Fig. 39. Rough grass pasture near the river, above that is arable land and still higher is woodland
Instances of these facts may be found in going down any hill 500 ft. or more in height: the top is usually wood or waste, being too cold for crops, below this may come grass land, lower still arable land. It is both warmer and moister in the valley (since water runs down hill), and so we can account for the proverbial fertility of valleys. But just near the river, if there is one, the ground may be too wet for crops, and therefore grass is grown. Clay land that is rather too wet to plough is usually left in grass.
CHAPTER IX
CULTIVATION AND TILLAGE
Apparatus required.
Plot experiments, hoeing and mulching. Thermometer. Soil sampler (Fig. 42, p. 88). This tool consists of a steel tube 2 in. in diameter and 9 in. long, with a slit cut along its length and all the edges sharpened. The tube is fixed on to a vertical steel rod, bent at the end to a ring 2 in. in diameter, through which a stout wooden handle passes. It is readily made by a blacksmith.
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.
