Growth of native trees in two agroforestry systems.

Agroforestry systems with eucalyptus prevail in Central and Southeast Brazil, and little information is available about systems using native trees. The aim of the present study was to evaluate the development of seven native tree species grown under two agroforestry systems. The experiment was conducted starting in 2007 in 12-hectare area in the municipality of São Carlos, São Paulo state, Brazil. The tree species planted in the two systems (a silvopastoral system and an agrisilvicultural system) were: 'capixingui' (Croton floribundus) and 'mutambo' (Guazuma ulmifolia) (tutors), 'jequitibá-branco' (Cariniana estrellensis), 'canafistula' (Peltophorum dubium) and 'ipê felpudo' (Zeyheria tuberculosa) (timber trees), and 'angico-branco' (Anadenanthera colubrina) and 'pau-jacaré' (Piptadenia gonoacantha) (N-fixing trees). Data were collected for 48 months. The results show differences among tree development, which was evaluated as growth in height and diameter, as well as sensitivity to insect and disease damage. The overall results show that the agrisilvicultural system allowed better tree development. The species with best performance in the two systems were capixingui, mutambo and canafístula. Ipê-felpudo and jequitibá-branco showed the worst results. The high variability among individuals of the same species indicates the possibility of high production advances with selective breeding of these species.

Nutrient content in aboveground biomass of Brazilian peanut cultivars in conservation tillage on sugarcane straw and pasture area.

Fields studies were conducted in 2004/2005 in order to evaluate the effects of tillage on nutrient content in aboveground biomass of two peanut cultivars, cultivated in rotation after mechanical harvested sugarcane and pastures. These trials were carried out in two types of soils; Oxisol and Ultisol, respectively in Ribeir?ao Preto and Mirassol, S?ao Paulo State, Brazil. The experimental design was split-plot with four replications. Tillage treatments (conventional, minimum and no-tillage) were main plots while sub-plots were peanut genotypes IAC-Tatu ST (Valencia market-type, erect growth habit, red seed coat, maturity range around 100 days after planting) and IAC-Caiap´o (Runner market-type, prostate growth habit, pink testa, maturity range more than 135 days). From 15 to 90 days after emergence, samples of leaves and stems were harvested, dried, weighted and ground to determine macro and micronutrient concentration. At 75 days after sowing, the cultivar IAC-Caiap´o showed higher contents of N, P, K, Cu, and Zn while IAC-Tatu presented higher concentrations of Ca, Mg, and S. Zn content was higher in conservation tillage than in conventional, mainly in Oxisoil for both of cultivars.

Initial growth of sunflower in soils with high concentrations of boron and heavy metals.

Phytoremediation studies have been conducted in an area contaminated by heavy metals, located in Piracicaba - SP, Brazil. This area was contaminated accidentally by the addition of auto scrap shredding to the soil and was limed later to reduce heavy metal mobility in the environment. Previous characterization showed that it also presents high concentration of boron, which has limited the initial plant development of some species. As sunflower plants require a high boron supply and the literature describes its use in the phytoremediation of soils contaminated with heavy metals under some conditions, the aim of this work was to evaluate its potential for the remediation of this area. In the present study, the results of preliminary tests are presented, aiming at the evaluation of sunflower plant germination and its initial development when cultivated in the contaminated soil described. Two sunflower hybrids were sown in soils treated with different rates of boron and in the soil from the contaminated area in study. The results showed that sunflower plants had a normal initial development, even in the soil from the contaminated area. Therefore, sunflower is a promising crop and further studies will be developed to evaluate the sunflower efficiency in phytoextraction or phytostabilization of heavy metals in areas where boron contamination also occurs, as is the case in the study area.

Different levels of water deficit induces changes in growth pattern but not in chlorophyll fluorescence and water relations of Hancornia speciosa Gomes seedlings.

Hancornia speciosa Gomes é uma espécie conhecida popularmente no Brasil como mangabeira, cujo fruto apresenta alto valor nutricional. O conhecimento sobre a sua fisiologia é ainda escasso, principalmente no que se refere ao desenvolvimento inicial. Dessa forma, o objetivo do presente trabalho foi avaliar os efeitos de diferentes níveis de déficit hídrico sobre o padrão de crescimento, fluorescência de clorofila e relações hídricas em mudas de mangabeira. Foi utilizado um esquema fatorial (tratamentos x época de avaliação) com quatro tratamentos hídricos com base na capacidade de campo (CC) (80%, 60%, 40% e 20%), com cinco repetições. Foram avaliados a altura das plantas, número de folhas, diâmetro do caule, produção e partição de biomassa, eficiência quântica do fotossistema II (PSII), potencial hídrico (?w), teor relativo de água (TRA) e teor de carboidratos, proteínas e prolina. O déficit hídrico severo (20% CC) levou a uma redução no crescimento e alterou o padrão de partição de biomassa nas mudas. No entanto, as relações hídricas não foram significativamente afetadas, pois as mudas mantiveram altos valores de ?w e TRA, sem acúmulos significativos nos teores de solutos orgânicos quando cultivadas com 20%CC. Além do mais, a eficiência quântica do PSII não foi afetada pelos diferentes regimes hídricos, sugerindo que não houve fotoinibição devido ao estresse hídrico. A mudança no padrão de crescimento, com um incremento no aprofundamento das raízes e redução no crescimento da parte aérea parece ser a principal estratégia das mudas de H. speciosa para a manutenção da hidratação dos tecidos durante períodos de déficit hídrico.

Effects of small scale non-mechanised forest management and high impact and mechanised forest management on the forest dynamics and growth of the residual trees.

This study was perfonned in PSPs located at the CPAr-ACRE EMORAPA expcrirnental area and at the PC Peixoto management areas. AI CPA F-ACR E the managed area was meehanically exploited in 1992 and at PC Peixoto animal traction was used to extract the planks.