6 



Bare Fallows. 



[APRIL, 



Thus, when followed by a dry autumn, the fallowing produces 

 an increase of more than 50 per cent, in the ensuing crop, 

 whereas if the winter be wet the increase due to fallowing is 

 little or nothing. 



It therefore follows that summer fallows are only likely to be 

 of direct benefit to the next crop where the climate is dry and 

 no great amount of percolation takes place through the soil 

 in the winter. It is, on the whole, more likely to result in a 

 permanent loss of fertility, and can only be justified on those 

 heavy soils which need an occasional rest to maintain their 

 condition and restore a good tilth. 



Another of the Rothamsted experiments illustrates how much 

 may be gained by a clover crop in place of a bare fallow. One 

 of the fields is farmed under a four-course rotation — swedes, 

 barley, clover or fallow, wheat ; one half of the plots growing 

 clover and the other fallowed before the wheat. The better the 

 clover the better the ensuing wheat, and if we compare the 

 succeeding crops after a good clover year its benefits are very 

 marked : — 





Clover 

 Hay. 



Wheat 



Swedes. 



Barley. 





Cwt. 



Bushels. 



Tons. 



Bushels. 



Clover plot 



767 



39*5 



19-4 



36-3 



t allow plot 





32-5 



19-0 



28-3 



Although nearly 4 tons of clover hay were removed, the 

 residues, roots and stubble were sufficient to increase the wheat 

 crop by 21 per cent. ; the root crop which came next by 2 per 

 cent., although the same manure was put on both crops ; and 

 finally the barley, three years after, by 28 per cent. 



From all these results it will be seen that a bare fallow can 

 never be a directly profitable operation and has no justification 

 on free working land. But with strong clays in dry climates, as 

 for example over much- of the East and South-East of England, 

 it may often be necessary to clean the land and restore its 

 friable texture ; on such soils also there is least likelihood of loss 

 through the washing out of the reserves of nitrogen which have 

 been rendered available by the process. 



A. D. Hall. 



