A field experiment was carried out to investigate the effect of fertilization level on the phenolic composition of tronchuda cabbage (Brassica oleracea L. var. costata DC) external and internal leaves. Eight different plots were constituted: a control without fertilization, one with organic matter, and six experiments with conventional fertilizers (nitrogen, boron, and sulfur, two levels each). The phenolic compounds were analyzed by reversed-phase HPLC-DAD. External and internal leaves revealed distinct qualitative composition. In the internal leaves were found 15 phenolics (5 kaempferol and 10 cinnamic acid derivatives), whereas the external leaves presented 3-p-coumaroylquinic acid and 13 kaempferol derivatives. Principal component analysis (PCA) was applied to assess the relationships between phenolic compounds, agronomical practices, and harvesting time. Samples obtained with conventional practices were quite effectively separated from organic samples, for both types of leaves. In general, samples developed without any fertilization presented the highest phenolics amounts: external and internal leaves contained 1.4-and 4.6-fold more phenolic compounds than the ones that received conventional fertilizer, respectively, and the internal leaves presented 2.4 times more phenolics than the ones grown with organic amendment. Additionally, samples from organic production exhibited higher total phenolics content than those from conventional practices, collected at the same time. Samples harvested first were revealed to be distinct from the ones collected later. The results show that it is possible to grow tronchuda cabbage without excess fertilizers, with highest amounts of phenolics and reduced environment contamination.

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In a changing world, the search for new agronomic practices that help crops to maintain and/or increase yields and quality is a continuous challenge. We aim to evaluate kaolin (KL) and salicylic acid (SA) effectiveness as summer stress alleviating agents through physiological, biochemical and immunohistochemical analysis. Olive trees (Olea europaea L. cv. Cobrançosa) grown under rainfed conditions were sprayed with 5% KL and 100 μM SA, at the beginning of summer, during two consecutive years. KL enhanced relative water content (RWC), stomatal conductance (g s) net photosynthesis (A) and leaf indole-3-acetic acid (IAA) signal, and decreased leaf sclerophylly, secondary metabolites and non-structural carbohydrates accumulation and abscisic acid (ABA).The trees treated with SA showed changes on IAA and ABA dynamics, and an enhancement in RWC, g s , A, soluble proteins, and leaf P and Mg concentrations during the summer. Notably, KL and SA also allowed a faster restauration of the physiological functions during stress relief. In sum, KL and SA foliar sprays alleviated the negative effects induced by summer stress in olive trees performance, by modulation of distinct physiological and biochemical responses.

The phenolic compounds of Rumex induratus leaves were determined by HPLC-DAD-MS/MS-ESI. The results revealed a profile composed of 19 compounds: caffeoyl-hexoside, two p-coumaroyl-hexoside isomers, feruloyl-hexoside, sinapoyl-hexoside, 6-C-hexosyl-quercetin, 8-C-hexosyl-luteolin, 6-C-hexosyl-luteolin, 6-C-hexosyl-apigenin, 3-O-hexosyl-quercetin, 3-O-rutinosyl-quercetin, 7-O-hexosyl-diosmetin, 3-O-rutinosyl-isorhamnetin, 7-O-(acetyl)-pento-hexosyl-diosmetin, 6-C-hexosyl-genkwanin, and four unidentified O-glycosyl-C-glycosylflavones. The quantification of the identified phenolics by HPLC-DAD showed 6-C-hexosyl-luteolin as the main compound. Organic acid composition was determined by HPLC-UV, revealing a high content of oxalic acid. R. induratus was also investigated for its capacity to act as a scavenger of DPPH and superoxide radicals. Good antioxidative results were obtained against both radicals. Unlike other species of the genus Rumex, R. induratus did not present any anthraquinone derivative.

Olive orchards, rainfed managed, are threatened by the current and predicted adverse environmental conditions, which change the yield and quality of olive products, largely known for its benefits to human health. To mitigate these problems, it is highly recommended to perform some adjustments in agronomic practices, such as the use of foliar sprays that cloud help the trees to cope with climate change. During two consecutive years, olive trees were pre-harvest sprayed with kaolin (KL) and salicylic acid (SA) to attenuate the adverse effects of summer stress. Olive yield was increased by 97% and 72% with KL and SA, respectively. Phenolics and antioxidant capacity of both olives and olive oil increased and decreased in the first and second year, respectively, in a closely association with the prevailing climatic conditions. The foliar sprays did not significantly affect the oil quality indices, free acidity, peroxide value and K 232 coefficient and decreased the K 270 coefficient. This study strongly suggests that the applied products might be effective in mitigating the adverse environmental conditions, without substantial changes in fruit and olive oil quality.

The current increase in the organic agriculture sector has created a new market for fertilisers approved for organic farming. Off-farm N sources for organic farming are scarce considering the restriction on the use of chemical fertilisers. Thus, when some commercial products are allowed for organic agriculture, commercial opportunities became available. In this study we compare the behaviour of Vegethumus (Veg) and Phenix (Phe), which are two manures allowed for organic farming, with several other manures, ammonium nitrate (AN) and control treatments. A three year field trial and a pot experiment were carried out in order to estimate dry matter yield, N uptake, and N nutritional status of the crops, as well as soil N availability by using anion exchange membranes inserted into the soil. Apparent N recoveries in the field trial were 6.3 % and 58.2 % in Veg and AN plots, respectively, after the application of 380 kg N/ha in the previous 5 growing seasons. In the pot experiment the ANR of Veg and Phe were -5.0 % and 13.6 %, respectively, while in AN pots it was 37.1%. The other organic manures used in the pot experiment gave higher apparent N recoveries than Veg and Phe if their C:N ratios or inorganic-N contents were taken into account. This work stresses that the use of manures approved for organic farming must first be carefully considered by farmers, with reference to price and agronomic value.

Jerusalem artichoke is commonly grown for its edible tubers, livestock feed and as an ornamental. The possibility of growing Jerusalem artichoke for energetic purposes has aroused scientific interest in this species. Despite several studies that have already been done in the last few decades, many aspects of the cropping practice are still relatively unknown. During the growing seasons of 2004-2006 field trials were carried out in NE Portugal. In the experimental period different cropping conditions were imposed, regarding planting density, N fertilization and propagation method. (2006) conditions. Nitrogen significantly increased tuber yield in 2005 only when seed-tubers were used. Averaged across N fertilization rates and planting densities mean tuber dry matter yields were 12.8 and 6.9 Mg ha -1 for seed-tuber and botanical-seed, respectively. Leaf mineral composition was little affected by cropping practices. The 'Bragança' clone showed high tuber yield potential, although the mean weight of the individual tubers was low which could make mechanization of the harvest difficult. The poor results achieved with botanicalseed argue against its use as an alternative to the seed-tubers.Additional key words: botanical-seed, leaf mineral composition, nitrogen fertilisation, planting density, seed-tuber. Resumen Producción de tubérculos y composición mineral en hojas de pataca (Helianthus tuberosus L.) utilizando diferentes prácticas de cultivoLa pataca se cultiva por sus tubérculos comestibles, también se utiliza como forraje y como planta ornamental. La perspectiva de que se pueda cultivar con fines energéticos ha incrementado el interés por esta especie. -1 ) combinados de forma factorial con las densidades de plantación. La máxima producción de materia seca en tubérculos fue de 18,4 Mg ha -1 (65,6 Mg ha -1 , en peso fresco) y se obtuvo en las parcelas en las que se combinaron 100 kg N ha -1 , 2 plantas m -2 y propágulos vegetativos. La mejor densidad de plantación fue de 2 plantas m -2 , tanto en regadío como en secano. La aplicación de nitrógeno aumentó significativamente la producción, pero sólo cuando se utilizaron propágulos vegetativos. Con propágulos vegetativos y semilla botánica se obtuvieron producciones medias de materia seca de 12,8 y 6,9 Mg ha -1 , respectivamente. La composición mineral de las hojas se vio poco afectada por la técnica de cultivo. El clon 'Bragança' ha mostrado elevado potencial de producción, aunque el peso medio de los tubérculos individuales haya sido bajo, lo que puede dificultar la mecanización de la cosecha. Los bajos resultados obtenidos a partir de semilla botánica disuaden su uso en alternativa a los propágulos vegetativos.Palabras clave adicionales: composición mineral de las hojas, densidad de plantación, fertilización nitrogenada, semilla botánica, tubérculo-semilla.

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