1921.] 



Effect of Chalk on Heavy Land. 



419 



THE EFFECT OF CHALK ON THE 

 CULTIVATION OF HEAVY LAND. 



E. J. KussELL; D.Sc, F.K.S., and B. A. Keen, B.Sc, F.I.P. 



Rothamsted Experimental Station, Harpenden. 



It has long been known in a general way that chalk or lime 

 facilitates the cultivation of land, but so far as we are aware 

 no field measurements are on record to show the magnitude of 

 the effect. In the winter of 1912-13 large plots of land were 

 chalked at Rothamsted, but strips of unchalked land were left 

 in each field for purposes of comparison. Records have been 

 kept of the crops ; these are given in Table I and show as a 

 result of chalking an increased yield of clover, which reacts on 



Table I. — E^ed of Chalking on Yield of Crop. Chalk applied 

 November, 1912, to March, 1913. 



j Saw pit Field. 



Gt. Harpenden Field. 







Yield per acre on 





Yield per acre on 



Year. 



Crop. 



1 o 



a ^ 



o 



Chalked 

 20Joads [ 50 loads 

 per acre. 



Crop. 



,i> 



.a 



o 



Chalked 

 20 loads 

 per acre. 



1914 



Oats, bush. ... 





44 -G 



37-3 



41-1 



Potatoes, tons 



9-3 



8-8 



1915 



Clover, cwt 





19-4 



35-8 



39-2 



Barley, bush. 

 Straw, cwt. ... 

 Wheat, bush. 

 Straw, cwt. ... 



36-2 



19- 1 



20- 9 



21- 4 



33*9 



18- 9 



19- 6 



20- 5 



1916 



Wheat, bush. 

 Straw, cwt. ... 





27-8 

 33 



33-8 

 40-3 



30-2 

 35-0 



Wheat, bush. 

 Straw, cwt. ... 

 Oats, bush. ... 

 Straw, cwt. .. 



31-7 

 39-7 

 31-4 

 20-0 



27-3 



37- 3 



38- 5 

 25-6 



1917 



Oats, bush. ... 

 Straw, cwt. ... 





25-8 

 23-4 



29-7 

 22-8 



27-1 

 22-9 



Wheat, l)ush. 

 Straw, cwt. ... 



24-5 

 18-5 



27-7 

 20-1 



1918 



Wheat 

















1919 

 1920 



Wheat 



Oats 





- Plots not separated. 









1021 



I'otatoes 

















subsequent crops, but there is no increase in wheat, oats or 

 potatoes, apart from that due to the growth of clover. On the 



2 



