Role of amendments in modifying clayey soil physical properties under conventional and reduced tillage in northern Lithuania

摘要

Investigations to improve clayey soil physical properties and conditions for applying reduced tillage to spring crops were carried out at Joniskelis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry in a glacial lacustrine clay loam on silty clay soil with deeper-lying sandy loam (Endocalcari–Endohypogleyic Cambisol). Amendments for soil improvement were the following: farmyard manure – 60 t ha-1, green manure – 27 t ha-1 and lime mud – 10 t ha-1 were incorporated by a mouldboard and segment plough at 0.25 and 0.40 m depths for winter crops twice every third year. Conventional mouldboard ploughing at 0.25 m and reduced ploughless tillage at 0.25 and 0.15 m depths was applied to spring crops after incorporation of amendments. The incorporation of amendments resulted in the decrease of soil bulk density, improvement of soil aeration and water conductivity. Ploughing by a segment plough, especially with incorporation of amendments, improved the subsoil physical properties and water conductivity. However, the segment ploughing resulted in a worsening of topsoil properties due to mixing the subsoil layer with topsoil. Lime mud was more effective for subsoil improvement. Reduced ploughless tillage determined the decrease of soil porosity, worsening the soil structure and seedbed quality. Incorporation of amendments, especially farmyard manure, helps to avoid or lessens the negative effect of reduced tillage on the clayey soil physical condition and on the decrease of the spring crop yield.