Tuesday 23 January 2018

Marl Pits

The 1839 field map of Church Pulverbatch shows two fields as being associated with marl pits. These lie between Newhouse Lane (previously called Coalpit Lane) and the Shrewsbury road where pits are still evident in the woodland there.

The “glacial drift” left behind by the Ice Age of ten thousand years ago created swathes of sand and marl (soft concentrations of secondary calcium carbonate and clay) along the contour lines of the slopes left by the retreating ice. It had been known, probably, since Roman times that spreading clay over sandy soils enriched the soil and improved it’s water holding capacity. This practice, known as “marling”, was widespread. The marl commonly occurred at depths of 1 to 2 metres and had to be dug out of the ground – creating marl pits.

The marl pits, very different from sand and brick (clay) pits, are easily distinguishable by the square edged gentle slope at one end of the pit and a steep rounded slope at the other. The shape was the result of a few hundredweights of marl being dug out and loaded into carts, which were then hauled up the sloping end of the pit, a process that was repeated time and time again. Over twelve months the pit would partly fill with water so another pit was dug a few yards away. This process was repeated over and over again. Later marl pits were often dug in the middle of fields to make the spreading of the marl an easier matter with another pit close by and even a third.

Documentation reveals that “marling” continued in general use throughout the 16th, 17th & 18th centuries, through an era of advances in agriculture such as the enclosure of land, the introduction of new crops like peas and the rotation of crops. It was found that fields left fallow (to help restore their fertility) were unproductive for a season but “marling” helped to overcome the problem. The marl remained effective for about twelve years before sinking. The value of dung as a fertilizer was well known, however as much of the winter stock were killed off each autumn it was difficult to accumulate sufficient dung as fertiliser.

Over the years “marling” became a part of the local way of life. Stimulated by the increase in food prices for food crops in the 1790’s, many marl pits were dug but by the mid nineteenth century the practice of “marling” was dying out. Even though marl was available and free it needed a great deal of labour for excavation, haulage and spreading. Labour for such tasks was now in short supply as many of the younger and more adventurous villagers had begun to seek their fame and fortune overseas in the colonies or in the growing manufacturing industries. As a result the practice of “marling” became expensive costing about £5 an acre It was also a time when alternative fertilizers such as lime, bone dust, sea sludge, soda and salt came into use. The improving methods of agriculture were seeing the growing of fodder to enable the over wintering of more stock. This practice provided an all year round source for the best enrichment of soil – natural manure.