956 EXPERIMENT STATION RECORD. 



Rows of oats and rape were planted on 3 sandy plats in the plant house on March 

 15. The first received no fertilizer, the second a small amount of sodium nitrate, 

 and the third double this amount. The nitric nitrogen in the plants decreased from 

 the first in those receiving no fertilizer, increased rather strongly in the second plat 

 at first but decreased largely as the i)lants matured, while the third plat showed a 

 slight decrease toward the end. On June 6, when the oats were in bloom, the per- 

 centage of proteid nitrogen on the first plat was 1.29, on the second plat 1.63, and on 

 the third 1.70, corresponding to 8.06, 10.19, and 10.63 percent of protein, respec- 

 tively. This shows a gain in the percentage of protein of 26.3 for the smaller amount 

 of nitrate fertilizer, and 31.88 for the larger amount. The analyses of the ripe seed 

 taken July 1 show a percentage of proteid nitrogen of 2.57 on the first plat, 2.79 on 

 the second, and 2.77 on the third. 



Corn Avas grown in the field on manured and unmanured plats and on soil planted 

 to potatoes on clover sod the year before. There was a considerable difference in 

 the amounts of nitric nitrogen in the soil water of the manured and unmanured 

 plats as determined July 8 and 29. This result is considered due to the actual differ- 

 ence in the soil fertility, the growth of the crop, and leaching rains. The amount 

 of nitrates was largest in the unnianure<l soil and the percentage of nitrates and of 

 proteid nitrogen in the plant was also greater on the unmanured land. The manure 

 decreased the percentage of protein in the crop but produced the greater total amount. 

 "Contrary to the general rule, the plants which made most vigorous growth con- 

 tained the smaller percentage of protein. It would seem that the stimulating 

 influence of the manure had been chiefly due to something other than the nitrogen 

 it contained, or at least to the nitrogen supplied the plant in the form of nitrates." 

 Corn following potatoes on clover sod in rotation contained a larger percentage of 

 protein than the crop from the manured plat. Corn grown near trees contained 0.97 

 per cent of proteid nitrogen on August 18 as compared with 1.31 per cent in corn 

 not affected by trees. On September 5 the result was 0.86 and 1.09 per cent, 

 respectively. 



An experiment with corn grown with oats and rape was made in the plant 

 house on 3 plats arranged and treated as described under the experiments with 

 oats. "The results of this experiment would point toward four conclusions: (1) 

 That the percentage of protein in the plant is dependent directly on the amount of 

 nitrates in the soil; (2) that corn on different fields may make very nearly equal 

 growth while differing materially in percentage of protein i)roduced; (3) that beyond 

 a certain point the ]>ercentage of protein is not increased by excess of nitrates; and, 

 (4) that in the presence of a sufficient amount of nitrates in the soil, variations in the 

 growth of the plant are caused by the amounts of salts in the soil other than nitrates." 

 The corn on plat 1 contained 8.44 per cent of protein; on plat 2, 9.94 per cent; and 

 on plat 3, 11.25 per cent. 



Cowpeas were grown in jars under the treatment that was given oats grown in the 

 same way. The fertilizers applied produced a greater effect on the growth of the 

 plants with cowpeas than with any other crop in these experiments. The percentage 

 of nitric and proteid nitrogen in the dry matter was largely in favor of the plants 

 having received the largest amounts of fertilizer. The soil did not contain tubercle- 

 forming bacteria, and plants inoculated about August 1 on the South Carolina cowpea 

 soil hatl their roots well covered with tubercles when examined in October. In a 

 field test cowpeas were grown on an inoculated and on an uninoculated plat. The 

 inoculated plat had produced a crop of cowpeas the year before. The nitric nitrogen 

 in the plants from the inoculated plat on August 15 amounted to 0.691 per cent 

 and in those from the uninoculated plat 0.265 per cent. In samples of the entire 

 plant above ground taken September 13 there was a difference of 48 per cent in the 

 proteid nitrogen in favor of the inoculated j^tlat. The causes to which this difference 

 is due are as yet undetermined. 



