282 Tlie Siigara and Albuminoids of Oat Straio 



practical value. Normal leail acetate gave concordant results but left 

 a considerable fraction unaccounted for. Copper hydrate gave very dis- 

 cordant results. The (N x 6J) precipitated by basic lead acetate added 

 to the (N •; 6J) volatile with steam and potassium hydroxide gave a 

 result on the average of 70 tests of -QUO per cent, above the total (N x 6^). 

 The average difference between the sum of those two parts and the whole, 

 neglecting signs, was -184 per cent. Of the 70 samples thus fully analysed 

 the average "albuminoids" was 3-26 per cent, and the average ''amides" 

 was -29 per cent, or only 8-9 per cent, of the total. 



I. Effect of Manure on the Composition of Oat Straw. 



The compilation of averages of large numbers of trials, such as these, 

 presents many difficulties. Classification is often rather difficult and 

 some observ'ations must be rejected as not capable of classification. By 

 dividing the results of the analysis of oat straw into three groups we 

 find the following figures. Unless otherwise expressed the results have 

 been calculated from 1919, 1920 and 1921 crops. 



A. 35 samjiles of oat straw grown with very much organic nitrogen 

 such as ploughed in leas, apparently rich, omitting doubtful "clover 

 takes" but including land with heavy dressings of dung. 



I.aevuloso ... 

 Total sugar 

 Albuminoids 



B. 29 samples of oat straw top dressed witli suljahate of ammonia. 



Laevulose 1U2 "„ +-21 



Total sugar 3-28 ±-24 



Albuminoids 2-54 ±"12 



C. 21 samples of oat straw grown with little if any nitrogenous 



manure in any form. 



Laevulo.se 1-65% i-28 



Total sugar 3-47 ±-45 



Albuminoids 2-57 ±-16 



The combinations of these results which give significant diflferences 

 are; Much organic nitrogen gives an oat straw richer in albuminoids 

 than that given by httle or no nitrogen, to the extent of 1-27 % ± -22, 

 as judged by 56 tests. Much organic nitrogen gives an oat straw richer 

 in albuminoids than that given by sulphate of ammonia top dressings, 

 to the extent of 1-30 % ± -21, as judged by 64 tests. Organic nitrogen 

 manures give oat straw richer in albuminoids than that given by all 

 other manures, to the extent of 1-28 % ± -17, as judged by 85 tests. 



Other probable results are: Organic nitrogen manures depress the 

 amount of laevulose in oat straw to the average extent of -59 % ± -21. 



