A VISIT TO ROTIIA.MSTED. 2-io 



That considerable differences would be observed in the ([uantity 

 of the cro]i was a result which tlieir experience with the same 

 manures ui»on other crops led them conliilently to expect, but 

 that the whole character of the crop should be wonderfully 

 alteiuid was certainly a result which even the most sanguine 

 could scarcely have anticipated. The soil of the park is a heavy 

 loam with a red clayey subsoil resting on chalk, having a good 

 natural drainage and a very uniform character and situation. 



It will be seen from an examination of the above taljle that 

 the weight of hay on the unmanur('(l ])lots (3 and 1.2) averaged 

 23 cwt. i)eracre; that the addition of 3i- cwt. superphosphate 

 (4 a) had no etiect in increasing the amount of the crop, a circum- 

 stance wliich may seem surprising to many wlio iiiid great 

 advantage from the use of super])lios})]iale u])on grass lauds ; Imt 

 it must be remembered that the soil here lias not been im- 

 poverished by the feeding of young cattle or of milk cows, both 

 of which abstract from the soil a large amount of phosphoric 

 acid. When to the superphosphate was added anniionia salts 

 (4 b), the crop was increased to 33 cwt., showing tliat the nitro- 

 gen was deficient, and that that deficiency caused the super]ihos- 

 phate to remain inactive. When to these were added mineral 

 manures (9), the crop was immediately increased to upwards of 

 50 cwt. per acre. Of the mineral manures, the sul])hate of 

 potash was the most important, for wlien it was omitted (10 h 

 and 8 h) the crop diminished a1)out 10 cwt.; the increased 

 amount of sulphate of soda not being competent to compensate 

 for the want of that constituent. When, in addition to the mixed 

 mineral manures, a dcnible application of ammonia salts, 80U lbs. 

 per acre, was given (11), a still further increase was obtained, 

 amounting during the first ten years to upwards of 60 cwt. per 

 acre, but this increase was not maintained during the second ten 

 years, showing tliat the quantity of mineral manures annually 

 api^lietl was relatively deficient, and tluit a large part of the 

 increase in tlie first decade was obtained at the expense of the 

 mineral wealth already in the soil. If, then, we limit our atten- 

 tion to the three important constituents, nitrogen, phos])horic 

 acid, and potash, we find tliat the supply of nitrogen naturally 

 in the soil was deficient, and capable of enabling only a limited 

 amount of the phosphoric acid and potash therein to be assimilated 

 by the crop. Tlie addition of a nitrogenous manure (■">) went far 

 to rectify that deliciency, but still did not pr(jduce a full crop, 

 the phosphoric acid and potash being now deficient. When the 

 phosphoric acid was added (4 h) a further increase was obtained, 

 but it was only when all three were applied (9) that a full crop 

 was the result. The smallness of crop on plot 7 was due to the 

 want of nitrogen, that on plot 4 h was due to the want of potash, 

 and had there been a plot on which phosphates had Ijcen omitted 



