• Grazed pasture;
  • soil solution nitrogen;
  • Zoysia japonica Steud


Soil solution nitrogen (N) concentrations in a non-fertilized Japanese lawngrass (Zoysia japonica Steud.; JL, native species) pasture were compared with those in a fertilized tall fescue (Festuca arundinacea Schreb.; TF, improved species) pasture from May to December (late spring to early winter). Both pastures were grazed rotationally by breeding beef cattle in May–October. The TF pasture received a summer topdressing with compound fertilizer (8 g m–2 N, P2O5 and K2O). Annual herbage N consumption by cattle was lower in the JL (9.9 g N m–2) than in the TF (19.8 g N m–2). Soil solution N concentrations at the 10 and 30 cm depths were lower in the JL pasture (<0.61 mg L–1) than in the TF pasture (0.15–7.4 mg L–1) from mid-summer or early autumn to late autumn. In the JL pasture the soil solution N concentrations at the 10 cm depth remained low irrespective of the soil inorganic N concentrations in the 0–10 cm layer (= 0.33, > 0.1), whereas the soil solution N in the TF pasture showed an increasing tendency with increasing soil inorganic N for the same soil depth and layer (= 0.87, < 0.1). The non-significant response of soil solution N to soil inorganic N in the JL pasture suggests that the lower soil solution N concentrations in this native grass pasture may not be explained only by the lack of fertilizer application to the pasture.