GREEN MANURES. 



GREEN MANURES. 



the advantages of collecting large quantities 

 of vegetable matter to form manures; whilst 

 scarcely any thing has been written upon the 

 state of decomposition in which decaying 

 vegetable substances can be employed most 

 advantageously to afford food to living plants. 

 Both the farmer and gardener, till lately, 

 thought that such manures ought not to be de- 

 posited in the soil until putrefaction had nearly 

 destroyed all organic texture, and this opinion 

 is, perhaps, still entertained by the majority of 

 gardeners ; it is, however, wholly unfounded. 

 Carnivorous animals, it is well known, receive 

 most nutriment from the flesh of other ani- 

 mals when they obtain it most nearly in the 

 state in which it exists as part of a living 

 body; and the experiments I shall proceed to 

 state, afford evidence of considerable weight 

 that many vegetable substances are best cal- 

 culated to reassume an organic living state 

 when they are least changed and decomposed 

 by putrefaction." The allusion to carnivorous 

 animals is misplaced ; as green food must be 

 soluble, and in a decomposing state, before it 

 can be taken up by plants ; but this does not 

 weaken the argument in favour of its utility. 

 "I had," continues Mr. Knight, been engaged 

 in the year 1810 in some experiments, from 

 which I hoped to obtain new varieties of the 

 plum, but only one of the blossoms upon 

 which I had operated escaped the severity of 

 the frost in the spring. The seed which this 

 afforded having been preserved in mould dur- 

 ing the winter, was in March placed in a small 

 garden pot, which was nearly filled with the 

 living leaves and roots of grasses mixed with 

 a small quantity of earth, and this was suffi- 

 ciently covered with a layer of mould which 

 contained the roots only of grasses, to prevent, 

 in a great measure, the growth of the plants 

 which wece buried. The pot, which contained 

 about one-sixteenth of a square foot of mould 

 and living vegetable matter, was placed under 

 glass, but without artificial heat, and the plant 

 appeared above the soil in the end of April. 

 It was, three times during the summer, re- 

 moved into a larger pot, and each time sup- 

 plied with the same matter to feed upon, and 

 in the end of October its roots occupied about 

 the space of one-third of a square foot. Its 

 height above the surface of the mould being 

 then 9 feet 7 inches. In the beginning of June 

 a small piece of ground was planted with po- 

 tatoes of an early variety, and in some rows 

 green fern, and in others nettles, were em- 

 ployed instead of other manure ; and, subse- 

 quently, as the early potatoes were taken up 

 for use, their tops were buried in rows in the 

 same manner, and potatoes of the preceding 

 year were placed upon them, and buried in the 

 usual way. The days being then long, the 

 ground warm, and the decomposing green 

 leaves and stems affording an abundant mois- 

 ture, the plants acquired their full growth in 

 an unusually short time, and afforded an abun- 

 dant produce, and the remaining part of the 

 summer proved more than sufficient to mature 

 potatoes of any early variety. The market 

 gardener may probably employ the tops of his 

 early potatoes and other green vegetable sub- 

 stances in this way with much advantage. 



"In the preceding experiments the plum 

 stone was placed to vegetate in the turf of the 

 alluvial soil of a meadow, and the potatoes 

 grew in ground in which, though not rich, was 

 not poor, and therefore some objections may 

 be made to the conclusions I am disposed to 

 draw in favour of recent vegetable substances 

 as manures. The following experiment is, I 

 think, decisive. I received from a neighbour- 

 ing farmer a field, naturally barren, and so 

 much exhausted by ill management, that the 

 two preceding crops had not returned a quan- 

 tity of corn equal to that which had been sown, 

 upon it. An adjoining plantation afforded me 

 a large quantity of fern, which I proposed to 

 employ as a manure for a crop of turnips ; 

 this was cut between the 10th and 20th of 

 June, but as the small cotyledons of the turnip 

 seed afford little to feed the young plant, and 

 as the soil, owing to its extreme poverty, could 

 not afford much nutriment, I thought it neces- 

 sary to place the fern a few days in a heap to 

 ferment sufficiently to destroy life in it, and to 

 produce an exudation of its juices, and it was 

 then committed in rows to the soil, and the 

 turnip-seed deposited with a drilling machine 

 over it. 



"Some adjoining rows were manured with 

 the black vegetable mould obtained from the 

 site of an old wood pile, mixed with the slen- 

 der branches of trees in every stage of decom- 

 position ; the quantity placed in each row ap- 

 pearing to me to exceed more than four times 

 the amount the vegetable mould, if equally 

 decomposed, would have yielded. The crop 

 succeeded in both cases, but the plants upon 

 the green fern grew with more rapidity than 

 the others, and even than those which had 

 been manured with the produce of my fold and 

 stable-yard, and were distinguishable in the 

 autumn from the plants in every other part of 

 the field by the deeper shade of their foliage. 

 I had made, in preceding years, many similar 

 experiments with small trees (particularly 

 those of the mulberry when bearing fruit in, 

 pots) with similar results ; but I think it un- 

 necessary to trespass on the time of the society 

 by stating these experiments, and conceiving 

 those I have stated to be sufficient to show 

 that any given quantity of vegetable matter 

 can generally be employed in its recent and 

 organized state with much more advantage 

 than when it has been decomposed, and no in- 

 considerable part of its component parts have 

 been dissipated and lost during the progress 

 of the putrefactive fermentation." (Trans. 

 Hort. Soc. vol. i. p. 248.) 



In an article upon this subject, M. Knoles, 

 of Secheim, writes thus : " My vineyard has 

 been manured for eight years on the branches 

 cut from the vines, without receiving any 

 other manure, and yet more beautiful and 

 richly-laden vines could scarcely be pointed 

 out. The branches are pruned from the vine 

 in August, whilst still fresh and moist, and 

 are traced into the soil after being cut into 

 small pieces. At the end of four weeks not 

 the smallest trace of them can be found." 



When green vegetable substances are bu- 

 ried in the soil, they first lose their green 

 colour, speedily wither, and then putrefaction 



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