H2 TILLAGE— MOVEMENTS OP SOIL WATER [chap. 



Woburn Fruit Farm of planting fruit trees and sowing 

 the seed of coarse meadow grasses at the same time, 

 show this competition at its highest degree, but even 

 when trees are planted in old pasture care should be 

 taken to keep a ring round the tree free from grass 

 and well cultivated or mulched for at least two years. 

 For similar reasons, when trees are planted in arable 

 land weeds should be kept down, nor should crops like 

 cabbages or mangolds be grown between the rows 

 of trees ; such crops are usually considered to " draw 

 the land " and deplete it of plant food, but the harm 

 they do lies in the water they withdraw just at the most 

 critical season, when the tree is making its first start in 

 its new quarters. 



Bare Falloivs. 



The custom of fallowing land, of leaving it entirely 

 bare for a season, during which the land is worked as 

 often as possible, is one of the oldest in agriculture ; a 

 rotation of wheat, wheat, fallow, .or of beans, wheat, 

 fallow, being almost universal, until the introduction! of 

 turnips gave the farmer a chance of cleaning his land 

 and yet growing a crop at the same time. The objects 

 of a fallow were various : in the first place, the summer 

 cultivations resulted in a thorough cleaning of the land 

 and in a free development of nitrates for the succeeding 

 crop ; also on the heavy soils, which are the most suited 

 to fallowing, a good tilth was obtained that was often 

 impossible otherwise. Indeed, at the present day it is 

 found desirable and even necessary to introduce an 

 occasional bare fallow when farming on the heavy clays 

 of the south and east of England, in order to obtain a 

 satisfactory tilth in that dry climate. 



One of the most notable effects of fallowing lies in 

 the production of a stock of nitrates from the stores of 



