Abstract
In the last two decades, permanganate has been used to define what is assumed to be a labile or “active” soil carbon (C) pool, commonly referred to as “permanganate-oxidizable carbon” (POXC). However, uncertainties in the reduction reaction (Mn7+ → Mn4+/Mn2+) and even greater uncertainties in the oxidation reaction (C? → C?) as well as the reaction of non-C reductants in the soil sample preclude the calculation of milligram C per kilogram of soil oxidized. Combined variation in the reduction–oxidation reactions can entail up to fivefold variation in how much soil organic C is oxidized per unit permanganate reduced. Without determining final reduction state of Mn and the initial and final oxidation states of C, the amount of C oxidized cannot be calculated. Unless a concrete understanding of the reduction and oxidation half-reactions is achieved, an alternative expression of permanganate reactivity of a soil sample (i.e., not mg C kg−1 soil) is needed.
Agricultural &Environmental Letters, Volume 9, Issue 1, June 2024. Leer más
Related posts:
Soil sampling and sensed ancillary data requirements for soil mapping in precision agriculture II: contour mapping of soil properties with sensed z-score data for comparison with management zone averages
Agroforestry systems affect soil organic carbon stocks and fractions in deforested landscapes of Amazonia
Soil health indicators reveal that past dairy manure applications create a legacy effect
Uncertainty resulting from constant bulk density assumption when interpreting soil nutrient concentrations
On-farm greenhouse gas emissions and soil carbon stocks of a soybean‒maize system
Investigation of Heat Transfer in Combined Infrared-Hot Air Drying: A Strategy for Evaluation in Potato Food Model