Effect of Reduced Tillage on Soil Enzyme Activity, Pests Pressure and Productivity of Organically Grown Spring Wheat Species

The possibility of using reduced tillage in organic farming is poorly recognized. The study aimed to assess the impact of the tillage method (shallow tillage and plowing) on soil biochemical activity, pest pressure, and grain yield of Triticum sphaerococcum, T. persicum, and T. aestivum ssp. vulgare, grown in organic farming systems. For this purpose, field experiments were conducted at three certified organic farms located in different regions of Poland. Enzyme activity was influenced to a greater extent by local soil and weather conditions compared to wheat species and the tillage method. Insect pests (Oulema spp.) slightly damaged the leaves of wheat, and the reduced tillage did not increase the damage. Under site conditions favorable for the development of diseases significantly fewer disease symptoms were observed in shallow tillage compared to plowing (powdery mildew by 9.6–46.1%; stripe rust by 15.5–89%; Septoria head blotch by 0–84.4%; Fusarium head blotch by 0–47.4%, Fusarium foot rot by 0–100%). T. aestivum was characterized by the highest yield and the yield stability in various locations and tillage methods. Ancient wheat species (T. sphaerococcum and T. persicum) had a higher yield in shallow tillage compared to plowing tillage (by 64% and 30%, respectively) only under effective weed control