The PRISMA satellite mission launched on March 22nd, 2019 is one of the latest spaceborne imaging spectroscopy mission for Earth Observation. The PRISMA satellite comprises a high-spectral resolution ...VNIR-SWIR imaging spectrometer and a panchromatic camera. In summer 2019, first operations during the commissioning phase were mainly devoted to acquisitions in specific areas for evaluating instrument functioning, in-flight performance, and mission data product accuracy. A field and airborne campaign was carried out over an agriculture area in Italy to collect in-situ multi-source spectroscopy measurements at different scales simultaneously with PRISMA. The spectral, radiometric and spatial performance of PRISMA Level 1 Top-Of-Atmosphere radiance (LTOA) product were analyzed. The in-situ surface reflectance measurements over different landcovers were propagated to LTOA using MODTRAN5 radiative transfer simulations and compared with satellite observations. Overall, this work offers a first quantitative evaluation about the PRISMA mission performance and imaging spectroscopy LTOA data product consistency. Our results show that the spectral smile is less than 5 nm, the average spectral resolution is 13 nm and 11 nm (VNIR and SWIR respectively) and it varies ±2 nm across track. The radiometric comparison between PRISMA and field/airborne spectroscopy shows a difference lower than 5% for NIR and SWIR, whereas it is included in the 2–7% range in the VIS. The estimated instrument signal to noise ratio (SNR) is ≈400–500 in the NIR and part of the SWIR (<1300 nm), lower SNR values were found at shorter (<700 nm) and longer wavelengths (>1600 nm). The VNIR-to-SWIR spatial co-registration error is below 8 m and the spatial resolution is 37.11 m and 38.38 m for VNIR and SWIR respectively. The results are in-line with the expectations and mission requirements and indicate that acquired images are suitable for further scientific applications. However, this first assessment is based on data from a rural area and this cannot be fully exhaustive. Further studies are needed to confirm the performance for other land cover types like snow, inland and coastal waters, deserts or urban areas.
•The PRISMA mission is successfully operating and collecting data after the launch.•In-situ simultaneous field/airborne spectroscopy data were compared to PRISMA.•PRISMA spectral resolution is 13–11 nm (VNIR-SWIR), smile is lower of 5 nm.•A radiometric difference of 2–7% was observed between PRISMA and in-situ data.•VNIR-to-SWIR spatial co-registration error is lower of 8 m.
► Biochar application to soil could be a viable option for carbon sequestration. ► Durum wheat yield is increased by biochar application and its quality maintained. ► Converting agricultural residues ...to biochar is a method to reduce CO
2 emissions.
Carbon sequestration in agricultural soils is a climate change mitigation option since most of cultivated soils are depleted of soil organic carbon and far from saturation. The management practices, most frequently suggested to increase soil organic carbon content have variable effects depending on pedo-climatic conditions and have to be applied for a long time periods to maintain their sink capacity. Biochar (BC), a carbon rich product obtained through carbonization of biomass, can be used for carbon sequestration by applying large amounts of carbon very resistant to decomposition. The BC remains into soil for a long time and there is evidence that the BC stores atmospheric carbon from centennial, to millennial timescales. However most of the agronomic studies on BC application have been made in tropical and sub-tropical climates, while there is a substantial lack of studies at mid-latitudes and in temperate climates. This paper presents the results on an investigation of large volume application of BC (30 and 60
t
ha
−1) on durum wheat in the Mediterranean climate condition, showing the viability of BC application for carbon sequestration on this crop. BC application also has positive effects up to 30% on biomass production and yield, with no differences in grain nitrogen content. Moreover no significant differences between the two BC treatments were detected, suggesting that even very high BC application rates promote plant growth and are, certainly, not detrimental. The effect of the biochar on durum wheat was sustained for two consecutive seasons when BC application was not repeated in the second year.
•Crop management strategies play an important role in the soil water content.•The impact of biochar application on soil–water relations and on Vitis vinifera water status was assessed.•Two rates of ...biochar application in two years were considered.•Biochar addition increases the soil water-holding capacity and plant available water content.•Biochar addition substantially affected ecophysiological parameters of V. vinifera.
Soil water status plays an important role in growth-yield and grape quality of Vitis vinifera (L.). In some cases, periods of moderate water stress have been indicated to exert a positive effect on the quality of grape production. However, prolonged water stress may have a strong negative affect grapevine photosynthesis and grape yield, especially in dry Mediterranean environments. Biochar is a co-product of a thermochemical conversion of biomass that is recognized to be a beneficial soil amendment, which when incorporated into the soil increases soil water retention. We investigated the effect of two rates of biochar application (22 and 44tonha−1) on plant water relations of V. vinifera in a field experiment in central Italy. Biochar obtained from the carbonization of orchard pruning waste was applied to the soil over two consecutive growing seasons. The treatments did not show a significant increase in soil hydrophobicity. Moreover, soil analysis and ecophysiological measurements indicated a substantial relative increases in available soil water content compared to control soils (from 3.2% to 45% in the 22 and 44tonha−1 application rates, respectively) and in leaf water potential (24–37%) during droughts.
•The addition of pelletized biochar suddenly increases soil water retention.•The use of pelletized biochar is effective as conditioner in a fine-textured soil.•The incorporation of pelletized biochar ...creates functional accommodation pores.•The amount of biochar directly influences AWC of amended soil.•The pyrolysis process influences biochar AWC.
The field application of pelletized biochar is seldom employed and its effect on soil hydrological behavior scarcely investigated. Biochar is usually added in powdered or granular form to improve the homogeneity of distribution, meanwhile favoring its interaction with soil matrix. In this paper we evaluated the possibility of applying pelletized biochar as soil conditioner during a single cropping season of a tomato cultivation. For that purpose, the water retention curves (WRCs) were determined three months after the addition of two differently pyrolysed biochars (B1 and B2), at the rate of 14Mgha−1, to a silty clay loam soil prone to compaction. Starting from the WRCs the pore size distribution was determined. The gravimetric water content at both field capacity (FC) and wilting point (WP) was also measured on biochar samples to assess their available water capacity (AWC).
In both the treatments, soil bulk density (BD) was significantly lower compared to control (Co), apparently as direct consequence of the addition of low density pellets. Actually, excluding the intrinsic biochar porosity from soil bulk density calculation, BD values of the treated soils remain lower of around 10% over Co. Such findings suggest that a modification of soil structural characteristics might have been induced by pellet addition. Data of the SWRCs indicate a significant increase in transmission (500–50μm), storage (50–0.5μm) and AWC pores (30–0.2μm) for the amended soils. The pyrolysis process seemed to differentiate the extent of direct biochar contribution expressed by AWC values The addition of pelletized biochar was able to enhance the soil water retention properties even in the short term, and such improvement might be correlated to both the inherent biochar retention capacity and to a more functional rearrangement of soil aggregates/particles with pellets.
•Field biochar application did not enhance tomato yield nor affect quality.•Biochar application had positive effects on soil fertility.•Biochar application in high fertility conditions can be a ...sustainable practice.
Biochar addition to soil is a promising option for climate change mitigation and is recognized to exert beneficial effects on soil fertility. However, recent meta-analysis documented controversial effects on soil–plant interactions and on crop yields response.
The data presented in this paper are the results of a field experiment on a processing tomato crop aiming to enhance the knowledge on the real applicability of biochar at farm scale in a high fertility alkaline soil. The effects of two biochar types on soil properties and on quantitative and qualitative parameters of processing tomato were evaluated. Biochar application significantly increased the soil carbon content, the soil cation exchange capacity and the availability of NH4+, P and K. Moreover, it stimulated plant growth and N, P and base cation contents at harvest, reducing the leaf water potential in the warmer period. These results demonstrate that also intensive cultivations in fertile soil can benefit from biochar amendment.
Vegetation responds at varying temporal scales to changing soil water availability. These process dynamics complicate assessments of plant-water relations but also offer various access points to ...advance understanding of vegetation responses to environmental change. Remote sensing (RS) provides large capacity to quantify sensitive and robust information of vegetation responses and underlying abiotic change driver across observational scales. Retrieved RS based vegetation parameters are often sensitive to various environmental and plant specific factors in addition to the targeted plant response. Further, individual plant responses to water limitation act at different temporal and spatial scales, while RS sampling schemes are often not optimized to assess these dynamics. The combination of these aspects complicates the interpretation of RS parameter when assessing plant-water relations. We consequently aim to advance insight on the sensitivity of physiological, biochemical and structural RS parameter for plant adaptation in response to emerging soil water limitation. We made a field experiment in maize in Tuscany (Central Italy), while irrigation was stopped in some areas of the drip-irrigated field. Within a period of two weeks, we measured the hydraulic and physiological state of maize plants in situ and complemented these detailed measurements with extensive airborne observations (e.g. sun-induced chlorophyll fluorescence (SIF), vegetation indices sensitive for photosynthesis, pigment and water content, land surface temperature). We observe a double response of far-red SIF with a short-term increase after manifestation of soil water limitation and a decrease afterwards. We identify different response times of RS parameter representing different plant adaptation mechanisms ranging from short term responses (e.g. stomatal conductance, photosynthesis) to medium term changes (e.g. pigment decomposition, changing leaf water content). Our study demonstrates complementarity of common and new RS parameter to mechanistically assess the complex cascade of functional, biochemical and structural plant responses to evolving soil water limitation.
•SIF shows a temporally graduated dual response to decreasing soil water.•SIF responds faster than other RS proxies to decreasing soil water.•Rigorous normalization is essential to derive subtle plant responses from RS data.
Urban afforestation is considered a promising nature-climate solution that may contribute to achieve climate neutrality by 2050, since it can increase C-storage and C-sequestration, whilst providing ...further multiple ecosystem services for citizens. However, the quantification of the CO2 sequestration capacity that may be provided by an urban forest as well as the capacity to impact the city-level C-balance and offset anthropogenic emissions is a complex issue. Methodological approaches, quantity and quality of information contained in urban tree database, and the level of detail of the planned urban forest can strongly influence the estimation of C-sequestration potential offered by urban forests. In this work, an integrated framework based on emission inventory, tree species/morphology and ecosystem modelling has been proposed for the city of Prato, Italy, a representative medium size European city to: i) evaluate the current C-sequestration capacity of urban trees; ii) upscale such capacity with different afforestation scenarios, iii) compare the sink capacity offered by ecosystems with current and projected anthropogenic emissions. Results indicated that the green areas within the Municipality of Prato can sequester 33.1 ktCO2 yr−1 under actual conditions and 51.0 ktCO2 yr−1 under the afforestation scenario which maximize the CO2 sequestration capacity, offsetting the 7.1 % and 11 % of the total emissions (465.8 ktCO2 yr−1), respectively. This study proves that, in the various afforestation scenarios tested, the contribution of urban afforestation to the municipality carbon balance is negligible and that carbon neutrality can only be reached by the substantial decarbonization of emission sectors.
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•The green areas within the Municipality of Prato can sequester 33.1 ktCO2 yr−1.•CO2 sequestration capacity from 1911 afforestation scenarios was evaluated.•Afforestation scenarios can offset city emissions in a range from 8.1 to 11 %.•An increase in the number of broadleaves resulted in increased CO2 sequestration.•The increase in urban green areas can only marginally contribute to C-neutrality.
The agronomic use of charcoal from biomass pyrolysis (biochar) represents an interesting option for increasing soil fertility and sequestering atmospheric CO2. However, before moving toward ...large-scale biochar applications, additional research must evaluate all possible land-atmosphere feedbacks. Despite the increasing number of studies investigating the effect of biochar on soil physical, chemical and biological properties, only a few have been done on surface albedo variations on agricultural lands. The present work had the aim of characterizing the annual albedo cycle for a durum wheat crop in Central Italy, by means of a spectroradiometer measurement campaign. Plots treated with biochar, at a rate of 30-60 t ha−1, showed a surface albedo decrease of up to 80% (after the application) with respect to the control in bare soil conditions, while this difference tended to decrease during the crop growing season, because of the prevailing effect of canopy development on the radiometer response. After the post-harvesting tillage, the soil treated with biochar again showed a lower surface albedo value (<20-26% than the control), while the measurements taken in the second year after application suggested a clear decrease of biochar influence on soil color. The modeling of the surface energy balance highlighted changes in the partitioning of heat fluxes and in particular a substantial increase of ground heat fluxes on an annual basis.
Mountain regions and the important ecosystem services they provide are considered to be very vulnerable to the current warming, and recent studies suggest that high-mountain environments experience ...more rapid changes in temperature than environments at lower elevations. Here we analysed weather records for the period 1975-2010 from the Eastern Italian Alps that show that warming occurred both at high and low elevations, but it was less pronounced at high elevations. This negative elevation-dependent trend was consistent for mean, maximum and minimum air temperature. Global radiation data measured at different elevations, surface energy fluxes measured above an alpine grassland and above a coniferous forest located at comparable elevations for nine consecutive years as well as remote sensing data (MODIS) for cloud cover and aerosol optical depth were analysed to interpret this observation. Increasing global radiation at low elevations turned out to be a potential driver of this negative elevation-dependent warming, but also contributions from land use and land cover changes at high elevations (abandonment of alpine pastures, expansion of secondary forest succession) were taken into account. We emphasise though, that a negative elevation-dependent warming is not universal and that future research and in particular models should not neglect the role of land use changes when determining warming rates over elevation.
Sunlight absorbed at the Earth's surface is re-emitted as longwave radiation. Increasing atmospheric concentrations of CO2 and other greenhouse gases trap an increasing fraction of such heat, leading ...to global climate change. Here we show that when a chlorophyll (Chl)-deficient soybean mutant is grown in the field, the fraction of solar-irradiance which is reflected, rather than absorbed, is consistently higher than in commercial varieties. But, while the effect on radiative forcing during the crop cycle at the scale of the individual experimental plot was found to be large (−4.1± 0.6 W m−2), global substitution of the current varieties with this genotype would cause a small increase in global surface albedo, resulting in a global shortwave radiative forcing of −0.003 W m−2, corresponding to 4.4 Gt CO2eq. At present, this offsetting effect would come at the expense of reductions to yields, probably associated with different dynamic of photosynthetic response in the Chl-deficient mutant. The idea of reducing surface-driven radiative forcing by means of Chl-deficient crops therefore requires that novel high-yielding and high-albedo crops are made available soon.
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