Biological indicators of soil quality in natural and cultivated subtropical systems

Abstract

The objective of this work was to evaluate the effects of forest conversion at to agricultural production on some biological indicators to quantify their relationship in subtropical ecosystems. The experimental design was in romized complete blocks, with four treatments: subtropical rainforest (F), yerba mate crops (I) (Ilex paraguariensis SH.); citrus crops (C) (Citrus unshiu Marc.); tobacco crops (T) (Nicotiana tabacum L.). Soil samples were taken from 0-0.10, 0.10-0.20, 0.20-0.30m deep. The variables measured were: APA, clay content, pH, total nitrogen (N), available phosphorus (P), respiration (RE) soil organic carbon (SOC). These soils showed an acid reaction clay content over 650 g.kg-1. SOC N content were higher in soils under subtropical rainforest, intermediate under citrus crops, lower under tobacco yerba mate crops. The highest APA was found under subtropical rainforest decreased in the three depths. In all treatments, APA was higher in the superficial layer; the 76% of APA variability was explained by N P. APA can indicate changes in soil quality, when comparing subtropical rainforest to agricultural systems. APA does not indicate effects between soils under different crops. Our data suggest that acid phosphatase activity is closely associated to soil nitrogen organic content as energy source.Â

Effects of Ferrous Iron Toxicity on Agronomic, Physiological, and Quality Indices of Flue‐cured Tobacco

“…On the one hand, sticky red soil could adsorb certain ferrous ions, which decreased the content of water‐soluble Fe 2+ in soil; on the other hand, the motion of ferrous ions in soil around rhizosphere was hindered owing to the water and gas permeability of red soil was poor (Silver et al, 2000; Toledo et al, 2013). Additionally, the results showed that in the two types of soils, the increase amplitude of browning scale of tobacco leaves of K326 variety was far larger than that of Hongda variety with increasing applied concentration of ferrous ions.…”

Building biological indicators for soil quality assessment in Dong Thap Muoi (Mekong Delta Vietnam): An application of the expert Delphi

“…Particulate organic matter Both are positioned within the most sensitive indicators, helping to identify changes manifested at different depths and in the face of management practices. Organic phosphorus allows the prediction of nutrient availability in the short term (Toledo, Arzuaga et al 2018).…”

“…It represents the quantity of organic soil nitrogen that microbial activity can convert into soluble inorganic forms. Due to its sensitivity, it can be employed as an indicator of the production capacity and the nitrogen contribution of the soil, informing recommendations for nitrogen application (Toledo, Arzuaga et al, 2018). It emerges as a highly sensitive indicator of land-use changes in subtropical soils (Nuñez, Orwin et al, 2022).…”

“…Linked to organic matter cycling and nutrient availability, it elucidates the connection between nitrogen mineralization capacity, the quality of plant residues, and soil respiration (Toledo et al, 2018;Huera-Lucero et al, 2020).…”

“…Correlates with soil disturbance and acidity that favor fungal growth, illustrating the relationship between organic matter, nitrogen mineralization potential, and edaphic respiration (Toledo et al, 2018;Huera-Lucero et al, 2020).…”