(Sicilian farmers look) Back to the future


Wheatfield with Crows, by Van Gogh. Van Gogh Museum, Amsterdam.
Wheatfield with Crows, by Van Gogh. Van Gogh Museum, Amsterdam.

Sicilian farmers are returning to cultivate ancient seed. This is to recover the ancient wisdom that feed the island and Italy since ancient times. Giuseppe Li Rosi is a local farmer and one of the strongest supporters of the return to traditional agriculture. He has converted a property of 100 hectares to traditional farming and proudly guards three local seed varieties (“Timilia”, “Maiorca” and “Strazzavisazz”), keeping at least 10 hectares for each one. Continue reading

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Connectivity: an emerging issue


Antonio Jordán (University of Seville, Spain)
Paulo Pereira (Mykolas Romeris University, Lithuania)
Saskia Keesstra (Wageningen University, The Netherlands)
Artemi Cerdà (University of Valencia, Spain)

 

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What is connectivity?

Over the recent decades, a growing number of studies have highlighted the role of hydrological and sediment connectivity processes in relation to watershed management, topography, aspect, soil erosion (Bracken and Croke, 2007; Heckmann et al., 2010; Hopp and Mc Donnell, 2009; Parsons et al., 2996), movement of nutrients and pollutants (Keesstra et al., 2012a; Puttock et al., 2013; Okin and Gillette, 2001; Turnbull et al., 2011), vegetation (Jordán et al., 2008) or infrastructures (Jordán and Martínez-Zavala, 2008; Müeller et al., 2008; Ocampo et al. 2006). Water and sediment connectivity has emerged as a significant conceptual framework for understanding the transfer of surface water and sediment and associated substances through landscapes. With “connectivity”, we make reference to the interdependence of hydrological processes with other elements of the landscape as soil, highlighting the strong relationship among them. This relation occurs spatially at different scales (Bracken et al., 2014; Wainwright et al., 2011), from molecular to landscape processes through intermediate scales as aggregates, pedons or landforms(Brown et al., 2009; Dosseto et al., 2010; Harvey, 2002; Fryirs et al., 2007; Hooke, 2003; Lane et al., 2008; Jain and Tandon, 2010), and in a time-dependent way (Benda and Dunne, 1997; Harvey, 2002; McGuire and McDonnell, 2007; Otto et al., 2009). Continue reading

Monday paper: Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards


A. Novara, L. Gristina, F. Guaitoli, A. Santoro, A. Cerdà. 2013. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards. Solid Earth, 4, 255-262, doi:10.5194/se-4-255-2013

Abstract

When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativacover crop). A 10 m-wide buffer strip was seeded with Lolium perenne at the bottom of the vineyard. Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. Lolium perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. Vicia sativa cover crop management contributed with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduced the nitrate by 42% with and by 46% with a 9 m buffer strip. Thanks to catch crops, farmers can manage the N content and its distribution into the soil over the year, can reduced fertilizer wastage and reduce N pollution of surface and groundwater.

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Solid Earth (SE) is an international scientific journal dedicated to the publication and discussion of multidisciplinary research on the composition, structure and dynamics of the Earth from the surface to the deep interior at all spatial and temporal scales. More at Solid Earth hompage.

Monday paper: Mean age of carbon in fine roots from temperate forests and grasslands with different management


E. Solly, I. Schöning, S. Boch, J. Müller, S.A. Socher, S.E. Trumbore, M.  Schrumpf. 2013. Mean age of carbon in fine roots from temperate forests and grasslands with different management. Biogeosciences, 10, 4833-4843, doi:10.5194/bg-10-4833-2013

Abstract

Fine roots are the most dynamic portion of a plant’s root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C) inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (14C) content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27) than in forests 3.1 ± 0.5 g (n = 27) (p < 0.05), the mean age of C in fine roots in forests averaged 11.3 ± 1.8 yr and was older and more variable compared to grasslands 1.7 ± 0.4 yr (p < 0.001). We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated with plant diversity (r = 0.65) and with the number of perennial species (r = 0.77). Fine root mean C age in grasslands was also affected by study region with averages of 0.7 ± 0.1 yr (n = 9) on mostly organic soils in northern Germany and of 1.8 ± 0.3 yr (n = 9) and 2.6 ± 0.3 (n = 9) in central and southern Germany (p < 0.05). This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

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Biogeosciences (BG) is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions. Experimental, conceptual and modelling approaches are welcome. More at Biogeosciences homepage.

How many years of four-years politics yet?


Antonio Jordán
Lorena M. Zavala

University of Seville, Spain

Recently, we and some members of our research group visited a burned area in Montellano (province of Sevilla, Southern Spain) to plan some field experiments. This area was affected by a wildfire during last August 2012.
The fire affected between 70 and 80 ha of a hardly accessible area, characterized by a pine dense forest, shallow soils and steep slopes. Originally an arson fire due to local struggles, fire quickly climbed the north face of the mountain, reached the top and moved down the southern slope in hours. The area is used by residents for recreative activities.

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