DEFRA have not made a specific assessment on the effects of changes in the price of agricultural land on the profitability and productivity of English agriculture.
DEFRA publish aggregate balance sheets for agriculture in "Agriculture in the United Kingdom". The balance sheet shows the value of fixed assets at a point in time (December each year) and the value of liabilities at a point in time. Fixed assets are dominated by land. As the volume of land is unchanging, the trend in the value of land and buildings is dominated by the effect of land prices. The latest balance sheet shows the value of UK agricultural land and buildings increasing by 40 per cent. at current prices, between 2003 and 2006.
Changes in profitability of farming are measured by changes to Farm Business Income. Data on Farm Business Incomes are provided by the annual Farm Business Survey conducted in England. These figures are for March/February years. The most recent published figures show Farm Business Income in England at the all types level falling by 2.5 per cent. at current prices, between the years 2003-04 and 2006-07 (to then increase sharply in 2007-08).
Productivity for UK agriculture, measured by Total Factor Productivity, is published in "Agriculture in the United Kingdom". The latest publication shows UK agricultural productivity increasing by 5 per cent. between the years 2003 and 2006.