Cultivate the land to cultivate crops

When soil crumbles like a moist chocolate cake, it teems with life. Crop yields increase and the nutrient stress on waterways is alleviated.

Farmer Tuomas Mattila is not measuring success merely in the amount of harvested grain. Alongside making a living, Mattila is giving consideration to clearing the water running in a nearby stream, biodiversity, close collaboration with customers and opportunities for the next generation.

“At our farm, we are not dedicated to producing as much feed barley as possible, but to conducting meaningful work.”

Healthy, living soil is important not only for crops. Soil stores double the amount of carbon compared to plants and the atmosphere, which makes its condition a significant climate issue.

In addition to being a farmer, Mattila is a researcher, and the landscape at Kilpiä betrays his inclination to experiment. The field plots in the downward slope next to the farmhouse do not follow traditional straight lines, but gently undulate, hugging the contours of the land.

At the highest elevation, Tuomas and Iiris Mattila established an orchard approximately five years ago, now growing apple, pear, cherry, plum and cherry plum trees. In addition binding the soil and providing cover, the trees increase biodiversity. On the slope’s summit, basket willows have been planted to hold back wind.


Tuomas Mattila is showing satellite images of the farm with superimposed contour lines. The curves reveal the channels in which rain and melt water end up. This takes us to the fundamental questions of farming: where does the field dry up easily and where does water stagnate? Where does run-off erode the soil?

With laser scanning technology, the contours are accurately outlined. Scanning data accumulated by geologists is often open access.

“Another positive side of a plot layout that adheres to contour lines is that you don’t have to fiercely keep accelerating the tractor and pivoting to reach the top of the hill when cultivating the soil,” Iiris Mattila explains.

Living plants or bare soil?

The Kilpiä farm observes a three-year crop rotation. During a visit to the farm in the last week of August, the rye grown on one-third of the plots has just been harvested, revealing a blanket of clover underneath the stubble. The next third is covered by grass and oats.

The rest of the land – according to the Mattilas, the ugliest bit – consists of grassland freshly worked over with a cultivator; there is some clover here and there, but mostly just soil, dead stalks and root clods.

“You can choose the state in which you wish to leave the field for the winter, either blank soil or soil covered by vegetation. In other words, you can choose whether you want the autumn rain to batter the exposed soil or not,” Tuomas Mattila points out.

Before cultivation, the grassland had a chance to store some energy through photosynthesis to be used for fertilising the following summer. The rye, soon to be sown into the broken ground, will hold the soil together and provide a harvest next year.

“No more than a decade ago, before the older generation gave way to the new, this farm relied on monoculture. The farming was part-time, so everything had to be simple. The sowing had to be completed in a single week in the spring, while the same amount of time was reserved for harvesting in the autumn.”

The new generation has given up on ploughing, since intensive soil cultivation and digging the lifeless layer of soil on the surface are a disservice to the community of organisms. So, the species chosen to be grown in Kilpiä need to fare well among weeds. “Rye does well with couch grass, and oats are a pretty easy one as well. The perennial clover has to be kept in check to prevent it from overwhelming the plots.”

On the other hand, clover is helpful in the heat of the summer. Oats and grass together maintain surface temperatures at a reasonable level and lively microbial activity, despite the hottest weather making the soil of the worn footpath a veritable furnace.


Tuomas Mattila is used to helping his colleagues when sustainable development requires new ideas. WWF Finland awarded Kilpiä with the title of the most environmentally friendly farm of the year, and Mattila receives financial support for his consultation work from the government.

“Farmers are good at solving problems. You stay put in the tractor’s cabin through the night if you have to. Taking stock and tending a farm with a proactive and comprehensive touch may pose more challenges,” Mattila thinks.

However, the life hidden beneath the tractor tyres is imbued with a force worth considering. There are tons of root fragments and other biomass connected to them in a single hectare, in addition to which healthy soil contains a large amount of necromass, or carbon originating in dead organisms. “Roots growing deep into the ground transport microbes that mummify inside soil crumbs.”


The stability of granular soil indicates its ability to resist consolidation. Healthy field soil resembles a moist chocolate cake. In a tightly packed field, water does not flow vertically but trickles along the surface to ditches, taking soil with it. Erosion makes nearby waterways eutrophic, a phenomenon that eventually reaches the sea.

During the hot summer of 2018, the Baltic Sea was covered by foul-smelling blue-green algae, rousing discussion on the environmental hazards of agriculture. “Farmers do not have to pose an environmental problem, but we can be part of the solution. We just have to help defective field ecosystems heal,” Tuomas Mattila stresses.

Since a granular soil structure is maintained by living organisms, such corrective work has the wellbeing of communities at its heart. Soil can be protected with year-round, living vegetation. A sturdy root system running deep underground does valuable work. If the soil is in danger of becoming too acidic for bacteria, it must be limed.

“Prospering perennials tell us that the roots are alive and feeding the ground. Root exudates attract nitrogen fixers, bacteria and other species important to the soil,” explains Iiris Mattila.


Many farmers treat their land as if all plots are identical, even though that’s not the case.

“You must learn to read the environment. You have to start by cultivating the land, only then can you cultivate crops,” Tuomas Mattila says.

If the soil is unhealthy, the focus should be on damage control. Leaving a field fallow is an underestimated solution to problems.

Relying on your wellingtons is an uncomplicated method for farmers concerned about the state of their land to gain information: pull your boots on after a heavy autumn rain, grab a shovel and start touring your farm. You learn a lot by just digging small holes in the soil and by examining the progress and spreading of water.

At the Kilpiä farm, a pit deep as to the shoulders of a grown man has been dug in the field for demonstrative purposes. Temporal layers, or the cross-section of the soil, can be seen in its sides.

The topsoil, lovingly cared for by the Mattilas, resembles a chocolate cake. A consolidation of soil originating from earlier farmer generations can be seen some dozens of centimetres lower, even more impenetrable than the layer further below from the last ice age. Only a single thistle root and a persevering earthworm seem to have burrowed into the hardest soil.


Consolidated soil should be eliminated. If the nutrients held in the deeper layers could be harnessed, artificial fertilising could be reduced or even given up entirely. Cutting back on phosphorus and nitrogen fertilisers would benefit both the climate and waterways, while providing savings for farmers.

Toxic organic compounds, mineral fertilisers, unbalanced farming and heavy soil cultivation have not dominated for long. Is now the time to change course? Tuomas Mattila gets to discuss his favourite subject. Why base farming on guesswork, when an abundance of information is available – and even more to be readily worked out?

“If a neighbour suspects nitrogen depletion as the cause of a yellowing plot of land and suggests you start fertilising, don’t take his or her word for it but collect a sample and get it analysed,” says Mattila from recent personal experience. The actual cause may be, for example, a manganese deficit.


Thanks to studies on fertilising needs, carried out by measurements of individual plots, the use of phosphorus and nitrogen has been as much as halved without diminishing crop yields. However, farmers base their actions primarily on signals from the industry and legislation concerning agricultural subsidies, which determine the maximum limits for fertilising.

“Data-based management has gained annoyingly little ground in agriculture and forestry. The old dogma is alive and well. I’m well aware that the people instructing farmers have a hard time admitting that their guidance has steered farmers towards costly practices that are detrimental to nature and the climate.”

In June, Mattila and Jukka Rajala, a colleague from the Ruralia Institute of the University of Helsinki, presented results from a three-year cultivation experiment and soil improvement instructions inspired by the results at a phosphorus conference held in Helsinki. The experiments were carried out around Finland in clay, sand and peat soils in field plots having varying cultivation history. In addition to the soil’s resistance to consolidation and the depth of the root systems, microbial respiration was among the soil qualities taken into account.

Improving soil structure to decrease surface run-off and to increase water storage in the soil turned out to be a significant corrective measure. Intact soil crumbs and retained water help plants make better use of phosphorus.


Applying gypsum to fields has received increased attention in Finland, as the blue-green algae issue of the Baltic Sea has worsened. There is hope that gypsum could provide a new method against nutrition run-off. Tuomas Mattila fears that its use will become overly simplified, overriding soil quality.

Mattila took part in a research project that found the benefits of gypsum to vary. Gypsum applied to clay soil improves its granular structure, provided there is enough magnesium, but in the case of light sandy soil, soil improvement fibres are often a more suitable solution. If a field plot is missing potassium and manganese, gypsum will only make things worse.

There are also plots where gypsum makes no difference to yields. In such cases, applying gypsum may be justified in terms of water pollution control, but should only be used on farms whose run-off ends up in the sea. Inland water cannot be burdened with sulphates dissolving from gypsum, since they activate old phosphorus sediments on the bottom and aggravate eutrophication. The sea already holds enough sulphate to make gypsum’s effect, according to estimates, very insignificant.


At the top of Iiris and Tuomas Mattila’s oat field, butterflies flutter and bumblebees buzz among mint flowers. At the bottom end, the plot is bordered by a strip of several flower species, flecked by cornflowers.

“A diverse community is resistant to diseases, pests and other troublemakers. It will recover better from hard times compared to less diverse ecosystems. It is productive thanks to smoothly working pollination and carbon fixation, as well as a functional water supply and nutrient cycle,” says Iiris Mattila.

Buckwheat and hairy vetch, planted late, are the last species in the autumn to bloom for the insects. To curb mole damage, birds are invited to help. There are plans to erect a post for falcons on the field’s edge, and an owl, a demonstrably effective partner in pest control, has already found the nesting box provided for it next to the forest.


Sustainability and fossil fuels do not mix, which is why the machinery used at the Kilpiä farm runs on biodiesel, while a landfill gas container is on order to provide energy for crop drying. An advisory group focused on the topic will also be established in the autumn.

“We too have been using an oil burner for drying. In addition to consuming oil, the system turns drying into a bottleneck in the harvesting process. We are now aiming to find an intermediate storage and drying solution based on renewable energy,” Tuomas Mattila describes his latest innovation.

However, the oil consumed at the farm is a trivial climate factor compared to the potential for enhancing carbon fixation by improving the condition of the soil.

“Growing catch crops alone can fix hundreds of kilograms more carbon in a single hectare."

Just by utilising this method, based on clover and other catch crops, the two million hectares cultivated in Finland could fix an additional half a billion kilograms of carbon. This is the equivalent of a couple of million tons of carbon dioxide emissions, whose storage would balance more than 25% of the agricultural greenhouse gas emissions in Finland.

By expanding to a global scale and by broadening the range of methods, the amount of potentially fixed carbon becomes enormous. Improving the carbon balance of countries involved in agriculture was indeed one of the central initiatives presented by France at the Paris climate negotiations. According to the initiative, a third of the mess caused by the use of fossil fuels could be remedied with the help of agriculture.

This article was published in Finnish in the Y/07/18 issue of Yliopisto magazine.

Award-winning Kilpiä research farm

The Kilpiä research and teaching farm is located some 50 kilometres north of Helsinki in Lohja. This 200-hectare farm, relying on sustainable agriculture and forestry, was awarded the national prize in the WWF Baltic Sea Farmer of the Year Awards in 2018.

Iiris Mattila graduated with a master’s degree in applied microbiology from the University of Helsinki.

Tuomas Mattila (@TuomasJMattila) was first educated as a master of science in technology, but then became interested in nature conservation and system analysis, completing two additional degrees: a master’s at the University of Helsinki and a doctorate at Aalto University. His doctoral dissertation focused on the economic modelling of environmental issues.

Mattila’s latest professional position, as part of the OSMO project (Knowhow and tools for resource-efficient soil health management in a collaborative network) at the University of Helsinki is ending at the end of 2018. From October onwards, he will resume his duties as a senior research scientist at the Finnish Environment Institute.