Biological Nitrification Inhibition (BNI): Phenotyping of a Core Germplasm Collection of the Tropical Forage Grass Megathyrsus maximus Under Greenhouse Conditions
Biological Nitrification Inhibition (BNI): Phenotyping of a Core Germplasm Collection of the Tropical Forage Grass Megathyrsus maximus Under Greenhouse Conditions
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DOI：
10.3389/fpls.2020.00820
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发表时间：
2020-06
影响因子：
5.6
通讯作者：
D. Villegas;A. Arévalo;J. Nuñez;Johanna Mazabel;G. Subbarao;I. Rao;J. D. de Vega;J. Arango
中科院分区：
文献类型：
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作者：
D. Villegas;A. Arévalo;J. Nuñez;Johanna Mazabel;G. Subbarao;I. Rao;J. D. de Vega;J. Arango
现代集约化管理的牧场，接受大量的外部氮（N）输入占硝酸盐（NO3-）淋溶和排放的强效温室气体一氧化二氮（N2 O）的形式高N损失。天然植物通过有机化合物的分泌来形成土壤氮循环的能力可以被利用来促进氮的保持而不影响生产力。在这项研究中，我们估计的生物硝化抑制（BNI），N2 O排放量和植物生产力的119种质资源的几内亚草（Megathyrsus maximus），一个重要的热带饲料作物畜牧生产。在温室实验中测试了这种关系，测量BNI为（i）土壤硝化速率;（ii）氨氧化细菌（AOB）和古细菌（AOA）的丰度;以及（iii）根组织提取物在体外抑制硝化的能力。然后，我们测量了N2 O排放量，地上生物量和牧草营养质量参数。硝化活性的降低幅度在30%至70%之间，发现整个种质收集的M。马克西姆斯加入低硝化率表现出较低的丰度AOB以及减少N2 O排放量相比，加入高硝化率。BNI能力与植物的N吸收量无关，表明该草种对不同N源的利用可能存在种内差异。一组加入（集群）与最理想的农艺和环境性状的集合中确定为进一步的现场验证。这些结果为M. maximus抑制土壤硝化作用和N2 O排放的作用及其与生产力和牧草品质的关系，为热带畜牧业生产中发展保氮改良牧草指明了方向。
Modern intensively managed pastures that receive large external nitrogen (N) inputs account for high N losses in form of nitrate (NO3–) leaching and emissions of the potent greenhouse gas nitrous oxide (N2O). The natural plant capacity to shape the soil N cycle through exudation of organic compounds can be exploited to favor N retention without affecting productivity. In this study, we estimated the relationship between biological nitrification inhibition (BNI), N2O emissions and plant productivity for 119 germplasm accessions of Guineagrass (Megathyrsus maximus), an important tropical forage crop for livestock production. This relation was tested in a greenhouse experiment measuring BNI as (i) rates of soil nitrification; (ii) abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA); and (iii) the capacity of root tissue extracts to inhibit nitrification in vitro. We then measured N2O emissions, aboveground biomass and forage nutrition quality parameters. Reductions on nitrification activity ranging between 30 and 70% were found across the germplasm collection of M. maximus. Accessions with low nitrification rates showed a lower abundance of AOB as well as a reduction in N2O emissions compared to accessions of high nitrification rates. The BNI capacity was not correlated to N uptake of plants, suggesting that there may be intraspecific variation in the exploitation of different N sources in this grass species. A group of accessions (cluster) with the most desirable agronomic and environmental traits among the collection was identified for further field validation. These results provide evidence of the ability of M. maximus to suppress soil nitrification and N2O emissions and their relationship with productivity and forage quality, pointing a way to develop N conservative improved forage grasses for tropical livestock production.