4 



Bare Fallows. 



[APRIL, 



fertilizing properties of the atmosphere." Arthur Young, on the 

 contrary, with his aversion to bare fallows, wrote about the 

 same time : " The quantity of gas or vapour that is hourly 

 exhaling from a fallow field after rain or every fresh ploughing 

 is improvidently lost, and argues a want of economy that is 

 truly reprehensible." But experience was against Arthur Young ; 

 the practical farmer knew that cultivation by itself made the 

 land better able to support a crop ; this was the basis of 

 Jethro TuU's horse-hoeing husbandry and of the Lois-Weedon 

 system of alternate husbandry. Anybody, again, who visits an 

 experimental farm, where the plots are separated by paths, will 

 recognise the " fallow effect " in the increased vigour of the 

 outside rows bordering the bare soil. An explanation, however, 

 was not possible until the discovery of nitrification some twenty 

 years ago and the investigations which have been made into the 

 conditions favouring the process. 



All soils contain considerable residues of nitrogenous material 

 which cannot reach the plant until they have been oxidized by 

 Various bacteria in the soil and so converted into nitrates. A 

 summer's fallow provides just the conditions favourable to 

 nitrification — warmth, aeration, the stirring of the soil, and the 

 greater amount of moisture which results from the absence of a 

 crop to dry the soil. 



It is easy to ascertain that the fallowing results in a great 

 gain of water to the soil ; for example, at Rothamsted in 1904, 

 half of certain plots were fallowed while the other halves 

 carried wheat. The soil was sampled in mid-September, after 

 harvest, with the following results : — 





Percentage of water in fine soil. 





Cropped . 



Fallow. 



1st depth of nine inches 



17-4 



17-2 



2nd „ 



i8-8 



20-0 



3^^ „ 



20- I 



22-3 



4th ,, 



20-9 



23-1 



or down to the depth of 3 ft. an average gain of 1-35 per cent, 

 of water equivalent to 3'i in. of rain. Of course, in a climate 

 like ours this extra water is a matter of little or no moment. 



