232 EXPERIMENT STATION RECORD. 



resenting 1,250 kg. of nitrate of soda and exceeding the requirements 

 of the most exhausting crops. Soils bearing crops produced a much 

 smaller quantity of nitrates, because the rapid evaporation from the 

 plants dried out the soil so completely that there was not sufficient 

 moisture for active nitrification. When rain was very abundant, 

 however, such soils even without fertilizer produced good crops, which 

 contained more nitrogen than was found to be nitrified in the fallow 

 soils. 



The experiments show that although a large proportion of the nitro- 

 gen of soils is in an inert form, the nitric ferments are capable, if 

 assisted by sufficient moisture, of converting this inert nitrogen into 

 available form with sufficient rapidity to supply the demands of the 

 largest crops. 



Variations in the temperature at the surface of soils of differ- 

 ent character, J. Joubert (Gompt. Bend. Acad. Sci. Paris, 124 (1897), 

 JVo. 21, pp. 1405, 1406). — Observations were made in the park of Mont- 

 souris on the temperature of the air above (1) the naked soil covered 

 with river sand, (2) asphalted soil, (3) soil paved with wood, (4) soil 

 paved with stones, and (5) sward. The annual averages were practi- 

 cally the same in each case. In summer the temperature above the 

 wood x>avement was greater than that above the sward, the mean dif- 

 ference for the months of June, July, and August being 1.4°. In winter, 

 however, there was practically no difference, although snow remained 

 much longer on the wood pavement than on the sward. The tempera- 

 ture above the asphalted soil was lower during the summer than that 

 above the wood pavement, the average excess over that above the 

 sward being only 1.2°. In winter, however, there was still an excess, 

 amounting to about 0.1°. The temperature above the stone pavement 

 and the bare soil was only 0.9° higher than that above the sward in 

 summer, and the same was true for the stone pavement during the 

 winter. The temperature above the naked soil in winter, however, was 

 from 0.1 to 0.2° lower than that above the sward. In the fall the dif- 

 ferences were very slight. In the spring the temperatures above all of 

 the soils were from 0.5 to 0.0° lower than that above the sward. The 

 smallest variations in temperature occurred during all seasons above 

 the stone pavement; the greatest during the hot months above the 

 wood pavement, and during the cold months above the asphalt. Occa- 

 sionally toward the end of winter the naked soil showed the maximum 

 variation. During all seasons the diurnal variation in temperature 

 was greater above the sward than above the other soils, the difference 

 being especially marked in the spring. 



Soil investigations, J. E. Payne (Colorado >si«. Rpt. IsOii, pp. 182- 

 184). — A brief account is given of the digging of holes 3 ft. deep every 

 5 rods each way over a portion of the experimental grounds of the 

 llainbelt Substation for the purpose of observing the character and 

 variations of the different types of soil. Microscopic and chemical 

 examinations of samples of soil taken in this way have been begun and 



