The economics of liming in arable crop rotations: analysis of the 35-year Rothamsted and Woburn liming experiments

Liming is a common management practice, but there exists uncertainty about the economic benefits. An economic analysis of the costs and profitability of liming arable crops was undertaken using data from the long-term liming experiment at Rothamsted and Woburn. There was a strong liming effect on gross margins, but large differences in the economic benefit between crops. For some crops (such as spring barley), liming greatly improved the gross margin, while for spring oats liming provided very little increase. Most economic benefit was achieved with the high lime treatment, but the cumulative discounted cash flow indicated that it took approximately 20 years before a distinct difference developed between the lime treatments. Therefore, lime should be considered a capital investment and economic evaluation undertaken over a long period. Liming rate increased the net present value expressed as an annual equivalent (NPVa). An additional £436 ha−1 year−1 at Rothamsted and £208 ha−1 year−1 at Woburn of profit was gained from the adoption of the most profitable liming treatments over not liming. Sensitivity analysis indicated that total liming costs had a weak effect on NPVa, but crop price had a strong effect. The eco�nomic performance of liming differed between sites and was higher at Rothamsted than at Woburn, mostly because of soil differences. Liming greatly improves eco�nomic returns of most arable crops, but the magnitude of the long-term economic benefit depends upon the sequence of crops within a given rotation