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'Resistant green manure is a weapon against nematodes'
There has never been a lack of attention for soil fertility on the farm of the Ooms family from Lepelstraat (NB). A few years ago, however, traps suddenly appeared in the potato crop due to an unnoticed increase in nematode populations.
After obtaining advice, they opted for the (intermediate) cultivation of the green manure mixture Nemaredux and a tightening of additional measures. Since then, no falls have been observed. Growing green manure? Uncles don't know any different. "I hate black soil, especially on sand. As soon as a crop is harvested, a green manure is applied. The main purpose of this habit is to keep the soil healthy over all years and to ensure that the structure remains good. the next generations to benefit from this", explains the entrepreneur.
Green manures fixed value
"Green fertilization is the vitamin for the soil and is fully at the service of all the products we grow," he says. The most important of these products are asparagus, almost 2,5 hectares and about 36 hectares of ware potatoes. The cultivation plan also includes sugar beets, onion sets, grains and sunflowers.
As far as the beetroots are concerned, this concerns the cultivation of the French fries varieties Markies (12 hectares) and Fontane (20 hectares) plus a few more hectares of Bintje for house sale. These grow on a variety of soils ranging from sand to heavy clay. These diverse soil types require a matching type of green manure or mixtures of several. These are not always the same, because times and (crop) choices change, says Ooms.
Control harmful nematodes
"We've had all kinds of things here, rye, Japanese oats, yellow mustard, radish, grass ..." For a long time, the choice mainly depended on the soil type, the pre-fruit and the crop to be grown afterwards. "After intensifying cultivation, such as that of potatoes, another factor was added and that is nematodes. We have been growing the crop in a 1-to-3 rotation for many years. With the cultivation of sunflowers in between, we partly have that. can stretch to 1 in 4.
This rather narrow rotation meant that a few years ago, the nematode populations increased so rapidly that visible damage was caused in the potatoes on a few light soils. We always try to grow as many AM-resistant varieties as possible, but they are not always resistant to all nematodes. At one point, we got traps in one of the potato plots. Then of course you wake up. We immediately took samples at that time and it turned out that it was a population of corn root knot nematodes, but there were also other nematodes in it, such as a number of free-living nematodes.
We then consulted with our cultivation advisor at CZAV as soon as possible. He advised to use the green manure mixture LG Nemaredux to sow. This contains 70% Doublet fodder radish with a resistance to the corn root knot nematodes Meloidogyne chitwoodi, hapla and fallax. It is also a non-host plant for the potato cyst nematodes Globodera rostochiensis and pallida. In addition, there are some resistances and not/poor host plant characteristics in this mixture for both potatoes and other crops, partly due to the presence of the green manure fertilizers facelia and Trio sword-herik.
Controlling Potato Storage
Another important measure to keep the nematode populations in check is the control of potato storage. After the potatoes, Ooms always grows as much grain as possible as after-fruit, and the storage plants can be tackled reasonably well. He has also been using the sprout inhibitor MH for as long as it has been allowed in the potatoes. You spray this sprout inhibitor into the crop at the end of the growth period. For example, with good absorption, almost all tubers contain the sprout-inhibiting active ingredient maleic hydrazide. So these are also the tubers that remain on the land after harvest. A large percentage of these remaining tubers do not grow into full storage plants in the following season. "In short, we use all measures to keep the nematode populations within limits."
Ooms experiences that the green manure mixture is currently the most important weapon in the battle. "Since we sowed Nemaredux, we have not seen a trap anymore and the soil samples also show that the nematode populations have decreased." An important factor for the success of green manure cultivation, including the effect on nematodes, is the choice of the right time for sowing. "A green manure with an effect on nematodes only gives optimum effect at full growth in the months of July to October. This means that you can sow it from June to the end of August at the latest. We harvest the onion sets in July, so after this crop we usually sow the first green manure crop.
As fertilizer and to improve soil (life) and structure, Ooms first applies solid goat manure to the land before sowing. "This fertilizer works great. It's a pity that we are only allowed to supply to a limited extent due to the fertilizer legislation, because it is a great soil improver. The best sowing time for the green manure is then on a slightly moist soil, not too deep, the seed must be just covered. If the weather is not good, too dry, too wet, then you just have to wait.The seed quantity is between 20 and 25 kilograms per hectare, depending on the soil and (expected) weather conditions.This involves a cost of about 100 euros per hectare. That is quite a considerable amount, but I am not going to calculate exactly whether and how much financial yield I will now achieve with this in the cultivation of potatoes, for example. We see that fall spots no longer return, that already saves a lot of tons of yield and the soil samples show that the nematode populations are decreasing, so I no longer have to calculate whether it is possible," laughs Ooms. He also leaves the green manure crop on the land for as long as possible. "Just before winter, we cut it short with the flail mower. After November, the green manure crop no longer works on nematodes. In winter, the clippings can digest, slowly sink into the soil, which is better for the soil life, and then during the spring work we no longer suffer from plant residues."
Read more about LG Nemaredux green manure mixture here >>
