Chiara Pistocchi

Phosphorus budget in the water‐agro‐food system at nested scales in two contrasted regions of the world (ASEAN‐8 and EU‐27)

Phosphorus (P) plays a strategic role in agricultural production as well as in the occurrence of freshwater and marine eutrophication episodes throughout the world. Moreover, the scarcity and uneven distribution of minable P resources is raising concerns about the sustainability of long-term exploitation. In this paper we analyze the P cycle in anthropic systems with an original multiscale approach (world region, country, and large basin scales) in two contrasting world regions representative of different trajectories in socioeconomic development for the 1961–2009 period: Europe (EU-27)/France and the Seine River Basin, and Asia (ASEAN-8)/Vietnam and the Red River Basin. Our approach highlights different trends in the agricultural and food production systems of the two regions. Whereas crop production increased until the 1980s in Europe and France and has stabilized thereafter, in ASEAN-8 and Vietnam it began to increase in the 1980s and it is still rising today. These trends are related to the increasing use of fertilizers, although in European countries the amount of fertilizers sharply decreased after the 1980s. On average, the total P delivered from rivers to the sea is 3 times higher for ASEAN-8 (300 kg P km−2 yr−1) than for EU-27 countries (100 kg P km−2 yr−1) and is twice as high in the Red River (200 kg P km−2 yr−1) than in the Seine River (110 kg P km−2 yr−1), with agricultural losses to water in ASEAN-8 3 times higher than in EU-27. Based on the P flux budgets, this study discusses early warnings and management options according to the particularities of the two world regions, newly integrating the perspective of surface water quality with agricultural issues (fertilizers, crop production, and surplus), food/feed exchanges, and diet, defining the so-called water-agro-food system.

A simple model to assess nitrogen and phosphorus contamination in ungauged surface drainage networks: Application to the Massaciuccoli lake catchment, Italy

Modeling is a common practice to evaluate factors affecting water quality in environmental systems impaired by point and nonpoint losses of N and P. Nevertheless, in situations with inadequate information, such as ungauged basins, a balance between model complexity and data availability is necessary. In this paper, we applied a simplified analytical model to an artificially drained floodplain in central-western Italy to evaluate the importance of different nutrient sources and in-stream retention processes and to identify critical source areas. We first considered only a set of chemical concentrations in water measured from February through May 2008 and from November 2008 through February 2009. We then broadened available data to include water discharge and hydraulic-head measurements to construct a hydrogeological model using MODFLOW-2000 and to evaluate the reliability of the simplified method. The simplified model provided acceptable estimates of discharge (ranging from 0.03-0.75 m s) and diffuse nutrient inputs from water table discharge and in-stream retention phenomena. Estimates of PO-P and total P retention (ranging from 1.0 to 0.6 μg m s and from 1.18 to 0.95 μg m s for PO-P and total P, respectively) were consistent with the range of variability in literature data. In contrast, the higher temporal variability of nitrate concentrations decreased model accuracy, suggesting the need for more intensive monitoring. The model also separated the dynamics of different reaches of the drainage network and identified zones considered critical source areas and buffer zones where pollutant transport is reduced.

Preliminary investigation on the potential use of two C4 turfgrass species to reduce nutrient release in a Mediterranean drained peatland

This study compared dry matter production, nutrient uptake and tissue nutrient concentration of two C4 turfgrass species (Cynodon dactylon × Cynodon transvaalensis Burtt Davy and Paspalum vaginatum Swartz) supplied with three different nutrient solutions in a sand and peat culture. The 8-week experiment was performed in mesocosms and simulated the conditions of an open-field phyto-treatment system located in a Mediterranean drained peatland (Tuscany, Italy). Peat was collected on the site, and one of the solutions mimicked drainage water flowing into it. Three hypotheses were tested: (i) the species chosen efficiently removed nutrients from both the solution and the substrate; (ii) peat contributed to the nutrient load; and (iii) the species chosen were suitable in the open-field system. Both species adapted well to the experimental conditions and demonstrated considerable ability to remove nutrients. P. vaginatum took up nitrogen more efficiently, mainly in conditions of high nutrient availability. We observed supplementary nutrient uptake by plants in the peat treatment. Performances of the two C4 turfgrasses extrapolated to the field scale seemed effective from a phyto-treatment perspective.