光谱学与光谱分析, 2018, 38 (3): 958, 网络出版: 2018-04-09
一种高效有机结合态磷肥的多谱学分子形态表征
Molecular Speciation of Phosphorus in an Organically Bound Phosphorus Fertilizer with High Phytoavailability Characterized by Multiple
摘要
当前, 磷肥不合理施用引发的资源危机和环境问题日益凸显, 创制新型磷肥、 提高磷肥利用率是保障农业生产、 环境安全及可持续发展的关键。 鉴于有机结合态磷肥不易被土壤组分固定, 在土壤中移动性强, 作物有效性高, 研发新型有机结合态磷肥有望从根本上突破并解决无机磷肥利用率低的问题。 新近, 新型有机结合态磷肥的研发方兴未艾, 而有机结合态磷肥的赋存形态及其高效机理尚不清楚。 基于多种有机结合态磷肥研制及肥效方面的研究成果, 选取价格低廉、 肥效稳定的淀粉基磷肥, 采用液相磷-31核磁共振(P-NMR)技术、 同步辐射X射线吸收近边结构谱(XANES)技术在分子层面上对其磷形态进行表征。 将供试淀粉基磷肥酶解制成α-极限淀粉糊精, 溶解于45%的二甲亚砜, 通过液相P-NMR分析发现该磷肥中总磷含量约为5 218 mg·kg-1, 与灼烧-比色法测得的结果一致; 其中磷主要以有机形态赋存, 正磷酸单酯占总磷比例达75.8%。 正磷酸二酯含量为17.3%, 而无机磷仅占总磷含量的6.9%。 另外, 通过指纹图谱比对, 供试样品磷的K-边XANES谱与植酸磷的谱图极为相似。 以上研究结果表明该淀粉基磷肥中磷以正磷酸单酯为主, 为深入揭示有机结合态磷肥的高效机制提供了重要依据。Spectroscopy
Abstract
While the global phosphorus (P) resources is running low, the environmental issues due to over-application of P fertilizers become increasingly urgent. There is a more pressing need than ever before to develop new types of P fertilizers with high phytoavailability with agronomic, environmental and sustainability benefits. Compared to generally applied inorganic P fertilizers, organically bound P fertilizers are less prone to soil fixation, and could remain relatively high mobility from where the fertilizer is added to the rhizosphere for crop utilization. Developing organically bound P fertilizers is increasingly recognized as an efficient way to fundamentally solve the current problem induced by the low phytoavailability of inorganic P fertilizers. In recent few years, related studies are becoming popular, but researches on the speciation of the emerging organically bound P fertilizers are not well-documented until now. Various organically bound P fertilizers were developed and their P phytoavailability were tested. Our previous study showed that the starch-bound P fertilizer had high P efficiency. Since the phytoavailability of P fertilizers was a function of the P species present in the fertilizer and the transformations in soils after application, this current study probed P speciation in the starch-bound P fertilizer at the molecular level by solution P-31 nuclear magnetic resonance (P-NMR) and synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy. To obtain quantitative results by P-NMR analysis, the fertilizer sample was hydrolyzed to α-limited dextrin, and then dissolved with dimethyl sulfoxide solution (45%). Nicotinamide adenine dinucleotide was added as an internal reference standard. It indicated that the total P concentration in the studied fertilizer by NMR agreed with that by the colorimetric chemical method. Phosphorus in the starch-bound P fertilizer was mainly presented as orthophosphate monoester, representing 75.8% of total P. Orthophosphate diester accounted for 17.3% of total P, while inorganic P only 6.9%. Furthermore, the XANES spectra of the P fertilizer closely resembled that of phytic acid, and was lack of the characteristic features of inorganic P species. Conclusively, these results illustrated the dominance of organic orthophosphate monoester in the studied fertilizer. Combining state-of-the-art of spectroscopic analysis, this study provides an important basis for further studies on the high phytoavailability mechanisms of organically bound P fertilizers.
刘瑾, 杨建军, Yongfeng Hu, 李菊梅, 张秀, 马义兵. 一种高效有机结合态磷肥的多谱学分子形态表征[J]. 光谱学与光谱分析, 2018, 38(3): 958. LIU Jin, YANG Jian-jun, Yongfeng HU, LI Ju-mei, ZHANG Xiu, MA Yi-bing. Molecular Speciation of Phosphorus in an Organically Bound Phosphorus Fertilizer with High Phytoavailability Characterized by Multiple[J]. Spectroscopy and Spectral Analysis, 2018, 38(3): 958.