Soil Carbon, Nitrogen and Phosphorus Fractions and Response to Microorganisms and Mineral Elements in <i>Zanthoxylum planispinum</i> ‘Dintanensis’ Plantations at Different Altitudes

The Carbon (C), nitrogen (N) and phosphorus (P) fractions, mineral element concentrations, microbial density, and biomass in 0–10 and 10–20 cm soil fractions under Zanthoxylum planispinum ‘dintanensis’ plantations, were measured at altitudes of 531, 640, 780, 871, and 1097 m in the mountainous karst areas of Guizhou Province, Southwest China, and the correlations between altitude and the soil variables were analyzed. The results showed that: (1) with the increase in altitude, there was no significant linear change in C fractions, total N, effective N, microorganism density, or mineral element concentration in each soil layer; however, ammonium-N and nitrate-N concentrations gradually decreased, and the P fraction was higher at the highest altitude; (2) soil C, N, and P fractions, concentrations of microorganisms and mineral elements at the same altitude showed a surface aggregation effect; (3) principal component analysis identified the main indicators affecting C, N and P fractions as total calcium, effective calcium, effective iron, total zinc, and bacteria; (4) correlation analysis showed that both total N and C fractions were positively correlated with effective N and P fractions and that mineral element concentrations were more closely correlated with C, N, and (especially) P fractions than with microorganism abundance. Overall, the effect of altitude on C, N, and P fractions showed that the correlation with soluble organic carbon was stronger than particulate organic carbon and easily oxidized carbon, inorganic N was closer correlated than organic N, and organic P was closer correlated than inorganic P. In conclusion, it shows that research focusing on soil N conservation, nutrient stoichiometry balance, and application of mineral-rich element fertilizers is important for Zanthoxylum planispinum ‘dintanensis’ plantation maintenance

Carbon and Nitrogen Stable Isotope Abundance and Soil Stoichiometry of Zanthoxylum planispinum var. dintanensis Plantations of Different Ages

Understanding the relationships between carbon; nitrogen, their stable isotopes &delta;13C and &delta;15N, and soil stoichiometry may further our understanding of the regulatory mechanisms of the soil quality index on the equilibrium on isotopic fractionation. Four plantations of Zanthoxylum planispinum var. dintanensis (5&ndash;7, 10&ndash;12, 20&ndash;22 and 30&ndash;32 years) in the karst plateau gorge area, Guizhou Province, China, were selected to determine the variation characteristics and interactions between leaves, leaf litter, soil carbon (C), soil nitrogen (N) and their isotopes with plantation age, and to explore the relationship between soil stoichiometry and the isotopes &delta;13C and &delta;15N. The results were as follows: (1) the &delta;13C in leaves, litter, and soil were &minus;28.04&permil; &plusmn; 0.59&permil;, &minus;26.85&permil; &plusmn; 0.67&permil;, and &minus;19.39&permil; &plusmn; 1.37&permil;, respectively. The contents of &delta;15N were 2.01&permil; &plusmn; 0.99&permil;, 2.91&permil; &plusmn; 1.32&permil;, and 3.29&permil; &plusmn; 0.69&permil;, respectively. The contents of &delta;13C and &delta;15N were ranked in the order, soil &gt; litter &gt; leaf. (2) With increasing plantation age, the soil 13C decreased; the leaf and the litter &delta;15N increased first then decreased, and the litter &delta;13C and the soil &delta;15N did not vary significantly. (3) The litter layer was positively correlated with soil &delta;13C and negatively correlated to &delta;15N. (4) Redundancy analysis showed that the soil microbial biomass carbon (MBC) and the bacteria/fungi (BAC/FUN) were the dominant factors affecting the natural abundance of C and N isotope

Carbon and Nitrogen Stable Isotope Abundance and Soil Stoichiometry of <i>Zanthoxylum planispinum</i> var. <i>dintanensis</i> Plantations of Different Ages

Understanding the relationships between carbon; nitrogen, their stable isotopes δ13C and δ15N, and soil stoichiometry may further our understanding of the regulatory mechanisms of the soil quality index on the equilibrium on isotopic fractionation. Four plantations of Zanthoxylum planispinum var. dintanensis (5–7, 10–12, 20–22 and 30–32 years) in the karst plateau gorge area, Guizhou Province, China, were selected to determine the variation characteristics and interactions between leaves, leaf litter, soil carbon (C), soil nitrogen (N) and their isotopes with plantation age, and to explore the relationship between soil stoichiometry and the isotopes δ13C and δ15N. The results were as follows: (1) the δ13C in leaves, litter, and soil were −28.04‰ ± 0.59‰, −26.85‰ ± 0.67‰, and −19.39‰ ± 1.37‰, respectively. The contents of δ15N were 2.01‰ ± 0.99‰, 2.91‰ ± 1.32‰, and 3.29‰ ± 0.69‰, respectively. The contents of δ13C and δ15N were ranked in the order, soil > litter > leaf. (2) With increasing plantation age, the soil 13C decreased; the leaf and the litter δ15N increased first then decreased, and the litter δ13C and the soil δ15N did not vary significantly. (3) The litter layer was positively correlated with soil δ13C and negatively correlated to δ15N. (4) Redundancy analysis showed that the soil microbial biomass carbon (MBC) and the bacteria/fungi (BAC/FUN) were the dominant factors affecting the natural abundance of C and N isotope