Visitors to the Dales cannot fail to notice the many lime kilns that dot the landscape. In Nidderdale, Toft Gate kiln on Greenhow Hill, is a substantial relic of that practice. Many of the kilns are small structures that clearly served a very local need, Toft Gate itself is an industrial scale structure, which served a much wider area, distributing its product through Pateley Bridge.
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Agriculturalists have been aware of the use of lime to improve land since ancient times. However, there is inconclusive evidence for the nature of its use in earlier times, until it started to appear in the written record from the sixteenth century onwards. The heyday of locally produced lime for agricultural purposes extended from that period to the nineteenth century.
Lime is not a fertiliser in itself, its benefit lies when used with nitrogen based fertilisers, such as dung, when the use of lime offsets increasing acidity in the soil, allowing more fertiliser to be applied, enriching the soil more than could otherwise be achieved and thus pushing up yields. It was perceived that the real benefit of liming was not simply making good land better, but that it allowed land that would otherwise have been marginal, or indeed unuseable - such as moorland, to be brought under cultivation.
Land based on acidic soil needs the periodic application of lime to keep it 'sweet', otherwise its capacity to produce nutirent rich grass to feed livestock deteriorates. Lime does have further benefits for the chemistry of soil in terms of supplementing calcium, which is taken up by plants, grazed by livestock and thus lost to the land. Also, lime fixes ammonia in the soil and helps control the supply of potash and soda to the soil.
This is not to say that farmers have always had a sure understanding of the process. Different experts had different explanations for the nature of the process and different regimes for application on the land. Writing in 1756, for example, Hale believed that the heat of the freshly burnt lime contributed to its beneficial powers and recommended spreading it on the land in small piles fresh from the kiln!
A very different use for lime was in the construction of 'dew' ponds, man made features on limestone - and thus porous- pastures, built to hold drinking water for livestock. The base of the ponds were lined with a thin layer of quicklime to discourage earthworm activity which would lead to penetration of the pond base and thus the development of leaks.
*The major source for this article is: David Johnson, 'Limestone Industries of the North Yorkshire Dales', Tempus Publishing, 2002