Multiple benefits of greenhouse gas reduction through inclusion of perennials in cropping systems

大气中温室气体（GHG）浓度的增加被认为是当前全球变暖的原因。农业是温室气体的重要来源，尤其是一氧化二氮。与所有经济部门一样，农业有望减少其排放。多年生作物对牲畜饲料很重要，并将越来越多地用于生物燃料生产。本研究项目考察了将多年生植物纳入作物轮作以减少温室气体排放和增进土壤健康的多重好处。多年生植物比一年生作物更好地利用氮肥和粪肥，这可以减少一氧化二氮的排放。多年生植物还可以降低氮肥作为非温室气体（氮气）流失到大气中的量。减少氮肥的损失可以增加利润，避免土壤直接排放温室气体以及与肥料制造和运输有关的排放。豆科多年生植物提供自己的氮营养，不依赖于氮肥的添加，这减少了与土壤、生产和运输直接排放相关的肥料的温室气体排放，但是豆科植物产生的氮的氧化亚氮排放是不确定的。多年生植物比一年生作物有更广泛的生根系统，在土壤中储存更多的碳，从而降低温室气体的排放。从长期来看，多年生植被将土壤食物网转变为更多样化的生物，特别是与根相关的有益真菌（称为丛枝菌根真菌）和更高营养的土壤生物，它们在种植系统内较短的3年内的影响是不确定的。最近有研究表明，这些真菌提供一种叫做球囊素的碳，它可以构建土壤有机质，改善土壤结构。该项目旨在发现从作物轮作的多年生阶段到一年生阶段的转化是否会释放储存在土壤中的碳和氮作为温室气体。同样，该项目旨在解决从多年生种植制度到一年生种植制度的转变是否保留了土壤食物网的球粒化和多样性，从而改善土壤健康。

Increasing concentrations of greenhouse gases (GHG) in the atmosphere are believed to be the cause of current realized global warming. Agriculture is an important source of greenhouses, particularly nitrous oxide. Like all sectors of the economy, agriculture is expected to reduce its emissions. Perennial crops are important for livestock feed and will increasingly be used for biofuel production. This research program examines the multiple benefits of inclusion of perennials in crop rotations to reduce greenhouse gas emissions and increase soil health. Perennials utilize nitrogen fertilizers and manures better than annual crops, which could reduce nitrous oxide emissions. Perennials may also lower the amount of fertilizer nitrogen lost to the atmosphere as the non-greenhouse gas, nitrogen gas. Lowering the loss of fertilizer nitrogen increases profitability and avoids direct greenhouse gas emissions from soil and emissions related to manufacturing and transporation of fertilizer. Legume perennials supply their own nitrogen nutrition and are not dependent upon nitrogen fertilizer addition, this reduces greenhouse gas emissions from fertilizers associated with direct emissions from soil, manufacturing and transportation, however emissions of nitrous oxide from legume produced nitrogen is uncertain. Perennials have more extensive rooting systems than annual crops, storing more carbon in soil thus lowering emissions of greenhouse gases. In the long term, perennial cover alters soil food webs to more diverse organisms, particularly beneficial fungi associated with the roots (called arbuscular mycorrhizal fungi) and higher trophic soil organisms, their effect on shorter terms of 3 years within cropping systems is uncertain. Recently it has been demonstrated that these fungi provide a form of carbon, call glomalin, that builds soil organic matter and improves soil structure. This program aims to discover if conversion from the perennial to annual phase in crop rotations, releases carbon and nitrogen stored in soil as greenhouse gases. Similarly, the program aims to resolved if glomalin and diversity of soil food webs is retained upon conversion from perennial to annual phases of cropping systems thus improving soil health.