Biomass and integrated forage/biomass yields of switchgrass as affected by intercropped cool- and warm-season legumes
Biomass and integrated forage/biomass yields of switchgrass as affected by intercropped cool- and warm-season legumes
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柳枝稷的生物量和综合饲料/生物量产量受间作冷季和暖季豆类的影响
DOI：
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发表时间：
2016
影响因子：
3.9
通讯作者：
C. Harper
中科院分区：
文献类型：
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作者：
K. S. Warwick;F. Allen;P. Keyser;A. Ashworth;G. Bates;D. Tyler;P. Lambdin;C. Harper
柳枝稷（Panicum virgatum L.）具有在不适合行栽作物生产的边际土壤上作为乙醇生产的生物燃料原料的潜力。此外，据推测，豆科植物可以间种到柳枝稷，以增加土壤有效氮（N），提高柳枝稷产量。因此，主要目标是确定与低地柳枝稷间作的相容豆科植物物种，并确定是否可以提高生物量产量和饲料质量。2009年和2010年，在田纳西州的三个研究和教育中心的一系列土壤中，将四种冷季型和两种暖季型豆科植物与67和134 kg N ha−1（59.8和119.6 lb N ac−1）的施用量进行了比较。冷季型豆科植物是苜蓿（Medicago sativa L.），红三叶草（Trifolium pratense L.），深红三叶草（Trifolium incarnatum L.），和毛野豌豆（Vicia villosa L.），暖季型豆科植物包括伊利诺伊束花（Desmanthus illinoensis L.）和豌豆（Chamaechrista fasciculata L.）。豆科植物进行了评估建立（植物密度）和柳枝稷产量和牧草质量的影响下，一个切生物量（单一的，postdormancy生物燃料）和一个综合的两个切（生物量/饲料[开花前]）系统。在一次收割系统中，柳枝稷的产量（16.6 Mg ha−1 [6.7 tn ac−1]）高于当前推荐的产量（67 kg N ha−1 [59.8 lb N ac−1]）（p < 0.05），超过了豆类处理的产量（平均13.5 Mg ha−1 [5.5 tn ac−1]）。在综合收获系统中，红三叶草（13.4 Mg ha−1 [5.4 tn ac−1]）和深红色三叶草（12.8 Mg ha−1 [5.2 tn ac−1]）间作的柳枝稷产量与67 kg N ha−1（14.5 Mg ha−1 [5.9 tn ac−1]）没有差异。134 kg N ha−1（119.6 lb N ac−1）的粗蛋白水平高于豆科间作（红三叶草除外）（p < 0.05）。豌豆作为一种暖季豆类，可以与柳枝稷兼容种植长达两年。因此，兼容的豆类间作候选人，如豌豆和红三叶草，可能会提高柳枝稷产量和饲料质量，同时取代合成N在综合生物燃料/饲料系统，但需要进一步研究，努力减少硝酸盐（NO3）的淋溶和排放量从秸秆。
Switchgrass (Panicum virgatum L.) has potential as a biofuel feedstock for ethanol production on marginal soils not suitable for row crop production. Further, it is hypothesized that legumes may be interseeded into switchgrass to increase available soil nitrogen (N) and enhance switchgrass yields. Therefore the primary objective was to identify compatible legume species for intercropping with lowland switchgrass and determine if biomass yields and forage quality can be improved. Four cool- and two warm-season legume species were compared to application of 67 and 134 kg N ha−1 (59.8 and 119.6 lb N ac−1) during 2009 and 2010 over a range of soils at three research and education centers in Tennessee. Cool-season legumes were alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), crimson clover (Trifolium incarnatum L.), and hairy vetch (Vicia villosa L.), and warm-season legumes included Illinois bundle flower (Desmanthus illinoensis L.) and partridge pea (Chamaechrista fasciculata L.). Legumes were evaluated for establishment (plant densities) and their effects on switchgrass yield and forage quality under a one-cut biomass (single, postdormancy biofuel) and an integrated two-cut (biomass/forage [preanthesis]) system. In the one-cut system, switchgrass yields (16.6 Mg ha−1 [6.7 tn ac−1]) from the current recommended rate (67 kg N ha−1 [59.8 lb N ac−1]) exceeded (p < 0.05) legume treatment yields (average 13.5 Mg ha−1 [5.5 tn ac−1]). In the integrated harvest system, switchgrass yields from red (13.4 Mg ha−1 [5.4 tn ac−1]) and crimson clover (12.8 Mg ha−1 [5.2 tn ac−1]) intercrops were not different from 67 kg N ha−1 (14.5 Mg ha−1 [5.9 tn ac−1]). Crude protein levels were greater (p < 0.05) for 134 kg N ha−1 (119.6 lb N ac−1), compared to legume intercrops (except red clover). Partridge pea showed promise as a warm-season legume that can be grown compatibly with switchgrass for up to two years. Therefore, compatible legume-intercrop candidates, such as partridge pea and red clover, may enhance switchgrass yield and forage quality while displacing synthetic N in integrated biofuel/forage systems, but need to be further investigated in efforts to reduce nitrate (NO3) leaching and emissions from fertilizing.