Soil restoration is key in regenerative agriculture
Regenerative agriculture is all about soil restoration. While tillage in agriculture does reduce the amount of organic matter, it is organic matter that ensures good water management, a higher nutrient content and carbon sequestration in the soil. If the soil becomes overworked, too much CO2 is released.
Regenerative agriculture is centred around rebuilding levels of organic matter within the soil and restoring soil biodiversity by working together with nature and the elements. The results are improved carbon sequestration, increased soil life and better water absorption.
Soil management is a decisive factor in water conservation and CO2 reduction. Some interventions promote the soil’s sponge-like properties, allowing it to retain CO2 for longer.
In 2022, we begun working with Soil Heroes in developing high-quality regenerative agricultural practices. We have selected seven plots (comprising over 70 hectares in total) where we (as a minimum standard) will not till the land or practise minimum non-inversion tillage, i.e. zero or shallow ploughing. Using soil samples, we have determined a baseline of the soil condition (physical, chemical and biological).
Throughout this process, we will continue to identify regenerative practices as we go along:
- Minimal or non-inversion tillage (mandatory)
- Sowing cover crops (indicating what type, when, etc.)
- Using organic fertilizer/compost/bokashi
- Creating or maintaining field margins
Soil Heroes will monitor these practices through satellite imagery and photographs. Based on this, they will be able to calculate any increase in biodiversity and CO2 storage within the soil by way of a scientific model. The stored CO2 can then be sold. Initially, VP Capital will buy the credits.
It is advisable to grow many different types of crops in the soil on an alternate basis. Our crop rotation is guided by an extensive ten-year plan that is aimed to maximise the number of crops rotated.
With this elaborate rotation plan, we are ensuring that there is a different crop on any particular piece of land per year. For the soil, this makes a big difference. Potatoes and sugar beets, for example, absorb a great deal of substances through the soil, which is why it is important to grow potatoes only once every three, four or even more years on any particular plot. Our rotation gap is much wider than average, regrowing only once every ten years.
This extensive crop rotation also avoids increases in crop-related diseases, pests and weeds.
One example is that of nematodes, which increase in number when certain crops on which they feed are present. If these crops are absent for a couple of years, the number of nematodes will once again fall, resulting in fewer problems for cultivation.
Some crops are considered ‘resting crops‘. These particularly include cereals and legumes (also known as protein crops due to their high protein concentration). Legumes are able to fix nitrogen from the air in the soil through symbiosis with rhizobium bacteria. The bacteria are found in the root nodules, also known as nitrogen nodules. These nitrogen nodules fix nitrogen from the air, before releasing it to the plant. Cereals and grasses, on the other hand, have large root systems and help build up organic matter in the soil.
Having a high proportion of grassland within a crop rotation plan means having a reliable resting crop, which ensures that a large amount of CO2 is absorbed into the soil. Capturing organic matter means capturing greater amounts of CO2.
For the same reason, most fields are bordered by a 4-metre green strip made up of grass and various types of herbs.
These field margins are the result of the active edge management project, which has been running for over 20 years with the province and water authorities, as well as supported by the European Union. The aim is to increase biodiversity, while limiting the amount of fertilisers and pesticides leaching into ditches. What’s more, these edges can be also driven over when using heavy agricultural machinery, thereby avoiding any damage to the crops themselves.
Tillage and cover crops
We keep ploughing to a minimum. Practising non- or minimum-inversion tillage, where ploughing the soil is avoided or done as little as possible (only surficial), has many benefits. It ensures better development of soil life, a more favourable soil structure and greater water infiltration and absorption. However, non-inversion tillage cannot be applied to all crops. Fine-seeded crops, such as spinach and carrots, grow better in a fully ploughed seedbed.
We also specifically grow cover crops (crops not intended for consumption), as these improve soil structure, help retain nutrients and stimulate soil life.
When it comes to crop protection (i.e. pesticides), we try to harm as few natural enemies as possible. For example, we make sure to spray aphids with an agent that only affects them, and not other insects.
Water management is crucial for agriculture
Water is crucial for agriculture. In Europe, no less than one third of all water is consumed by the agricultural sector (as high as 70% globally). At the same time, the quality of water also depends to a large extent on our industry. As a result, the European Environment Agency calls first and foremost for efficient irrigation.
Weirs and dams
The aim of water authorities is to retain as much water as possible, so that it can infiltrate the soil and be stored as groundwater (without being drained away via streams and rivers). At VP Landbouw, we are actively working with management at the Gorp and Roovert Estate to help achieve this, by installing around 55 weirs and dams over an area totalling some 1,200 hectares. A further 14 weirs are set to be added in 2022, bringing the total to almost 70.
On the south-western side of the estate, water enters from Belgium. However, there is also a big drop towards the north-east. Thus, we built weirs to compensate for this diverted flow of water. These ensure that the water does not flow through to Tilburg and Den Bosch too quickly, rather it is given time to infiltrate into the soil. As a result, more water is still available, allowing the fields to draw on the groundwater for longer. The weirs and dams therefore help prevent flooding as much as possible.
Groundwater level regulation
In a bid to maintain the groundwater level, we are building more and more weirs in the ditches by our fields. In winter, we retain as much water as possible. At that time, there are no consumable crops in the fields, as these would become flooded. However, the fields are still in use for cover crops. The large amount of retained water is released in phases, when necessary, often in periods of reduced rainfall, i.e. during spring and summer.
For this purpose, we use models that measure when the soil has become saturated, how much water has evaporated and how much precipitation has fallen.
This allows us to figure out how much water needs to be sprayed over the fields.
Because our fields at the Gorp & Roovert Estate lie between stretches of woodland, the water management has to be carefully fine-tuned. The plan has to work for both the fields as well as the entire estate, with some trees needing to be kept wet, others dry. If more appropriate, we sometimes make very deep ditches shallower, all while making sure we maintain the accessibility of our fields.
Monitoring water quality
Besides improving water efficiency, model-adjusted irrigation also improves overall water quality. Ditches should not be allowed to dry up, and we should not spray with surface water from ditches either, as they contain diseases and bacteria that spread when sprayed. We therefore have to be careful not to let the ditches overflow, as this could damage the crops with brown rot bacteria, for example.
In addition to interventions based on water quantity, we also safeguard water quality by using fewer pesticides or artificial fertilisers, both of which are harmful to the soil, soil life and soil water.
Minimum and dosed fertilisation
Fertilisation is done both in both dosed and minimal fashion. We use manure from our own cows or from other farmers in the area to close the cycle as much as possible.
When we do decide to use fertilisation, it is done so based on four factors:
- Time: Just before we sow the crop. Later, we take crop samples to see if a small amount of additional manure is required. This is not only cost-effective, but it also prevents over-fertilisation, while also stopping manure draining into the soil in case of a downpour.
- Quantity: The amount of fertilisation needed per crop is known, meaning we can match the exact amount each crop requires.
- Type of fertiliser: We try to minimise the use of fertilisers that are susceptible to leaching into the groundwater, opting instead for fertilisers that bind quickly to the crops, which stops them leaching into the soil.
- Location: We fertilise in specific and correct locations. By using GPS equipment, we are able to fertilise with great accuracy. This helps us fertilise crops right up to the field margins, all while still avoiding the ditches, as well as any potential overlap.
By introducing more organic matter (roots, plants, small animals, manure, carbon-absorbing substances) into the soil, we are increasing its sponge-like properties. This is especially true for crops that have elaborate root structures. Soil that is able to retain water is also able to release it more gradually. However, increasing the level of organic matter in the soil can prove tricky. It is especially important to avoid situations where the organic matter is decomposing faster than it is being accumulated.
We therefore process as much organic matter as possible in the soil, including organic manure (from cows or pigs) and compost.
We have partnerships with various projects that send residual flows of various origins to the fields from within a 5 kilometre radius:
- Local municipalities (Municipality of Goirle and Municipality of Hilvarenbeek)
- Dommel Water Authority
- Brabant Delta Water Authority
- Stichting Brabants Landschap
These sorts of partnerships are encouraged by the water authorities in order to prevent flooding as much as possible. If the soil is able to collect and retain more water as a result of these interventions, this creates a win-win situation for all parties involved.
In strip cropping, fields are divided into strips, with each alternate strip used to grow a different crop. This is in stark contrast to traditional monoculture, where only one crop is grown on an entire field. The variety of crops used when strip cropping contributes to an increase in the overall diversity in crop-specific micro-organisms, both above and below the soil level. Diseases and pests also spread less quickly, meaning that fewer pesticides are required. As we grow in narrow strips (often six metres), there is a lot of subterranean and above-ground interaction between the different crops, as well as the insects that are attracted to them. This in turn helps further optimise the use of nutrients, water and sunlight.
The alarming decline in biodiversity, along with the increase in extreme weather conditions, mean that there is an urgent need for resilient production systems. With these new strip pilots, we are conducting large-scale research into the potential of increased crop diversity for creating a robust, plant-based food production system. The downside of this system is that the scale, both in terms of labour and mechanisation, is greatly reduced, resulting in higher cultivation costs.
When choosing the right crops, we opt for ones that we are already familiar with and have experience growing.
FAB and fallow
These are strips of fallow land, arranged around the field, as well as several strips in between, and partially sowed with a mix of different flowers. These flowers essentially form an insect buffet (FAB mixture = Functional Agro Biodiversity). Also known as banker fields, these provide a habitat for insects that have a positive effect on other crops.
Strips of grain
Grain is used as concentrate in cow feed.
Strips of clover
Strips of clover serve two main purposes. Firstly, they are used as cow feed. With the cows grazing on fresh grass every morning during spring, this provides them with an increase in healthy nutrient intake. Secondly, the strips are also used as tracks for heavy farm machinery.
Strips of onions
These are one of the marketable crops from vegetable cultivation.
Strips of potatoes
Another marketable crop from vegetable cultivation, potatoes are often used by customers to make fries, among other things.
Strips of field beans
Field beans are a high and firm crop that act as an excellent wind breaker between crops. We also use the straw generated from this crop in our barns. Field beans are a protein-rich food source for our cows, a good alternative to overseas imported soya. In addition, this crop flowers abundantly, which attracts a whole variety of useful insects. For example, the flowers attract the bees, who create a type of honeydew. This honeydew then attracts the aphids. Where aphids appear, so do their predators. The presence of aphid-eating insects has a positive effect on the other vulnerable crops. Therefore, we can say that strip cropping sparks a positive chain of events.