According to Iiri Raa, head of the agroecology department at the Estonian Agricultural Research and Knowledge Center (METK), science plays a vital role in agriculture by helping bridge farmers' practical needs with environmental protection.

"Environmental protection, biodiversity and soil health all need to be studied directly in agricultural fields, because farming does not affect nature only in a general sense. It does so through very specific mechanisms that require measurement, observation, monitoring and experimentation," she said, explaining the importance of METK's work.

Environmental impacts often emerge very slowly and can remain hidden, meaning it is impossible to draw far-reaching conclusions based on a single year's data. "Changes in soil fertility or biodiversity may not become visible within a single growing season. They develop over years or even decades. That's why long-term field trials and monitoring are essential," Raa told ERR.

Over a four-year period, METK's Kuusiku Experimental Center conducted a comprehensive study of organic and conventional farming. The results confirmed the positive effects of crop rotation. The study examined the impact of crop rotations that comply with the requirements for organic farming and environmentally friendly farming support schemes.

Karli Sepp, an agroecology specialist at METK, said that because crop rotation requirements are part of agricultural environmental support programs, it was important to evaluate how well they work and whether they produce better results in the field than farming systems that do not meet those requirements.

For the study, researchers established two crop rotation systems that met the minimum requirements for organic farming and environmentally friendly management: a cereal-clover rotation and a cereal-cover crop rotation. These were compared with a non-compliant cereal monoculture rotation consisting solely of alternating cereal crops.

Rotating crops produced better results because it led to healthier plants and higher yields. Sepp explained that growing only one type of crop, such as cereals, allows plant diseases and pests to accumulate over time while also degrading soil structure.

"When we started the trial, we assumed that conventional farming would outperform organic farming in terms of gross margin. At the same time, organic farming support payments have always been much higher than those for conventional farming, so we thought the difference might not be that large. But as the trial continued over a longer period, it turned out that organic farming actually generated a higher gross margin in most years," he said.

Sepp added, however, that soil fertility at a particular site also plays an important role. The shallow, stony soil at Kuusiku dries out quickly and produces somewhat lower yields than some other fields, even when fertilized in the same way as conventional farms elsewhere in Estonia.

"On our less fertile soil, we've seen this paradox where organic farming produces lower yields in most years but still generates a higher gross margin than conventional farming, even though conventional yields are much higher," he said.

The multi-year trial found that the cereal-clover rotation generally produced higher gross margins than the other crop rotation systems. For example, in the cereal-clover rotation, winter wheat grown after red clover produced grain yields that were, on average, 21 percent higher under organic farming than in the cereal monoculture system and 11 percent higher than in the cereal-cover crop rotation.

The study also found that cover crops had a significant effect on grain yields specifically in conventional farming, where unused nutrients remaining in the soil after harvest enabled the cover crops to produce greater biomass by autumn.

"One of the biggest challenges in conventional farming is that a great deal of nutrients remain unused in the soil by autumn. Organic farmers have long made greater use of cover crops because they help build and improve soil fertility. For several years now, there has also been a separate support payment for growing cover crops," Sepp said.

--

Follow ERR News on Facebook and X and never miss an update!