SOILS. 



123 



as a limit, below wliicli applicatious of nitrogenous fertilizers are almost 

 always indispensable. 



As regards the form of nitrogenous fertilizers adapted to different 

 kinds of soil, it is stated that sulphate of ammouia decomposes readily 

 in highly calcareous soils, and is therefore subject to loss of nitrogen 

 in such cases. To such soils organic nitrogen is especially applicable. 

 This form is also adapted to very light sandy soils, in which tlie nitrates 

 would be rapidly carried away in the drainage water. For ordinary 

 loam soils nitrate of soda is a good form of nitrogen, provided it is 

 applied fractionally as required by the jdant at different stages of 

 growth. 



Barnyard manure appears to be adapted to all kinds of soils. To 

 light soils and calcareous soils it supplies nitrogen in organic form, and 

 to heavy soils it furnishes nitric nitrogen, since, from the nature of the 

 material, it furnishes nitrogen in three forms, besides supplying a con- 

 siderable amount of mineral matter and increasing the humus content of 

 the soil. The very (pialities, however, which make this material so gen- 

 erally applicable may become sources of loss on certain soils. The 

 ammoniacal nitrogen maybe lost in very calcareous soils and the nitric 

 nitrogen maybe washed down by rains into the subsoil of very light soils. 

 If nitrification is too slow, plants suffer; if it is too rapid, the excess of 

 nitrate maybe injurious to the plant or may be lost in the drainage. 

 The rational use of manure, therefore, in ordinary culture is attended 

 with more difficulties than that of chemical fertilizers. 



Soil temperatures, D. B. Brace {Nebraska Sta. Bui. 33, pp. 129- 

 141). — Tabulated summaries of daily observations during each month 

 of 1893 with soil thermometers at depths of from 1 to 30 in. are reported 

 in connection with the readings of the dry bulb, maximum, >'.,nd mini- 

 mum thermometers. The maximum and minimum temperatures during 

 the year at the different depths were as follows: 



Muxhnmn and minimum 8oil ieviperatitren fur 1S93. 



