Applied Soil Ecology 46 (2010) 405–412 Contents lists available at ScienceDirect Applied Soil Ecology journal homepage: www.elsevier.com/locate/apsoil Influence of mouldboard plough and rotary harrow tillage on microbial biomass and nutrient stocks in two long-term experiments on loess derived Luvisols Stefanie Heinze a,∗ , Rolf Rauber b , Rainer Georg Joergensen a a Department of Soil Biology and Plant Nutrition, University of Kassel, Nordbahnhofstr. 1a, 37213 Witzenhausen, Germany b Department of Crop Sciences, University of Göttingen, Von-Siebold-Str. 8, 37075 Göttingen, Germany article info Article history: Received 6 May 2010 Received in revised form 1 September 2010 Accepted 29 September 2010 Keywords: Rotary harrow Mouldboard ploughing Microbial biomass Ergosterol Basal respiration abstract The nutrient-specific effects of tillage on microbial activity (basal respiration), microbial biomass (C, N, P, S) indices and the fungal cell-membrane component ergosterol were examined in two long-term exper- iments on loess derived Luvisols. A mouldboard plough (30 cm tillage depth) treatment was compared with a rotary harrow (8 cm tillage depth) treatment over a period of approximately 40 years. The rotary harrow treatment led to a significant 8% increase in the mean stocks of soil organic C, 6% of total N and 4% of total P at 0–30 cm depth compared with the plough treatment, but had no main effect on the stocks of total S. The tillage effects were identical at both sites, but the differences between the sites of the two experiments were usually stronger than those between the two tillage treatments. The rotary harrow treatment led to a significant increase in the mean stocks of microbial biomass C (+18%), N (+25%), and P (+32%) and to a significant decrease in the stocks of ergosterol (-26%) at 0–30 cm depth, but had no main effect on the stocks of microbial biomass S or on the mean basal respiration rate. The mean micro- bial biomass C/N (6.4) and C/P (25) ratios were not affected by the tillage treatments. In contrast, the microbial biomass C/S ratio was significantly increased from 34 to 43 and the ergosterol-to-microbial biomass C ratio significantly decreased from 0.20% to 0.13% in the rotary harrow in comparison with the plough treatment. The microbial biomass C-to-soil organic C ratio varied around 2.1% in the plough treatment and declined from 2.6% at 0–10 cm depth to 2.0 at 20–30 cm depth in the rotary harrow treat- ment. The metabolic quotient qCO 2 revealed exactly the inverse relationships with depth and treatment to the microbial biomass C-to-soil organic C ratio. Rotary harrow management caused a reduction in the microbial turnover in combination with an improved microbial substrate use efficiency and a lower contribution of saprotrophic fungi to the soil microbial community. This contrasts the view reported else- where and points to the need for more information on tillage-induced shifts within the fungal community in arable soils. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Tillage is one of the major tools for farmers to control the growth of crops and weeds and to regulate the microbial process of plant residue decomposition and the resulting nutrient release (Dick, 1992). A reduction in tillage intensity has often been dis- cussed in terms of energy saving, increasing rainfall infiltration, thus reducing erosion, and enhancing C sequestration to reduce CO 2 emissions (Frede et al., 1994; Paustian et al., 2000). Mouldboard ploughing is still the most widespread method used in humid Cen- tral Europe (Derpsch, 1998; Holland, 2004), especially in organic ∗ Corresponding author. Present address: Department of Environmental Chem- istry, University of Kassel, Nordbahnhofstr. 1a, 37213 Witzenhausen, Germany. Tel.: +49 5542 98 1575. E-mail address: heinze@uni-kassel.de (S. Heinze). farming (Kouwenhoven et al., 2002). This type of ploughing can be replaced in the order of decreasing intensity by rotary cultivators (Meyer et al., 1996; Ahl et al., 1998), rotary harrows (Stockfisch et al., 1999; Jacobs et al., 2009) or grubbers (Berner et al., 2008). Most studies focussed on soil organic C and microbial biomass C(Stockfisch et al., 1999; Wright et al., 2008) as indicators for tillage effects, sometimes in combination with total N and micro- bial biomass N (Jacobs et al., 2009). Information on tillage-specific effects on total P and microbial biomass P are rare (Saffigna et al., 1989; Meyer et al., 1996), whereas that on total S and microbial biomass S is entirely lacking. Microbial biomass C and microbial biomass N are closely related in C-limited agricultural systems (Dilly et al., 2003; Joergensen and Emmerling, 2006) where N rarely limits microbial growth (Joergensen and Mueller, 1996). Microbial biomass P and microbial biomass S are less intimately connected with microbial biomass C(Heinze et al., 2010). One reason is that different storage com- 0929-1393/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.apsoil.2010.09.011