Linda Pieri

The effects of biochar on the physical properties of bare soil

The pyrolysis conversion of vegetable residues into energy and biochar, and its incorporation in agricultural soil, reduces CO 2 emission and provides a longterm soil carbon sequestration. Moreover, biochar application in soil seems to increase nutrient stocks in the rooting layer, improving crop yield. Compared with the numerous studies assessing the positive effect of biochar on yield, however, little research has been published elucidating the mechanisms responsible for the reported benefits. Few studies cited soil moisture as the key factor, attributing the increased yield to the higher soil water availability. The aim of this study was to investigate the effect of biochar on the physical and hydraulic properties of a bare Padana Plain (Cadriano, Bologna) agricultural soil. A preliminary plot experiment in 2009 explored the influence of 10 and 30 kg ha –1 of biochar on soil moisture, without effects from plants. Results of the first experiment suggested using higher biochar rates in a similar experimental scheme. During the second experiment, 30 and 60 t ha –1 doses were investigated. Soil water content, bulk density, electrical conductivity and soil water retention were measured. The comparison between treated soils and the control indicates that the biochar rate is directly correlated to electrical conductibility and inversely correlated with bulk density. The effect on the density of soil can be very positive in case of heavy soils. The dark colour of the char increased the surface temperature with respect to the control, while no differences were detected at 7·5 cm depth. No influences were found on other soil characteristics, including soil pH, moisture and water retention.

Integrated environmental quality monitoring around an underground methane storage station.

The study reports an integrated environmental quality monitoring of a 100 km2 area in central Italy mostly occupied by an underground station of methane storage, working since 1982. The nitrogen oxides, ozone and isoprene concentration detached with a network monitoring of passive filters were compared with the results of lichens biomonitoring. Data from the two monitorings were in accordance: there was an inversely correlation between lichen biodiversity index (IBL) and NOx (-0.96) and ozone (-0.80), and a positive correlation between IBL and isoprene (0.67). IBL indicated that the area ranged between medium naturalness and medium alteration status, values fully compatible with the medium-high level of eutrophication, caused by intensive agriculture. Only two areas were in high alteration status, due to their proximity to glass factories and to a quarries area. Despite almost thirty years of activity, the environment quality of the area around the station did not show signs of declining.

Chemical characteristics of atmospheric bulk deposition in a semi-rural area of the Po Valley (Italy)

This study provides an analysis of a five-year time series chemical composition of the bulk deposition (2009–2013), collected within a farm surrounded by industrial and urban settlements in a semi-rural area of the Po Valley, with the aim of characterizing potential emission sources affecting precipitation composition at the site. Most monitoring efforts in this region, recognized as one of the most polluted in the world both due to the intense industrialisation and urbanisation as well as to frequent air stagnation conditions, are presently devoted more to gaseous and particulate pollutants than to precipitation chemistry. The bulk deposition samples were very concentrated in chemical species, both acidic and alkaline, high compared to other polluted sites in the world and to locations in the same district. The mean ions concentrations (in μeq l−1) are: NO3− (243)xa0>xa0SO42− (220)xa0>xa0PO43− (176)xa0>xa0Cl− (153)xa0>xa0NO2− (29)xa0>xa0F− (2.6); NH4+ (504)xa0>xa0Ca2+ (489)xa0>xa0K+ (151)xa0>xa0Na+ (127)xa0>xa0Mg2+ (127). pH data shows a trend toward slightly alkaline conditions attributed to the large presence of ammonium and crustal elements, in spite of high concentrations of nitrates and sulphates. The relevant concentrations of Ca2+ and Mg2+ further suggests that these alkaline conditions might be due to the correspondingly significant concentrations of carbonates/bicarbonates in our dataset. While back-trajectories analysis suggests the stronger importance of local resuspension over long-range transport, statistical analyses on ion composition highlight the key role exerted by agricultural activity, especially in the case of NH4+, K+, Ca2+ and PO43− (especially linked to fertilisation practices and soil resuspension due to mechanical operations). Apart from Na+ and Cl− ions which correlate well as expected, indicating their likely common origin from marine salt, the identification of the origin of the other ions is very complex due to the contribution of diverse local sources, such as industrial and residential settlements.

Changes in the rainfall–streamflow regimes related to climate change in a small catchment in Northern Italy

Climate change has become an important issue for scientific community, for its numerous impacts, especially on agriculture and environment. To shed light on this phenomenon, long data-sets of meteorological data as well as temperature and rainfall extreme events are needed, since they are important climate variability indicators. In a small semi-agricultural catchment of the Italian Apennines, drained by the Centonara Stream, weather data have been monitored for 30xa0years (1986–2015). Here, their trend was identified with Mann–Kendall test, and the temperature and precipitation extremes were characterized by means of specific indices. Data were analyzed at event, daily, seasonal, and annual bases. In addition, to understand implications of rainfall patterns on catchment hydrological response, a total of 388 rainfall–streamflow events (recorded during 1994–2009) were analyzed. Results showed a significant increase of temperature (minimum (Tn), mean (Tm), and maximum (Tx)), both at annual and seasonal base, except for Winter, with an annual mean increase of 0.08, 0.09, and 0.13xa0°Cxa0year−1 for Tn, Tm, and Tx, respectively. Annual rainfall data showed a positive trend for the number of wet days, but not in the quantity. In Winter, the rainfall amount and the number of wet days increased. The annual number of rainfall extreme events (Pu2009>u200920.2xa0mm and Du2009>u200918.3xa0h) significantly increased, especially in spring and autumn. The rainfall–streamflow relationship suggested that the flow response of the Centonara Stream depends mainly on the rainfall amount. So, since the number of extreme events (Pu2009>u200920.2xa0mm) is increasing in spring and autumn, an increase of events with high streamflow in these seasons may occur.

Atti del XIX Convegno Nazionale di Agrometeorologia.Nuove avversità e nuovi servizi per gli agroecosistemi.New adversities and new services for agroecosystems. Bologna 14-16 giugno 2016

Ogni anno lAssociazione Italiana di AgroMeteorologia organizza un convegno in cui vengono trattati i temi piu attuali della ricerca e delle applicazioni in ambito agrometeorologico. Questo appuntamento nel corso degli anni e ormai diventato un momento dincontro molto atteso dalla comunita agrometeorologica italiana. n nLa XIX edizione del Convegno AIAM in programma dal 14 al 16 giugno 2016 a Bologna (BO) e stata intitolata: Nuove avversita e nuovi servizi per gli Agroecosistemi. n nIl programma di questa edizione ha previsto due sessioni: nSupporti agrometeorologici e nuove avversita nStrumenti per la mitigazione e l’adattamento ai cambiamenti climatici

Integrated Approach to the Evaluation of Denudation Rates in an Experimental Catchment of the Northern Italian Apennines

This paper presents the main results of a multidisciplinary study, aimed at the quantitative direct and indirect evaluation of erosion rates. The investigation was carried out in the small semi-agricultural Centonara catchment, in the Northern Italian Apennines, within the Mediterranean climate region. The Centonara catchment is heterogeneous from the point of view of lithology, geology, slope angle, vegetation and land cover. 20 % of the entire area is occupied by badlands (calanchi), characterized by bare soil and slope gradient over 40 % and affected by rapid morphogenesis mainly due to rill and gully erosion. For this study, 21-years monitoring data of sediment rate were compared with the results of the grid analysis of the “Tu Denudation index”. Direct monitoring of sediment transport showed the high variability of rainfall, flow and erosion rates. Moreover, during a single year a few very intense rainfall events determine peak flow of the Centonara stream and exceptional sediment transport, influencing the overall erosion rates. The zonation of the estimated erosion rates highlighted that more than 40 % of the sediment rate derived from the calanchi badlands, while the arable lands and the areas occupied by natural vegetation (both herbaceous and woody) contributed only minimally to the generation of surface runoff and erosion.