Soil solution nitrogen concentrations in a Japanese lawngrass (Zoysia japonica Steud.) and a tall fescue (Festuca arundinacea Schreb.) pasture under cattle grazing

Authors


  • Present addresses: Taishin Gotoh, National Chamber of Agriculture, Chiyoda, Tokyo, Japan.
    Makoto Kaneko, National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, Japan.
    Yuzo Kurokawa, Graduation School of Biosphere Science, Hiroshima University, Higashihiroshima, Hiroshima, Japan.

Yuzo Kurokawa, Graduation School of Biosphere Science, Hiroshima University, 2-2965 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan.
Email: yuzokuro@hiroshima-u.ac.jp

Abstract

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.

Ancillary