From slug battles to seedbed dilemmas, George Hosford looks back at the trials of autumn sowing and the effects of heavy rains
The rain rendered autumn sowing a little challenging this year. Holding off as long as we dare to reduce the risk of aphids infecting our crops with barley yellow dwarf virus (yes, it affects wheat too) then runs the risk of autumnal rain settling in and making good seedbed days hard to find.
Luckily, the drilling team threw in some long hours on the good days and we got the job wrapped up. It would have been a different story had we not been direct drilling. Previously cultivated seedbeds do not dry out anything like as quickly as those that have not been touched by machines. The worm holes and airways in the soil remain intact and it is amazing how quickly they drain down after rain.
The current downside of the direct drilling model, however, is the underlying slug burden – especially in fields that grew oilseed rape in the previous year. Cultivation can disrupt the slug lifestyle, damage their eggs and reduce the ability of the slimy devils to move through the soil. Direct drilling does not, and in a wet year like this we are seeing a slugfest in the wheat following rape.
Slug pellets (now ferric phosphate based, the nasty ones have all been banned) are in short supply, and timing is difficult. Based on the forecast, we took a punt and spread many hectares with a dose, hoping for a good kill overnight before the rain arrived and washed the uneaten pellets away. Waking up to the sound of rain already on the roof was annoying to say the least. Soggy pellets are not attractive to slugs and therefore useless as they wash into the soil. The slugs will continue to paddle around, nibbling off newly emerged seedlings while we look on helplessly.
We are assured by our regenerative friends that as soils get healthier, things will improve. Slug-predating ground beetle numbers will build as we disturb the soil less and apply fewer harmful chemicals, and our in-field wildflower strips should also act as reservoirs for other potential slug predators.
But when we can expect to go slug pellet free is currently anyone’s guess.
Clay cap pudding
Above is an image of a good old fashioned seedbed from mid September when the weather was dry. It’s been over-worked and is consequently vulnerable to run-off and capping during heavy rain events – as I write, it’s like a soil pudding.
This is the second time we have tried to establish an AB15 mix on the headlands of a handful of fields. This one is a two-year legume fallow – intended to help farmers get on top of troublesome grass weeds. The rules state that we must mow off the foliage several times during the two years to prevent any re-seeding of weed grasses like blackgrass or brome, and also to ensure that we do not benefit some other area of our business by, for example, making hay out of it for our animals.
DEFRA are determined that in rewarding us for one thing, we should certainly not be able to benefit from it in any other way than that which was intended.
We overcooked the seedbed here because when we first tried to establish this mix of vetch and clovers in 2022, it did not emerge and grow at all well. Fear of being penalised at an inspection made us try again.
First time round we direct drilled it – which we now feel is not the best way to establish small-seeded crops like clover – and the second time we went to town. First we used the Sumo cultivator, which cultivates quite deep, then the discs to create a good tilth, followed by drilling with the old Vaderstad Rapide drill, which further breaks up the soil as well as firming the ground and placing the seeds.
Topped off with the ring rolls, the intention was to create good seed-to-soil contact to optimise the chances of a speedy and even germination. The result, however, reminds us why we now try to direct drill wherever we can!
This clay cap soil can run together when wet, and capping can prevent seedling emergence; not only that, it will turn to a pudding and dry out very slowly because all the cultivation has destroyed any worm holes and natural fissures between undisturbed soil particles. These are what allow water and air to percolate through the soil, keeping it aerated and free draining. Ploughing has the same effect of damaging soil structure, to a greater depth than simply cultivating – and it can take a whole season or more to recover from.
Small-seeded crops are much trickier to establish than larger ones like cereals and beans. Getting the conditions right and judging the right amount of cultivation to suit them is a big challenge. Even after all that work, sadly the germination of the clovers in the mix has not been particularly good.
A popular Farmer Cluster meeting was held in late summer on the Tory family’s land by the Stour at Shapwick, led by Nicola Hopkins of Dorset FWAG (Farming and Wildlife Advisory Group). She had two of us wade into the river with waders and nets to see what we could find on the river bed. We then passed the nets ashore for emptying and sorting, before spending ages trying to identify what we had found!
There was a wonderful diversity of species; caddis fly larvae in their characteristic grit-covered duvets, there were damsel fly larvae and even a dragon fly larva, quite a few small fish, as well as snails, water boatmen and a number of what we’ll call ‘unidentifiable wrigglers’.
After marvelling at what we had found, we were soon sobered up when Nicola told us what was missing. The river faces many challenges from sewage treatment outflows and leakage from farmland. There was at least a good exchange of ideas among the cluster on how to improve the health of the river.
This autumn, as the Stour burst its banks and rather murky brown water spread across our meadows, I was reminded of that delightful evening, and how important it is to prevent soil being carried into rivers. It buries the grits and gravels which are such important habitats for the creatures we found, and threatens their survival. Not only that, but phosphate is often attached to the soil, which can cause algal blooms and other problems in the water, further challenging aquatic ecosystems.
Our cluster group has been carrying out some citizen science over the summer: every couple of weeks a group of us take water samples from the river and some of its tributaries, and Claire our leader collects them up and sends them for testing. Suspended solids and other contents are quantified, and we look forward to seeing a whole year’s results, in the hopes we can learn from them.
Our own main river samples, taken following a few days of rain (image, left), looked pretty awful alongside a still clear bottleful taken from the Iwerne Brook, which flows down to the Stour from the Fontmell Magna and Iwerne minster direction. Identifying where pollution enters the river is very tricky. In some cases the contributors can simply be impatient drivers in country lanes, squeezing past each other’s vehicles. Tyres rub soil off the bank and into the road, from where it will only wash one way – downhill, to the nearest river.