Characterization of soil fertility and soil biodiversity with dsDNA as a covariate in a regression estimator for mean microbial biomass C

Abstract

The analytical determination of microbial biomass carbon is time‐consuming, which limits its use as a reference biochemical property for characterizing soil fertility and soil biodiversity of soil mapping units (SMUs). This paper explores whether the efficiency of sampling strategies for estimating the means of microbial biomass C (MBC) of SMUs can be increased with dsDNA as an ancillary variable in a regression estimator, leading to a model‐assisted sampling strategy. The map unit means of dsDNA are unknown; therefore, to implement the regression estimator a two‐phase sampling strategy is required. The two‐phase sampling design was tested in three soil units of the Brtonigla area (Istria, Croatia) that are widely involved in wine production. In the first phase, 20 locations per SMU were selected at which the ancillary variable dsDNA was determined in field‐moist and air‐dried soil. In the second phase, a subsample of ten locations per map unit were selected at which MBC was determined. The estimated sampling variances of the regression estimator were compared with the sampling variances of the design‐based estimator with a cost‐equivalent number of sampling points. The model‐assisted strategy was more accurate in two of the soil units in which the correlation between MBC and dsDNA was strong (adjusted R2 larger than 0.55). Measurements of dsDNA on field‐moist samples gave more precise estimated means of MBC than those on air‐dried samples. Highlights Use of dsDNA to estimate the means of microbial biomass C (MBC) within soil mapping units (SMUs). Comparison of model‐assisted and design‐based sampling strategies to estimate mean MBC of SMUs. Model‐assisted strategy was more efficient in two SMUs; field‐moist dsDNA was better than air‐dried dsDNA. dsDNA increased the efficiency of sampling strategies to estimate mean MBC of SMUs with homogeneous land use.

Improvement of Soil Microbial Diversity through Sustainable Agricultural Practices and Its Evaluation by -Omics Approaches: A Perspective for the Environment, Food Quality and Human Safety

“…Not less important, co-extraction of humic substances was much lower compared to traditional procedures and extraction time was very low. Enzymes can be efficiently desorbed by heteromolecular exchange with a bead-beating procedure [ 54 ] that improves the extraction yields and greatly shortens the extraction time as shown also for dsDNA quantitation [ 56 ] as soil microbial biomass indicator [ 57 ]. Ferrarini et al showed that the assay can be performed on 384-well microplates using fluorogenic substrates and a number of enzymes (>20) can be assayed by using the same soil extract [ 47 ].…”

Effects of Seed-Applied Biofertilizers on Rhizosphere Biodiversity and Growth of Common Wheat (Triticum aestivum L.) in the Field

“…Soil microbial biomass was determined as double-strand DNA (dsDNA) content (Bragato et al, 2016) in 300-mg DW soil samples through DNA extraction with a 0.12 M, pH 8 Na 2 HPO 4 buffer using bead beating and quantification with PicoGreen reagent, as described by Fornasier et al (2014). Biomass was expressed as µg dsDNA g -1 soil D. W.…”

Early impacts of marginal land‐use transition to Miscanthus on soil quality and soil carbon storage across Europe

“…All measurements were taken in triplicate and the activities were expressed as nanomoles of 4‐methylumbelliferone (MUF) (or 7‐amino‐4methyl coumarine [AMC]) g −1 dry soil h −1 . MB was determined using the double‐stranded DNA (dsDNA) content as a proxy (Bragato et al., 2016). DNA was extracted as described by (Fornasier et al., 2014).…”