No. 6. DEPARTMENT OF AGRICULTURE. 233 



PROF. COOKE: I should say not. There is no acre of asparagus 

 that can come anywhere near using that much nitrate of soda. It is 

 customary to put on more nitrate of soda than the crop can use up, 

 putting it on so that we can be sure of having enough. 



MR. WAGNER: Is not the soluble mineral matter of potash and 

 phosphoric acid lost in the liquid manure if applied to a soil, es- 

 pecially on hillsides, when there is no plant growth to take it up 

 and heavy rainfall to carry it off? 



PROF. COOKE: Not if the soil is in such condition that the liquid 

 manure can ever get into the soil. Of course if the hillside is very 

 steep and then a heavy rainfall comes so as to wash the whole thing 

 off the hill, it will be lost. 



A Member: Can the fertility of a farm be retained without the aid 

 of commercial fertilizers by feeding the hay and fodder on the farm? 



PROF. COOKE: You can't build up a farm unless you bring some- 

 thing from the outside or else save every bit of the fertility produced 

 on the farm; even then the process of building up will be very slow. 



A Member: Will corn crops plowed under help out in this case? 



PROF. COOKE : What you are doing in all this sort of operation 

 is, merely helping to set free the plant food that is already in the soil. 

 You are not adding anything; you can't build up the amount of plant 

 food there in that way; the most that you can do is to keep the farm 

 from running down. 



MR. PERHAM: Is it advisable to sow nitrate of soda on sod for 

 growing grass? 



PROF. COOKE : Nitrate of soda is an expensive plant food. Hay 

 is one of the comparatively cheap crops, and I very much doubt if 

 there are many conditions in Pennsylvania where a person can af- 

 ford to pay for nitrate of soda to raise grass. 



A Member: Will Nature not take care of the soil and make it 

 better at all times where man does not interfere? 



PROF. COOKE: If you turn the soil out and leave it to itself, it 

 does improve in the sense that some plant food there becomes avail- 

 able; it is a very slow way, though, of doing it. 



A Member: Does not Nature make new soil and hence new avail- 

 able plant food from the rocky crust of the earth? 



PROF. COOKE: It does, but this is too slow for our modern agri- 

 cultural methods. 

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