SLU long-term field experiments: Soil organic matter in a cereal-only cropping system (R3-0020), crop and soil data from 1971 and onwards

The SLU long-term agricultural field experiments are a nationwide research infrastructure consisting of experiments in hydrological management, tillage, landscape ecology, plant nutrition, weed biology and control, cropping systems, and cropping systems in northern Sweden. They are used to study how crop rotations and cultivation measures in agriculture affect soil properties and crop yields in the long term, and the effect of weather and climate on the efficacy of these treatments. The experimental sites and the data collected in the long-term experiments are a valuable resource for research, teaching and consulting. The experiments are open for those who want to use data already collected or who want to do their own sampling. All long-term experiments are funded by the NJ faculty and administered by an academic department, with the activities coordinated by a committee.  Twenty-four long-term field experiments in plant nutrition and soil fertility are currently managed by the Department of Soil and Environment at the Swedish University of Agricultural Sciences. These experiments, starting as early as 1936 or as recently as 2010, are grouped into eight different experimental series that focus on themes such as agronomically relevant factors including liming, long-term soil fertility, soil organic matter and soil biology. Plant and soil samples have been collected, measured for standard parameters, and archived since the start of the experiments, forming the basis of over 200 theses and papers across a broad range of disciplines. The soil organic matter in a cereal-only cropping system experimental series (also called "the humic balance trials") R3-0020 was established at four locations between 1970 and 1980. These experiments were designed to examine the impact of continuous cereal cropping on soil organic matter content. The design also tested the effects of nitrogen fertilization and of removing versus leaving straw in the field. This experimental series is connected to R3-0021 (soil organic matter in a ley-only cropping system), which includes four experiments at the same locations as R3-0020. The data collection includes yield, crop and soil data from the four currently active experiments from the year 1971 to 2023. Yield and crop data has been collected every year, and soil data has been collected at regular intervals depending on time period and location. The data has been checked for obvious outliers or faulty values, but caution is advised since this collection spans many years and has been collected and compiled by different people during this period. Please contact soilnutrientcycling@slu.se if there are any questions regarding the data, or regarding the design and management of the long-term experiments. Links to metadata records in the GLTEN (Global Long-Term Agricultural Experiment Network) platform are provided under Relations.