ECOLOGY. 345 



in containers large enough to permit normal root growth. The containers were 

 filled in such a manner that the soil had the same relative position it occu- 

 pied in the field. Before filling the containers, the soil from each level was 

 thoroughly mixed, brought to the desired water-content, and certain levels 

 impregnated with the proper amount of NaN0 3 or Ca(HP0 4 ) 2 . The soil was 

 separated into layers a foot or less in thickness by means of the usual wax 

 seal, which is easily penetrated by roots but prevents the movement of 

 water and solutes. Barley was grown in a row of 30 plants across each con- 

 tainer, the latter being placed in trenches in the field and barley sown 

 about them to simulate normal field conditions. Twenty-five containers were 

 used, 9 for nitrate, 9 for phosphorus, 3 for control crops, and 1 without a crop 

 for checking nitrification and denitrification. 



The amounts of N0 3 absorbed where the soil was fertilized only in the first 

 foot, at 1 to 1.5, 1.5 to 2, or 2 to 2.5 feet, were respectively 462, 291, 269, 312, 

 and 134 parts per million. Where the fertilizer was placed both in the first 

 foot and at 1 to 1.5, 1.5 to 2, or 2 to 2.5 feet, the amounts removed were 351 

 and 175 parts per million in the first case, 401 and 485 in the second, and 431 

 and 152 in the last. Thus, the total amount removed when an additional layer 

 was fertilized was at least 14 per cent greater than the highest amount when 

 any single layer was fertilized. In the series with single fertilizing the average 

 height per stalk increased progressively from 55 cm. when the nitrate was in 

 the first foot to 81 cm. when in the 2 to 2.5 foot layer. With double fertilizing 

 it was slightly less than with single and much less than when the latter was in a 

 deeper layer. The average height of the controls (65 cm.) was greater than in 

 any of the double-fertilized series and also than in any of the single-fertilized, 

 except at the depth of 2 to 2.5 feet. The plants of the phosphorus series 

 averaged taller than those double-fertilized with NaN(>3, and also than those 

 single-fertilized, except at depths greater than 1.5 feet. 



The number of stalks per container decreased progressively from 60 to 36, 

 depending upon the depth at which the nitrate was placed. In the double- 

 fertilized series they varied in number from 65 to 71, considerably greater than 

 the average number, 47, in the controls, thus indicating that double fertilizing 

 promotes tillering, in addition to retarding the height growth of barley. 

 This also gave an average weight of straw 42 per cent greater than for the 

 controls and likewise increased the yield of straw over that obtained for a 

 single application. The weight of grain was least for the single-fertilized 

 series and was slightly less in the double one than in the controls. The 

 nitrogen-content of the grain of the double series was practically the same for 

 all combinations of depths of fertilizing. It was 35 per cent greater than that 

 of the controls and 12.5 per cent more than where the fertilizer was placed in 

 the surface foot alone. 



Relation of Holard to Root Development and Yield, by F. C. Jean and 



J. E. Weaver. 



Crops of Marquis spring-wheat, corn, alfalfa, sugar-beets, and potatoes 

 have been grown in plots of one-thirtieth of an acre at Greeley, Colorado, 

 on dry land and under semi-irrigated and fully irrigated conditions. The 

 methods of preparing the seed-bed, tilling, etc., were essentially those of the 

 usual farm practice, the main objective being to determine the effect of the 

 different quantities of water on root development and yield. In addition to 

 continuous records of temperature, humidity, and evaporation, the holard 



