Assessment of environmental impacts of agricultural practices
- Autores: Awais Shakoor
- Directores de la Tesis: Angela Dolores Bosch Serra (dir. tes.), José Ramón Olarieta Alberdi (codir. tes.)
- Lectura: En la Universitat de Lleida ( España ) en 2022
- Idioma: inglés
- Tribunal Calificador de la Tesis: María Rosa Yagüe Carrasco (presid.), Rosa Maria Poch Claret (secret.), Francesc Domingo Olivé (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología Agraria y Alimentaria por la Universidad de Lleida
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Intensive agricultural management practices contribute to significant greenhouse gas emissions (GHGs), nitrate (NO3-) leaching from the soil, and increased soil heavy metal content. Hence, it is extremely important to evaluate these agricultural practices in terms of their ecological feedback effects in agro-ecosystems. From the data-synthesis (48 peer-reviewed publications) on animal manure, it appears that the application of animal manure together with nitrogen fertilizer is the main contributor to higher GHGs emissions (i.e., CO2, CH4, N2O). Poultry manure was responsible for higher GHGs emissions from croplands when compared to pig and cattle manure. In another data synthesis, where we selected 50 peer-reviewed publications, no-till (NT) agriculture resulted in an increase in GHGs emissions, CO2 by 7.1%, N2O by 11.9%, and CH4 by 20.8%, compared to conventional tillage. However, a meta-analysis of only those studies that measured the emissions of the three gases showed that NT reduces global warming potential (GWP) by 7.5% in comparison to conventional tillage. Therefore, no definite conclusion can be reached, and further work is required to elucidate the effects of both practices in terms of GHGs. In Mediterranean rainfed agriculture, the fallow periods can be included within the existing EU common policy for crop diversification as an agronomic practice. In this field, this research aimed to quantify the effects of previous mineral fertilization on the soil mineral nitrogen (N) content and on potential NO3- leaching during fallow periods of a crop rotation using the LEACHM model. The estimate of N leached ranged from 11 to 98 kg N ha-1. Finally, a field experiment showed in the mid-term (7 years) that pig slurry significantly increased soil organic carbon (OC) from 13.5 to 24.7 kg ha-1 for every ton of slurry OC applied. The concentrations of B, Cu, and Zn increased in the soil surface horizon over time. Moreover, pig slurry also increased the bioavailability of Cu and Zn, but not at toxic levels. From this research work, it can be concluded that the effectiveness and the environmental impacts of different agricultural land use practices will vary depending on soil and climatic conditions. Such conditions may be included in the framework of policy incentives and regulations related to the use of fertilizers and manures in order to prevent the negative environmental impacts associated with their management in agriculture. Keywords: agricultural management practices; meta-analysis; GHGs emissions; Mediterranean rainfed agriculture; LEACHM model; nitrate leaching; soil heavy metal
