Factors influencing the percentage of nitrogen in the barley grain of Hoosfield

The effect of rainfall, sowing date and yield on the percentage of nitrogen in the barley grain of certain representative plots on Hoosfield is studied. All these factors are shown to have marked effects. The farmyard manure plot differs from the others, both in mean percentage and in the effects of rainfall and yield. Changes in variety appear to have had little apparent influence, but there is a progressive decrease in the percentage of nitrogen which cannot be accounted for by changes in any of the above factors, and which may well be due to varietal improvement Comparison is made with the results of the similar study on the permanent barley plots at Woburn.