The eco-adaptability of an introduced grass species is important for its grassland construction in the semiarid conditions on the Loess Plateau. Maximum biomass yield, absolute growth rate (AGR) and relative growth rate (RGR), soil water seasonal dynamics, and water use efficiency (WUE) in switchgrass (Panicum virgatum), an introduced grass species were compared among lowland, terrace land and slope land during 2001~2002 at semiarid loess hilly-gully region in Ansai, Shaanxi province. The aboveground dry bi...

加强优良引种禾草植物的生态适应性研究对促进我国黄土高原半干旱区草地建设和草业科学发展具有十分重要的意义。比较研究了引种禾草柳枝稷(Panicumvirgatum)在黄土丘陵半干旱区不同立地条件下地上生物量的大小和季节累积差异及其水分利用特征。2001~2002年川地柳枝稷草地地上生物量达13000~16000kg/hm2,山地梯田和坡地为2300~2650kg/hm2。不同立地条件柳枝稷返青后的生物量累积过程呈二次或三次多项式。柳枝稷的绝对生长速率(AGR)在整个生长季内呈双峰曲线变化,川地柳枝稷草地的现存量和总量AGR最大值分别为158.93和169.83kg/(hm2·d),梯田分别为27.31和38.25kg/(hm2·d),坡地为37.0和36.69kg/(hm2·d)。坡地柳枝稷生物量较大值和AGR最大值出现时间最早。不同立地柳枝稷生物量相对生长速率(RGR)在整个生长季内呈双峰曲线变化,均以返青后的20d内最大,平均AGR以川地最大,坡地和梯田相近,但坡地两峰值高于梯田。不同立地柳枝稷草地土壤水分主要利用层次为0~2m,月平均含水量顺序为梯田>坡地>川地。川地柳枝稷叶片和整体生物量水分利用效率均最高，梯田整体生物量水分利用效率大于坡地，但二者叶片水发利用效率相近。川地和山地地表下5cm生育期平均地温均为17.60℃，但4~5月份川地地温高出山地1.2~2.8℃，川地4~10月份平均气温较山地高1.5℃，这些差异影响不同立地条件柳枝稷草地水分利用和生长进程。

In order to deeply understand biomass formation for Panicum virgatum in the semiarid loess hilly-gully regions, we investigated the biomass production, ramet generation, and resource supply and demand at the plot and tussock scales during the yearly life cycles of two switchgrass species, i.e. early-maturing and late-maturing ones, respectively. Here, the reproduction ratio for early-maturing switchgrass at the scale of tussock was nearly 100% with the absence of size-dependent reproduction, and the height-size pattern was nearly normal with obviously relaxed competition among those ramets. However, the later-maturing switchgrass represented significantly different ramet-population ecology. At the scale of plot, the biomass yield in a year for the later-maturing switchgrass was 15 t / hm2, nearly one time more than that of the early-maturing one. However, the soil water content in the soil profile of 80-400 cm was lower than 7% for the later-maturing switchgrass, therefore deeper-profile drought had happened in 2005-2006, with phasic growing stop in June and extensive lodging in August or September. Contrarily, multiple vegetation, Panicum virgatum and Pennisetum flaccidum as the dominant species, had been formed in the early-maturing switchgrass plot, with the balance of supply and demand for soil water, while the water content of above 10% can be kept and extended to the next year. In conclusion, the efficiency of biomass formation at the tussock scale was decided in certain degree with the size-dependent reproduction and competitive relation pattern among ramets. And the early-maturing switchgrass presented higher efficiency of biomass production based on its size-independent reproduction and relaxed competitive relationship. At the farm scale, the early-maturing switchgrass also represented its better ecological adaptability than later-maturing one, for the balance between utilization and storage of limited rainfall, although the later achieved more biomass yields by the fully utilization of rainfall during the rainfall season. The balance between utilization and storage of limited rainfall during the rainfall season should be considered as a basic rule for the sustainable production of biomass in the semiarid loess hilly-gully regions.

为深入认识半干旱黄土丘陵沟壑区引种能源植物柳枝稷生物质生产的开发潜力及其约束机制，调查了农田、植丛尺度上早熟和晚熟柳枝稷年度生命周期内生物量累积、分株建成动态，以及土壤水分供求平衡过程。研究发现，植丛尺度早熟柳枝稷抽穗比例近100％，分株生殖发生大小阈值依赖基本丧失，高度大小分布近似正态，种群内光资源竞争强度明显弱化，与晚熟类型形成明显差异。农田尺度晚熟柳枝稷生物质产量可以达到15 t/hm2，高出早熟类型近1倍，但是其立地80～400 cm土层的含水量稳定在7％ 以下，土壤干旱已经发生，早期干旱胁迫导致的生长停滞，以及生长中后期的成片倒伏现象在两年的观测周期内连续出现。早熟柳枝稷立地则形成相对稳定的白草、柳枝稷复合优势植被结构，深层土壤水分含量稳定在10％以上，实现了跨年度的土壤水分供求平衡。植丛尺度的生物质形成在一定程度上取决于分株生殖发生的大小依赖程度和分株间竞争关系格局，基于植丛尺度普遍的生殖发生和明显弱化的光资源竞争，早熟柳枝稷表现出更为高效的生物质形成机制。农田尺度晚熟柳枝稷尽管在雨热同步期的降水资源利用效率上存在明显比较优势，但是在降水资源利用分配策略和效应上，早熟柳枝稷表现出了综合的生态适宜性优势。保证雨热同步期降水资源利用和保蓄的平衡，是半干旱黄土丘陵沟壑区生物质生产应该遵循的基本原则之一。

Bioenergy grass is one of the biomass resources with great development potential.In order to obtain the basic data about the fertilizer effect on bioenergy grasses on marginal lands of North China,a field experiment was conducted to study the effect of nitrogen fertilizer on growth characteristics and biomass yield of switchgrass( Panicum virgatum L.),silverreed( Triarrhena sacchariflor (Maxim.) Nakai),and giantreed( Arundo donax L.) on abandoned sand excavation lands in Beijing suburban areas.The results show that nitrogen fertilizer had significant promoting effects on the plant height,tiller number,leaf SPAD value,and biomass yield of the above three bioenergy grass species( P -1 for the maximal biomass yield of switchgrass,silverreed and giantreed,respectively,on abandoned sand excavation lands.

能源草是目前最具发展潜力的生物质资源之一,为获得能源草在华北地区边际土地种植过程中肥料效应方面的基础数据,在京郊挖沙废弃地上开展了能源草柳枝稷( Panicum virgatum L.)、荻( Triarrhena sacchariflora (Maxim.) Nakai)和芦竹( Arundo donax L.)的氮肥效应试验。结果表明:氮肥对边际土地上种植的3种能源草的株高、分蘖数量、叶片SPAD值和生物质产量均具有显著的促进作用( P -1 、131.0mg·kg -1 、125.1mg·kg -1 。

Eight sweet sorghum cultivars (lines) were studied on forage yield, nutrition and feeding value in saline soil. The results showed that there were significant difference on forage yield and leaf to stem ratio, and no significant difference on dry to fresh weight ratio among all cultivars (lines). There were three varieties with fresh forage yield over 70 000 kg ha-1, while Jitian118 reached 86 194.31 kg·ha-1, which showed the feasibility that a forage crop could be planted on saline soil. By comparing nutritive and feeding values, Jitian No.1, Jitian 111 and Jitian118 could be used as new sorghum cultivars (lines) to plant in saline soil of Yellow River Delta.

研究了8个甜高粱（Sorghum bicolor subsp.bicolor）品种（系）在盐碱地上的产草量、营养及饲用价值。结果表明，不同甜高粱品种（系）的鲜草产量和叶茎比有显著差异，干鲜比差异不显著。8个品种（系）中，鲜草产量在70 000 kg·hm-2以上的品种（系）有3个，其中产量最高的为济甜118，达到86 194.31 kg·hm-2，说明在盐碱地上种植甜高粱作为饲草饲料具有可行性。进一步通过营养和饲用价值比较，选出济甜1号、济甜111和济甜118三个品种（系），作为适宜黄河三角洲盐碱地种植推广的饲料作物新品种（系）。

An experiment was conducted in an artificial climate chamber to study the growth and physiological characteristics of switchgrass (Panicum virgatum) seedlings exposed to 0, 50, 100, 150, and 200 mmol·L -1 of NaCl solutions. With the increasing concentration of the NaCl, the seedling growth was obviously inhibited. The plant height decreased, leaves became smaller, photosynthetic leaf area and net photosynthetic rate reduced, and dry matter accumulation decreased gnificantly, presenting the general traits of glycophyte. Meanwhile, the seedlings also showed relatively high salt tolerance. After exposed to 200 mmol·L -1 of NaCl for 30- ays, the seedlings still survived, with the green leaf area per plant and net photosynthetic rate being  491.9 cm 2 and 0.93 μmol CO 2 ·m -2 ·s· -1 , respectively. In this experiment,the salt tolerance threshold for P. virgatum was 178.6 mmol·L -1 when taking 50 % drop in biomass as the standard.

2010年,在人工气候室中设置了0、50、100、150和200 mmol·L -1 5种NaCl浓度处理,分析盐胁迫对柳枝稷苗期生长的影响.结果表明: 随着NaCl浓度的增加,柳枝稷的生长明显受到抑制,株高降低、叶片变小、光合叶面积减少、净光合速率下降,干物质积累量显著降低,表现出甜土植物的特点.柳枝稷的耐盐能力较强,在200 mmol·L -1 NaCl溶液中处理30 d后仍能存活,单株绿叶面积为491.9 cm 2 ,净光合速率为0.93 μmol CO 2 ·m -2 ·s -1 .本试验条件下,以生长量下降50%为标准求得柳枝稷的耐盐阈值为178.6 mmol·L -1 .

Seeds and seedlings of ten switchgrass( Panicum virgatum ) materials(five are wild types,five are breeding materials) were treated using different concentrations of NaCl solution.Effects of salt stress on seed germination,plant height,fresh weight,proline and chlorophyll contents,and membrane permeability were analyzed to study the feedback mechanism of different swichgrass seeds and seedlings under salt tolerance and to provide information for species introduction and breeding work of switchgrass.Results show that seed germination rate,plant height,fresh weight,chlorophyll content declined as NaCl concentration increased whereas proline content and membrane permeability increased as NaCl concentration increased.‘Cave-in-rock’,‘Sunburst’ and ‘Pathfinder’ materials have better salt tolerance than other varieties.The wild-type materials have development potential for further breeding of switchgrass due to good salt tolerance of their seedlings.

采用不同浓度NaCl溶液对10份柳枝稷( Panicum virgatum )材料(其中5份为育成品种,5份为不同地理来源的野生种质)种子和幼苗进行胁迫处理,通过分析种子发芽率和幼苗株高、鲜重、脯氨酸含量、叶绿素含量、细胞膜透性的变化,研究其种子和幼苗对盐胁迫的反馈机制,分析不同材料的耐盐性水平,为柳枝稷的引种、育种工作提供参考。结果表明:随着NaCl浓度增加,柳枝稷发芽率、株高、鲜重、叶绿素含量下降,而脯氨酸含量、细胞膜透性增加。品种中,Cave-in-rock,Sunburst和Pathfinder耐盐性相对较强;地方野生种质播种期耐盐性较差,苗期耐盐性良好,具有较好的研发潜力。

The effects of row spacing and fertilizer application on yield of switchgrass have been widely reported overseas,but related domestic research is seldom available.In order to select the best combination of those factors,the effect of different planting row spacing and nitrogen application rate on switchgrass yield and crude protein content were studied in 2009 at China Agricultural University Experiment Station located in Daming County,Handan,Hebei Province.The results show that the fertilizer input significantly influenced the yield and low row spacing was favorable to the higher yield.The optimum combination for improved yield comprised was row spacing at 20 cm and nitrogen fertilizer application rate at 225 kg·hm -2 and the resulted yield was 5615.31 kg·hm -2 .The nutritive quality of switchgrass biomass was best at tillering stage with higher crude protein content.Fertilizer input amount had significant effect on the biomass quality and the optimum combinations were row spacing at 20 cm or 60 cm with nitrogen fertilizer application rate at 225 kg·hm -2 ;the content of crude protein under such combination treatments was 17.75% or 17.6% at tillering stage and 11.16% or 12.81% at florescence stage,respectively.

旨在选出最优的种植行距与施肥量的组合,为柳枝稷( Panicum virgatum L.)在国内种植时的耕作方式提供理论依据,因此研究了不同种植行距(20、60 cm)和施肥量(0、150和225 kg·hm -2 )对其产量和粗蛋白质含量的影响。结果表明:施肥量对干草产量的影响差异极显著( P -2 ),干草产量为5615.31 kg·hm -2 ;在柳枝稷生长初期粗蛋白质含量较高,营养品质最好;随着时间的推延,柳枝稷粗蛋白质含量逐渐降低,营养品质也逐渐变差;氮肥的施用量对柳枝稷粗蛋白质的含量影响较大;提高粗蛋白质含量的种植行距和施肥量最优组合为施肥量为225 kg·hm -2 的2个组合A 1 B 3 、A 2 B 3 ,分蘖期粗蛋白质含量分别为17.75%、17.6%;开花期粗蛋白质含量分别为11.16%、12.81%。

目前，可再生能源特别是能源作物成了能源研究的新热点。柳枝稷适应性强，产量潜力大，且对环境友好，是理想的能源作物。本研究从生物学特性、生态适应性、柳枝稷能源生产管理措施等方面综述了能源作物柳枝稷的研究进展，讨论了柳枝稷能源生产利用方式与存在的问题，分析了柳枝稷在我国的发展潜力。认为现阶段我国柳枝稷能源利用应以固体成型燃料与小型生物质发电为主，将来最有发展潜力的利用方式之一为第二代燃料乙醇。