Academic journal article
By Bakels, C. C.
Antiquity , Vol. 71, No. 272
Fields and their manuring
In his 1981 paper entitled 'Plough and pastoralism', A.G. Sherratt discussed innovations which increased the productivity of arable land. The use of the plough and draught animals made it economical to prepare land which would otherwise have yielded poorer crops (Sherratt 1981: 287). Sherratt did not mention a third way of increasing productivity - by using manure, possibly because there is so very little evidence for ancient manuring.
One problem, of course, is that most archaeological excavations concentrate on settlements and cemeteries, rather than prehistoric fields, although the number of publications on this topic is increasing.
A second problem is that the arable soil of former fields has undergone changes that have totally obliterated the soil's original properties. More often than not, the layout of the fields is the only feature that can still be studied. Nevertheless, some arable soils have escaped severe alteration thanks to the fact that they became buried beneath sediments.
Manuring has been discussed in connection with 'Celtic' fields (see for instance Bowen 1961; Brongers 1976: 60; Zimmermann 1976), but our knowledge of older instances is still scanty (Jankuhn 1969; Fowler 1983; Barker 1985).
Evidence for early manuring
The subject of manuring was brought to my attention during a study of Middle and Late Bronze Age fields near the town of Haarlem, in the Netherlands. These fields, with beautifully preserved ard-marks, had been laid out on a sandy ridge in the middle of a peat area. There were several superimposed layers of arable soil, alternating with layers of wind-blown sand. On top of the last layer of soil was a layer of peat, whose base was dated to 700 BC - the terminus ante quem for the last field (Poldermans 1987). A few shallow pits yielded just enough sherds to show that the sequence dated from the Middle and Late Bronze Ages (1500800 BC).
The dark brown colour of the layers of soil, which were 15-40 cm thick, formed a marked contrast with the yellow of the subsoil and the layers of drift sand. Pollen analysis by C.E. Vermeeren revealed a remarkably high percentage of freshwater algae, mostly Pediastrum, alongside the usual low percentage of cereal and the much higher percentage of plants growing on fallow land (Mook-Kamps & Van Zeist 1987). The Middle Bronze Age algae remains amounted to 28%, those from the Late Bronze Age to 17%. Pond weeds (Potamogeton sp.) showed the same trend. No such high percentages of algae remains were encountered in the samples of subsoil and yellow sand. At first it was thought that water from the surrounding marsh had splashed over the fields during storms; as the fields were surrounded largely by dense alder carr, this is not very likely. Another possibility is that the remains of the waterplants are attributable to human activities. The Bronze Age farmers may have watered their crops in dry summers, or they may have manured their sandy fields with mud from the near-by swamp. That would account for the colour of the arable soils. Moreover, some layers of arable soil were thicker than the 15-20 cm reported for layers of soil tilled with a standard ard (Hansen 1969; Reynolds 1981; Varisco 1982). Manuring with mud was common practice in the Netherlands until quite recently (cf. Bieleman 1992: 66). The Bronze Age fields near Haarlem may show that this practice has a long history.
Other, possibly more convincing, evidence for manuring in the Middle and Late Bronze Ages has been brought forward by J. Buurman (1988), describing agricultural practices on a sandy ridge in West-Friesland, a Dutch wetland region more or less comparable with that mentioned above. Extensive excavations brought to light the remains of large farmhouses surrounded by ditches on the flanks of the ridge. The top of the ridge showed layers of arable soil tilled by an ard. The ditches were found to contain large amounts of refuse, including pottery, bones and plant remains. …