170 EXPERIMENTAL P^RMS. 



64 VICTORIA, A. 1901 



the nitrogenous portion of the ration, for it really stands for albuminoids, which, as 

 already stated, are the most important of all food constituents in maintaining life 

 and building up of the ananal tissues. With green and immature fodders, however, 

 the term ' crude protein ' comprises not only the albuminoids, but also other nitrogenous 

 substances (nitrates, amides, &c.), which, it may be remarked, have a very much lower 

 feeding value — indeed; it is not probable that these compounds are a source of nitrogen 

 to the animal system. In order to ascertain the propoi'tion of these two forms of 

 nitrogenous compounds and thus arrive at a more correct knowledge of the feeding 

 value of rape at different periods of its growth, we determined the nitrogen present 

 ill the non-albuminoid compounds, as well as in the true albuminoids. A suivey of the 

 data will reveal that as the plant grows the proportion of the latter to the former 

 increases, and, therefore, the nitrogenous matter of the older plants is more valuable 

 from the food standpoint; in other words, the non-albuminoid nitrogenous substances 

 tend to decrease with the growth of the plant. This statement, however, must be 

 considered in connection with another fact, made equally clear by our data, namely, 

 that as the season advances the rape shows a falling off of both the albuminoid and 

 non-albuminoid nitrogen. Weight for weight, the younger plant is .richer in both 

 classes of these compounds than the older rape. This is due to the fact that the 

 assimilation of nitrogen from the soil by the plant goes on more rapidly during the 

 first month or six weeks of growth than later. The larger yield per acre obtained 

 from a crop three months old compared with that of two months, very largely offsets 

 this decline in the percentage of albuminoids, and no doubt makes it desirable from 

 an economic standpoint in many instances to allow the crop to come to the more 

 mature period, provided always that the plant is not becoming unpalatable from the 

 development of hard and fibrous stalks. 



Nitrogen-free Extract or Carbohydrates. — The percentage of nitrogen-free extract 

 increases greatly in the fresh fodder, as well as in the dry matter, during the latter 

 weeks of growth. 



Ash or Mineral Matter. — A comparison of the percentages of this constituent in 

 the dry matter makes it evident that it is more particularly during the earlier weeks 

 of growth that the rape plant makes its greatest draught upon the available stores of 

 mineral plant food in the soil. 



To sum up the foregoing observations, we may conclude: (1) that the rape plant 

 of four to six weeks old contains more water and less dry matter than that of three 

 months; (2) that the dry matter of the younger plant is relatively richer in fat and 

 albuminoids (protein) than that of the older rape; (3) that the non-albuminoid nitro- 

 genous compounds decline as the se^ason advances; (4) that the percentage of fibi-e 

 increases with the age of the plant, due to the greater development of stalk; (5) that 

 the nitrogen-free extract increases with the growth of the plant; (6) that the per- 

 centage of ash in the dry matter decreases as growth progresses. It would appear, 

 therefore, that on the whole the dry matter of the six weeks old rape has a higher 

 feeding value than that of rape of three months' growth, but that, owing to the 

 increased percentage of dry matter in the mature plant and the much larger yield of 

 crop obtained from the latter, the feeding value per acre at the more advanced period 

 of growth is the greater. And this will probably be more emphasized in rape sown 

 broadcast than in drills, as the proportion of stalk to foliage in the former will be less. 



The fact that the assimilation of the soil phxnt food elements takes place chiefly 

 during the first six weeks of growth points to the benefit to be derived from a thorough 

 preparation of the soil. 



Compared with other forage crops, rape, although it possesses a large percentage 

 of water, takes a high place, owing to its, comparatively speaking, large percentage 

 of nitrogenous constituents (albuminoids). In this pespect it closely resemble? clover 

 and other legumes, which, for the same re»ason, arc justly considered to have a feeding: 

 value above most of the grasses and root crops in general. 



