SOURCES OF NITROGEN OF PLANTS. 99 



long cultivation, especially of light soils, the vegetable matter rapidly disap- 

 pears, the land seems to bleach out and clover is not a success. May not this 

 be caused by a deficiency of the very material upon which clover exerts such a 

 wonderful power? The need of keeping up the supply of humus in the soil 

 and thus securing one condition for the best developmeut of clover appears 

 evident. In this battle of life, if the charge of the clover brigade ends in 

 defeat, the rest of the campaign becomes a desultory skirmish with hard times. 



THE PKOCESS OF RIPE^STIXG. 



In the clover and wheat plants of 188'-2 no ripe seeds were formed, and the 

 wheat did not head out. In 1883 the plants grew all winter, the wheat formed 

 heads, but the blighting of the crop by excessive hear prevented seed formation. 

 In 1884 the spring wheat headed out, and I suspect seed formation took place, 

 from the way the mouse overhauled the heads of wheat. In 1885 the four 

 wheat plants with thin branches formed a number of shrunken grains weighing 

 5.29 grains (air dry). The grains had about the appearance of some wheat I 

 cut just as the milk began to appear in the kernel, in some experimental 

 researciies in 1879. The shrunken and immature grain in the experiments of 

 1879 was found to be richer in albuminoids than the phimp and fully ripened 

 grain. The same result comes out in the imperfect grain of this experiment, 

 the amount of allniminoids being 15.37 percent. It is the common impression 

 tluit the shrunken wheat has but little vahie for food as compared with plump 

 grain, whereas it is of greater value pound for pound, because richer in the 

 most highly developed constituents of animal food. 



VALUE OF THE STRAW. 



The straw of this imperfectly ripened gram was much richer in nitrogen 

 than ordinary wheat straw. Wheat straw from the straw stack was analyzed 

 during this investigation and found to contain .28 of one per cent of nitrogen, 

 whereas this straw with partially ripened grain contained 1.2 per cent of nitro- 

 gen, or more than four times as much as ordinary wheat straw. It is nearly 

 as rich in albuminoids as timothy hay. 



This suggests an inquiry into the fodder- value of wheat straw at different 

 periods of ripening. In the investigation into the value of wheat at different 

 periods of cutting, no attention was paid to tho straw. I propose this year to 

 extend the investigation into the value of the straw of wheat and other grains 

 at various periods of ripening, to see whether it is worth while for the farmer 

 to cut his grain at a certain stage of ripening with a view to the value of the 

 straw as food for stock. If early harvesting will give greater profit in the value 

 of the straw, as it certainly does in the grain of wheat, then it is a fact which 

 the farmer should know and use. 



Mr. Ball: What are the practical deductions from these experiments regard- 

 ing nitrogen? 



J)r. Kedzie: Grow clover or other legumes and see that they are provided 

 with plenty of humus from which to draw their nitrogen. 



Whether plants can use the free nitrogen of the air has been decided in neg- 

 ative by numberless experiments. 



Mr. Ball: I understand that clover can utilize inert nitrogen which wheat 

 cannot, and convert it into a form in which wheat can use it. 



Dr. Kedzie: Exactly. In cultivation, a certain amount of nitrogen is avail- 

 able in any soil, but the larger part is not available for cereals. 



