Impact of harvest residues, fertilisers and N-fixing plants on growth and nutritional status of young Eucalyptus globulus plantations under Mediterranean conditions

Growth and nutritional status of young plants of Eucalyptus were assessed in a field trial, under different scenarios of harvest residue management and nutrient availability. Treatments were as follows: incorporation of harvest residues into the soil by harrowing (I); I with N fertiliser application (IF); I with leguminous, Lupinus luteus L., seeding (IL); removal of harvest residues (R); R with N fertiliser application (RF); R with leguminous seeding (RL); distribution of harvest residues on the soil surface (S); S with N fertiliser application (SF). Treatments were replicated four times in four blocks with a fully randomised design. Tree growth (height and diameter at breast height) was measured and understory biomass destructively recorded. Tree nutritional status was assessed by foliar analysis (N, Ca, Mg, P, K and leaf area). Significant differences in growth between I, R and S treatments were only detected at early stage. Intercropping with Lupinus decreased tree growth during the early phase, but after 5 years growth was similar to that measured in the I and R treatments. Application of fertiliser enhanced tree growth especially when harvest residues were retained on the soil surface. Combining incorporation of harvest residues with fertiliser application (IF) was the best option to increase tree growth, which was significantly greater than in the R and S. Initially, leaf N was positively affected by the leguminous (RL and IL), but, after the first fertiliser application (1 year after planting), greater N was observed in the IF, RF and SF, the difference decreasing gradually over the following year

Studies on the association of the Quercus suber decline disease with Phytophthora cinnamomi in Portugal

En Portugal, la enfermedad de la “seca” se ha descrito en los Quercus de hoja perenne (Quercus suber L. and Q.ilex subsp. rotundifolia Lam.) desde el final del siglo XIX. La mortalidad de estas especies afecta, particularmente las regiones centrales y meridionales del país, siendo uno de los problemas forestales más graves. Phytophthora cinnamomi Rands es el principal patógeno responsable de la mortalidad de alcornoques y encinas en Portugal. Se han desarrollado varios estudios teniendo como objetivo una mejor comprensión del efecto de la acción de P. cinnamomi en el decaimiento de los Quercus. El actual trabajo describe resultados preliminares de algunos de estos estudios.___________________________________In Portugal, the decline disease has been described in evergreen oaks (Quercus suber L. and Q.ilex subsp. rotundifolia Lam.) since the end of the 19th century. The mortality of these species affects, particularly the central and southern regions of the country, being one of the most severe forest problems. Phytophthora cinnamomi Rands is the main pathogen responsible for the cork and holm oak mortality in Portugal. Several studies have been developed aiming at a better understanding of the effect of the P. cinnamomi action on the cork oak trees decline. The present work describes preliminary results of some of these studies

Local factors have a greater influence on the abundance of alfalfa weevil and its larval parasitoids than landscape complexity in heterogeneous landscapes

Context The alfalfa weevil Hypera postica Gyllenhal (Coleoptera: Curculionidae) is one of the most destructive pests of alfalfa worldwide. Both local and landscape-scale factors can significantly infuence crop pests, natural enemies, and the efectiveness of biological control services, but the relative infuence of these factors is unclear. Objectives We investigated the infuence of the local variables and surrounding landscape composition and configuration on the abundance of alfalfa weevil, and on the abundance and parasitism rates of its larval parasitoids, Bathyplectes spp. Methods We sampled 65 commercial alfalfa fields along the Ebro Basin, Spain, over a period of 3 years, recording the field characteristics and landscape structure at three buffer radii of 250, 500 and 1000 m from the center of each field. Results The abundance of weevil larvae was positively associated with the field perimeter and with the uncut alfalfa surrounding the pipes of the sprinkler irrigation system, but only one configuration variable was positively correlated: the alfalfa edge density. No local characteristics or landscape structures were associated with the abundance of adult weevils. The abundance of Bathyplectes spp. adults was positively associated to local factors such as the densities of alfalfa weevils and aphids. Few landscape structure variables, such as alfalfa edge density and Simpson’s Diversity Index, had explanatory value only at 250 m buffer radius. The rate of larval parasitism was affected by local variables, such as alfalfa weevil abundance and field age. Conclusion Our results provide, for the first time in the Mediterranean region and Europe, evidence of the relative importance of landscape structure and local factors on the abundance of the alfalfa weevil and its larval parasitoids, Bathyplectes spp. The strongest infuences were based on local characteristics.Springer Nature; Spanish Government; Universitat de Lleida; Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Caracterização da cadeia produtiva de brássicas no Brasil

Brassica crops worldwide provide the greatest diversity of products used by man derived from a single genus. Collectively, leafy, flower and root vegetables can be eaten fresh, cooked and processed. The production of these vegetables in Brazil has been growing exponentially in the last decades, due to its economic importance, with major production volumes in several states and a quick monetary return for growers in areas considered of small acreage. With expansion, a number of aspects, including demands for quality and safety of these foods introduce themselves, strictly attached to the forms of production, logistics and their appearance. To meet the challenges and list the trends within the activities of different agents, a multiple case study was held in the states of Amazon, Minas Gerais, Paraná and Rio de Janeiro. Altogether, 55 stakeholders were interviewed, along with the compilation of different sources of data to characterize this productive chain. Changes in the scenario are imperative in order to maintain the activity of overcoming years, being related to cultivars adaptation, plant health, productions costs and difficulties during the establishment of crops. To overcome these adversities, a collective effort in terms of organization, technology transfer and R&D from official and private agents, technical assistance, and regional sanitary inspection is imperative, aiming, especially, in actions regarding themes like protected cultivation, mechanization/automation and adding value to products by processing and packaging, listed by stakeholders as priority. © 2019, Sociedade de Olericultura do Brasil. All rights reserved

Morphological Interpretation of Reflectance Spectrum (MIRS) using libraries looking towards soil classification

The search for tools to perform soil surveying faster and cheaper has led to the development of technological innovations such as remote sensing (RS) and the so-called spectral libraries in recent years. However, there are no studies which collate all the RS background to demonstrate how to use this technology for soil classification. The present study aims to describe a simple method of how to classify soils by the morphology of spectra associated with a quantitative view (400-2,500 nm). For this, we constructed three spectral libraries: (i) one for quantitative model performance; (ii) a second to function as the spectral patterns; and (iii) a third to serve as a validation stage. All samples had their chemical and granulometric attributes determined by laboratory analysis and prediction models were created based on soil spectra. The system is based on seven steps summarized as follows: i) interpretation of the spectral curve intensity; ii) observation of the general shape of curves; iii) evaluation of absorption features; iv) comparison of spectral curves between the same profile horizons; v) quantification of soil attributes by spectral library models; vi) comparison of a pre-existent spectral library with unknown profile spectra; vii) most probable soil classification. A soil cannot be classified from one spectral curve alone. The behavior between the horizons of a profile, however, was correlated with its classification. In fact, the validation showed 85 % accuracy between the Morphological Interpretation of Reflectance Spectrum (MIRS) method and the traditional classification, showing the importance and potential of a combination of descriptive and quantitative evaluations