Switchgrass (Panicum virgatum L.) has been identified in the USA as an ideal biomass crop, in relation to its wide environmental suitability, mainly linked to the availability of both upland and lowland ecotypes, allowing the possibility of growing this species in most of the North American region. Switchgrass is conventionally grown for forage, but more recently, it has been considered as a model biofuel crop. Early European studies on switchgrass as a bioenergy crop started in the late 1990s, when a multi-location field trial was established in Greece (Aliartos) and Italy (Ozzano) to compare the productivity of 13 switchgrass genotypes, including upland (Carthage, Blackwell, Caddo, CIR, Forestburg, SU 94-1, Summer) and lowland (Alamo, Kanlow, Pangburn, SL 93-2, SL 93-3, SL94-1) genotypes. The scope was to identify the most suitable ecotype within each environment and, possibly, the best performing variety. The trials lasted 17 years (1998–2014) in Greece and 13 years (1998–2010) in Italy. While in Italy the trial was rainfed and unfertilized, in Greece, where the soil was marginal, drip irrigation was always applied, and the plots were fertilized regularly. The biomass yields in Greece, as averages across the 17 years, were similar for the lowland and upland varieties (11.5 vs. 11.1 Mg ha⁻¹, respectively), while in Italy, as averages across the 13 years, the differences were relevant: 15.4 vs. 11.3 Mg ha⁻¹ for lowland and upland, respectively. Alamo (lowland) was the most productive variety, both in Greece and Italy, with average annual yields of 12.7 and 16.6 Mg ha⁻¹, respectively; CIR in Greece (10.1 Mg ha⁻¹) and Forestburg in Italy (9.1 Mg ha⁻¹) (both upland) were the least productive genotypes. The present results demonstrate the good suitability of switchgrass as biomass crop for the Mediterranean climate. Despite the very marginal soil (i.e., very shallow and with a sandy texture) in the Greek trial, the application of regular fertilization and irrigation produced biomass yields above 11 Mg ha⁻¹ (grand mean) in the present 17-year-long study.

中文翻译：

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地中海地区13种低地和高地柳枝Eco生态型的长期生产力

柳枝（（Panicum virgatum（L.）在美国已被确定为理想的生物量农作物，因为它具有广泛的环境适应性，主要与高地和低地生态型的可获得性相关，从而使该物种在北美大部分地区都能生长。柳枝conventional通常用于饲草种植，但是最近，它被认为是典型的生物燃料作物。欧洲早期对柳枝as作为生物能源作物的研究始于1990年代后期，当时在希腊（Aliartos）和意大利（Ozzano）建立了一个多地点田间试验，以比较13种柳枝switch基因型的生产力，其中包括高地（Carthage，Blackwell， Caddo，CIR，Forestburg，SU 94-1，夏季）和低地（Alamo，Kanlow，Pangburn，SL 93-2，SL 93-3，SL94-1）基因型。范围是确定每种环境中最合适的生态类型，可能是表现最好的品种。该试验在希腊进行了17年（1998-2014年），在意大利进行了13年（1998-2010年）。在意大利，试验是雨养和不施肥的；在希腊，土壤很少，总是进行滴灌，并定期对田块施肥。低地和高地品种的希腊生物量产量（过去17年的平均值）相似（分别为11.5和11.1 Mg ha^-1），而在意大利，这是13年的平均值，差异是相关的：低地和高地分别为15.4和11.3 Mg ha ^-1。阿拉莫（低地）是希腊和意大利产量最高的品种，平均年产量分别为12.7和16.6 Mg ha ^-1。基因型最低的是希腊的CIR（10.1 Mg ha ^-1）和意大利的Forestburg（9.1 Mg ha ^-1）（均为陆地棉）。目前的结果证明了柳枝as作为地中海气候生物量作物的良好适应性。尽管在希腊试验中土壤非常贫瘠（即非常浅且有沙质纹理），但常规施肥和灌溉的应用产生的生物量单产超过11 Mg ha在为期17年的当前研究中，^-1（平均数）。