(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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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.

Soils at Imaggeo: soil erosion in olive groves


Artemi Cerdà, Spain

Soil erosion effects in olive-crpped soils, by Artemi Cerdà. Click to see the original picture at Imaggeo.

Olive-cropped soils in Spain cover more than 2.4 million ha, 75% in southern Spain. Historically, high soil erosion rates have been determined in olive groves due to soil management, mostly.

Due to Mediterranean climate conditions and low water inputs, traditional management is based on reduced tree density, canopy size control by pruning, and intensive weed control. Weed control by conventional tillage is a traditional practice and only very recently alternative methods have been considered, as reduced tillage, no tillage or cover crop strips.

In the picture, the effects of intense tillage during decades are evident after trees have been removed.

This post was also published simultaneously in the EGU Blog Network.

Biogeosciences: Comparison of soil greenhouse gas fluxes from extensive and intensive grazing in a temperate maritime climate


Skiba, U., Jones, S. K., Drewer, J., Helfter, C., Anderson, M., Dinsmore, K., McKenzie, R., Nemitz, E., and Sutton, M. A.: Comparison of soil greenhouse gas fluxes from extensive and intensive grazing in a temperate maritime climate, Biogeosciences, 10, 1231-1241, doi:10.5194/bg-10-1231-2013, 2013.

Abstract

Greenhouse gas (GHG) fluxes from a seminatural, extensively sheep-grazed drained moorland and intensively sheep-grazed fertilised grassland in South East (SE) Scotland were compared over 4 yr (2007–2010). Nitrous oxide (N2O) and methane (CH4) fluxes were measured by static chambers, respiration from soil plus ground vegetation by a flow-through chamber, and the net ecosystem exchange (NEE) of carbon dioxide (CO2) by eddy-covariance. All GHG fluxes displayed high temporal and interannual variability. Temperature, radiation, water table height and precipitation could explain a significant percentage of seasonal and interannual variations. Greenhouse gas fluxes were dominated by the net ecosystem exchange of CO2 at both sites. Net ecosystem exchange of CO2 and respiration was much larger on the productive fertilised grassland (−1567 and 7157 g CO2eq m−2 yr−1, respectively) than on the seminatural moorland (−267 and 2554 g CO2eq m−2 yr−1, respectively). Large ruminant CH4 (147 g CO2eq m−2 yr−1) and soil N2O (384 g CO2eq m−2 yr−1) losses from the grazed grassland counteracted the CO2 uptake by 34%, whereas the small N2O (0.8 g CO2eq m−2 yr−1) and CH4 (7 g CO2eq m−2 yr−1) emissions from the moorland only impacted the NEE flux by 3%. The 4-yr average GHG budget for the grazed grassland was −1034 g CO2eq m−2 yr−1 and −260 g CO2eq m−2 yr−1 for the moorland.

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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.

Makhosazana Sika: Biochar and soil researcher


Makhosazana was born to be a soil scientist!

Makhosazana Sika grew up in Soweto, Johannesburg, South Africa. Having lived in a city throughout her childhood, she would not have guessed a decade ago that she would call a small town in the Cape Winelands District her other home. Continue reading

Solid Earth: Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters


A. Morugán-Coronado, V. Arcenegui, F. García-Orenes, J. Mataix-Solera, and J. Mataix-Beneyto. 2013. Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters. Solid Earth, 4, 119-127.

Abstract
The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. These indices represent the balance reached among properties in “steady state” soils. This study was carried out in four study sites from SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.

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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.