Zarezadeh Somayeh, Moheimani Navid R, Jenkins Sasha N, Hülsen Tim, Riahi Hossein, Mickan Bede S
Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
Algae R and D Centre, Murdoch University, Perth, WA, Australia.
Front Plant Sci. 2019 Sep 27;10:1193. doi: 10.3389/fpls.2019.01193. eCollection 2019.
Microalgae (MA) and purple phototrophic bacteria (PPB) have the ability to remove and recover nutrients from digestate (anaerobic digestion effluent) and pre-settled pig manure that can be Utilized as bio-fertilizer and organic fertilizer. The objective of this study was to compare the effectiveness of MA and PPB as organic fertilizers and soil conditioners in relation to plant growth and the soil biological processes involved in nitrogen (N) and carbon (C) cycling. To this end, a glasshouse experiment was conducted using MA and PPB as bio-fertilizers to grow a common pasture ryegrass ( Gaudin) with two destructive harvests (45 and 60 days after emergence). To evaluate the rhizosphere bacterial community, we used barcoded PCR-amplified bacterial 16S rRNA genes for paired-end sequencing on the Illumina Mi-Seq. Additionally, we used phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis for the detection of putative functional genes associated with N and soil-C cycling. There was a significant increase in plant growth when the soil was amended with PPB, which almost performed as well as the chemical fertilizers. Analysis of the rhizosphere bacteria after the second harvest revealed a greater abundance of Firmicutes than in the first harvest. Members of this phylum have been identified as a biostimulant for plant growth. In contrast, the MA released nutrients more slowly and had a profound effect on N cycling by modulating N mineralization and N retention pathways. Thus, MA could be developed as a slow-release fertilizer with better N retention, which could improve crop performance and soil function, despite nutrient losses from leaching, runoff, and atmospheric emissions. These data indicate that biologically recovered nutrients from waste resources can be effective as a fertilizer, resulting in enhanced C- and N-cycling capacities in the rhizosphere.
微藻（MA）和紫色光合细菌（PPB）有能力从沼液（厌氧消化废水）和预沉淀猪粪中去除和回收养分，这些养分可作为生物肥料和有机肥料使用。本研究的目的是比较MA和PPB作为有机肥料和土壤改良剂对植物生长以及氮（N）和碳（C）循环所涉及的土壤生物过程的有效性。为此，进行了一项温室试验，使用MA和PPB作为生物肥料种植一种常见的牧草黑麦草（高丁），并进行了两次破坏性收获（出苗后45天和60天）。为了评估根际细菌群落，我们使用条形码PCR扩增的细菌16S rRNA基因在Illumina Mi-Seq上进行双端测序。此外，我们使用通过重建未观察状态对群落进行系统发育研究（PICRUSt）分析来检测与N和土壤C循环相关的假定功能基因。当用PPB改良土壤时，植物生长显著增加，其效果几乎与化肥相当。第二次收获后对根际细菌的分析表明，厚壁菌门的丰度比第一次收获时更高。该门的成员已被确定为植物生长的生物刺激剂。相比之下，MA释放养分的速度较慢，并通过调节氮矿化和氮保留途径对氮循环产生深远影响。因此，MA可以开发成一种具有更好氮保留能力的缓释肥料，尽管会因淋溶、径流和大气排放造成养分损失，但仍可改善作物性能和土壤功能。这些数据表明，从废弃资源中生物回收的养分作为肥料可能有效，从而增强根际的碳和氮循环能力。
