HOLKHAM EXPERIMENTS 39* 



Ibs. of ammonia salts with phosphates and potash, yielded in 

 the three best seasons an average produce of 49-2 bushels, or 

 rather of 51 bushels if we take the bushel to be 60 Ibs. in 

 weight. The return for i cwt. of sulphate of ammonia applied 

 is now 8'3 bushels on plot 6, and 7-4 bushels on plot 7 ; or 8*7 

 and 7-7 bushels respectively if we take the bushel at 60 Ibs. 

 There is also at the same time a return of 9 cwts. of straw. In 

 seasons of average character the produce from the same dress- 

 ings of sulphate of ammonia was 5 bushels of corn, and 5 cwts. 

 of straw. 



In a very fine season the yield of the soil, and the return 

 from the manure applied, is so much increased, that moderate 

 dressings of manure suffice to produce the fullest crops. The 

 produce of plots 7 and 8 is more nearly alike in a fine season 

 than in one of inferior character. A fine climate thus occasions 

 a great economy in manure. 



2. Holkham and Rodmersham Experiments. 

 The field experiments on wheat carried on at Holkham, 

 Norfolk, and at Rodmersham, Kent, were repetitions of the 

 trials made at Rothamsted ; the manures employed were in 

 each case supplied from Rothamsted. The results are of 

 interest as made on different soils, and as showing a very 

 different return for the ammonia applied. Reports of these 

 experiments will be found in the Journal of the Royal Agricultural 

 Society, 1855, 207; 1862, 31. 



The Holkham soil is described as a light, rather shallow, 

 brown sand loam, resting upon an excellent marl. The crop 

 preceding the wheat was white turnips manured with farm- 

 yard manure and guano. The turnips had been carted off. 

 The land was evidently in high condition, the unmanured plot 

 in the first year of the experiment yielding 39! bushels of 

 wheat. The addition of 400 Ibs. of ammonia salts resulted in 

 an increase of only 3 bushels. The quantity of ammonia 

 applied was clearly far larger than the condition of the land 

 and the character of the season could turn to profitable 

 account. In Table VII. the results of the first season are 

 excluded, and the average produce of the three following 

 seasons is given. 



