23 



GREEN MANURING. 



The importance of increasing the amount of organic matter 

 in the soil is widely recognised, and experiments have been carried 

 out at Rothamsted for some years to determine the best ways in 

 which this could be done. Mr. Page has been studying green 

 manuring, and he has now been able, thanks to the intervention 

 of the Research Council of the Royal Agricultural Society, to 

 arrange for a number of experiments at outside centres, and thus 

 to obtain direct information on the extent to which soil and 

 climatic factors influence the method. 



In practice two kinds of green manuring are possible, though 

 they are not always practicable : — 



1. Summer catch crops may be turned in before the winter 

 corn. 



2. Winter catch crops may be turned in before roots. 



In general, the first method can be practiced only on fallow land, 

 early ploughed seeds leys, or land that has carried a crop harvested 

 early, such as a silage or soiling crop. The eastern counties 

 appear to offer the best opportunities for success. 



Trials of this method, using mustard as the green crop, are 

 in progress at six centres, one in the west (Gloucestershire), and 

 five in the east (Kent (2), Suffolk, Beds, and Northants.). The 

 results of the test at Rothamsted give a forcible illustration of 

 its value. Mustard was sown on the bare fallow after cleaning 

 on 20th August, 1923. It was turned under on October 18th, 

 and winter oats wire drilled at once. The yields of oats in 

 August, 1924, were as follows : — 



The turning in of mustard thus added, on the average, 20 

 bushels per acre to the crop. The cost per acre for mustard 

 seed and the extra operations involved in drilling and turning 

 under amounts to 18/-, whilst the increased yield of oats was 

 worth 79/6 per acre, without reckoning the value of the extra 

 9 cwts. of straw per acre. 



The turning in of winter catch crops before roots is probably 

 of even greater practical importance. Climatic factors play a 

 great part since the green crops have to pass through the winter : 

 if this is too cold, crops sown in the autumn do not usually 

 make sufficient growth, by the time when the land needs to be 

 prepared for roots, to produce any marked effect on the root 

 yield. It is probably only within the region, with an average 

 winter temperature exceeding 40° F. and an annual rainfall 

 between 30 and 40 inches, that the present set of autumn sown 

 green crops can as a rule be successfully grown for turning under 



