. Cassell's popular gardening. Gardening. MANURINa IN THEORY AND PRACTICE. 255 Httle from that which existed above it, hecame highly charg-ecl -with, carbonic acid, which decomposed the mineral substances contained in the soil; and in this manner year by year more and more of the nitrogen, collected by each generation of plants, became avail- able for the generation that succeeded it. In order to start with definite notions on the in- herent quality of soils, lot us take, as an example, some ordinary arable soil, of a clayey nature, in fair cultivable condition. Such a soil, when all roots and
. Cassell's popular gardening. Gardening. MANURINa IN THEORY AND PRACTICE. 255 Httle from that which existed above it, hecame highly charg-ecl -with, carbonic acid, which decomposed the mineral substances contained in the soil; and in this manner year by year more and more of the nitrogen, collected by each generation of plants, became avail- able for the generation that succeeded it. In order to start with definite notions on the in- herent quality of soils, lot us take, as an example, some ordinary arable soil, of a clayey nature, in fair cultivable condition. Such a soil, when all roots and veget- able debris have been removed, will contain in the first nine inches of the surface mould a quantity of organic matter containing about ;j,000 lbs. of ni- trogen and 30,000 lbs. of carbon per acre. This nitro- genous organic matter of the soil has been derived either entirely from the decay of vegetable growth, left in the land by pre- ceding genera- tions of plants, or possibly, to some extent, also from past applications of organic ma- nure. In a fertile soil the formation of nitrates is always in pro- gi'ess, and it is very important for gardeners to bear in mind that the nitrogenous capital of a soil, which represents to a considerable extent its fertility, depends, as a rule, on the bulk and composition of the previous plant residues. The present condition of a soil is thus, in great measure, a consequence of its past fertility, which fact may be exemplified by another of the Rothamsted Accumulation of Plant-food in Soils.âIn one field wheat has been grown continuously for forty-one years (1844â1884), and during the last thirty years the manuring has not been changed on any of the plots to which reference is about to be made. The range of produce has been very con- siderable, rising from an average of 14 bushels of dressed wheat and 12 cwt. of straw without manure (Plot 4), to an average of 32j bushels of grain and 32|- cwt. of straw on the highly-m
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1884
