NOTES AND ABSTRACTS. 
245 
most rapid during the first few minutes, though the process appears to continue 
for several days. Heating a soil for six hours at a temperature of 200 0 C. and 
over reduces its power of ammonia-fixation. Aluminium, iron, and potassium 
salts added to soils prior to the addition of ammonia reduce the ammonia-fixing 
power of the soils to a marked degree, while calcium, magnesium, and sodium 
salts have little effect on this power in semi-arid soils. — A. B. 
Soils cf the Southern Island of New Zealand, with Special Reference to their 
Lime Requirements. By Leonard John Wild (Jour. Agr. Sci. viii. 2, pp. 154- 
177 ; March 1917). — This work was undertaken by the author with a view to 
testing the applicability of Hutchinson and MacLennan's method (Jour. Agr. 
Sci. March 191 5) to New Zealand soils. The essence of this method is the, 
treatment of a known weight of soil with a known volume of calcic bicarbonate 
of known strength, afterwards determining by titration with standard acid 
the loss of lime suffered by the solution. This loss is deemed to be the lime 
requirement of the soil. Hutchinson and MacLennan state, with reference 
to barley plots at Woburn, that in all cases where the soil is neutral in reaction 
high returns are obtained, but where the lime requirement is more than 18 per 
cent, (corresponding to 1 ton of quicklime to the acre) the crop shows almost if 
not complete failure. 
The New Zealand work does not accord with the Woburn experience. In 
his experiments the author did not obtain concordant results, the difference in 
indicated " lime requirement" of the same soil being as much as 25 per cent., 
and one soil which contained so much as 10 per cent, of calcic carbonate yet 
indicated a small lime requirement. Further experiments on washed sand, a 
limestone soil, samples of soil already presumably saturated by the bicarbonate 
solution, and finally on the bicarbonate solution itself, suggested that calcic 
bicarbonate solution might undergo change, but whether chemical or physical 
the author has not ascertained. 
Tests were next made of the time necessary for the completion of the reaction, 
and of the effect of using solutions of bicarbonate of varying strengths. Hutchin- 
.. ; , J} 
son and MacLennan recommended a strength of about and a period of four 
hours. Broadly speaking , the author agrees that these will generally give satis- 
factory results from a practical standpoint, but adds that the position from a 
theoretical standpoint is unsatisfactory since his experiments indicate that the 
" lime requirement " is not constant, but varies directly as the concentration 
of the bicarbonate solution. Field experiments also afford discrepant results : 
some New Zealand soils possessing an indicated acidity of less than o'i per cent, 
nevertheless are known to demand lime and cannot be farmed without lime 
dressings. Other soils possessing a decided acid reaction will yet give good crop 
returns without liming. — /, E. W. E. H. 
Soils, Semi-arid, Nitrification in. By W. P. Kelley (U.S.A. Jour. Agr. Res. 
vol. vii. No. 10, Dec. 1916, pp. 417-438). — In these experiments the author 
shows the amount of nitrate formed from dried blood, bone meal, and ammonium 
sulphate varied greatly during four weeks' incubation when different concentra- 
tions were employed. This is true in regard both to the absolute amount of 
nitrate formed and the percentage of nitrogen added that was nitrified. 
When 1 per cent, of dried blood was used, the nitrifying activity was feeble 
or even negative in certain soils in which 1 per cent, of bone-meal, and "i to 
•3 per cent, of ammonium sulphate underwent active nitrification. However, 
when low concentrations of dried blood were employed, active nitrification 
took place in every case, and when equal amounts of actual nitrogen were added 
the yields of nitrates were similar, whether it was derived from dried blood, 
bone-meal, or ammonium sulphate. 
It was found that high concentrations of bone-meal with a nitrogen content 
were highly toxic to nitrification, very much as was the case with 1 per cent, 
dried blood. 
The inability to nitrify 1 per cent, of dried blood was not confined to any 
one type of soil, or to soils low in organic matter, as many varying types of soil 
were employed from different localities in Southern California. — A. B. 
Soils, The Shrinkage of. By H. A. Tempany (Jour. Agr. Sci. viii. June 
1 91 7). — Observations by previous experimenters on thirty -four different types 
of soils in St. Lucia and Dominica had established the fact of the correlation 
between the shrinkage of the soils when dried and their suitability for growing 
cacao. A linear shrinkage (as determined by measuring the distances between 
marks on soil blocks at different stages of dryness) of 10 per cent, or more in 
