INFLUENCE OF AMMONIA ON QUALITY 49 



straw to corn is but little increased on plot 7, and is much more 

 increased on plot 8, where an excessive dressing of ammonia 

 salts is applied. At Woburn the proportion of straw on 

 plot 8 is very little more than on plot 5. At Woburn, the 

 ammonia salts yield a rather greater proportion of corn than 

 at Rothamsted. We have already seen in Table IX., that a 

 spring dressing of ammonia salts yields a somewhat larger 

 proportion of straw than an autumn dressing. 



The weight per bushel of the grain is improved by the 

 use of ammonia salts, except where the supply of the ash con- 

 stituents of the crop is defective. The average weight per 

 bushel at Rothamsted during forty years was for the un- 

 manured wheat 58-2 Ibs., and for that continuously manured 

 with farmyard manure 60*2 Ibs., while for the three plots 

 receiving ammonia salts with superphosphate and alkalies the 

 weights per bushel were 59*6, 59-7 and 59-5 Ibs. \Vhen, how- 

 ever, the ammonia salts were applied alone, the average 

 weight per bushel sank to 57-2 Ibs. Similar results appear at 

 Woburn. 



The wheat grain obtained in the experimental field at 

 Woburn in 1897 has been valued by experts (Journal of the 

 Royal Agricultural Society, 1898, 551). The crop that year was 

 a very small one. The highest value was given to the wheat 

 grown on plots 5 and 8, with sulphate of ammonia, superphos- 

 phate, and alkali salts ; the price per quarter of this wheat 

 was judged as from 2/- to 2/6 above that yielded by the corres- 

 ponding plots receiving nitrate of soda. The weight per 

 bushel is generally somewhat higher when wheat is grown by 

 ammonia salts than when grown by nitrate of soda; this 

 difference is more marked at Woburn than at Rothamsted. 



The percentage of nitrogenous matter in the grain is very 

 slightly affected by the use of ammoniacal manures. Lawes 

 and Gilbert have published the average percentages of 

 nitrogen found in the grain and straw of some of the wheat 

 plots during twenty years, 1852-71, Transactions of the Chemical 

 Society, 1884. Dr. T. B. Osborne has shown that the mixed 

 albuminoids of wheat grain contain 17-6 per cent of nitrogen. 

 Making use of this fact we are able to calculate from Lawes 



