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In Japan, additional potassium fertilization is used as a countermeasure for radiocesium-contaminated grasslands in the Tohoku and North Kanto regions. A 2-year pot experiment was conducted to assess the efficacy of using tall fescue (Festuca arundinacea Schreb.), a low-cesium-absorption grass species, to replace orchardgrass (Dactylis glomerata L.), the most common forage grass species in these regions, to reduce potassium fertilization and improve the forage mineral balance. The treatments were a combination of two grass species (tall fescue and orchardgrass) and two potassium application rates (0 [K0] and three times the conventional amount [K3]) with four replications. The grass species and potassium application rate had significant (p < .001) effects on plant cesium-137 concentrations. The results of the generalized linear mixed-model analysis indicated that when tall fescue replaced orchardgrass, cesium-137 in the forage grass was reduced to 34% and that the K3 treatment reduced cesium-137 to 46% relative to the K0 treatment. The difference in cesium-137 concentration between the two grass species increased as the soil exchangeable K2O content decreased. The equations for estimating the cesium-137 concentration (y [g/kg]) from the exchangeable K2O content (x [g/kg]) were obtained as y = 63.7e-2.095x for tall fescue and y = 185.5e-3.327x for orchardgrass. These equations indicate that tall fescue cultivation can reduce the risk of elevated radioactive Cs in the grass by reducing potassium fertilizer to approximately half that of orchardgrass. There were no differences in the response of plant potassium concentrations or the potassium/(calcium + magnesium) equivalent ratio to soil exchangeable K2O content among the grass species. However, the mineral balance of forage can be improved by reducing potassium fertilizer applications for cesium-137 remediation. Tall fescue has good potential to remediate contaminated grasslands as it reduces additional potassium fertilization and improves the mineral balance of forage. [ABSTRACT FROM AUTHOR]

Various climate adaptation strategies are being studied for the agricultural sector to address the effects of climate change. Global warming is predicted to have a significant influence on cool‐season grass production in Japan in terms of decreasing grass dry matter yield. The authors have studied adaptation strategies to maintain grass dry matter yield using orchardgrass, a cool‐season grass. However, it may be difficult to adapt to future climate conditions using management methods such as fertilizer application or changing grassland renovation cycles using only one grass species. In this study, a model was constructed formulating the relationship between temperature and yields of the main cool‐season grasses in Japan, and the effects of global warming on grass productivity were predicted. Two models were constructed, and the optimal one was selected using Akaike's information criterion. The selected model was then validated using correlations with observation data. We also compared areas suitable for cultivation at current and higher temperatures, which were produced as maps using the selected model. Bahiagrass, which is a warm‐season grass, was suitable for cultivation in coastal areas in southern Kanto under increased temperature condition. It may be useful, therefore, to convert to heat‐resistant grasses, such as orchardgrass or tall fescue, as temperatures rise. [ABSTRACT FROM AUTHOR]

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 ( r = 0.33, P > 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 ( r = 0.87, P < 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. [ABSTRACT FROM AUTHOR]

Grasslands in Tohoku and North Kanto, Japan were contaminated with radiocesium released from the Fukushima Dai-ichi Nuclear Power Plant in March 2011. The dominant pasture species in the permanent grasslands of these areas is orchardgrass (Dactylis glomerata L.). Two field studies were conducted to determine the potential of a low radiocesium-uptake forage grass to replace orchardgrass for remediation of contaminated grasslands. From 2012 to 2014, tall fescue (Festuca arundinacea Schreb.) showed lower 137Cs uptake than orchardgrass under harvesting condition. The annual mean 137Cs activity concentration and transfer factor in tall fescue were half of those in orchardgrass. There was no significant difference in the 137Cs activity concentration among the five cultivars of tall fescue at the third harvest in 2012. From 2016 to 2019, another field study was conducted in a pasture with tall fescue and orchardgrass introduced by overseeding under heavy grazing pressure after the Fukushima Dai-ichi Nuclear Power Plant accident. Tall fescue and orchardgrass were collected in May, July, and September from four paddocks before rotational grazing. Three grasses that were originally present, Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), and white clover (Trifolium repens L.), were collected each time that tall fescue and orchardgrass were sampled in 2016–2017. They were also collected at the sampling time in May of 2018 and 2019. Tall fescue showed a consistently lower transfer factor than orchardgrass during the four years. Tall fescue had the lowest transfer factor compared with the three originally grown plant species. The Ministry of Agriculture, Forestry and Fisheries of Japan recommends an exchangeable K 2 O content of 0.3–0.4 g kg−1 in soil (0–15 cm depth) to keep the 137Cs activity concentration in forage grass below the provisional tolerance level for feed. The soil exchangeable K 2 O content in both field studies was lower than this. Tall fescue is considered a low radiocesium-uptake grass and a potential replacement for orchardgrass in Japan. The use of tall fescue might reduce the amount of potassium fertilizer needed in contaminated grasslands. • What pasture species have lower radiocesium uptake than orchardgrass, the major grass in Japanese grasslands? • Tall fescue presented lower 137Cs uptake than orchardgrass under harvesting and grazing. • Tall fescue provides a good option of remediation strategy for contaminated grasslands. • The use of tall fescue might reduce the amount of potassium fertilizer application. [ABSTRACT FROM AUTHOR]

The article presents the registration of Nanryo Tall Fescue that was developed by the Kyushu Okinawa National Agricultural Research Station in Kumamoto, Japan.