Ravenna grass, Tripidium ravennae (L.) H. Scholz, is known to produce an abundance of biomass, but how plant density affects its biomass potential remains unknown. The objectives were to determine the effects of plant density on biomass yield; plant growth traits; biomass‒carbon, nitrogen, and ash concentrations; heating value; nitrogen removal; and sucrose concentration in leaves and culms. The treatments consisted of five plant densities (1,250; 2,500; 5,000; 10,000; and 20,000 plants per hectare) in a randomized complete block design with four blocks. Plots were nonirrigated, unfertilized, and harvested once during the dormant season each year. Data were collected from 2015‒2019. Dependent variables that varied with plant population density (p < .05) were biomass yield, number of reproductive culms per plant, reproductive culm diameter, reproductive culm sucrose concentration, and nitrogen removal with biomass. Biomass yield ranged from 5.6 to 16.3 Mg/ha for plant densities of 1,250–20,000 plants per hectare, respectively. Combined over years, nonlinear regression of the data showed the equation for biomass yield to plateau at 16.2 Mg/ha at a plant density of 10,640 plants per hectare. As plant density increased, the number of reproductive culms per plant, culm diameter, and culm sucrose concentration significantly decreased. At 1,250 plants per hectare, the number of reproductive culms per plant, culm diameter, and culm sucrose averaged 70, 10.2 mm, and 63.2 g/kg, respectively. Nitrogen removed with biomass significantly increased as biomass yield increased with plant density. At a density of 10,000 and 20,000 plants per hectare, the amount of nitrogen removed annually in the harvested biomass averaged 88 kg/ha. The data suggest that 10,000 plants per hectare would produce the greatest annual biomass yields; however, research is needed to determine the nutrient requirement for Ravenna grass to sustain biomass production at that density.

中文翻译：

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植物种群密度如何影响拉文纳草的生物量？

已知拉文纳草（Rapidium ravennae（L.）H. Scholz）会产生大量生物量，但是植物密度如何影响其生物量潜力仍然未知。目的是确定植物密度对生物量产量的影响；植物生长特性 生物质碳，氮和灰分的浓度；热值 脱氮 和叶和茎中的蔗糖浓度。这些处理包括五种植物密度（每公顷1,250、2,500、5,000、10,000和20,000株植物），以四个块为单位的随机完整块设计。在每年的休眠季节，不灌溉，不施肥并收获一次地块。数据收集自2015年至2019年。因变量随植物种群密度而变化（p <.05）是生物量产量，每株植物的生殖杆数，生殖杆直径，生殖杆蔗糖浓度和生物质氮去除率。种植密度为每公顷1,250–20,000株植物时，生物量产量范围为5.6至16.3 Mg / ha。结合多年以来，数据的非线性回归表明，在每公顷10,640株植物的植物密度下，高原生物量产量为16.2 Mg / ha。随着植物密度的增加，单株生殖茎的数量，茎直径和茎蔗糖浓度均显着降低。每公顷1,250株植物，每株生殖茎的数量，茎直径和蔗糖的茎平均分别为70、10.2毫米和63.2克/千克。随着生物量产量随植物密度的增加，生物量去除的氮显着增加。以每公顷10,000和20,000棵植物的密度计算，收获的生物量中每年去除的氮量平均为88 kg / ha。数据表明，每公顷10,000株植物将产生最大的年度生物量产量；但是，需要进行研究以确定拉文纳草在该密度下维持生物量生产所需的养分。