SOIL AND ITS PRODUCTIVENESS. 951 
Now let us assume some arbitrary fraction of these figures, say, 
for instance, =1,th, as representing the favourable influence of the 
lime on the productiveness of the soil. The above figures divided 
by 500 are, respectively :— 
43 51 79 49 
Let these be added to the figures representing the effect of the 
nitrogen and phosphoric acid ; we thus arrive at the following :— 
Supposed effect of nitrogen and phos- Plot3. Plot 7. — Plot 11. Plot 14. 
GMTC HACE pieces. otacins rosette owxeristensoiae 1,065 1,036 942 850 
Supposed effect of lime...............s00eeees 43 51 19 49 
Supposed effect of nitrogen, phosphoric 
PGC TOL RENIN MLNS serge ecg wiovstantacloainlalavelese cher tetels 10S 087) sagO2a 899 
This lowest line of figures is represented in the second curve of 
the diagram—dotted lines. It will be seen that the irregularity 
which occurred in our first curve in regard to Plot 11 is now 
corrected ; but there is an irregularity apparent in Plot 7, which, 
as seen by the lowest curve, yielded less than would have been 
anticipated from the influence of the nitrogen, phosphoric acid, 
and lime, as disclosed by the analysis. I have little doubt that 
this deficiency was caused by an excess of soluble salts in the soil. 
That this plot contained more soluble salts than the other plots 
did is shown by two facts of the analysis: first, it contained the 
largest amount of chlorine, which was, moreover, mainly in the 
surface layer ; and secondly, the potash was mainly in the surface 
layer. 
Tf we assume that any potash in this soil above 129 parts per 
100,000 is indicative of soluble salts, we may subtract 120 from 
the figures showing the amount of potash in the different plots, 
and we thus get the following :— 
Potash, indicative of Soluble Salts in the Soils. 
Plot 3. Plot 7. Plot 11. Plot 14. 
Saileerrcocttenanceeecticcs 0 105 8 36 
Sab Swill Yesdcpaceacevettneete 123 5 1 106 
Assigning, as before, only half value to the subsoil figures, we 
get the following :— 
Plot 3. Plot 7. Plot 11. Plot 14. 
SO erence cuassccecc 0) 105 8 36 
Sulbsoiletecnccsieccntees 61 2 0 53 
Mo tality ssccahok 61 107 8 89 
We take an arbitrary fraction of these figures—say, for instance, 
1th—and obtain the following—12, 21, 2, 18, which we may 
arbitrarily assume as indicating the deterrent or negative effect 
of the excess of soluble salts, as indicated by the potash figures. 
