WATER SOILS. 735 



warming and cooling capacity than precipitated carbonate. The mix- 

 ing of calcium carbonate with other mineral constituents, clay, sand, 

 etc., had the effect of lowering the soil temperature and reducing 

 the temperature variations. Iron compounds exerted only a slight 

 influence upon the temperature conditions of the soil. 



Investigations on the influence of frosts on the temperature 

 conditions of soils with different salt contents, R. Ulrich (For.se It. 

 Agr. Phys. [ Wolhiy], 20 (1897), No. 1, pp. 218-229).— -In these investiga- 

 tions soil (fine kaolin) was mixed in cylinders with 0.05, 0.1, and 0.2 per 

 cent of calcium hydroxid, sodium chlorid, potassium chlorid, calcium 

 chlorid, potassium nitrate, sodium nitrate, potassium sulphate, magne- 

 sium sulphate, sodium phosphate (NaELPO,), potassium phosphate 

 (KEl 2 P0 4 ), potassium carbonate, sodium carbonate, and potassium 

 hydroxid, and subjected to temperatures ranging from 0° C. to — 10° C. 

 The results show that the temperature of freezing was lowered by the 

 addition of the salts — the larger the amount of salts present the 

 greater the lowering of the temperature. When the soil water froze 

 the temperature of the soil rose at once to 0° C, remained for a time 

 at this point, and then gradually fell under the influence of low temper- 

 atures. Certain salts, such as calcium hydroxid, chlorid, and nitrate, 

 retarded this fall of temperature; others, such as potassium hydroxid, 

 phosphate, and carbonate, hastened it. The sulphates exerted no 

 inflii ence in this respect. This difference in behavior of the various 

 salts is partly explained by their effect on the physical character of the 

 soils. The hydroxids, carbonates, as well as the phosphates of the 

 alkalies, make the soil more compact and thus increase its conductivity, 

 while other salts, especially calcium hydroxid, have an opposite effect. 



Soil moisture, E. F. Ladd (North Dakota Sta. Rpt. 189(i, pp. 9-13).— 

 Monthly summaries (April to October) are given of weekly observa- 

 tions during 1892-'96 on soils at depths of from 1 to 3 and 5 to 7 in. 

 Determinations of moisture in soils at two different places in the State 

 where the Campbell method of soil culture was being tested are also 

 reported, and results are tabulated of an experiment undertaken for 

 the purpose of determining the influence of different methods of culti- 

 vation on soil moisture during drought. The methods of cultivation 

 were as follows: (1) Ground kept free from growing weeds, but other- 

 wise not disturbed; (2) surface cultivated to a depth of 1 in. every 

 fourth day; (3) surface cultivated to a depth of 3 or f in. every fourth 

 day; (4) ground rolled and then the surface stirred to a depth of 1 in. 

 every fourth day; (5) mulched with dry straw manure, and weeds not 

 permitted to grow. The results of this experiment are irregular and 

 inconclusive and the investigation is to be continued. 



Protection and improvement of worn soils, J. S. Newman (South 

 Carolina Sta. Bui. 32, pp. 12, figs. 5).— It is explained that the principal 

 cause of the injury to the cultivated soils of the cotton States is surface 

 washing, which is a result of the system of clean culture and hillside 



