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RESUMO -A Acacia holosericea é uma espécie leguminosa arbórea bastante utilizada na recuperação de áreas degradadas. O conhecimento dos sintomas de deficiência nutricional apresentados por esta espécie possibilita a identificação e a correção de deficiências em exemplares plantados em substratos degradados. Os objetivos deste trabalho foram caracterizar a sintomatologia visual de carências de macronutrientes e avaliar a produção de biomassa e o acúmulo de nutrientes nas raízes e na parte aérea de mudas de Acacia holosericea, submetidas a diferentes soluções nutritivas com exclusão de macronutrientes. Os tratamentos constituíram-se de sete soluções nutritivas: 1) solução completa (SC); 2) SC -N; 3) SC -P; 4) SC -K; 5) SC -Ca; 6) SC -Mg; e 7) SC -S. Os tratamentos -N e -Mg foram os que mais afetaram a produção total de biomassa. O decréscimo de produção manifestou-se na seguinte ordem: -N = -Mg > -K > -S > -Ca > SC > -P. As plantas do tratamento -N formaram nódulos no sistema radicular, exibindo teores foliares de N maiores que as plantas do tratamento SC. Com exceção dos tratamentos SC e -P, todos os outros apresentaram sintomas de deficiência. A ausência de S alterou a disposição natural dos filódios novos da A. holosericea. Palavras-chave:Leguminosas arbóreas, recuperação de áreas degradadas, nutrição de plantas e Acacia holosericea. SYMPTOMS OF NUTRITIONAL DEFICIENCY IN SEEDLINGS OF Acacia holosericea SUBMITTED TO ABSENCE OF MACRONUTRIENTS ABSTRACT -Acacia holosericea is a leguminous species that has been extensively used in land reclamation programs. The knowledge of its nutritional symptoms allows the identification and correction of deficiencies in

Monitoring and evaluating forest restoration projects is a challenge especially in largescale, but the remote monitoring of indicators with the use of synoptic, multispectral and multitemporal data allows us to gauge the restoration success with more accurately

Abstract:Termites play a critical role in the regulation of soil processes, for example, water retention, nutrient cycling, and the formation and maintenance of soil structure. There is a consensus that mound-building termites modify physical and chemical soil properties in clay soils, but there is limited investigation into their influence for sandy soils in the Brazilian Atlantic rain forest. We tested the hypotheses that the termitosphere effectively improves properties of sandy soil, and that the role of termite soil particle selection is of greater importance in soils with higher sand concentration and lower nutrient status. The work was conducted in three vegetation physiognomies: woodland, savanna and grassland. In the woodland physiognomy we sampled in the border and in the interior, totalling four studied areas. We described a soil profile and collected five samples of termitaria and surface soil in each area. Also, in three 100-m2 plots allotted in each area, termite-mound density and volume were estimated, and termites were collected for taxonomic identification. Soil samples were submitted to physical and chemical analysis, and regression models were employed to analyse termite particle selection ability in different soil conditions. In most areas, the concentrations of nutrients, organic carbon and clay-size particles were significantly higher in termite mounds than in surface soils. On a weight basis, termite mounds had up to 32 times more nutrients, 12 times more organic carbon, and five times more clay than surrounding soils, however, aluminium toxicity was lower in termite mounds. Regression models demonstrated that the role of termites in soil particle selection is of greater ecological importance with decreasing soil nutrient status and increasing sand concentration. Therefore, termites greatly improve soil properties, representing truly ecosystem engineers in sandy soils, with an average soil turnover by mound-building activity reaching 10.5 m3 ha−1.

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