Reduced tillage for silage maize on sand and clay soils: effect on yield and soil organic matter

Maize (Zea mays) cultivation for silage has negative impacts on soil and water quality: reduced soil organic matter, nitrate leaching, soil-biota decline, etc. These problems can be caused partly by intensive soil tillage, like ploughing. The suitability of less-intensive tillage alternatives for farmers, in terms of effects on yield and soil quality, is unknown. On three field experiments, two on sandy soils and one on marine clay soil, we compared ‘full-field inversion tillage’ with two reduced tillage systems: ‘full-field non-inversion tillage’ and ‘strip-cutter’. Reducing tillage intensity in silage maize cropping influenced both yields and soil quality: at two locations yields tended to be reduced, and at two locations soil organic matter content was lower in inversion tillage compared to reduced tillage. The possible implications of reduced soil organic matter mineralisation for nitrogen dynamics are discussed.