Soil. 33 



sorts, like sea-weed, or the refuse of fish, as may render 

 it profitable to cultivate them ( I12 ). 



5. It is a wise maxim in husbandry, that the soil, like the 

 cattle by which it is cultivated, should always be kept up in 

 good condition, and never suffered to fall below the work it 

 may be expected to perform ( II3 ). 



Probably, in ordinary cases, in ground of middling ferti- 

 lity, and with a good climate, the substances which vegetables 

 collect from the atmosphere, will nearly compensate for 

 what is sold off in corn and in live stock, provided there is a 

 suitable proportion of grain, and of green or fallow crops. 

 It is established, however, as a fact, that where other pro- 

 ductions are sent off, besides grain and live stock, or where 

 straw and grain for forage are repeatedly abstracted, without 

 any equivalent being supplied, the soil soon loses its ferti- 

 lity (" 4 ). 



6. Depth of soil is of great importance. The roots of 

 some plants, as carrots, and wheat ( II5 ), go deep into the 

 earth, and often require all the moisture it contains ; but depth 

 is likewise desirable, where such plants as the grasses, (which 

 in general penetrate but a short way), are sown. If the soil 

 be thin, water, in wet weather, is apt to lie on the subsoil, 

 and to injure the roots of the plants ; and in dry weather k 

 may be too suddenly evaporated. Whereas when the soil is 

 deep, in wet weather the rain escapes downwards, and the 

 plants sustain no injury ; and in dry weather, if the moisture 

 is exhausted at the top, new moisture arises from the bot- 

 tom, and makes up for the deficiency. 



7. There are various modes of improving soils. When 

 they contain acids, or salts of iron, they may be ameliorated 

 by the application of lime or chalk. The sulphate of iron is 

 thus converted into a manure. If there be an excess of cal- 

 careous matter in the soil, as in chalky land, it may be im- 

 proved by the application of sand or clay, or earthy sub- 

 stances. Soils too abundant in sand, are benefited by the 

 use of clay, or marl, or vegetable matter ; and a deficiency of 

 vegetable or animal matter, must be supplied by enriching 

 manures. 



The substances necessary for improving the texture of 

 soils, may frequently be discovered in their immediate neigh- 

 bourhood. Coarse sand is often found under chalk, and al- 

 most always near it. Beds of sand and gravel, are commonly 

 found below clay, while clay and marl frequently occur be- 

 low sand. 



The labour and expense of improving the texture or con- 



c 



