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Growing potatoes without plowing

04 January 2021


Does it make sense not to plow the field before putting potatoes on it? Does the yield not drop and what does non-plowing do with biodiversity, water management and nitrogen leaching? On Potato Demonstration Day, Wageningen researchers Janjo de Haan and Derk van Balen will discuss plowing and alternative processing methods.

What is plowing really?

Derk van Balen: “Plowing is standard tillage. Plows turn the soil and work intensively. According to many, less intensive tillage is better for the soil. We call this reduced tillage and the best known form of this is non-inversion tillage. There is great variation in reduced tillage systems. Digging can be seen as an intermediate form of turning - non-turning tillage. ”

Do you have a good crop of potatoes if you don't plow?

Janjo de Haan: “The research in the system tests of the PPP Beter Soil Management has shown that growing potatoes without plowing, or with reduced tillage, is possible. It does not entail any additional costs and does not cost any revenue. There even seems to be a small plus for potato cultivation. ”

What else does not plowing yield?

Janjo de Haan: “In terms of water regulation and water purification, reduced tillage on clay scores better than plowing. Due to the better structure, the water balance is better and water is removed more easily. No clear effect on structure and water management is visible on sandy soil. "

And what does non-plowing do with biodiversity?

Janjo de Haan: “Not plowing is demonstrably positive for the biodiversity on clay soil. There we measured more worms, insects and spiders with reduced tillage. These also provide the better structure. We have not carried out these kinds of measurements on sand and valley soil. ”

What are effects on nutrient leaching?

Derk van Balen: “There is no effect of reduced tillage on the nutrient surpluses, although reduced tillage on clay and sand appears to have a lower risk of nitrogen leaching. We are still investigating how this works. ”

Can a farmer switch to reduced tillage just like that?

Janjo de Haan: “No. You have to think carefully about incorporating reduced tillage into your whole way of working. Weed pressure can certainly be significantly higher in the first years. Keeping the soil covered for as long as possible helps suppress weeds. Frost-sensitive green manures are preferred, but sometimes you still need to flap in the spring. To be able to sow in crop residues, special seeders with discs are required. ”

Derk van Balen: “Switching to reduced tillage can also have an effect on crop rotation, choice of green manure, weed control strategy and fertilization. For example, in this dry spring we see that the digestion of crop residues starts late. This has consequences for the release of nitrogen. ”

And the weather conditions?

Derk van Balen: “Thanks to better drainage, we see, especially this year, that the unplowed soil in the subsoil is drier than plowed soil, which is favorable for working in the spring. The top layer is generally more moist than plowed soil and requires prep to dry before sowing or planting. This year we see that the unplowed soil is significantly drier in the arbor than plowed, which may have an effect on the final yield. However, we experience that the potential of reduced tillage in a changing climate is greater than with plowing. ”

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