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alone to 42 bushels per acre as tbe average of seven years. We have not been 

 able to increase it any further by any addition of nitrogen, or potassium, or 

 both. On another of these farms, which had been subjected to exhaustive hus- 

 bandry before it came into the possession of the station, the average unfertilized 

 yield of wheat has been between 8 and 9 bushels to the acre. Where acid phos- 

 phate has been iised on this exhausted soil it has raised the yield for the seven- 

 year period to about IS bushels to the acre, and we have been able to raise it by 

 the use of acid phosphate, potassium, chlorid, and sodium nitrate to 29 bushels 

 to the acre. I mention this to bring out the point that experiments made on 

 unexhausted soils may give a very different result from those conducted on old 

 and exhausted lands, and we must take that fact into consideration in our 

 advice to the farmers of the State. It is paying us, on this exhausted land, to 

 purchase nitrate of soda for the purpose of growing wheat and corn and oats, 

 but we are trying to teach the lesson there in Ohio that nitrogen may be 

 obtained infinitely cheaper by the growing of leguminous crops and saving the 

 barnyard manure. Therefore we join Professor Hopkins heartily in saying that 

 Tio farmer can afford to purchase nitrogen in the form in which we find it in 

 these so-called " complete fertilizers," notwithstanding the wonderful effect such 

 fertilizers are producing on this exhausted land. 



H. P. Aemsby. I suppose Pennsylvania has the oldest experience in plat ex- 

 periments, and our results there fully confirm the experience of Professor 

 Thorne and Professor Hopkins, in so far as the economic feature goes. Our 

 soil is formed of disintegrated limestone. We find a marked increase, of pro 

 duction from the use of nitrogen, applying about 120 pounds to the acre. But 

 tliis increase is in no instance, I believe, a profitable increase. With potash on 

 our soil we get more marked results than Doctor Hopkins reports upon his soil, 

 but with the nitrogen the results fully confirm his, so far as the profit is con- 

 cerned, on a soil of probably rather more than average fertility. 



William P. Brooks, of Massachusetts. The experiments in the Hatch experi- 

 ment stations have been on soil which had been subjected to cultivation jjossi- 

 bly longer than most of the soils which have been referred to, and I rise to 

 make two or three points clear, if possible, in connection with the results upon 

 one field where we have followed a system of fertilization, similar at least in 

 outline, to, though differing in detail from th.it to which Doctor Hopkins has 

 referred. These ex]ieriments have occupied a field that had been in grass a 

 good many years without manure. This was broken up in the spring of 1889 

 and planted to corn. The average yield of four nothing plants was at the rate 

 of about 30 bushels to the acre. It was replowed in the fall and replanted 

 in corn the next year, and gave a yield at the rate of about 40 bushels to the 

 acre, without manure or fertilizer. Those same four nothing plats have been 

 left without manure or fertilizer ever since, and we have followed a general 

 rotation for the last seventeen years, including in the seventeen years eight 

 corn crops, while the land has been seeded to mixed grasses and clover twice. 

 Each time it remained in grass two years and each year it was mown twice. 

 Now at tbe present time the plats in that field which have not received manure 

 or fertilizer in all this period yield what, by courtesy, I call about four bushels 

 c-f shelled corn to the acre — at that rate. I say " by courtesy " because I fig- 

 ure bushels not by shelling, but by weight, and call 80 pounds at husking time 

 a bushel. But the crop on these plats was practically all " nubbins " — there 

 was really no corn there. This land, then, has produced, and will now produce, 

 after sixteen or seventeen years without manure or fei'tilizer, three or four 

 bushels of corn to the acre. We have had one plat in that field which evei'y 

 year throughout tbe seventeen years has bad an ai)plication at the rate of IGO 

 pounds of muriate of potash per acre, and the last time that plat was in corn 



