Abstract
The ash left after plants or plant derivatives are incinerated consists of the minerals that the plants had contained. Measurements of ash content and mineral analyses of the ash were made on 79 different plants or plant parts, plant products, and humuses or extracts, including plants of different ages or ones grown in different soils. Results are presented in tables of incineration and mineral analyses. The table of mineral analyses lists the percentages of water-soluble salts, insoluble phosphates and carbonates, silica, alumina, and metallic oxides in the ash.
In general, herbaceous plants contain more ash than do woody plants. Ash is more abundant where transpiration is profuse. Leaves yield more ash than stems or fruits, and bark more than wood. The leaves of deciduous trees, which have greater transpiration than the leaves of evergreen trees, yield more ash. The ash of herbaceous annuals increases at first, but declines as leaves gradually die and are shed or minerals are lost to leaching by rain. A decayed plant that has not been exposed to heavy leaching yields more ash than a living plant of the same kind.
Mineral amounts are presented as percentages. Thus, after the leaching or other loss of certain minerals, the remaining, less easily leached minerals occur in apparently greater abundance, although they are not so in absolute terms. For example, the alkaline salts are easily leached, so, as plants age and are exposed to weathering, the relative proportions of the other minerals increase.
The proportions of the elements in plant ash are almost always related to the soils in which the plant grew. Thus, plants growing in a soil rich in silica contain more silica and less lime than the same kinds of plants growing in a calcareous soil. Plants grown in the open air, with their roots immersed in distilled water, develop abnormally because they can obtain minerals only from the dust that settles from the atmosphere. The ash of these same kinds of plants, grown in humus, contains significantly more saline and earthy materials, including minerals that could not have come from the seed.
Minerals are essential to plants. Certain minerals that are taken in might indeed be inessential, but this has not been demonstrated for those minerals that are always present in plants of the same species.
The text concludes with a lengthy description of the chemical methods used to analyze the mineral composition of ash.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsNotes
- 1.
Mémoire sur les Engrais, by Kirwan, Société royale d’Irlande, Vol. 5, p. 129; and Rückert’s Feld-Bau.
- 2.
Statique des végétaux, French edition, pp. 3 and 43.
- 3.
Recherches sur l’usage des feuilles, p. 77, 8° edit.
- 4.
I adopt here the oldest accepted meaning, which confers the name of alkaline salts only on those in which potash, soda, or ammonia is one of the constituents. We must exclude only ammonia, because it cannot enter into the composition of ash.
- 5.
Opuscules chimiques of Marggraf, Vol. 1, p. 68.
- 6.
I would have been able to obtain much more vigorous growth, no different from that in open ground, at least up to the fruiting stage, if I had sown these seeds in pots full of pure sand or gravel, but I do not know whether the juices of the roots would have attacked the stones themselves. The erosion that lichens sometimes seem to cause on rocks suggests this. Moreover, the prodigious number of insects that, in open country, leave their remains on leaves, and the debris of all kinds that the winds transport there, would cast doubt on the results of the experiment.
- 7.
Karsten and Westrumb noted that water that is distilled with the greatest care and, if recently prepared, is not at all modified by reagents, undergoes, after exposure for a fortnight to light or 4 weeks to darkness, changes that have all the characteristics of fermentation products. It then somewhat clouds solutions of lead and silver. It gives slight indications of ammonia and, at other times, of acid. (Kleine Physikalisch-chemische Abhandlungen von Westrumb. Zweites Heft [spelling of title corrected by translator]).
- 8.
Viscosity of the lye of ash, and its reduction to gel by evaporation, is an almost certain indication of the presence of phosphate of potash and lime or magnesia. However, this salt may be present without this characteristic, if there is a large excess of potash. Phosphate of potash is not viscous or gelatinous by itself, whatever the proportions of its components. It has this property only when it contains lime or magnesia without excess potash.
- 9.
Perhaps it would be more exact to eliminate this first operation (a), which separates, by vinegar and alcohol, only a part of the excess potash and removes a little phosphate of potash. I used this procedure only because it makes the rest of the analysis less cumbersome and saves much acetic acid and calcium acetate.
- 10.
Vinegar dissolves phosphate of lime a little, if it has not been dried after its precipitation.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Copyright information
© 2013 Springer Science+Business Media New York
About this chapter
Cite this chapter
Hill, J. (2013). Observations on the Ash of Plants. In: Chemical Research on Plant Growth. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-4136-6_9
Download citation
DOI: https://doi.org/10.1007/978-1-4614-4136-6_9
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-4135-9
Online ISBN: 978-1-4614-4136-6
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)