Chemical and structural characterization of soil humic substances under agroforestry and conventional systems

Studies have proven that the agroforestry systems in the semi-arid region of the State of Ceará, Brazil, induce an increase in soil organic C levels. Notwithstanding, there is no information if this increase also results in qualitative changes in different pools of soil organic matter. The objective of this study was to verify the possible chemical and structural alterations in fulvic and humic acids of a Luvisol in areas adopting agroforestry, traditional intensive cultivation and native forest in a long-term experiment conducted in the semi-arid region of Ceará State, Brazil. The study was conducted in an experimental area of the National Goat Research Center (Embrapa) in Sobral, CE. The following treatments were evaluated: agrosilvopasture (AGP), silvopasture (SILV), intensive cultivation under fallow (ICF), and areas with native forest (NF). Soil fulvic and humic acids fractions were extracted from the 0-6 and 6-12 cm layers and characterized by elemental composition, thermogravimetry and infrared spectroscopy analyses. The elemental composition analysis of humic acids confirmed the data found for fulvic acids, showing reduction in the C, H and N levels, followed by an increase in O contents in the AGP and ICF treatments over SILV and NF. In all treatments, except to SILV in the 0-6 cm layer, the percentage of mass loss was highest (300-600 °C) for humic acids in the thermally most stable region. Despite the similarity between infrared spectra, soil fulvic acids in the SILV treatment extracted from 6-12 cm depth decrease the absorption bands at 1708 and 1408 cm-1 followed by an increase in the absorption band at 1608 cm-1 attributed to aromatic C=C groups. This behavior suggests an increase in the aromatic character of the structure. The AGP and ICF treatments, which increase the soil tilling, favored the maintenance of humic substances with a more aromatic character in the soil than SILV and NF. The less aromatic humic substances in the SILV treatment resulted in an increase of exchange sites of soil organic matter, indicating improved nutrient cycling and maintenance of productivity in the system.

ASPECTS OF THE SILVOPASTORAL SYSTEM CORRELATED WITH PROPERTIES OF A TYPIC QUARTZIPSAMMENT (ENTISOL) IN MATO GROSSO DO SUL, BRAZIL

In Brazil, grazing mismanagement may lead to soil and pasture degradation. To impede this process, integrated cropping systems such as silvopasture have been an effective alternative, allied with precision agriculture based on soil mapping for site-specific management. In this study, we aimed to define the soil property that best sheds light on the variability of eucalyptus and forage yield. The experiment was conducted in the 2011/12 crop year in Ribas do Rio Pardo, Mato Grosso do Sul State, Brazil. We analyzed linear and spatial correlations between eucalyptus traits and physical properties of a Typic Quartzipsamment at two depths (0.00-0.10 and 0.10-0.20 m). For that purpose, we set up a geostatistical grid for collection at 72 points. Gravimetric moisture in the 0.00-0.10 m layer is an important index of soil physical quality, showing correlation to eucalyptus circumference at breast height (CBH) in a Typic Quartzipsamment. With an increase in resistance to penetration in the soil surface layer, there is an increase in eucalyptus height and in neutral detergent fiber content in the forage crop. From a spatial point of view, the height of eucalyptus and the neutral detergent fiber of forage can be estimated by co-kriging analysis with soil resistance to penetration. Resistance to penetration values above 2.3 MPa indicated higher yielding sites.

European Agroforestry Conference. 3rd. Book of Abstracts

Agroforestry is considered nowadays as a sustainable form of land management that is being promoted by different global institutions like FAO and its Global Alliance Smart Climate Agriculture to mitigate and adaptate to Climate change. The European Commission through the protection of landscape features, greening and Rural Development Programs is promoting the essential presence of woody vegetation across Europe, but in a way that is difficult to recognize by farmers. AGROFE and AGFORWARD projects are both demonstrating the important value of Agroforestry at European level, which together with EURAF are pushing European Commission to include measures enhancing Agroforestry. However, there is a need of a European Agroforestry Strategy that recognizes the drawbacks of Agroforestry to be implemented at European level. This strategy should include the main mechanisms to show farmers how to implement it and at the same time to get funded for the important ecosystem services that they provide when implementing agroforestry. AGFORWARD project has identified the main agroforestry practices in Europe, highlighting silvopasture, but showing the importance that others forms of agroforestry have to play like homegardens with multipurpose trees, or the adequate improvement of fallow lands where woody vegetation can enhance the levels of organic matter in the soil if adequately managed. AGFORWARD also shows the lack of information of the real implementation of agroforestry practices like forest farming, in spite of the important productive and ecosystem benefits it provides. EURAF through the participation in the different civil dialogue groups (CAP, Direct Payments and Greening, Forestry and Cork, Organic Farming, Arable, Environment and Climate Change and Rural Development) has included and promoted agroforestry within the European Agenda. The role of Agroforestry has been also enhanced in the Groups of experts of European Structural and Investments funds and as part of the European Network for Rural Development and its derived groups: innovation, evaluation and CLLD/LEADER. EURAF is pleased to announce that Agroforestry will be discussed as part of a focus group of the European Innovation Partnership, so, apply and join the group. This book represents the lastest findings on agroforestry in Europe, integrating the participation of researchers but also policy makers and farmers and farmers' associations. It was a pleasure for EURAF to integrate all this needed knowledge to be disseminated at European levels. On behalf of EURAF, I wish all of you a successful meeting and invite you to strengthen agroforestry within the different European Union countries when you go back home. Rosa Mosquera-LOSADA President of EURAF