 

 the best form in the nitrate. Give nature time, and she will 

 make nitrates out of sulfate of ammonia, out of dry blood 

 and out of barn-yard manure, but it takes time. 



If we want to get spinach or roots or a crop of asparagus 

 early in the spring, nitrate of soda is very much superior to 

 sulfate of ammonia or dry blood. We have found in our 

 experience, when it comes to tomatoes or corn or second 

 crops of spinach or beets, the sulfate of ammonia gives as 

 good and sometimes better results than nitrate of soda. You 

 see the reason. The nitrate of soda is ready to feed the crop 

 you put it on, hence it is important for the crops that make 

 their growth in the early part of the season. The dry blood 



