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Soil management principles in climate-smart conservation <BR>agriculture to halt and reverse land degradation (Communication session)
EUROSOIL2020CONT-1849
IMPACT OF SOIL COVERING AND TILLAGE ON SOIL PHYSICAL QUALITY IN NORTHERN ITALY
Felice Sartori* 1, Ilaria Piccoli1, Antonio Berti1
1DAFNAE, University of Padova, Legnaro (PD), Italy
Content: Despite Conservation Agriculture (CA) is broadly considered a soil improving cropping system, its application in Europe is still limited to less than 3% of the total cropland. The reason could be the controversial results obtained, especially in the transition period from conventional tillage (CV) to CA. One of the main issues during this phase is soil compaction, due to the slow dynamics of soil C and, thus, the slow improvement of soil structure. Maintaining and improving soil physical quality is then a crucial aspect passing from CV to CA.
In this work, the effects of three different soil tillage intensities (conventional: ploughing and harrowing; minimum: harrowing; no-till: sod seeding), in combination with three soil coverings (bare soil, winter wheat and tillage radish), were monitored on soil physical property in a two-year experiment, in order to determine which combination could mitigate soil compaction.
The experiment was conducted at field scale in a typical northern Italy farm, with a silty loam soil, high bulk density along all the profile (>1.35 g/cm3), the presence of a plough-pan, and low organic carbon content. Saturated soil hydraulic conductivity (ks) was measured after the first and the second year of the experiment, with the double ring infiltrometer method, to simulate a vertical flux. Higher ks values are associate to a lower risk of water logging and, in general, to better soil function. At the end of the second year, penetration resistance in the 0-80 cm profile was also measured. In this case, higher levels of penetration resistance are in general correlated with higher soil compaction and lower root growth.
Even though tillage radish should reduce soil compaction and improve soil physical quality, in this experiment it showed contrasting results. Specifically, it was associated with lowest ks values. Moreover, it needed a strict sowing schedule, and, in both years, it was not frost-killed during the winter. These issues, and the relative high seed price, seem to reduce the potential of this cover crop. Winter wheat, in contrast, was associated with lower soil compaction both in no tillage and minimum tillage. After the first two years of contrasting tillage and cover crop management, winter wheat showed the best results in terms of ks improvement (more than double, compared to other soil covering) and penetration resistance reduction. Furthermore, the seeds are cheaper than tillage radish, and it has a larger seeding time window, that reduces the risk of crop failure.
After two years of the experiment, the minimum tillage combined with the winter wheat cover crop seems to ensure the cropping system sustainability. Northern Italy soils requires longer transition time from conventional tillage to CA, therefore long term effects of the treatments need to be evaluated. At the same time economic sustainability must be ensured every year, and to that end, this factor combination seems the most promising.
The research leading to these results has received funding from the European Union HORIZON2020 Programme for research, technological development and demonstration under grant agreement no 677407. (SOILCARE project).
Disclosure of Interest: None Declared
Keywords: conservation agriculture, Cover crop, minimum tillage, no-tillage, Soil compaction, soil hydraulic properties, sustainable agriculture