Agriculturae Conspectus Scientificus, Vol 84, No 2 (2019)

Soil dehydrogenase activity and organic carbon as affected by management system


Pages: 135-142


Tillage and agrochemicals negatively affect soil organic matter (SOM) content and microbial activity. Intense cultivation of the Nadin valley began in the 1950s after hydro melioration. Our objective was to assess the microbial activity and SOM and to propose the improvements in soil management. Samples were collected according to randomized stratified design from organic (O) and conventional (C) plowed agricultural soils, from natural grass vegetation soils (G) and from abandoned vineyard soils (A). Dehydrogenases activity (DHA) and soil moisture were analyzed at 6 cm increments and C (total, organic and inorganic) and total N were analyzed at 2 cm increments, both to the depth of 18 cm. DHA was higher in G and in A than in C or O. DHA decreased with depth from 0-6 cm to 6-12 cm and 12-18 cm depth. Soil water content was higher in O than in C or G. Soils contained 67±16 mg/g total carbon (organic + carbonate), 17±8.0 mg/g organic carbon, and 1.5±0.49 mg/g total soil nitrogen (organic and inorganic). Soils were carbonate-rich with 42±13% CaCO3. C:N ratio was approximately 12:1. Soil organic carbon (SOC) and total nitrogen (TN) positively correlated to DHA, regardless of the soil management. Principal component analysis showed soil grouping based mainly on the position in landscape and not based on management. Results showed that higher inputs of organic matter in agricultural soils would increase enzymatic activity, and shallow chisel plowing conserves soil water content.


C:N, conventional management, grass vegetation, microbial activity, organic management

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