“The analysis from the construction sector is correct,” says Peter van Bodegom, professor of environmental biology and department head Environmental Biology at Leiden University, “the emissions are already far too high and will only increase further, especially related to the use of concrete and steel in the world. The question is whether the analysis from an agricultural point of view is also correct.”
The livestock farmer as a supplier of biobased building materials
Van Bodegom wonders whether Dutch farmers will gain anything on balance. Won’t this new sport just as easily lead to intensification, monoculture and loss of biodiversity, in other words: won’t the same problems arise as we now face? He definitely thinks it makes sense to think carefully about this option, but at first sight he sees more in capturing carbon in the residual flows from agriculture, for example straw. Not all of that is now being plowed back, because it is less controllable than fertilizer, says Van Bodegom.
According to him, the question is whether you aim to reduce a maximum amount of carbon from residual materials into the soil (because a good carbon level in soils is crucial for their functioning), or whether you want to store carbon in buildings. He also points out that a lot of land will be needed to make the biobased materials. What does this mean for other sectors? For example, the opinion authors, says van Bodegom, do not take into account a relocation of part of our food production. He also notes that they also do not take into account that a change in land use in itself leads to a lot of extra emissions. According to Van Bodegom, this is an important source of global CO2emissions. “A whole system picture is needed, in which various sectors are included at the same time, to be able to say whether it is a good plan for a cattle farmer to make biobased materials for construction.”
Straw in construction competes with healthy soils rich in organic matter
Wouter van der Weijden, founder and director of the Foundation for Agriculture and the Environment, finds the opinion writers’ approach fresh and challenging, but a bit too optimistic. In his view, a lot of calculation and other thinking is still needed. Some ifs and buts from his perspective.
For example, buying out is only relevant when it comes to land-based livestock farms; these are mainly dairy farms. But are these lands suitable for arable farming? In any case, not the peat meadows, because there the groundwater has to go up rather than down. At most, some wet cultivation is possible, for example of cattails, useful insulation material. There is more to choose from on sandy and clay soils, for example cultivation of flax, a good building material. Like Bodegom, Van der Weijden points to the depletion of the soil that occurs when the construction industry wants to use straw for construction. Straw in construction competes with healthy soils that are rich in organic matter.
Dutch agricultural land too expensive
Van der Weijden also expects that the former livestock farmer will only start growing raw materials if he can earn more with it than with the cultivation of food crops. The question then is: is the land in the Netherlands not too expensive for the production of materials? Elsewhere in Europe, agricultural land is worth much less. In the Netherlands, a farmer pays €70-120,000 per hectare against, for example, €5,000-10,000 in Brittany and considerably less in Eastern Europe. The expected rising CO . will also2emissions price have its impact. The opinion does not include the fact that the cultivation of crops for biobased materials also requires energy and therefore, when it comes to fossil energy, CO2 produces. In addition to nitrous oxide, which is also a greenhouse gas. You have to deduct that, says Van der Weijden, from the calculated climate gain.
Civil engineer Andy van den Dobbelsteen, professor of Climate Design & Sustainability and sustainability coordinator at TU Delft, thinks to start with that farmers do not hooves to disappear. They can achieve a healthy nitrogen and carbon balance through a balanced way of farming. He thinks that organic, circular farming with fewer animals and more vegetable cultivation, while simultaneously managing landscape and nature, is the way to go. He also sees a very interesting option in growing crops that can be used in biobased products. “They are going to take off enormously, because of the requirements from the climate objectives and to prevent further nitrogen disturbance in the Netherlands.”
The former livestock farmer will only start growing raw materials if he can earn more with it than with the cultivation of food crops. The question then is: is the land in the Netherlands not too expensive for the production of materials?
Martin van Ittersum, professor of Plant Production Systems at Wageningen University, says that only soil-bound livestock farmers could benefit from cultivating biobased materials. So in the Netherlands we are mainly talking about dairy farmers. But 70 to 80% of the acreage of dairy farmers is grassland, which in the Netherlands is largely on peat soil. You cannot and should not want to grow crops on it. And in general he states that if you convert grass into crops for construction, you lose a lot of carbon from the soil. That would not be good for BV Nederland’s greenhouse gas emissions. A portion of land remains on which, for example, silage maize is grown for or by the dairy farmers. The cultivation of biobased products could in principle be possible, but Van Ittersum wonders whether it would be economically attractive enough with our high land prices. It seems obvious that in the future this would involve large areas of bulk crops. Wouldn’t the construction industry be able to buy that cheaper abroad? “If I was a cattle farmer with land and was no longer allowed to keep livestock, I would rather grow vegetables or seeds or seed potatoes, with a higher financial yield.”
The consequences for agriculture, nature and climate
Van der Weijden notes that if we buy out livestock farms in the Netherlands, but continue to consume the same amount of meat and dairy, cows will be added abroad, with their emissions of methane and nitrous oxide. The profit for the climate is then zero.
He also indicates that on a global scale the cultivation of materials competes with the cultivation of food. You then need more agricultural land, often at the expense of nature reserves and (when it comes to forests) also of the climate. There will also be more competition for increasingly scarce raw materials, such as phosphate. On the other hand, suppose the world population starts to consume less meat and dairy, then we would need less land to produce the same amount of proteins, and more acreage would become available for the cultivation of biobased raw materials. That chance is real in rich countries, but much smaller in other countries. Van der Weijden seems to expect more profit from reducing food waste. There are great opportunities there. Then less cultivation of food crops is needed and there is more room for the cultivation of biobased raw materials.
Van den Dobbelsteen thinks that we can grow our food spatially most efficiently in modern greenhouse horticulture and in vertical farms that can be integrated into the built environment. TU Delft does a lot of research into the way in which food production in the city can be smartly connected with nutrient, water and energy flows – the so-called nexusapproximation). “This makes us completely circular and it saves a lot of space. And then we can use a lot of agricultural land for all kinds of crop cultivation: vegetable food or biomass for biobased products, or better yet: in combination and in rotation, which makes us more ecological and resilient.”
There is a good chance that production elsewhere will be less efficient. If so, then the world food system is exporting a challenge from one place to another
According to Van den Dobbelsteen, it would not be the case that forests and nature reserves would disappear if we switched to biobased construction. “In Europe, most forests are managed sustainably – with an FSC label. There is currently a growth surplus of trees, especially in Scandinavia. Trees are used senselessly: for the paper industry and as biofuel, for example. There is now a lot of plant material that we don’t use that will wear off after pruning or on its own. The latter creates methane and CO2, which is bad for the climate.” So binding these materials in products is better for the climate and the environment in many respects, says Van den Dobbelsteen. And we should only use trees and wood-like materials in high-quality products, not as paper or firewood. According to him, we will then have more than enough to serve the construction task.
Van Ittersum believes that if the demand for animal proteins remains the same, production will move elsewhere. There is a good chance that production there is less efficient. If so, then the world food system is exporting a challenge from one place to another. His point of departure is that you produce biomass on suitable grounds to feed people, if that is not possible for animals and only if that is not possible, should you see whether it can be used properly in industry. But at the same time he does not think that this is a law of the Medes and Persians.
As far as Van Ittersum is concerned, livestock does not necessarily have a higher priority than construction. He sees the usefulness of plant materials for construction. But primarily use by-products for this or soils that are unsuitable for the production of human food. He thinks it is a realistic question whether you are going to plow in all by-products (eg straw) mainly to increase the soil carbon content in the long term, or whether you are better off using them in construction. The latter can be effective in sequestering carbon for a longer period of time.
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