Maintaining soil fertility despite intensive forage maize production?

Whoever practices an intense forage maize crop rotation has to keep an eye on humus content, soil structure, erosion and nitrogen output. However, it is still possible with an intensive maize rotation to achieve a healthy soil and a good nutrient balance.

F. Wiering
F. Wiering
Felix Wierling is technically oriented, adventurous and fond of travelling. For his Master of agricultural engineering he enjoyed looking into the “agricultural world” of other countries. From Australia, England and Brazil as well as Dithmarschen and the South of Germany he brought back the awareness that if you are not willing to try something out you can neither change nor develop yourself. “We try out a lot, although or perhaps more because we are basically a part-time farm. However, the farm is still too big to be a pure “hobby”-farm.” The wide range of soil types is typical for the Muensterland. “It’s possible to go from sand to clay loam soil in less than 30 meters.”

On the lighter sites maize and winter wheat are grown as main crops in a relation of 2/3 to 1/3. On the more loamy soils maize is grown before winter wheat and winter barley which has been replaced partly by winter oilseed rape since 2016. The forage maize is grown completely for a nearby biogas plant. Fermentation residues are returned as fertiliser. Additional, organic fertiliser is supplied by local pig and beef farms.

Non-inversion cultivation: more soil life, less time intensive

Table 1: Summary of maize based cropping systems
Table 1: Summary of maize based cropping systems
Since 2009 the farm has been farmed without a plough. “The most important argument to give up ploughing (especially against the background of being a part-time farm) was the time and cost savings. I have experienced that a long-term non-inversion cultivation system enhances the biological activity of the soil and improves the soil bearing capacity”, explains Wierling. “We are always one of the first that are able to apply slurry and have also fewer problems with field trafficability during maize harvesting.”

Additionally he has observed an improvement of the soil water balance. In 2016 his oilseed rape has not emerged optimally due to the lack of rainfall but significantly better than on ploughed fields with a comparable soil quality. “Thanks to the loose soil structure and plenty of earthworm channels, the roots of the young plants grew quickly out of the dried out top soil layers”, believes the agricultural scientist.

Catch crops: Humus supplier, N-fixer, work time saver

Catch crops have always been firmly established on the farm. In the past mainly pure mustard after cereals and forage rye after maize (maize/maize) were used and nowadays primarily catch crop mixtures. The mixtures after cereals contain 2-3 components. Since 2015 they are drilled directly on some fields. “After late maize there is not enough time to establish a catch crop mixture. In this case forage rye is still used which has the advantage that weeds are suppressed superbly.

In spring 2016 for the first time the mixture viterra® UNTERSAAT has been applied together with the slurry into the maize in order to vegetate the soil and to save nutrients. The establishment of a catch crop in parts of the maize crop has also been planned for 2017.

Felix Wierling und adviser Klaus Schulze Kremer
Felix Wierling und adviser Klaus Schulze Kremer
Due to the cereal straw removal (only 1/3 of the straw remains on the fields) and the cultivation of maize (both lead to a high removal of nutrients) catch crops are especially important for building up the soil humus content. The biological soil activity is enhanced and the excess nitrogen locked up effectively. Combined with non-inversion cultivation, the soil is so loose that even in the loamy areas of the field the soil clods crumble in the hand - no mechanical aid needed anymore. This work is done by the roots and the biological soil activity, especially the earthworms”, points out the farm manager pleased.

Strip tillage: well placed, economical fertilisation

The farm is situated in a groundwater drainage area (Gelsenwasser AG, Kat.II). Therefore, plant protection and fertilisation measures are also aiming to be groundwater protective. Splitting the herbicide application in maize, which had been recommended by the advisor, has been a successful weed control.

On freely drained fields strip tillage is used in maize without any extra soil cultivation. The applied slurry (varying with soil type 35 to 40 m3/ha) is stabilised with Piadin®. This treatment has the important advantage of enabling an early slurry application (if possible already in March). Thereby, the exact placement of the slurry band below the seed is essential for the growth of the young plants and the reduction of leaching losses.

Although it has only been implemented since 2015, the strip tillage method has already shown clear advantages in the first year. “Like that we are able to drill the maize shortly after the slurry application. The seed can also be drilled a bit shallower so that the plants are able to emerge quicker and reach an earlier canopy closure. This reduces the weed pressure and I am also very content with the yields. With this method fertiliser, time and water can be saved as well as the soil structure maintained.”

Seed rates leading to lower herbicide application

Additionally the farm is experimenting with varying row widths in maize: 75 cm on light soils, 45 cm on heavy sites, respectively (Table 1). Narrow row widths lead to a quicker canopy closure and suppress weeds. Often a second herbicide treatment does not need to be carried out. That is good for the environment, the wallet and the work time account. However, if late emerging wild millet grass had been a problem herbicide reduction would surely be more difficult.

Which maize varieties are suitable?

SAATEN-UNION Variety Susann
SAATEN-UNION Variety Susann
Using this production technique is it necessary to consider certain plant characteristics when choosing the variety? “Here, a vigorous variety with a quick seedling development is needed” believes Felix Wierling. Therefore, besides maturity class, main use and starch yield, he places a lot of emphasis on seedling development when choosing a variety. The variety S260 Susann has been grown for years on the farm and has again and again convinced with its cob yield. “We are paid on the base of fresh weight per hectare with a dry matter basis of 33%.
Even this year Susann yielded 50 to 55 tons fresh weight per hectare, although the maize had suffered especially on the heavy soil. This was mainly achieved by the high cob yield as Susann also showed a reduced plant development due to the unfavourable weather conditions.” A variety change is not on the agenda as:” Why should I experiment with more than 80 varieties in the medium late segment if I am satisfied with my present varieties?”


Declining maize yields after long-tern intensive forage maize production due to reduced humus content and poor soil structure can be avoided. Everything has to be taken into account: Economic efficiency, humus and nutrient balance, groundwater protection, achieving high yields. New fertilisation and cultivation techniques as well as greening help to practice an effective crop production.


Dr. Anke Boenisch and Klaus Schulze Kremer

Farm details:
Senden-Ottmarsbocholt nearby Muenster (NRW)

  • Arable farm (part-time) approx. 65 ha arable land, approx. 30 % maize
  • Crop rotation of light soils: Maize (forage rye or undersown) – Maize – WW – (catch crops)
  • Crop rotation of other soils:
    With oilseed rape: Maize – winter wheat – winter oilseed rape – winter wheat (catch crops)
    Without oilseed rape: Maize –  winter wheat  – winter barley (catch crops)
  • Wide range of soil types

Status: 27.12.16

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