Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
Animal. 2013 Jun;7 Suppl 2:322-32. doi: 10.1017/S1751731113000761.
Agriculture and livestock production systems are two major emitters of greenhouse gases. Methane with a GWP (global warming potential) of 21, and nitrous oxide (N2O) with a GWP of 300, are largely emitted from animal production agriculture, where livestock production is based on pasture and feed grains. The principal biological processes involved in N2O emissions are nitrification and denitrification. Biological nitrification inhibition (BNI) is the natural ability of certain plant species to release nitrification inhibitors from their roots that suppress nitrifier activity, thus reducing soil nitrification and N2O emission. Recent methodological developments (e.g. bioluminescence assay to detect BNIs in plant root systems) have led to significant advances in our ability to quantify and characterize the BNI function. Synthesis and release of BNIs from plants is a highly regulated process triggered by the presence of NH4 + in the rhizosphere, which results in the inhibitor being released precisely where the majority of the soil-nitrifier population resides. Among the tropical pasture grasses, the BNI function is strongest (i.e. BNI capacity) in Brachiaria sp. Some feed-grain crops such as sorghum also have significant BNI capacity present in their root systems. The chemical identity of some of these BNIs has now been established, and their mode of inhibitory action on Nitrosomonas has been characterized. The ability of the BNI function in Brachiaria pastures to suppress N2O emissions and soil nitrification potential has been demonstrated; however, its potential role in controlling N2O emissions in agro-pastoral systems is under investigation. Here we present the current status of our understanding on how the BNI functions in Brachiaria pastures and feed-grain crops such as sorghum can be exploited both genetically and, from a production system's perspective, to develop low-nitrifying and low N2O-emitting production systems that would be economically profitable and ecologically sustainable.
农业和畜牧业生产系统是温室气体的两个主要排放源。甲烷的全球变暖潜势（GWP）为 21，一氧化二氮（N2O）的 GWP 为 300，主要由动物生产农业排放，其中畜牧业生产基于牧场和饲料谷物。N2O 排放的主要生物过程是硝化和反硝化。生物硝化抑制（BNI）是某些植物物种从根部释放硝化抑制剂的自然能力，抑制硝化剂活性，从而减少土壤硝化和 N2O 排放。最近的方法学发展（例如，用于检测植物根系中 BNIs 的生物发光测定法）使我们能够更准确地量化和描述 BNI 功能。植物中 BNIs 的合成和释放是一个高度调控的过程，由根际中 NH4 +的存在触发，从而使抑制剂在土壤硝化菌种群主要存在的地方精确释放。在热带牧草中，BNI 功能最强（即 BNI 能力）的是 Brachiaria sp。一些饲料谷物作物，如高粱，其根系中也存在显著的 BNI 能力。一些 BNIs 的化学性质现已确定，其对 Nitrosomonas 的抑制作用模式也已得到描述。Brachiaria 牧场上的 BNI 功能抑制 N2O 排放和土壤硝化潜能的能力已经得到证明；然而，其在控制农牧系统 N2O 排放中的潜在作用仍在研究中。在这里，我们介绍了目前我们对 Brachiaria 牧场上的 BNI 功能以及高粱等饲料谷物作物中的 BNI 功能如何在遗传和生产系统方面得到利用的理解现状，以开发具有经济盈利和生态可持续性的低硝化和低 N2O 排放生产系统。
