sJohan Lavens has regularly taken soil samples for years. Several years ago, he noticed that his organic carbon continued to decline steadily. The experiences in the field – large yield differences in one field and a larger nitrogen application that was required to obtain a good yield – also pointed to a declining soil fertility.
He then decided in 2019 to scan a few plots in detail every year. This would allow him to work very precisely on the pH and organic carbon content, in order to ultimately achieve a more uniform yield on each plot.
Start with a soil analysis
Before Johan took the step to a soil scan, he took samples of the construction layer on a very regular basis (pre-construction analyzes or general soil analysis). This is a first and very accessible step towards more insight into soil nutrients. Such an analysis clearly shows the concentration in which the main elements are present, and the pH and organic carbon content. In addition, it indicates where the measured value is relative to the target zone, which is adjusted according to the soil texture.
Based on the analysis, a crop-specific advice is formulated for the next 3 crops. Johan has always faithfully followed the advice for liming and that for phosphorus, potassium, magnesium and calcium administration. It is important to know that the absorption of the elements stands or falls with a correct pH. Both at a pH below and above the target zone, the plant absorbs certain elements less well.
How do you maintain the organic carbon content? Johan has been sowing catch crops where possible for years, but with his crop rotation (carrot, salsify, spinach, maize and potato) and the use of slurry from pigs and sows, the organic carbon content continues to fall. That is why he decided to use compost on his plots and to apply a lot of organic matter in one go.
Compost also contains nitrogen and phosphorus, these must also be included in the company balance sheet (in the context of manure legislation) (if the compost is Vlaco-approved, 15% active nitrogen and only 50% of the phosphorus count). He then decided to process more manure in order to create space to apply compost to a few plots. According to him, this is the only right decision to maintain good soil fertility on his plots and to guarantee good harvests in the future.
Would you like to gain insight into the variation of pH, organic carbon and electrical conductivity within your plot and receive advice per 10m2? Then have your soil scanned! The Veris soil scan covers the entire plot in order to measure these parameters on a very frequent basis. For each plot, general soil analyzes are also performed for a few places via manual sampling (for calibration of the soil scan). By combining this data you get a detailed map.
Tip from Johan: Have your plots scanned in the autumn! Afterwards it takes another 4 to 6 weeks until the task cards are available. This way you have all the necessary information in time to carry out the work.
How to apply?
Ask yourself what you will do with the information obtained before you have your parcel scanned. Ideally, apply site-specific lime and compost (for example per grid of 10m by 10m) to bring the plot everywhere within the target zone. The example was cited in which the recommended liming amount on the same plot goes from 2,600 to 6,300 kg lime/ha (note: never apply more than 4,000 kg lime/ha of arable land at a time) and the compost application from 15 to 43 tons of compost/ha.
If you do not have this option, you can also obtain a simplified map with, for example, 3 different zones. At Johan’s, the lime is applied on a location-specific basis by the contractor, he can also spread the compost on a location-specific basis with his recently purchased compost spreader.
You can also view your plot from the air via the online platform WatchItGrow, where you as a grower can create a free account. Add your plots and view the (historical) satellite images in a simple way. The program even generates maps that illustrate the yield potential of different zones in a field.
These maps are made based on the ‘greenness’ of the plot throughout the growing season, and show where the yield was good or less good over the years. Via this platform you can also upload soil scan data and drone images and compare them with each other to gain a better insight into the strengths and weaknesses of your plot.
You can also check whether alternative water sources are available nearby for possible irrigation, and weather data (for example temperature and precipitation) are available for each plotted plot from 1 January of that planting year.
Is the technology expensive?
Everything starts with taking a general soil analysis. You can get a lot of information from it for a small price. WatchItGrow is free and can also tell you a lot about the uniformity of your plot.
A soil scan has its price tag (it is best to contact the supplier for this), but if you apply site-specific improvements on the basis of the information obtained, you create a more optimal and uniform plot for the following years, which certainly means a higher yield. A soil scan can be useful, especially on plots where you already notice a lot of differences (in yield or via satellite images).
In addition, a lot of subsidies are available through the pre-eco schemes or through PDPO projects.
With hands in the ground
When Bert D’haene and his wife started their farm in Staden about 15 years ago, there was clearly something wrong with the soil quality. He immediately decided to take care of his soil and to invest in it. He believes it is very important to apply sufficient carbon to his plots and to minimize its degradation.
That is why Bert explicitly chose to put his pigs on straw, because the straw returns to his own country in no time. Bert also switched his company to an organic farm: by growing organic pigs, the organic manure can be used on the organic fields. In addition, he works non-turning and he attaches great importance to a well-considered crop rotation.
Bert grows vegetables as well as arable crops, including potatoes and grains. Because vegetables often provide less organic carbon, Bert always ensures that grains are grown every 4 years. A plot also regularly remains in grass-clover (= rest crop). The clover absorbs nitrogen from the air, which is stored in the root nodules. During incorporation, that nitrogen is released to the next crop.
In 2020 it was no longer possible for Bert to sow beans after the spinach, so he sowed a catch crop that provides extra carbon. “If I can’t get a profit from my beans, I want to add extra organic carbon to upgrade my plot and get more yield from it in the future”, Bert reasoned. He chose to sow sorghum in June 2021, it grew up to 3 m high and was a great source of organic carbon! Sorghum is a very temperature sensitive crop that dies quickly during the winter. He reduced the crop with a flail mower and worked it in very superficially a few weeks before planting, thus speeding up the digestion of the crop.
Tip from Bert: be patient and start on time to flail/destroy your catch crop (6 weeks before the next crop).
When everyone is already on their field, Bert usually waits a little longer. He thinks it is important to only drive on his plot when it is dry enough. By planting or sowing a little later, it is ultimately never later with the cultivation or harvest, because temperature is also important for development.
Bert tries to till the soil as little as possible: if it is not necessary, no tillage is carried out. He hasn’t used the plow for years and has since replaced it with 2 non-turning machines.
Moreover, he wants to go out into the field with heavy harvesters or carts as little as possible and the tire pressure is sacred to him. Contractors therefore have to adapt to the requirements he sets in this regard and have to lower their tire pressure.
With the spade to the field
Bert’s concern for the soil soon became clear when the spade was put into the ground during the thematic exchange moment. There was immediately a lot of soil life to see and everyone was impressed by the large commuters (= earthworms) that crawled around. When the clods were broken open, the large corridors of these commuters became visible, they provide aeration and drainage.
We compared this plot with one that Bert had only been using for a year. Much less soil life was observed there. Through a short ‘vase test’ we showed the difference in organic material and structure on both plots. A clod of earth was placed in both vases. Due to the higher content of organic carbon and a better structure of the root ball in the vase on the right, we see that the soil crumbles much more slowly and that the water becomes less cloudy than with the root ball in the vase on the left.
It doesn’t matter how you look at your bottom, but it is important that you do it! Investing in the soil takes a lot of time, so it is important to start on time. That doesn’t always have to be expensive, with a spade you can do a lot.
Would you also like to attend a thematic exchange moment or would you like to know more about B3W? Then surf to the B3W webpage (b3w.vlaanderen.be), create an account and become a member of the group that interests you (choose ‘groups’ in the drop-down menu and then choose the correct group), or keep the event page in the holes.