Voiko maan kasvukuntoa kehittää? Kokemuksia 8 peltolohkolta neljältä vuodelta.

Agricultural fields have clear differences in productivity and resilience towards extreme weather events. “Good fields” produce better yields than other fields even with the same level of inputs. On the other hand, the same “good fields” are usually productive in rainy and dry years. Developing field resilience is important in changing climate conditions, but the reasons behind the differences and the methods of developing productivity are still unclear.

Soil health is a novel approach for describing field productivity. In that approach a field is thought as an ecosystem with interacting biological, chemical and physical factors, which contribute to water balance, primary productivity, nutrient cycling and disease suppression. The OSMO project tested how the approach of soil health would work in improving the productivity of “problem fields”. The test was arranged as a four year field plot study focusing on 8 test fields in different parts of Finland. The test plots were chosen as they had low productivity, but the reason for the low productivity was unclear for farmers and advisors.

The test fields were compared to an adjacent well growing field and also a part of the test field was left as an untreated control for the duration of the study. The test fields were subjected to soil health management practices based on annual planning. At the beginning of the study (2015-2016), the condition of the fields was mapped through a combination of soil laboratory analyses, field observations and remote sensing (62 chemical, 7 physical and 13 biological variables). Based on the survey the fields had multiple problems, which were shown as poor drainage, poor structure, nutrient deficiencies and low numbers of earthworms. After identifying the causes of the problems, a soil management plan was designed for each field and the improvement in soil conditions was monitored through soil- and plant testing and field observations (38 monitoring variables). In the year 2018 the extensive beginning survey was repeated in order to check the changes in soil condition. Various aspects of managing for soil health have been presented in previous reports.

This report presents a conclusion to the main question of the study: “can soil health be improved?” Based on the results improving soil health is relatively easy in many cases, but all soil health problems may not be fixable. Examples of simple soil health solutions would be repairing failed drainage systems, fertilizing low boron or phosphorus levels or impro-ing soil structure through grass crops and subsoiling. Examples of hard soil problems are increasing manganese availability, increasing potassium levels in sandy soils and improving low organic matter sands without the possibility of increasing organic matter levels. The results support a field-by-field approach, where soil health development is based on a plan which is based on the individual properties of the field. The aim of the report is to provide examples on improving soil productivity and offer case studies on the influence of management to soil health. The report is published along with the dataset available at: https://www.doi.org/10.5281/zenodo.3589102