Temporal changes of soil physical quality under two residue management systems

Abstract

Although crop residue management is known to affect near-surface soil physical quality, little is known about the temporal variability of these indicators over short time intervals. This study evaluates the temporal changes of nine indicators of soil physical quality. These are organic carbon content, structural stability index, bulk density, macroporosity, air capacity, relative field capacity, plant available water capacity, Dexter's S-index and saturated hydraulic conductivity. A second set of soil physical indicators, based on the distribution of soil pore volume, was also evaluated. The indicators were determined in three different times during the growing cycle of winter durum wheat cultivated within a long-term field research carrying out in Southern Italy and comparing two types of crop residue management, that is, burning (B) and soil incorporation (I). Only the bulk density changed over time for both treatments, although the air capacity also changed for the incorporation of wheat residues. Residual effects of the autumnal soil tillage and soil compaction were a common source of variability, irrespective of which treatment was used. Based on the existing guidelines for evaluating the physical quality of these agricultural soils, optimal or near-optimal values were detected in about half of the cases under consideration. This suggests that both B and I create sufficiently good conditions for crop growth during the crop cycle. The comparison between observed and optimal soil pore distribution function was always poor. The pore volume distributions showed lower densities of small pores and relatively higher densities of large pores than the proposed optimal distribution. This study also suggests that the considered optimal or references curves probably cannot be applied successfully to a wide range of agricultural soils.

Impact of biochar addition on the physical and hydraulic properties of a clay soil

“…6a). Similar values for saturated water content (on average equal to 0.471 cm 3 cm À3 ), were observed for this clay soil at the end of a crop cycle (May and June) in a dryland continuous winter durum wheat crop rotation (Castellini et al, 2014). A good agreement was also detected for the TDR measurements for the treatments C0 and C10 (see Section 2).…”

“…These have been calibrated for the studied soil in previous research (unpublished data). Since, it is well known that the field saturation is generally lower than that obtained in laboratory (as discussed in the results section), a reference mean value of saturated water content, u s , was first chosen for each soil cylinder, by comparing the measurements obtained from the TDR probes and the water retention curves for the studied soil during previous research (Castellini et al, 2014). This evaluation was carried out after some rainfall events and infiltration tests in order to establish if the theoretical values of full saturation obtained in the laboratory could be achieved under field conditions.…”

“…Several studies have been carried out throughout the world to identify the effects of incorporating organic matter into the soil, and the resulting advantages for its physical and hydraulic properties are well known (Castellini et al, 2014). In recent years there has been increased use of biochar as an addition to agricultural soils, since it is seen as potentially improving both crop productivity and soil quality (Vaccari et al, 2011;Baronti et al, 2014).…”

“…In recent years there has been increased use of biochar as an addition to agricultural soils, since it is seen as potentially improving both crop productivity and soil quality (Vaccari et al, 2011;Baronti et al, 2014). It is an alternative that may be potentially integrated into sustainable agricultural systems, especially those in the clayey soils of Southern Italy (Castellini et al, 2014). However, an accurate evaluation of the biochar effects on the physical and hydraulic properties of the soil is needed, since the effects of excessively high inputs are difficult to remedy.…”

Environmental effectiveness of GAEC cross-compliance Standard 2.1 ‘Maintaining the level of soil organic matter through management of stubble and crop residues’ and economic evaluation of the competitiveness gap for farmers

“…Il colore del suolo, la stabilità degli aggregati e il tasso di infiltrazione dell'acqua risultano differenti a seconda che la paglia venga bruciata o interrata (Rasmussen et al, 1980). Dopo 10 anni di bruciatura delle stoppie, in un dispositivo sperimentale di lungo periodo della provincia di Foggia, Castellini et al (2014) non hanno riscontrato differenze significative nella qualità del suolo rispetto alla pratica dell'interramento. I residui che restano dopo la bruciatura decompongono molto lentamente perché il carbonio bruciato è meno attivo biologicamente e ha un lungo turnover, tanto che si è perfino pensato di proporre la bruciatura come tecnica per favorire il sequestro nel suolo di questo elemento.…”