Abstract

This research under field experimental conditions was conducted to evaluate the effects of nutrient management on δ¹⁵N, δ¹³C isotopes and soil enzyme activities in higher altitude agricultural soils. Three composite soil samples were collected from each of the organic management (ORG), inorganic management (IM) and control (CON) experimental plots from the fall of September 2017 to August 2018. δ¹⁵N was significantly higher (8.95‰) in ORG soils compared than IM (8.07‰) and CON (6.36‰). In contrast δ¹³C was higher (-16.49‰) in CON soils compared to IM (-19.26‰) and ORG (-19.8‰). Soils from ORG had significantly higher levels of total N, total C, total S, organic carbon, available N, extractable P, Soil organic carbon stock, exchangeable K and enzyme activities compared to IM and CON. Urease, β – glucosidase, acid phosphatase, alkaline phosphatase, invertase, cellulase and dehydrogenase activities were significantly increased the δ¹⁵N and reduced δ¹³C in agricultural soils. Our results suggested that organic management had improved the δ¹⁵N, plant available nutrients and soil enzyme activities. Stable δ¹⁵N and δ¹³C isotopes are good indicators to monitor the soil health and C and N biogeochemical cycles in higher altitude agricultural soils.

摘要

场的实验条件下本研究，以评估在δ营养管理的效果¹⁵ N，δ ^13个Ç同位素和土壤酶活性在更高的高度农业土壤。从各有机管理（ORG），无机管理（IM）和对照（CON）从2017年9月的下降试验田收集到八月三个复合土壤样品2018δ ¹⁵ n为显著更高（8.95‰）在ORG土壤比IM（8.07‰）和CON（6.36‰）高。相比之下δ ¹³与IM（-19.26‰）和ORG（-19.8‰）相比，CON土壤中的C较高（-16.49‰）。与IM和CON相比，来自ORG的土壤具有更高的总氮，总碳，总硫，有机碳，有效氮，可萃取磷，土壤有机碳储量，可交换钾和酶活性。脲酶，β -糖苷酶，酸性磷酸酶，碱性磷酸酶，转化酶，纤维素酶和脱氢酶活性显著增加δ ¹⁵ N和减少δ ¹³在农业土壤℃。我们的研究结果表明，有机管理有所改善的δ ¹⁵ N，植物可利用养分和土壤酶活性。稳定δ ¹⁵ N和δ ¹³C同位素是监测高海拔农业土壤中土壤健康以及C和N生物地球化学循环的良好指标。