Soil Biochemical Indicators and Biological Fertility in Agricultural Soils: A Case Study from Northern Italy

Livia Vittori Antisari,Chiara Ferronato,Gianluca Bianchini,Claudio Natali,Mauro De Feudis,Gloria Falsone

doi:10.3390/min11020219

Livia Vittori Antisari, Chiara Ferronato + Show 4 more

Open Access

https://doi.org/10.3390/min11020219

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Abstract

Industrial farming without considering soil biological features could lead to soil degradation. We aimed to evaluate the biochemical properties (BPs) and biological fertility (BF) of different soils under processing tomato cultivation; estimate the BF through the calculation of a simplified BF index (BFIs); determine if the crop was affected by BP and BF. Three farms were individuated in Modena (MO), Ferrara (MEZ) and Ravenna (RA) provinces, Italy. Soil analysis included total and labile organic C, microbial biomass-C (Cmic) and microbial respiration measurements. The metabolic (qCO2), mineralization (qM) and microbial (qMIC) quotients, and BFIs were calculated. Furthermore, plant nutrient contents were determined. The low Cmic content and qMIC, and high qCO2 found in MEZ soils indicate the occurrence of stressful conditions. The high qMIC and qM, and the low qCO2 demonstrated an efficient organic carbon incorporation as Cmic in MO soils. In RA soils, the low total and labile organic C contents limited the Cmic and microbial respiration. Therefore, as confirmed by the BFIs, while MO showed the healthiest soils, RA soils had an inefficient ecophysiological energy state. However, no effects on plant nutrient contents were observed, likely because of masked by fertigation. Finally, BP monitoring is needed in order to avoid soil degradation and, in turn, crop production decline.

Highlights

Anthropogenic actions deeply influence processes occurring in the Earth’s critical zone (CZ), and a typical example is what is observed in agroecosystems where soils are processed for crop production
Checking the correlations among the values of indicators used for biological fertility index (BFI) calculation (Table 3), we found a strong positive correlation between organic carbon (OC) amount and the CO2 evolved during the 28-day incubation time (r = 0.62 and 0.63 for basal respiration (BR) and CO2 cumulative (Ccum), respectively) as well as between BR and Ccum (r = 0.99)
The highest OC content resulted in a higher cation exchange capacity (CEC), which is an important soil feature in cropland ecosystems because it allows retention of the nutrients added through fertilization

Summary

Introduction

Anthropogenic actions deeply influence processes occurring in the Earth’s critical zone (CZ), and a typical example is what is observed in agroecosystems where soils are processed for crop production. Soil features reflect parent rock and climatic characteristics and the effect of biological activities, including those triggered by man-made actions. These features are important to understand the soil fertility, i.e., the soil attitude to sustain crop productivity, a characteristic that has to be maintained to carry sustainable agricultural practices. In this view, studies must be carried out with a multidisciplinary approach and there is a need to develop analytical methods that measure biogeochemical indexes for a detailed CZ understanding. Conventional and industrial agriculture are considered unsustainable because they are eroding natural resources (i.e., soil and water) faster than the capacity of ecosystem to regenerate them

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