76 
JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
plenty of organic matter to furnish nitrogenous plant-food and 
to favourably influence the supply of water. It is for this reason 
that horticulturists find leaf-mould, pasture-turf soils, and 
peat soils so beneficial for plant-growing. 
The total quantity of nitrates found in fertile soils is very 
considerable. Table YI. shows the amount of nitrogen as 
nitrates in drainage water passing through an unmanured soil 
and a recently dunged soil. The quantities are given in pounds 
per acre during each of the seasons of spring, summer, autumn, 
and winter; also the total amount for the whole year. 
TABLE YI. —Nitrogen as Nitrates in Drainage Water. 
Quantities in pounds per acre. 
Seasons 
Unmanured soil 
Dunged soil 
lbs. 
lbs. 
Spring ...... 
19-5 
46-1 
Summer. 
18*5 
22-2 
Autumn ...... 
28-3 
38*2 
Winter ...... 
13-5 
17-4 
Yearly total 
74-8 
1 
123-9 
The figures show that in the unmanured soil nearly 75 lbs. 
of nitrates were produced in the year, whilst in the dunged soil 
about 124 lbs. were produced in the year. In the unmanured soil 
the largest production of nitrates was in the autumn, while in 
the dunged soil the maximum amount was formed in the spring. 
But it may be well to note that the whole of this nitrogen would 
not be available to our ordinary cultivated crops, for the reason 
that many of them only assimilate the spring or early summer 
nitrates, the principal growth and power of assimilation having 
ceased by the month of July. 
Vegetable crops, such as cabbage, beet, onions, turnips, 
carrots, parsnips, celery, peas, &c., may still get hold of 
summer-formed nitrates, but that produced late in autumn and 
winter is of little use in so far as this applies to outdoor plants. 
The spring nitrification of the soil is, as a rule, quite in¬ 
sufficient to meet the food requirements of early-sown spring 
crops ; hence the advisability of using some stimulating manure, 
