No. 4.] MODERN POTATO CULTURE. 71 



nitrate and phosphoric acid, and another nitrate and potash. 

 We have repeatedly, in the course of the last dozen years or 

 a little more, sowed this entire field with mixed grass and 

 clover seed, and have seen the clover come up all over the 

 field, only to die out completely on every part of the field 

 to which potash had not been applied. 



Ex-Governor Hoard. Winter-killed? 



Professor Brooks. No, — starved. 



Ex-Governor Hoard. Do you mean to say it died in the 

 winter, or in the summer? 



Professor Brooks. It died out in the summer. It did 

 hot find the right conditions of soil for its growth. To o - et 

 the most advantage from the growth of clover, you want to 

 enrich the soil with phosphoric acid and potash, lightly, 

 and withhold nitrogen. Farmyard manure is not the best; 

 that makes the grass too strong. On the field I have been 

 talking about, where the phosphoric acid and potash have 

 been used, there is to day a splendid sod of mixed grass 

 and clover, and we usually cut two good crops of hay. 

 There has been no nitrogen applied to that for fourteen 

 years. In 1899, when the field was last in corn, one plot 

 gave a yield of at the rate of sixty bushels of hand-shelled 

 corn to the acre. It has had no nitrogen put upon it, and 

 it gets its nitrogen because of the profuse growth of clover. 

 If you get a growth of clover after your manure, you do not 

 get this advantage I am talking about, because the clover, 

 if it cannot find all the nitrogenous food it needs in the 

 ground, will take it out of the ground. In order to get this 

 great advantage, you must grow it where potash, lime and 

 phosphoric acid are abundant, and where nitrogen is present 

 in relatively small quantities. 



We have another field where every year for twelve years 

 Ave have used two-quarters of the acre manured at the rate 

 of six cords to the acre, and on the other two-quarters we 

 have used half that quantity of manure first and later two- 

 thirds, that is, four cords to the acre, with potash. The 

 field to-day is in grass and clover, and the clover is much 

 stronger on the part on which we put the little manure and 

 the potash. On the other the timothy is stronger and the 



