Since 2021 the Kerns must work without glyphosate in water protection areas. For a cultivation system without ploughing this means extra work and increased risk of erosion. The extra cultivation required per crop not only increases diesel consumption, but also stimulates the soil to mineralise. The process breaks down humus and releases nutrients, which are then at the mercy of leaching. “So, I’m doing everything I don’t really want to do right now. But I have no choice,” says Alexander. This is precisely why the farmer and master butcher attaches so much importance to catch crops and conservation tillage. In 2019, he also adopted the principles of regenerative agriculture.
Some farmers who have worked the soil without ploughing for many years have been intensifying tillage again since 2021. The ban on the herbicide glyphosate in healing spring and water protection areas – and as a late application before harvest under the Order on the Use of Plant Protection Products (PflSchAnwV) 2021 – is to blame. “In certain crop rotations, nitrate levels are therefore rising again in water protection areas in the Karlsruhe district,” says Rolf Kern, crop production adviser at the Karlsruhe district office. Despite the restrictions, this expert on crop nutrition, erosion and soil protection considers minimum tillage to be possible, perhaps even the only sensible option. “I’m convinced that we can’t beat climate change any other way. Our soils need to become more resilient, and we can only do that without ploughing, as it depletes soil fertility and wastes water,” he explains. “Shallow and flat” is the motto of the future.
The Kern family’s work shows how it is possible to combine gentle tillage with catch crops to farm without glyphosate. Alexander values species-rich catch crop mixtures to protect against erosion. He wants to use the resulting good soil structure for the following crop instead of destroying it by ploughing.
Cutting off freezing catch crops during frost
When the farmer realised that he would have to do without glyphosate, he invested in a 6m-wide flat cultivator with a high productivity (approx. 6ha/hr) and wide cultivator coulters. This allows him to cut off catch crops and weeds 2-3cm below the soil. Thanks to the high area output, the operators get through the necessary additional tillage passes more quickly. “I can recommend this to everyone,” says the farmer.
Depending on the catch crop and main crop, he uses one of two methods to kill off the growth: The standard method, which is used before most crops, or the surface rotting method before late crops. In the standard method, the freezing catch crop is crushed with a blade roller during a frost and then worked in with the shallow cultivator, also during frost. “Chopping the catch crop in a frost is more successful than later cultivation with a cultivator, disc harrow or shallow cultivator,” explains Alexander. Phacelia and Niger seed (Guizotia abyssinica) can also be safely killed off with this method.
Chopping the catch crop in a frost is very successfulAlexander Kern
In principle, it would be sufficient to work the catch crop in with the field cultivator during a frost. However, the barely crushed plant parts could then bung up the shallow cultivator in the spring. Instead, as soon as the catch crop has been cultivated, earthworms take over to process the residues. And for Alexander, keeping as much mass as possible within the soil surface provides protection against erosion and heat.
He then sows the following crop directly into the seedbed. His beet seeders have a mulch seeding system and the power harrow for the barley seed also passes through without any problems.
Surface rotting before late crops
Before late crops like maize, Alexander adopts surface rotting – a procedure common to regenerative agriculture which provides long soil cover. In this process, the overwintering catch crop is killed off in spring with a cultivator or disc harrow, simultaneously shredding it with the mulcher. The longer the catch crop can grow beforehand, the better for the soil. The disadvantage: “If a catch crop stands for so long, you naturally have noxious weeds in it,” says Alexander. In maize, however, he is still allowed to use many herbicides to eliminate grass weeds.
The rotary cultivator is equipped with a tank for surface rotting, which makes it possible to spray effective microorganisms (EM) into the catch crop which has been cut off close to the ground. These are intended to ensure an effective rotting process. For surface rotting, the soil needs a certain temperature: The soil life must be active. Cutting, chopping, and incorporating the catch crop then take place in one operation. “This is quite labour-intensive. You must drive slowly,” says the farmer. It would be easier with the disc harrow, but it cuts the catch crop less cleanly.
Depending on the weather, the surface rot remains in place for about one to two weeks. Before sowing the next main crop, only one more cultivation pass with the shallow cultivator follows.
Even good plans can fail
So much for the theory. This year, the weather thwarted the Kern family’s plans. The overwintering catch crop was supposed to be worked in 2-3cm deep by mid-March. But it was not possible to travel until mid-April. To make matters worse, the catch crop had not grown well in the dry summer of 2022. Field foxtail and the previously cultivated rye did not miss this opportunity and grew vigorously. So surface rotting is not an option this year.
I am convinced that we cannot master climate change in any other way.Rolf Kern
But Alexander is not dissatisfied. After all, the catch crop sequestered nitrogen for eight weeks, revitalised the soil and ensured green cover. “I had no erosion and could spread compost, fermentation residues and manure in the growing crop in winter. That was what I wanted,” explains Alexander. In return, he now has to accept the weeds. “You just have to adapt,” he says. So this year he did not cultivate the catch crop until shortly after Easter, cutting 8cm deep over the entire surface. About a week later, he took the field cultivator through the remains of the catch crop, with a final tillage after another week, immediately before drilling the maize, at which point the grasses should have finally died off.
Gradually adapting tillage
Crop consultant Rolf advises farmers who want to reduce ploughing not to suddenly change tillage from one day to the next. “That doesn’t work,” he warns. Instead, it is better to proceed gradually and to combine the conversion with appropriate crop rotation, intercropping and, where possible, under sowing. “With the help of the plants, you build up soil structure and humus. The more humus-rich the soil becomes, the easier it is to work,” explains the soil expert.
For gradual adaptation, one could, for example, work 10-15cm deep with the field cultivator for the first one to two years. After that, farmers could go less deep from year to year and then switch from the cultivator to the disc harrow. About four years, it is then possible to work only shallow and flat.
Alexander is still undecided about how the glyphosate ban will affect his farm in the long term. “It may be that I’ll have to plough again in the future, although I’d need erosion protection (because of the grass weed problem),” he ponders. For the moment, however, a farm without both ploughing and glyphosate seems feasible to him.
As an advocate of conservation tillage, Rolf is convinced that it is possible to work without glyphosate. Farmers who only cultivate shallowly already have the necessary know-how and experience. “With more working time, more equipment, more wear and tear on machinery, more passes and more diesel, they can do it.”
Without investing in the right technology, however, it would be hard to avoid going back to the plough, says Rolf – particularly if glyphosate can no longer be used. Alexander also swears by a wide range of ground-working implements – despite the high fixed costs. This is because they enable him to react better to in-field conditions. The current long delivery times of machine manufacturers, of six to 10 months, can therefore delay the conversion to minimum tillage. But, Rolf adds: “Only by working shallow and wide can you get good weed and volunteer cereal control without glyphosate and ploughing.”
The farm of Alexander and Martin Kern
Location: 75015 Bretten (Baden-Württemberg)
- Location: 75015 Bretten (Baden-Württemberg)
- Web: www.spitalhof-kern.de
- Area: 200ha, mostly arable
- Soil: Predominantly very good, even soils with a high loess (porous) layer
- Farming: Conventional, with regenerative agriculture practices since 2019, plough-free for 40 years
- Crops: Sugar beet, maize, soyabean, winter wheat, winter barley, rye, spring barley, lucerne, and flowering strips
- Enterprises: Mixed farm with arable, suckler cows, finishing cattle, direct marketing through the farm shop with its own butchery, and events like children’s birthday parties
- Employees: Family business with mother, father, son, and daughter, plus two part time sales assistants
- Machinery: 4m disc harrow, 4m heavy cultivator, 6m light cultivator, 3m field cultivator with subsoiler, 6m blade roller with horizontally arranged blades