Enzymatic Activity of Soil under Spelt Grown in An Organic Farming System in Poland’s Temperate Climate

Abstract

Wheat spelt is a very valuable plant, especially in organic farming. Its high nutritional values combined with low soil and climate requirements increase the interest in growing spelt in various soils. Spelt can be grown in different soil types, including sandy, wet, poor, non-draining and low-fertility soils. It is well adapted to cold climate. Compared to common wheat, it requires less nutrients and is more competitive against weeds. Activities of enzymes in soil under winter spelt have not been studied yet. We sought to determine whether the choice of varieties will also shape the enzymatic activities in different soil types and whether these activities will be the same under different climatic conditions of 2007, 2010 and 2013 year. The aim of this field experiment was to assess the impact of growing different winter spelt varieties (Oberkulmer Rotkorn, Franckenkorn, Schwabenkorn, Ostro) on the enzymatic activity on two different soil complexes. In the years 2007–2013, two three-year rotations of the experiment were carried out (the first ended in 2010 and the second in 2013). Spelt was cultivated in an organic system. Physicochemical properties of the two different types of soil after three and six years of the experiment were compared to the soil properties before the experiment. The catalase activity ranged between 3.33 and 6.75 µmol H2O2 g−1 d.m. min.−1, the dehydrogenase activity ranged between 1.6 and 87.7 nmol TPF g−1 d.m. 24 h−1, and the arylsulfatase activity ranged between 37.5 and 157 µmol pNF g−1 d.m. h−1. The enzymatic activity in the soil depended on the type of soil (as a rule, the activity was higher in a stagnic luvisol than in a haplic cambisol) and on the spelt variety (although no variety had a clear beneficial effect on the activities of all enzymes). Spelt cultivation in an organic system led to an increase of enzymatic activity in a stagnic luvisol, but not always in a haplic cambisol soil type.