Root water conductivity of some herbaceous species.

In this study, the values of water conductivity of roots are reported for eleven crops and grapevine. For some crops, two methods (pressure chamber and transpiration method) were compared. The effects of salt and water stress were evaluated on different crops , as the effect of chloride mercury treatment, nitrogen deprivation and the interactive effects of salt, water, nitrogen and mercury stress. Root water conductivity was evaluated, for almost all the crops, during the whole plant cycles. The transpiration method always showed values of root water conductivity higher than the pressure chamber. In almost all the species, the mercury chloride reduced root water conductivity during all the plant cycle. Nitrogen deprivation and salt stress induced higher root water conductivity reduction than mercury stress. Water stress induced also a reduction but its effect on root water conductivity was lower than that of nitrogen and salt stress. Mercury chloride treatment did not show any effect on nitrogen and salt stressed plants, while in the water stressed plants its effect was additiv

Ozone Damages to Italian Crops: Environmental Constraints

The main environmental features of Italian cropping systems are described with particular emphasis on their effects on crop responses to ozone pollution. High ozone levels have been recorded all over Italy and daily patterns show, at nighttimes, strong decreases in plain areas, while ozone levels remain high in hilly areas. In the latter sites, therefore, the contribution of nocturnal stomatal conductance (gsto) to ozone uptake should be further studied. It is well known that summer drought and soil salinity reduce the soil water potential, thus causing gsto to decrease. These are likely to be the most important factors reducing crop gas-exchange and yield under environmental conditions occurring in Italy. However, the stressinduced reduction of gsto also restricts ozone uptake and, consequently, its potential damage. In Southern Italy, gasexchange limitations have been also measured in irrigated crops between two successive irrigations. Finally, the effect of water stagnation, which often occurs in clay soils of southern Italy, should be not underestimated. In these soils, in fact, root anoxia will cause stomatal closure and, consequently, will also interfere with ozone uptake and damage

Tecniche di gestione della fertilità del suolo in una coltura di pomodoro.

Due tipi di sovescio (favino puro e favino + avena) con due epoche di interramento (inizio aprile e fine aprile) in combinazione fattoriale, sono stati confrontati in una azienda sperimentale della Campania, per valutare gli effetti sulla produzione di pomodoro. Dai primi risultati, si può evidenziare come la fertilità residua del terreno, dovuta alla precessione di leguminose, è stata sufficiente a sostenere almeno in parte le produzioni di pomodoro (311 q ha-1). Gli apporti di N sono stati più alti nel caso del sovescio di favino puro e con l’interramento tardivo: 72 e 142 kg ha-1 di N per il favino e 45 e 80 kg ha-1 di N per il sovescio misto, rispettivamente nelle due epoche di interramento. Il rapporto C/N delle biomasse è stato più alto nel caso del sovescio misto e dell’interramento tardivo. Dai dati ottenuti dopo l’interramento dei diversi tipi di sovescio, appare evidente come la presenza della graminacea ha depresso le produzioni, a causa del minore apporto e della più bassa disponibilità di N minerale (438 e 346 q ha-1 rispettivamente con il sovescio di favino e di favino+avena). Non ha avuto effetti sulla produzione il ritardo di circa 20 giorni dello sfalcio e dell'interramento delle colture da sovescio (398 e 386 q ha-1 rispettivamente per il sovescio precoce e tardivo)

Potential role of compost and green manure amendment to mitigate soil GHGs emissions in Mediterranean drip irrigated maize production systems

Organic fertilization can preserve soil organic matter (SOM) and is foreseen as an effective strategy to reduce green house gases (GHGs) emissions in agriculture. However, its effectiveness needs to be clarified under specific climate, crop management and soil characteristics. A field experiment was carried out in a Mediterranean drip irrigated maize system to assess the pattern of soil CO2 and N2O fluxes in response to the replacement of a typical bare fallowemaize cycle under urea fertilization (130 kg N ha1 y1) (CONV) with: (i) bare fallow-maize cycles under two doses of compost (COM1 and COM2, 130 and 260 kg N ha1 y1, respectively) and (ii) a vetch-maize cycle, with vetch incorporation as green manure (130 kg N ha1 y1) (GMAN). Along the maize period (MP), reduced daily N2O emissions were detected in organic treated soils compared to CONV, mainly in the first stages of the cultivation, thanks to the slow release of available nitrogen from the organic substrates. Cumulative N2O fluxes (kg N2O-N ha1) in MP scored to 0.24, 0.14, 0.12 and 0.085 for CONV, COM1, COM2 and GMAN, respectively, with significantly lower emissions in GMAN respect to CONV. CO2 fluxes partially reflected the ranking observed for maize yields, with cumulated values (Mg CO2-C ha1) of 2.2, 1.5, 2.1, 2.1 for CONV, COM1, COM2 and GMAN, respectively, and significantly lower in COM1 respect to the other treatments. During the fallow period (FP), compared to CONV (0.77 Mg CO2-C ha1 and 0.25 kg N2O-N ha1), enhanced GHG fluxes were detected in COM treatments (about 0.90 Mg CO2-C ha1 and 0.37 kg N2O-N ha1, as averaged values from COM1 and COM2), likely driven by the slow prolonged mineralization of the added organic matter. GMAN showed comparable CO2 (0.82 Mg CO2-C ha1) and N2O emissions (0.30 kg N2O-N ha1), in consequence of restrained post-harvest residual N coupled with the counteracting effect of vetch uptake. Respect to the total yearly GHG emissions in CONV (about 194 kg CO2 eq ha1 y1), the overall results showed commensurate slightly higher GWP in COM treatments (þ11% as averaged value from COM1 and COM2). The yield-scaled global warming potential (GWP) resulted 60% higher and nearly doubled for COM2 and COM1 respectively, according to the lower COM yields, markedly dampening at halved compost dose. GMAN appeared the best performing organic treatment, with lower GWP (27%) and competitive yields respect to CONV. All treatments showed N2O emission factors consistently lower compared with the default IPCC 1% value

Geospatial and visual modeling for exploring sediment source areas across the Sele river landscape, Italy

This study uses the revised universal soil loss equation (RUSLE) and Geographic Information System technology to map erosion-prone areas in the Sele basin (Campania-Basilicata regions, southern Italy). Current land use/cover, soil erodibility and climate factors were evaluated to determine their effects on average annual soil loss. Geospatial technologies were applied to generate RUSLE factors and erosion map. Long-term soil losses were 53 Mg ha-1 per year averaged over an area of 2500 km2 and more than 30% of the Sele basin was subjected to soil losses higher than 20 Mg ha-1 per year. Data available in the study area allowed to estimate soil losses, but the absence of direct sediment measurements prevents an accurate evaluation of the model performance. Nevertheless, the results are similar to the ones from other studies, and provide useful preliminary information for landscape management and restoration

Ozone and Water Stress: Effects on the Behaviour of Two White Clover Biotypes

ozone pollution, water stress, stomata conductance, ozone uptake, clover, OTC. Ozone is a strong oxidizing pollutant which derives by alteration of the photolytic NOx cycle and it accumulates in the troposphere spreading in rural areas and therefore determining injuries on natural vegetation and crops. Since its penetration occurs mainly through stomata, all factors which alter plant-atmosphere relations could be able to modify plant response to ozone. Interaction between ozone and water stress in Mediterranean environment was studied on ozone resistant and sensitive biotypes of white clover, which were grown in charcoal filtered and notfiltered Open Top Chambers in factorial combination with different levels of water supply. Measurements of biomass, leaf area and stomatal conductance were made during the growth period. Ozone injuries were estimated as not-filtered/filtered OTC yield ratio; the stomatal flux of ozone was estimated multiplying stomata conductance x diffusivity ratio between ozone and water vapour (0.613) x ozone hourly concentrations. The hourly values of ozone uptake were cumulated throughout the cropping periods of the two years. In the sensitive biotype, water stress reduced yield losses due to ozone from 38% to 22%, as well as yield losses due to water stress were reduced by the presence of ozone from 43% to 29%, while no interaction between ozone and water stress was observed in the resistant biotype. Biomass yield losses of the sensitive biotype were strictly correlated to cumulated ozone uptake (R2 = 0.99), while biomass yield losses of the resistant biotype were not affected by the ozone fluxes variations created by the treatments. Flux based models could better estimate yield losses due to ozone in Mediterranean environments in which other stresses could be contemporary present; therefore, the new European directives might replace the actual thresholds based on ozone concentration with others based on ozone flux models

Biotechnological synthesis of succinic acid by actinobacillus succinogenes by exploitation of lignocellulosic biomass

Succinic acid is increasingly used in pharmaceutical industries, for the production of additives in food industries, in agriculture and in refinery processes as a precursor of many chemical compounds among which the most important is the succinate salt. It is also used as an ion chelator and surfactant, and for the biochemicals production. Currently, succinic acid is mainly produced through chemical petroleum-based processes, usually from n-butane using maleic anhydride. However, the use of petrochemical feedstocks raises serious environmental problems, due to the higher values of temperature and pressure required. The biotechnological production of succinic acid by microbial conversion of lignocellulosic biomass is attracting growing interest due to the environmental and economic advantages offered. This research is focused on the exploitation of Arundo donax (Giant reed) as a source of lignocellulosic biomass. Arundo donax is a perennial crop particularly suitable for energy production, as it offers high yields per hectare, even in partially fertile or polluted soils, not used for agriculture. Hydrolyzate of Arundo donax will be used as growth media for the Actinobacillus succinogenes 130Z, a bacterium typically found in the bovine rumen, that is recognized as one of the most promising for the biotechnological production of succinic acid, as it is able to produce higher concentrations of succinic acid. The experimental analysis is carried out to optimize the production of succinic acid taking into account the effect of the most critical parameters of the process (microbial biomass, pH, reducing sugars, volatile fatty acids, and succinic acid). Tests have shown that in 48h the sugars are completely biodegraded with a total production of bio-succinic acid of 5.9 g for 9.1 g of reducing sugars, an hourly production 0.12 g h-1 with a yield equal to 65%

Durum Wheat in Conventional and Organic Farming: Yield Amount and Pasta Quality in Southern Italy

Five durum wheat cultivars were grown in a Mediterranean area (Southern Italy) under conventional and organic farming with the aim to evaluate agronomic, technological, sensory, and sanitary quality of grains and pasta. The cultivar Matt produced the best pasta quality under conventional cropping system, while the quality parameters evaluated were unsatisfactory under organic farming. The cultivar Saragolla showed the best yield amount and pasta quality in all the experimental conditions, thus proving to be the cultivar more adapt to organic farming. In all the tested experimental conditions, nivalenol (NIV) and deoxynivalenol (DON) occurrence was very low and the other mycotoxins evaluated were completely absent. These data confirm the low risk of mycotoxin contamination in the Mediterranean climate conditions. Finally, it has been possible to produce high-quality pasta in Southern Italy from durum wheat grown both in conventional and organic farming

Investigating Lead Bioavailability in a Former Shooting Range by Soil Microanalyses and Earthworms Tests

Shooting ranges are among the major anthropogenic sources of Pb contamination in soils worldwide. Once they have reached the soil, bullet residues can have different fates according to the characteristics of the soil environment, leading to the formation of different Pb weathering products whose stability is crucial for Pb accessibility to soil biota. In this study, Pb availability in a former polluted shooting range was investigated with a combination of conventional soil analyses, X-ray microanalyses and assays with the bio-indicator earthworm Eisenia andrei. Chemical extractions evidenced a rather low mobility of soil Pb, while micro-X-ray fluorescence spectroscopy (mu XRF) and scanning electron microscopy coupled with microanalysis (SEM-EDX) showed the formation of a weathering crust around Pb-containing bullet slivers dispersed within the soil. Such crusts consisted of a mixture of orthophosphates, including the highly insoluble Cl-pyromorphite. Furthermore, no acute toxicity effects and low Pb concentration values were measured in earthworm tissues (94.9 mg kg(-1)) and coelom fluids (794 mu g L-1) after 28 days of exposure to the polluted soil. These results allow us to assume that most of the Pb in the shooting range soil underwent stabilization processes promoted by phosphatic fertilization. The soil was in fact used for agriculture after being dismissed for firing activities. Such a combined approach can be applied to study Pb bioavailability in other shooting ranges or, more generally, in soils heavily polluted with P

Agronomic and environmental benefits of ‘re-using’ a biodegradable mulching film for two consecutive lettuce cycles

Biodegradable films are a valuable and sustainable alternative to plastic films for mulching soils since they avoid the environmental and economic problems related to plastic removal and dis posal. Nevertheless, the fast degradation of such materials could make them unsuitable for mid-to long-term use. In a field experiment, the agronomic performance of a biodegradable mulching film (MB) was compared to that of conventional low-density polyethylene (LDPE) film for two consecutive lettuce cycles (winter and spring). In the conditions of this trial, MB showed good resistance to atmospheric agents, with a reduction of its integrity and mechanical properties only after six months. The effects on soil temperature and lettuce yield did not differ from those obtained with LDPE films. The effect on harvest timing was the same as that with LDPE in the spring cycle, while in the winter cycle, the harvest was delayed by about five days compared to LDPE. Mulching films reduced nitrate accumulation in leaves mainly during the winter cycle. However, the effect needs to be further explored with experiments in different pedoclimatic conditions that consider the effects of mulching on nitrification and nitrate-reductase activity that could be affected by changes in soil temperature and moisture