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they require a different treatment to enable them 
to produce their full effects in agriculture* I shall 
therefore describe in detail the properties and 
nature of the manures in common use, and give 
some general views respecting the best modes of 
preserving and applying them. 
All green succulent plants contain saccharine or 
mucilaginous matter, with woody fibre, and readily 
ferment. They cannot, therefore, if intended for 
manure, be used too soon after their death. 
When green crops are to be employed for enrich- 
ing a soil, they should be ploughed in, if it be 
possible, when in flower, or at the time the flower 
is beginning to appear, for it is at this period that 
they contain the largest quantity of easily soluble 
matter, and that their leaves are most active in 
forming nutritive matter. Green crops, pond 
weeds, the paring of hedges or ditches, or any kind 
of fresh vegetable matter, requires no preparation 
to fit them for manure. The decomposition slowly 
proceeds beneath the soil ; the soluble matters are 
gradually dissolved, and the slight fermentation 
that goes on checked by the want of a free com- 
munication of air, tends to render the woody fibre 
soluble without occasioning the rapid dissipation 
of elastic matter. 
When old pastures are broken up and made 
arable, not only has the soil been enriched by the 
death and slow decay of the plants which have left 
soluble matters in the soil ; but the leaves and 
roots of the grasses living at the time and occupying 
so large a part of the surface, afford saccharine, 
mucilaginous, and extractive matters, which be- 
