834 



EXPERIMENT STATION RECORD. 



"Another important difference in temperature was observed to result from cultiva- 

 tion. Temperatures Avere taken on soil that had been newly cultivated for seeding 

 and upon soil that had not lieen worked for several days. Thermometers were 

 placed at the surface of the ground, and at 3, 6, and 12 in. l^elow the surface. These 

 were read at 2.30 p. m. and 2.30 a. m. the following day. The readings are given in 

 the table below: 



Temperature uf cultivated and uncuiti rated soil. 



"The table shows, first, that the newly cultivate 1 soil was 6° warmer at the surface 

 of the ground than the uncultivated; second, that the temperature 3 in. below the 

 surface was 5.5° higher on the uncultivated soil. These facts show that the newly 

 cultivated soil conducts heat much more slowly than the uncultivated, probably 

 because it is less compact. The amount of evaporation from each is probably about 

 the same for a short time after cultivation, hence this can not be considered as a 

 cause of the difference in temperature. When cultivation is carried on continuously, 

 the surface of the soil is warmer, and the first few inches below the surface cooler, 

 than upon the same soil uncultivated; while at a defjth of 6 in. the cultivated soil 

 has the same or a higher temj^erature than the uncultivated. These are all desirable 

 conditions during the growing season. The warmer surface soil hastens the process 

 of growth in the plant and is a protection against frost. The soil just below the 

 surface being cooler, retards capillarity and thereby retains the soil moisture, while 

 the temperature about the roots of the plant 5 or 6 in. below the surface is the same 

 or a little higher than on the uncultivated soil. The plan of cultivating the soil about 

 growing crops during the afternoon of a day when the conditions are favorable for 

 frost at night is often recommended, and the table shows that there is much to ]>e 

 gained by so doing. The temperature at the surface of the cultivated soil was 3° 

 higher than on the uncultivated at 2.30 a. m., hence the danger of frost was materi- 

 ally lessened. The heat absorbed during the day is held near the surface of the 

 ground in the cultivated soil, instead of being conducted to lower depths, and the 

 air becomes more moist from the rapid evaporation at the surface, which is a condi- 

 tion unfavoral)le for the ijccurrcnce of frost." 



On a modification in the method of using the electric thermometer for 

 determining underground temperatures at the Museum of Natural History, 

 H. Becquerel {Compt. Bend. Acad. Sci. Paris, 133 {1901), No. 21, jtp. SOO-803) . 



The soil cover of forests and the r61e of earth-worms {Gaea, 37 {1901), pp. 

 634, 635). 



FERTILIZERS. 



Report on fertilization, C. F. Eckakt {Rejit. to Havaiian Sugar Planters' Assn., 

 1901, Nov., pp. 45). — This article sununarizes the results of determinations at the 

 Hawaiian Sugar Station of total and available (soluble in aspartic acid) fertilizing 

 constituents in Hawaiian soils, and of the amounts of these constituents lost in the 

 drainage waters, taken up by the sugar cane crop, and returned in the cane refuse 

 (E. S. R., 10, p. 525; 11, p. 507). The total and available fertilizing constituents in 

 the soils of the different islands of Hawaii are given as follows: 



