NOTES AND ABSTRACTS, 
575 
3. From 12 to 50 per cent, of the colonies on plate cultures are those of Actino- 
mycetes. The author finds about seventy different types occur ; three of 
them are of fairly common occurrence, and of these one is considered to be 
a new species, A. pheochromogenus ; another appeared to be associated with 
potato-scab organism ; while the third is not a distinct species. Indications show 
that they are an active and numerically important group of micro-organisms in 
soils, — A, B s 
Soil Moisture, The Movement ^of Soluble Salts with the. By F, S. Harris 
(U.S.A. Exp. Stn., Utah, Bull. 139, May 1915). — Large tracts of low -lying lands 
have of late years accumulated alkali salts to such an extent as to cause them 
to go entirely out of cultivation. 
It is found that this infertility is caused by the movement of soluble salts 
from the uplands through the excessive irrigation of same, — C, P, C. 
Soil, Potassium from. By C. G, Hopkins andf J. P. Aumer (U.S.A. Exp. 
Stn., III., Bull. 182, May 1915). — The addition of green and farm manures to the 
soil will normally release more than sufficient potassium for the use of most 
farm crops, particularly corn and clover. The authors suggest that no further 
artificial additions should be made. — C. P, C. 
Soil, Summer Treatment of Greenhouse. By W. J. and S. N. Green (U.S.A. 
Exp. Stn., Ohio, Bull. 281, Jan. 1915). — It is customary in the above State to 
allow the greenhouses to lie fallow for six to ten weeks in the summer, expecting 
that the dryness and heat would clear off most of the pests inherent to glasshouse 
cropping. 
By some comprehensive experiments the authors show that it is better to 
manure, mulch, and water the top soil, such treatment considerably adding to 
the crop later on. 
The only exception being a following crop of lettuce which seems to do almost 
equally well in the dry or mulched soils. 
Sterilization is recommended, but the authors deprecate the constant applica- 
tion of steam for this purpose, as it tends to strong stimulation of growth leading 
to malnutrition. It has also been shown that harmful compounds as well as 
beneficial are formed, and when the former overbalance the latter the fertility of 
the treated soil is affected adversely. Some hints as to feeding and watering 
are given. — C. P. C, 
Soil, The Effect of Sulphate of Ammonia on. By R. W. Rupprecht and 
F. W. Morse (U.S.A. Exp. Stn., Mass., Bull. 165, Nov. 1915).— From the 
numerous experiments carried out over a number of years, the authors deduce 
that the constant application of sulphate of ammonia to unlimed soils does 
not tend to create acidity. In the various trials both unlimed and limed 
plots remained neutral under repeated yearly doses. The decomposition of sul- 
phate of ammonia in the soil is, in the first stage, an absorption of the ammonia 
until the soil cannot hold anymore, such absorption being greater in the limed 
soil. Any sulphate remaining is then decomposed in the soil, first attacking 
the calcium carbonates and in their absence the salts of iron and aluminium, 
and it is to the presence of the resulting compounds of iron and aluminium that 
the harmful effects of the constant application of sulphate of ammonia to unlimed 
soils appear to be due. — C. P. C % 
Soils, Effect of Temperature on Some of|the most Important Physical Processes 
In. By George J. Bouyoucos (U.S.A. Exp. Stn., Mich., Tech, Bull. 22, July 
I 9^5)- — Many valuable and interesting results are tabulated in this bulletin. 
The most striking conclusions are : (1) " That there is practically no loss 
of vapour during the night, and that contrary to popular belief the dew is not 
caused by the water vapour rising from the soil. (2) That the influence of 
temperature on'the aeration of soils is very great." 
This is caused not only by the expansion of the gases, but by absorption by 
soils at different temperatures, and particularly through the presence of soil 
moisture as vapour. — C. P. C, 
Soils, Factors influencing the Lime and Magnesia Requirements of. By 
W. H. Maclntyre (U.S.A. Exp. Stn., Tenn., Bull. 105, Jan. 1916; 23 tables) , — 
The above is a purely technical bulletin dealing with a " Method for the determina- 
tion of the immediate lime requirements." 
Therein is described the newest methods and the apparatus to be used. 
It is demonstrated that Si0 2 is very active in the decomposition of lime and 
magnesium carbonates in soils. — C. P. C k 
