Brought to you by Limagrain
'Digging ensures a more even emergence of maize'
Erik Immink and his brother Johan, dairy farmers in Hellendoorn, finished second in the Limagrain National VEM competition in 2024. Using the LG 31.205 maize variety, they achieved a silage yield of 1.072 VEM, narrowly below the winner's 1.075 VEM. They believe that digging contributes to a higher VEM yield from their maize.
The Immink partnership's dairy farm is relatively small, but the family members are deeply involved. Besides partners Erik and Johan, father Marten, Martijn (Erik's son), and Guus (Johan's son) also enjoy working on the farm. "Because the farm is small, I also work four days a week at a compound feed factory," says Erik Immink. "And my brother Johan works in milking technology and automation, also four days a week."
In 2024, due to the shorter growing season, the corn yield was generally lower than in 2025. This was also the case at Immink. "In 2024, our 5 hectares of corn yielded a total of 198 tons with 439 starch. In 2025, the yield was higher at 265 tons on 5 hectares with 341 starch, resulting in 67 tons more corn," says Marten, who has a good grasp of the figures.
In 2024, the 700 corn silage submitted for Limagrain's National VEM competition had a record-high feed value. They averaged 1.016 VEM/kg dry matter, 388% starch, and 58,1% NDF digestibility at 39% dry matter. Immink, with their corn silage submitted at that time (2024 harvest), scored 1.072 VEM/kg dry matter, an impressive 439% starch, and 58% NDF digestibility at 39,8% dry matter. This earned them second place in the VEM competition and a long hotel weekend on the Zeeland coast. Marten and his wife, Martha, visited Zeeland. "Everything was perfectly taken care of; we enjoyed a very pleasant and fully catered stay," says Marten.
Digging the ground
Immink chooses early maize varieties to be able to sow a rest crop or grass on time. "We've been sowing Limagrain maize varieties for years. Compound feed supplier CAV Den Ham is a dealer of LG varieties and supplies us with the maize seed. For several years now, we've been sowing LG 31.205. We're very pleased with it, because this very early variety ripens on time and produces a lot of VEM," says Erik. In 2024, 5 hectares were sown with LG 31.205 on April 25th. Before sowing, the soil was tilled twice with a cultivator and then fertilized with 45 to 50 cubic meters of liquid manure.
"Since 2022, we've been digging the soil with our own spading machine, after which we sow the corn. Digging ensures good initial development and even corn emergence. Probably because the rooting improves," thinks Guus, Johan's son. The contractor sprays weeds. "Mainly to tackle cock's foot and chickweed, which are a big problem for us," says Erik. "2024 was a strange season. First it was very cold and wet, and later it became very dry, which also caused some corn to dry out." The Immink family believes that the qualities of the chosen corn variety and their tillage contributed to an above-average VEM content. "Luck with the weather is also a factor. Frisian dairy farmers often win the VEM competition, and in 2024, the two best silage pits came from Overijssel. The weather conditions certainly played a role."
Do the harvest yourself too
Erik's son, Martijn, has bought a corn chopper, which he plans to use to chop the corn himself this fall. "This way, you control the harvesting time, which is important for sufficient dry matter and plenty of starch," says Martijn, who works at a mechanization company. "Although the harvesting time sometimes depends on regulations. In 2024, we harvested on September 20th when the corn was fully ripe and then sown Italian ryegrass. In 2025, the corn was sown on April 19th and harvested on August 29th to be able to sow a rest crop, in our case winter barley, in time for September 1st. But actually, the corn wasn't quite ripe yet."
Immink is participating in the VEM competition again this year, but she doesn't expect to win. "We should have actually harvested two weeks later in 2025. Due to the early harvest, the dry matter content is too low at 33,5%, as is the starch content at 341%," says Erik. In 2026, the Overijssel dairy farmers will again sow the LG 31.205 maize variety. "You shouldn't change something that's good," says Erik.
VEM not only from starch, but also from residual plants
In 2024, the sowing season was on average late. "It got off to a somewhat slow start, but the maize still grew well into a nice, vital crop with good cobs. Maturation was usually good as well, resulting in an average excellent starch content," says Jos Groot Koerkamp, commercial manager of livestock farming at Limagrain.
The exceptionally high feed value figures in 2024 can be partly explained by a shorter growing season with less mass, resulting in higher feed quality. "A high VEM content isn't solely due to a high starch content. Much of the feed value in maize silage also comes from the residual plant material, i.e., from the digestion of cell walls. The average cell wall digestibility of the LG silages (2024 harvest) was 58,7%, a full 1,8% higher than that of non-LG varieties, which partly explains the higher feed value of LG: 1.021 VEM (LG) versus 1.009 VEM. Digestibility has therefore been a key breeding goal in our breeding program for many years."
