On yesterday's session of government sanctioned exercise, this field in the eWoodhall estate near Tewin in Hertfordshire stuck out to me.
At first I thought it was rape coming into flower... I then noticed it seemed to be a volunteer crop... and the leaves were wrong. Then out of the blue a quote "...Fields yellow with charlock..." popped into my head. I took a closer look, got out my faithful friend Francis Rose's Wildflower Key and I checked it out.
It was indeed charlock (Sinapsis arvensis)
For me this sight had brought to life a quote from Arthur Young's General View on the Agriculture of Hertfordshire (1804). The work of this eminent agricultural improver captured a moment of transition between pre and post improvement agricultural practices.
As a conservationist it was a valuable read as it gave me a new perspective into the reality of those pre fertiliser, pre pesticide days of abundant plant life. It made me realise just how much farmers struggled with those crop weeds we now try desperately to conserve as they spiral towards extinction. Many of us are guilty of looking down on the agricultural improvers as callous destroyers of biodiversity, but they believed they were making things better for everyone, however tragic the story of loss that subsequently unfolded.
It bolstered the idea that conservation should never be all or nothing. To be truly sustainable, it needs to balance the needs of both nature AND humans.
Anyway, I digress.
In an excellent chapter about turnips (Young really loved a turnip), he commented with scorn on the state of the turnips "over-run with charlock in full bloom" all about Hertford and Hatfield (Young, 1804 p,103-4). On enquiry he found a decline rather than advancement in Hertfordshire husbandry.
Advanced practice held that one should hoe for weeds at least twice, but many mid Herts farmers were taking the lacksadaisical approach of hoeing but once, which he disparaged as "..a most reprehensible fault in their husbandry; every motive should incline them to the necessary exertion of giving a second hoeing", going on to emphasise that GOOD farmers in other counties might even give them a third going over.
He concludes his assessment of the situation with the the damning indictment that "..here they are contented with fields yellow with charlock", hoping that by drawing attention to it, he might shame farmers into upping their game and getting with the 20th century program!
Charlock was considered by other authors of the time (e.g. Long, 1938) as the most problematic arable weed in the UK. In another of Young's writings (sadly I cannot recall which), he dreams of a day when the scourge of Charlock is eradicated from the countryside. He would be ecstatic to see that today his dreams had largely come true.
All apart from this field, which takes us back to that very scene he described so venomously back in 1804.
Frequnt in most soil types, other than acid; charlock abundance increases with the calcium carbonate loams (Bond, Davies & Turner, 2007). In central Hertfordshire's geological mosaic, this is one such place; a hilltop patch where the chalk rises through the gravels and clays to be exposed at the surface. The green patches on the below map show where this is happening.
One soil charlock isn't so keen on is an acid soil (Bond, Davies & Turner, 2007). As many soils in this area are disposed to acidity, it's likely the old practice of chalking (to bring the acidity down to the neutral range) allowed it to gain a more widespread hold over the county.
Now the big question is why would this farmer have allowed this situation to arise? Charlock doesn't just compete for space and resources, it is a host of pest and disease, their seeds reduce the quality of oilseed rape oil and poisonous to stock. However the seeds are important to farmland birds (Bond, Davies & Turner, 2007)
Well from what I can gather, this and the adjacent Bramfield Park woods are probably an outlying part of the Woodhall estate, centred a few miles north at Watton at Stone. This is an innovative estate that works closely with the University of Hertfordshire on a wide range of agro-ecology research projects in the aim of marrying the twin goals of quality local food production with rewilding.
It could be they're testing control mechanisms on our local genetic variant whilst working out how it can be tolerated as part of the agricultural ecosystem, Whatever it is they're up to. I'd love to know more!
You can find out more at their website (https://www.woodhallestate.co.uk/).
Bond, W., Davies, G., Turner, R. (2007). The biology and non-chemical control of Charlock (Sinapsis. arvensis. L). The Organic Association. Available at: https://www.gardenorganic.org.uk/sites/www.gardenorganic.org.uk/files/organic-weeds/sinapis%20arvensis.pdf
Young, A (1804). General view of the Agriculture of Hertfordshire, drawn up for the consideration of the board of agriculture and international improvement. London: G & W Nicol.