Permangant-oxidizable carbon as a marker of soil quality in agrolandscapes

Different laboratory methods of soil quality assessment are considered by the example of soils of the North-Pre-Caucasian province. The article presents a detailed protocol for quantitative determination of Permanganate oxidizable carbon (POXC) fraction using 0.2 M potassium permanganate solution. The data are presented for chernozem type soils of Rostov region belonging to different agroecological groups. Samples of ordinary chernozems (Haplic Chernozems) and meadow-chernozems (Gleyic Chernozems) soils of agrolandscapes were used. Data from non-tilled plots were used to estimate background parameters. Correlation POXC with fraction of bichromate-oxidizable carbon, light fraction (LF< 1.6 g/cm 3 ) and waterhydrolysable fractions were estimated. It was found that the content of POXC fraction varied in the range of 126–1 006 mg/kg, with maximum values, on average 925 mg/kg, in samples of humus horizons of ordinary chernozems of plakorny agroecological group of untreated plots. The minimum content of POXC fraction was characteristic for samples of AB horizons of arable plakorny and arable low- and medium eroded agroecological soil groups, on average 218 and 137 mg/kg, respectively. POXC has significant correlations with the fraction of bichromate-oxidizable carbon, the content of light fraction, the content of total nitrogen and soil density, and has shown to be a good marker of agro-ecological conditions on the studied set of samples.