Soil nitrogen dynamics in fallow periods in a rainfed semiarid Mediterranean system
Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events. As an agronomic practice, fallow periods can be included even within the existing EU common policy for crop diversification. This research aimed to quantify the effects of a pr...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Universitat de Lleida (UdL) |
| Repositorio: | Repositori Obert UdL |
| OAI Identifier: | oai:repositori.udl.cat:10459.1/84566 |
| Acceso en línea: | https://doi.org/10.1016/j.pedsph.2022.06.051 http://hdl.handle.net/10459.1/84566 |
| Access Level: | acceso abierto |
| Palabra clave: | Nitrogen Composició dels sòls Anàlisi dels sòls Soil composition Soil analysis |
| Sumario: | Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events. As an agronomic practice, fallow periods can be included even within the existing EU common policy for crop diversification. This research aimed to quantify the effects of a previous mineral fertilization on the soil mineral nitrogen (Nmin) content and on potential nitrate leaching during no-tilled fallow periods of a crop rotation. Water and Nmin soil measurements obtained during three fallow seasons were used. Data were also used to check if the Leaching Estimation and Chemistry Model (LEACHM) can be used for the soil Nmin prediction after fallow. During these periods, the Nmin measured in the soil profile increased on average by 125 kg N ha-1, while the model averaged an increase of 95 kg N ha-1. The estimate of N leached ranged from 11 to 38 kg N ha-1. The N balance simulated using LEACHM might differ from the actual processes. After a drought period followed by a soil water replenishment, the calibrated LEACHM underestimated soil Nmin probably due to the 'Birch effect'. After occasional rainy spells when soil quickly became saturated, LEACHM overestimated soil Nmin probably due to occasional N2O emissions not being fully accounted by the model and to specific preferential water flow, which might produce a greater nitrate leaching than that simulated by LEACHM using the convection-dispersion equation. The results show that soil Nmin measurements by sampling after the fallow period cannot be replaced by LEACHM simulations. These samplings are of interest in fallow established inside a rotation and to avoid over-fertilization in the following cropping season, while reducing N environmental impacts. |
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