78 Development and Activities of Roots of Crop Plants. 



V. INVESTIGATIONS AT ALL STATIONS IN 192L 



In order to further check the results on root development, crops were 

 again grown at all the stations during 1921. These consisted of University 

 No. 21 oats, Marquis Spring wheat, and Manchuria barley. At the Peru 

 station. Early Ohio potatoes and Iowa Silver Mine corn were also grown. 



The small cereals were planted in plats of 25 square meters each and at 

 the same rate (which was somewhat greater than the preceding years, p. 41) 

 at all stations, viz, oats 64, wheat 90, and barley 72 pounds per acre. The 

 seed was from the same lot and the time of planting at the several stations 

 was approximately the same (March 24 to 30). 



Investigations at Peru, Nebraska. 



The experimental plats at Peru were the same as those of the preceding 

 year, the small cereals being planted on the land formerly occupied by corn. 

 A good seed-bed was prepared, the seed sowed evenly, hoed in, and the 

 plats leveled off with a rake. The plat for potatoes was prepared by spading 

 the soil to a depth of 8 inches. The tubers, from which all but one bud had 

 been excised, were planted in rows which were 3 feet apart. The pieces 

 of tubers were placed 2 feet apart in the row and at a depth of 4 inches. 

 The corn was level-planted on May 17 at a depth of 3.5 inches after the 

 plat had been spaded to a depth of 6 inches. The rows were 3 feet apart and 

 the kernels were placed at intervals of 1.3 feet in the row. Both corn and 

 potatoes were tilled with a hoe in such a manner as not to disturb the roots. 



Owing to a deficiency in rainfall, coupled with poor distribution, the crops 

 did not develop normally. At the time of harvest, about June 30, the oats 

 averaged 2.4 feet in height; the crop, though evenly developed, was thin, 

 having tillered so poorly that many single stalks occurred, while many others 

 had but one or two tillers. However, the grain was well filled. The stand 

 of barley was even thinner, single stalks being numerous and few plants having 

 the usual numbers of tillers. Barley averaged 2.4 feet in height and had 

 well-filled heads. Wheat was the poorest. The crop was very thin and 

 uneven in development; more single stalks occurred than those with tiUers. 

 It varied in height from 1.6 to 2.8 feet, with an average of about 2 feet. 

 The heads were small and only partly filled. Compared with 1919, also 

 a drought year, oats and wheat were 7 or 8 inches shorter in average height, 

 but the barley sHghtly taller. The stand was thinner in every case. 



An examination of the rainfall and soil-moisture records makes clear the 

 degree of drought. The rainfall during April was only 1.79 inches, over 

 70 per cent of which fell at one period (April 13 to 16). The rainfall for 

 May, 3.07 inches, was 1.56 inches below normal and also poorly distributed, 72 

 per cent faUing on May 7 to 10. June,^ with 3.35 inches of precipitation, 

 practically all of which occurred befoie the middle of the month, had a 

 deficiency of 1.38 inches. 



The available water-content of the soil in the oat plat and also in a check 

 plat of similar size kept free from all vegetation, is given in table 21. The 

 relatively low water-content at the time of planting, and especially during 

 June, is quite unusual for this station (c/. fig. 12). Table 21 indicates that 



* Record from rain-gage installed at Peru; other records from Nebraska City. 



