122 The Control of the Soil [pt. ii 



very suited for ordinary agricultural purposes, but well 

 adapted to fruit, market gardening, etc., wliile the light 

 loams round Porlock are famous as the source from 

 which many prize samples of barley have come to the 

 Brewers' Exhibition. 



Chalk soils 



Chalk soils are usually very light loams but they re- 

 quire special attention because of their great economic 

 importance. Like all light soils they are hable to drought 

 but they possess the unfortunate property- of drjdng to 

 hard steely fragments unless they are worked to a good 

 tilth at the proper time : they therefore require special 

 care in cultivation. Organic matter is very necessary 

 for them, and sheep therefore play a large part in chalk 

 districts. Further, during frosty weather they become 

 so puffed up and lightened that the young crops are 

 sometimes almost forced out of the ground: rolling is 

 therefore necessary in the spring not only on the grass 

 but also on the arable land. 



Leguminous crops are especially valuable on the chalk 

 bj'- reason of the organic matter they introduce ; among 

 the most useful are sainfoin and lucerne, the latter 

 especially in the drier regions or where there is no sub- 

 soil water. 



Chalk soils are highlj^ favourable to plant and animal 

 life, but this has its disadvantages: they carry a very 

 varied flora and care is needed to keep down weeds, 

 especially charlock. Swedes and the brassica tribe 

 generally are liable to attack by the turnip fly {Phijllo- 

 treta iiemorum), and all crops to damage by wireworm. 



The central feature of the manuring is the folding of 

 sheep: superphosphate is needed for the roots, and 



