Edward J. Russell

“ If there is a sand pit near you, or a field of sandy soil, you should get a supply for these experiments; if not, some builder's sand can be used. When the sand is dry you will see that the grains are large and hard. Further, they are all separate and do not stick together; if you make a hole in a heap of the sand, the sides fall in, there is nothing solid about it, and you can easily see the mistake of the foolish man who built his house upon the sand. When the sand is wet it sticks better and can be made into a good many things; at the seaside you can make a really fine castle with wet sand. ”

“ The surface soil contains a great deal of the black material, which forms plant food, while the subsoil does not. Thus plants grow well on the surface soil and starve on the subsoil. We can also explain why gardeners and farmers speak of black soils as rich soils; they contain more than other soils of this black material that makes plant food. Still further, we can explain why the farmer often sows plants like mustard, tares or clover, and then ploughs them into the ground. They are not wasted, but they make food for the next crop that goes in. ”

“ We have seen that a change in the soil produces a change in the plants that grow on it. The flora (i.e. the collection of plants) of a clay soil is quite different from that of a sandy soil, and both are different from that of a chalk or of a fen soil. In like manner draining a meadow or manuring it alters its flora: some of the plants disappear and new ones come in. Even an operation like mowing a lawn, if carried on sufficiently regularly, causes a change. In all these cases the plants favoured by the new conditions are enabled to grow rather better than those that are less favoured ”

“ Bulbs and cuttings are sometimes forced out of the ground, whilst grass and young wheat may be so loosened that they have to be rolled in again as soon as the weather permits. When the ground has been dug in autumn and left in a very rough state all this loosening work of the frost is very much helped, because so much of the soil may become frozen. If in spring you dig a piece of land that has already been dug in autumn, and then try digging a piece that has not, you will find the first much easier work than the second in all but very sandy soils. ”

“ In a clay country there is also a great deal of grass land and not much ploughed land; if you live where there is much clay you can easily discover the reason. Clay becomes very wet and sticky when rain falls, and very hard in dry weather: it is, therefore, difficult to cultivate. Farmers cannot afford to spend too much money on cultivation, and so they prefer grass, because once it is established it goes on indefinitely and does not want ploughing up and re-sowing. And besides, farmers have learned by experience that grass can tolerate more water and less warmth than most other English crops. ”

“ The experiment shows that the top soil gives the plant something that it wants for growth and that it cannot get either from sand or from the subsoil; this something we will call "plant food."
Further proof is easily obtained. At a clay or gravel pit little or no vegetation is to be seen on the sloping sides or on the level at the bottom, although the surface soil is carrying plants that shed innumerable seeds. A heap of subsoil thrown up from a newly made well, or the excavations of a house, lies bare for a long time. The practical man has long since discovered these facts. ”

“ Earthworms are very useful: they make burrows in the soil, thus allowing air and water to get in: they drag in leaves and they keep on covering the surface with soil from below. Besides these and the other large creatures, there are micro-organisms so small that they cannot be seen without a very good microscope: they live and breathe and require air, water and food. Some are very useful and change dead parts of plants or animals into valuable plant food. Almost anything that can be consumed by fire can be consumed by them. ”

“ Farmers and gardeners throughout the spring, summer and autumn, are busy ploughing or digging, hoeing or in other ways cultivating the soil. Unless all this is well done the soil fails to produce much; the sluggard's garden has always been a by-word and a reproach. In trying to understand why they do it we must remember that plant roots need water, warmth and air; if the soil is too compact or if there is too much water the plant suffers, as we have seen.
Fig. ”

“ Plants require water, air, warmth, food, and light, and they will not grow if harmful substances are present. The rain-water that falls remains for some time in the soil, and does not at once run away or dry off: water can also move from wet to dry places in the soil. Therefore the plant does not need rain every day, but can draw on the stock in the soil during dry weather. A sandy soil is usually drier than a loam or a clay, especially if it lies rather high: plants growing on a sandy soil make less growth and have narrower and smaller leaves than those on a moister soil. ”

“ If you now measure with a ruler any of the bricks that have not cracked, you will find that they have shrunk a little and are no longer quite an inch long. This fact is well known to brickmakers; the moulds in which they make the bricks are larger than the brick is wanted to be. But what would happen if instead of a piece of clay one inch long you had a whole field of clay? ”

“ Frost plays havoc with walls built of flints and with old bricks that are beginning to wear. If there are several frosts, with falls of rain or snow and thaws coining in between, the soil is moved about a good deal by the freezing and melting water. ”

“ As soon as the little plants are up the soil must be hoed, and the more often this is done the better. Hoeing keeps the soil cool and moist in hot weather, the loose layer acting like a mulch of straw. Anything else that shields the soil from the sun or the wind has the same action but is not so effective as the mulch. Further, hoeing keeps down weeds, which successfully compete against almost any cultivated plants. Humus also prevents the loss of moisture from soils. ”

“ In almost any lane, field, or garden a sufficient number of illustrations may be obtained for our purpose; if a stream and a hill are accessible the material is practically complete, especially if the children can be induced to pursue their studies during their summer holiday rambles. Of course this entails a good deal of work for the teacher, but the results are worth it. Children enjoy experimental and observation lessons in which they take an active part and are not merely passive learners. ”

“ Now put some soil into A. At once the soil is stirred up, the water becomes muddy, and the muddy liquid flows into B. But very soon a change sets in, the liquid in A becomes clear, and only the grit and stones are left in the bottom: all the mud—the clay and the silt—is washed into B. There it stops for a long time, and some of it will never wash out. The liquid flowing into C is clearer than that flowing into B. If you keep on putting fresh portions of soil into A you can keep B always muddy, although A is usually clear. ”

“ As the plant root is alive it wants air. The effect of keeping air out can be seen by sowing some barley or onion seeds in the ground and then pouring a lot of water on and plastering the soil down with a spade. Sow another row in nicely crumbled soil, not too wet, press the seeds well in, but do not plaster the soil. This second lot will generally do much better than the first. If the ground round a plant is frequently trodden so that it becomes very hard the plant makes much less growth than if the soil were kept nice and loose. ”

“ These properties of clay and sand are very important for plants. Sow some seeds in a little jar {16} full of clay kept moist to prevent it cracking, and at the same time sow a few in some moist sand. The seeds soon germinate in the sand but not in the clay. It is known that seeds will not germinate unless they have air and water and are warm enough. They had water in both jars, and they were in both cases warm, but they got no air through the clay and therefore could not sprout. Pure clay would not be good for plants to grow in. ”

“ After harvest the farmer breaks up his land with a plough and then leaves it alone until seed time
One great object of cultivation is, therefore, to prevent the soil being too compact and too wet. After the harvest the farmer breaks up his ground with a plough and then leaves it alone till seed time (Fig. 40) . A gardener does the same thing with a fork in his kitchen garden—he cannot very well elsewhere, or the plant roots might {83} become too cold. If there is frost during the winter both farmer and gardener are pleased because they say the frost "mellows" the ground ”

“ If you had very magnifying eyes and could see things so enlarged that these little creatures seemed to {62} you to be an inch long, and if you looked down into the soil, it would seem to you to be an extraordinarily wonderful place. The little grains of soil would look like great rocks and on them you would see creatures of all shapes and sizes moving about, and feeding on whatever was suitable to them, some being destroyed by others very much larger than themselves, some apparently dead or asleep, yet waking up whenever it becomes warmer or there was a little more moisture. ”

“ The surface soil is seen to contain more material that will burn away than the subsoil does. When the burnt soil is moistened it does not become dark and sticky like it did before, it has completely changed and cannot be made into soil again. It is more like brick dust than soil. ”

“ The top layer of soil in the wood is soft, dark in colour, and is evidently leaf mould mixed with sand or soil.
Leaf mould is highly prized by gardeners, indeed gardeners will often make a big heap of leaves in autumn and let them "rot down" and change into mould. If you can in autumn collect enough leaves to make a heap you {34} should do so and leave it somewhere where the rain can fall on it, but cover it with a few small branches of trees to prevent the wind blowing the leaves away. ”

“ The great variety of flowers attracts a corresponding variety of butterflies, moths and other insects; there are also numbers of birds and rabbits—indeed a chalk country teems with life in spite of the bare look of the Downs. The roads running at the foot of the chalk Downs and connecting the villages, and farmhouses built there for the good water supply, are particularly rich in plants because they sometimes cut into the chalk and sometimes into the neighbouring clay, sand or rock. ”

“ The addition of chalk or lime to soil was found in Chap. III. to improve it very much by making it less sticky and less impervious to air and water. Chalk or lime does more than this. It puts out of action certain injurious substances or acids that may be formed, and thus makes the conditions more favourable for plants and for the useful micro-organisms; farmers and gardeners express this by saying that it "sweetens the soil." A United States proverb runs: "A lime country is a rich country." Very many soils in England are improved by adding lime or chalk. ”

“ The wind helps to dry the soil very much, and a hedge {92} that shields from the wind not only protects the crop but also keeps the soil moist: a road with high hedges at each side remains wet for a long time after more exposed parts have dried. The effect on the temperature can be well seen on a day when a N.E. wind is blowing. Fix up on a piece of the experimental ground a little hedge made of small pea-stakes or brushwood, and take the soil temperature at one inch depth, both on the windward and on the leeward side. ”

“ And just as the guide is successful only when he directs the attention of the stranger to the important features of the place, and fails directly he becomes garrulous and distracts attention, so a Nature Study book succeeds {xii} only in as far as it helps in the study of the actual thing, and fails if it is used passively and is substituted for an active study. No description or illustration can take the place of direct observation; the simplest thing in Nature is infinitely more wonderful than our best word pictures can ever paint it. ”

“ Then get some more jars and still keep on till the liquid is no longer muddy but nearly clear. The part of the soil that remains behind and will not float over into the jars is at once seen to be made up of small stones, grit, and sand. Set the jars aside and look at them after a day or so. The liquid remains muddy for some time, but then it clears and a thick black sediment gathers at the bottom. If now you very carefully pour the liquid off you can collect the sediments: they are soft and sticky, and can be moulded into patterns like clay. ”

“ Fragments have split off and the rock has broken {118} down into soil which stops where it is unless the rain can wash it away. If there are no cliffs where you live you can see the same kind of action in the banks of the lanes, in a disused quarry, gravel pit or clay pit. Wherever a vertical cutting has been made this downward rolling begins and a heap quickly forms, making the vertical cut into a slope. Plants soon begin to grow, and before long it is clear that soil has been made out of the fragments that have rolled down. ”

“ For this reason they do not go on piling up year after year till finally they fill the wood; instead they decay or "rot down" to form leaf mould: the big pile of the autumn has changed by the next summer to a thin layer which mixes with the soil.
We want now to see what happens on a common or a piece of waste ground that is not cultivated. Grass and wild plants grow up in summer and die during winter; their stems and roots are not taken away, but clearly they do not remain where they are, because next year new plants grow up. ”