| Seed. | Straw. | |
| 1 | 2·30 | |
| 2 | 3·25 | 3·43 |
| 3 | 4·27 | 3·62 |
| 4 | 3·40 | 3·39 |
| 5 | 2·99 | 3·90 |
| 6 | 3·19 | 6·80 |
| 7 | 2·53 | 3·90 |
| 8 | 2·27 | 6·59 |
| 9 | 2·69 | 3·49 |
| 10 | 1·61 | 3·91 |
| 11 | 3·11 | 5·28 |
| 12 | 3·34 | 7·57 |
| 13 | 2·78 | 3·76 |
| 14 | 3·01 | 3·38 |
Although those differences are very large, especially in the straw, and must be attributed to the soil, it has hitherto been found impossible to ascertain the nature of the relation subsisting between it and the crops it yields; indeed, it must obviously be dependent on very complicated questions, which cannot at present be solved, for it may be observed that the increase in the grain does not occur simultaneously with that in the straw, and in several cases a large proportion of ash in the former is associated with an unusually small amount in the latter. A priori, it might be expected that those soils which are especially rich in the more important constituents of the ash should yield a produce containing more than the average quantity, but this is very far from being an invariable occurrence, and not unfrequently the very reverse is the case. In some instances the variations may be traced to the soil, as in the following analyses of the fruit of the horse-chesnut, grown on an ordinary forest soil, and on a rich soil, produced by the disintegration of porphyritic rock, in which the latter yields a much larger quantity of ash:—
| Kernel of seed. | Green husk. | Brown husk. | |
| Forest soil | 2·26 | 4·53 | 1·70 |
| Porphyry soil | 3·36 | 7·29 | 2·20 |
In the majority of instances we fail to establish any connection between the nature of the soil and the plants it yields, chiefly because we are still very deficient in analyses of those grown on uncultivated soils; and on cultivated land it is impossible to draw conclusions, because the nature of the manure exerts an influence quite as great, if not greater, than that of the soil itself.
The relative proportion in which the different mineral matters enter into the composition of the ash varies within very wide limits, as will be apparent from the following table, containing a selection of the best analyses of our common cultivated and a few uncultivated plants.
Table of the Composition of the Ash of different Plants in 100 Parts.
Note.—Alumina and oxide of manganese occur so rarely, that separate columns have not been introduced for them, but their quantity is stated in notes at the end of the table.
| Potash. | Soda. | Chloride of Potassium. | Chloride of Sodium. | Lime. | Magnesia. | |
| Wheat, grain | 30·02 | 3·82 | ... | ... | 1·15 | 13·39 |
| straw | 17·98 | 2·47 | ... | ... | 7·42 | 1·94 |
| chaff | 9·14 | 1·79 | ... | ... | 1·88 | 1·27 |
| Barley, grain | 21·14 | ... | 5·65 | 1·01 | 1·65 | 7·26 |
| straw | 11·22 | ... | ... | 2·14 | 5·79 | 2·70 |
| Oats, grain[B] | 20·63 | ... | 1·03 | ... | 10·28 | 7·82 |
| straw | 19·46 | 1·93 | 2·71 | 4·27 | 7·01 | 3·79 |
| chaff[C] | 6·33 | 3·93 | ... | 0·24 | 1·95 | 0·38 |
| Rye, grain | 33·83 | 0·39 | ... | ... | 2·61 | 12·81 |
| straw | 17·20 | ... | 0·30 | 0·60 | 9·10 | 2·40 |
| Maize, grain | 28·37 | 1·74 | ... | trace | 0·57 | 13·60 |
| stalks and leaves | 35·26 | ... | ... | 2·29 | 10·53 | 5·52 |
| Rice, grain | 20·21 | 2·49 | ... | ... | 7·18 | 4·26 |
| Buckwheat, straw | 31·71 | ... | 7·42 | 4·55 | 15·71 | 1·66 |
| Peas (gray), seed | 41·70 | ... | 3·82 | 1·24 | 4·78 | 5·78 |
| straw | 21·30 | 4·22 | ... | ... | 37·17 | 7·17 |
| Beans (common field), | ||||||
| grain | 51·72 | 0·54 | ... | ... | 5·20 | 6·90 |
| straw | 32·85 | 2·77 | ... | 11·54 | 19·85 | 2·53 |
| Tare, straw | 32·82 | ... | 3·27 | 4·03 | 20·78 | 5·31 |
| straw | 31·72 | ... | 7·41 | 4·55 | 15·71 | 1·66 |
| Flax, seed | 34·17 | 1·69 | ... | 0·36 | 8·40 | 13·11 |
| straw | 21·53 | 3·68 | ... | 9·21 | 21·20 | 4·20 |
| Rape, seed[D] | 16·33 | 0·34 | ... | 0·96 | 8·30 | 8·80 |
| straw[E] | 16·63 | 10·57 | ... | 2·53 | 21·51 | 2·92 |
| Spurry | 26·12 | 1·14 | ... | 8·90 | 14·46 | 8·88 |
| Chicory root | 34·64 | ... | 8·92 | 2·98 | ... | ... |
| Red clover | 25·60 | ... | 9·08 | 6·02 | 21·57 | 8·47 |
| Cow grass, Trifolium medium | 22·78 | ... | 12·39 | 1·86 | 24·42 | 8·86 |
| Yellow clover | 27·48 | ... | 11·72 | 8·16 | 17·26 | 8·39 |
| Alsike clover | 29·72 | ... | 6·29 | 1·05 | 26·83 | 4·01 |
| Lucerne | 27·56 | ... | 11·64 | 1·91 | 20·60 | 5·22 |
| Anthoxanthum odoratum | 32·03 | ... | 7·03 | 4·90 | 9·21 | 2·53 |
| Alopecurus pratensis | 37·03 | ... | 9·50 | ... | 3·90 | 1·28 |
| Avena pubescens | 31·21 | ... | 4·05 | 5·66 | 4·72 | 3·17 |
| Bromus erectus | 20·33 | ... | 10·63 | 1·38 | 10·38 | 4·99 |
| Bromus mollis | 30·09 | 0·33 | ... | 3·11 | 6·64 | 2·60 |
| Cynosurus cristatus | 24·99 | ... | 11·60 | ... | 10·16 | 2·43 |
| Dactylis glomerata | 29·52 | ... | 17·86 | 3·09 | 5·82 | 2·22 |
| Festuca duriuscula | 31·84 | ... | 8·17 | 0·62 | 10·31 | 2·83 |
| Holcus lanatus | 34·83 | ... | 3·91 | 6·66 | 8·31 | 3·41 |
| Lolium perenne | 24·67 | ... | 13·80 | 7·25 | 9·64 | 2·85 |
| Annual ryegrass | 28·99 | 0·87 | ... | 5·11 | 6·82 | 2·59 |
| Poa annua | 41·86 | ... | 0·47 | 3·35 | 11·69 | 2·44 |
| Poa pratensis | 31·17 | ... | 11·25 | 1·31 | 5·63 | 2·71 |
| Poa trivialis | 29·40 | ... | 6·90 | ... | 8·80 | 3·22 |
| Phleum pratense | 31·09 | ... | 0·70 | 3·24 | 14·94 | 5·30 |
| Plantago lanceolata | 33·26 | ... | 4·53 | 8·80 | 19·01 | 3·51 |
| Poterium Sanguisorba | 30·26 | ... | 3·27 | 1·35 | 24·82 | 4·21 |
| Achillea Millefolia | 30·37 | ... | 20·49 | 3·63 | 13·40 | 3·01 |
| Potato, tuber | 43·18 | 0·09 | ... | 7·92 | 1·80 | 3·17 |
| stem | 39·53 | 3·95 | ... | 20·43 | 14·85 | 4·10 |
| leaves | 17·27 | ... | 4·95 | 11·37 | 27·69 | 7·78 |
| Jerusalem Artichoke | 55·89 | ... | 4·88 | ... | 3·34 | 1·30 |
| stem | 38·40 | 0·69 | ... | 4·68 | 20·31 | 1·91 |
| leaves | 6·81 | 3·72 | ... | 1·82 | 40·15 | 1·95 |
| Turnip, seed | 21·91 | 1·23 | ... | ... | 17·40 | 8·74 |
| bulb | 23·70 | 14·75 | ... | 7·05 | 11·82 | 3·28 |
| leaves | 11·56 | 12·43 | ... | 12·41 | 28·49 | 2·62 |
| Mangold Wurzel, root | 21·68 | 3·13 | ... | 49·51 | 1·90 | 1·79 |
| leaves | 8·34 | 12·21 | ... | 37·66 | 8·72 | 9·84 |
| Carrot, root | 42·73 | 12·11 | ... | ... | 5·64 | 2·29 |
| leaves | 17·10 | 4·85 | ... | 3·62 | 24·05 | 0·89 |
| Kohl-rabi, bulb | 36·27 | 2·84 | ... | 11·90 | 10·20 | 2·36 |
| leaves | 9·31 | ... | 5·99 | 6·66 | 30·31 | 3·62 |
| Cow cabbage, head | 40·86 | 2·43 | ... | ... | 15·01 | 2·39 |
| stalk | 40·93 | 4·05 | ... | 2·08 | 10·61 | 3·85 |
| Poppy seed | 9·10 | ... | 7·15 | 1·94 | 35·36 | 9·49 |
| leaves | 36·37 | ... | 2·50 | 2·51 | 30·24 | 6·47 |
| Mustard seed (white) | 25·78 | 0·33 | ... | ... | 19·10 | 5·90 |
| Radish root | 21·16 | ... | 1·29 | 7·07 | 8·78 | 3·53 |
| Tobacco leaves | 36·37 | ... | 2·50 | 2·51 | 30·24 | 6·47 |
| Fucus nodosus[F] | 20·03 | 4·58 | ... | 24·33 | 9·60 | 6·65 |
| Fucus vesiculosus[G] | 20·75 | 6·09 | ... | 24·81 | 8·92 | 5·83 |
| Laminaria digitata[H] | 12·16 | ... | 2·30 | 19·34 | 4·62 | 10·94 |