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Soil organic carbon (SOC) associated with minerals is considered to be one of the most fundamental long-term SOC storage strategies, but little research has integrated the organo-mineral complexes regulated by long-term fertilization. Here, soil samples under three fertilization treatments (Control, no fertilization; NPK, chemical nitrogen, phosphorus and potassium fertilization; NPKM, NPK plus manure) from four 23-34 years long-term field experiment sites across China were examined. Chemical analyses indicated that vigorous iron (Fe) mobilization could be regulated by long-term fertilization regimes. Meanwhile, Fe K-edge X-ray absorption near-edge fine structure (XANES) demonstrated that compared to NPK treated soils, NPKM treated soils contained significantly higher concentration of poorly crystalline ferrihydrite. Results from both the Fourier transform infrared combined with two-dimensional correlation spectroscopy analyses (FTIR-2DCOS) and C 1 s X-ray photoelectron spectroscopy (XPS) revealed that aliphatic carbohydrate might play an important role in binding exogenous Fe(III) in all tested four soils. In addition, greater amounts of aromatic C (the most resistant soil C fraction) were under long-term treated NPKM than NPK soils. Furthermore, multiple regression analyses showed a significantly positive relationship between poorly crystalline Fe minerals and SOC or aromatic C. Such relationships indicated that aromatic functional groups had been attached to the poorly crystalline Fe minerals, which could also be protected from being transformed to the crystalline counterpart. In conclusion, results from our integrated spectroscopic analyses have evidenced greater improvement of both poorly crystalline Fe minerals and aromatic C in organically fertilized than in chemically fertilized soils., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Various parameters were measured during the period of composting of dairy manure and rice chaff in different ratios (dairy manure/rice chaff=V/V, pile 1: 75/25; pile 2: 80/20; pile 3: 85/15) to evaluate their suitability as indicators for the composting process. The temperature in pile 1 increased rapidly and remained above 60 °C for 30 days, while the temperature in pile 3 increased slowly relative to the other two piles. Furthermore, the degradation of organic substrates, as indicated by the reduction of C/N ratio, was rapid in pile 1 (below 20% 28 days after beginning of the composting). The major fluctuations of various water-soluble fractions in all piles were observed during the first 3 weeks, and the results in general showed that the highest microbial populations and enzymatic activities also appeared in this phase. Various parameters indicated that the rapid composting method was a feasible one for treating agricultural wastes., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Opportunity costs seriously limit the large-scale production of bio-organic fertilizers (BOFs) both in China and internationally. This study addresses the utilization of amino acids resulting from the acidic hydrolysis of pig corpses as organic nitrogen sources to increase the density of TrichodermaharzianumT-E5 (a typical plant growth-promoting fungi, PGPF). This results in a novel, economical, highly efficient and environmentally friendly BOF product. Fluorescence excitation-emission matrix (EEM) spectroscopy combined with fluorescence regional integration (FRI) was employed to monitor compost maturity levels, while pot experiments were utilized to test the effects of this novel BOF on plant growth. An optimization experiment, based on response surface methodologies (RSMs), showed that a maximum T-E5 population (3.72 × 108 ITS copies g−1) was obtained from a mixture of 65.17% cattle manure compost (W/W), 19.33% maggot manure (W/W), 15.50% (V/W)hydrolytic amino acid solution and 4.69% (V/W) inoculum at 28.7°C after a 14 day secondary solid fermentation. Spectroscopy analysis revealed that the compost transformation process involved the degradation of protein-like substances and the formation of fulvic-like and humic-like substances. FRI parameters (PI, n, PII, n, PIII, n and PV, n) were used to characterize the degree of compost maturity. The BOF resulted in significantly higher increased chlorophyll content, shoot length, and shoot and root dry weights of three vegetables (cucumber, tomato and pepper) by 9.9%~22.4%, 22.9%~58.5%, 31.0%~84.9%, and 24.2%~34.1%, respectively. In summary, this study presents an operational means of increasing PGPF T-E5 populations in BOF to promote plant growth with a concomitant reduction in production cost. In addition, a BOF compost maturity assessment using fluorescence EEM spectroscopy and FRI ensured its safe field application. [ABSTRACT FROM AUTHOR]

The binding characteristics of organic ligands and minerals in fulvic acids (FAs) with Al are essential for understanding soil C sequestration, remain poorly understood. In this study, Fourier transform infrared (FTIR) spectroscopy combined with two-dimensional correlation spectroscopy (2DCOS) analysis was applied for the first time to explore the binding of Al with organic ligands and minerals in soil FAs. For these analyses, two contrasting treatments were selected from a long-term (i.e., 22-year) fertilization experiment: chemical (NPK) fertilization and swine manure (SM) fertilization. The results showed that the long-term application of organic and inorganic fertilizers to soils had little effect on the compositions of the fluorescent substances and organic ligands in the soil FAs. However, long-term SM fertilization increased the weathered Al and Si concentrations in the soil FAs compared with long-term chemical fertilization. Furthermore, organic ligands in the soil FAs were mainly bound with Al in the NPK treatment, whereas both organic ligands and minerals (Al-O-Si, Si-O) were bound with Al under the M fertilization conditions. Both transmission electron microscopy (TEM) images and X-ray diffraction spectra demonstrated that amorphous and short-range-ordered nanominerals were abundant in the soil FAs from the SM plot in contrast to the soil FAs from the NPK plot. This result illustrates the role nanominerals play in the preservation of soil FAs by during long-term organic fertilization. In summary, the combination of FTIR and 2D correlation spectroscopy is a promising approach for the characterization of the binding capability between soil FAs and Al, and a better understanding FA-Al binding capability will greatly contribute to global C cycling. [ABSTRACT FROM AUTHOR]

The composting industry has been growing rapidly in China because of a boom in the animal industry. Therefore, a rapid and accurate assessment of the quality of commercial organic fertilizers is of the utmost importance. In this study, a novel technique that combines near infrared (NIR) spectroscopy with partial least squares (PLS) analysis is developed for rapidly and accurately assessing commercial organic fertilizers quality. A total of 104 commercial organic fertilizers were collected from full-scale compost factories in Jiangsu Province, east China. In general, the NIR-PLS technique showed accurate predictions of the total organic matter, water soluble organic nitrogen, pH, and germination index; less accurate results of the moisture, total nitrogen, and electrical conductivity; and the least accurate results for water soluble organic carbon. Our results suggested the combined NIR-PLS technique could be applied as a valuable tool to rapidly and accurately assess the quality of commercial organic fertilizers. [ABSTRACT FROM AUTHOR]

While the properties of biochar are closely related to its functional groups, it is unclear under what conditions biochar develops its properties. In this study, two-dimensional (2D) 13C nuclear magnetic resonance (NMR) correlation spectroscopy was for the first time applied to investigate the development of functional groups and establish their relationship with biochar properties. The results showed that the agricultural biomass carbonized to biochars was a dehydroxylation/dehydrogenation and aromatization process, mainly involving the cleavage of O-alkylated carbons and anomeric O-C-O carbons in addition to the production of fused-ring aromatic structures and aromatic C-O groups. With increasing charring temperature, the mass cleavage of O-alkylated groups and anomeric O-C-O carbons occurred prior to the production of fused-ring aromatic structures. The regression analysis between functional groups and biochar properties (pH and electrical conductivity) further demonstrated that the pH and electrical conductivity of rice straw derived biochars were mainly determined by fused-ring aromatic structures and anomeric O-C-O carbons, but the pH of rice bran derived biochars was determined by both fused-ring aromatic structures and aliphatic O-alkylated (HCOH) carbons. In summary, this work suggests a novel tool for characterising the development of functional groups in biochars. [ABSTRACT FROM AUTHOR]