Concentrações de alguns macro e micronutrientes em essências florestais do parque da Escola Superior de Agricultura «Luiz de Queiroz»

Five trees growing on the campus of Escola Superior de Agricultura "Luiz de Queiroz" were analysed in relation to their macro and micronutrient concentrations. These trees belong to the following species: Aspidosperma polyneuron Mitell, Tabebuia roseo-alba, Aleurites moluccana Willd, Cariniana estrellensis Randü, and Piptadenia rigida. Three samples of young, intermediate and old leaves were collected from each of the above species. The 15 samples obtained, were washed for micronutrient analysis, dried in an incubator at 70°C, macerated and analysed for N, R, K, Ca, Mg, Cu, Fe, Mn and Zn. Each analysis was repeated three times. The differences between treatments (trees and leaf types were analysed according to the completely randomised statistical design. The following observations were made: a) At least one of the trees differed from the others in relation to nutrient concentration. b) The nutrients that appeared in higher concentration were N and Ca in all trees, but Aleurites mollucana Willd, presented higher concentrations of N and K. c) Piptadenia rigida and Corinmna estrellensis Raddi, showed higher concentrations of Fe than other species. d) Young leaves showed a tendency to have high concentrations of N, R, K and Cu.Em cinco árvores do parque da Escola Superior de Agricultura "Luiz de Queiroz", pertencentes às espécies, Aspidospernia polyneuron Müell, Cariniana estrellensis Raddi, Paratecoma peroba Record, Aleurites moluccana Wield e Piptadenia rígida, foram coletadas três amostras constituídas de folhas consideradas novas, medianas e velhas, aparentemente. As 15 amostras obtidas foram lavadas para micronutrientes, secadas em estufa a aproximadamente 70ºC, moídas e analisadas sob três repetições, quanto a seus teores em N, R, K, Ca, Mg, Cu, Fe, Mn e Zn. O delineamento experimental utilizado foi o inteiramente casualizado, e as diferenças estatísticas significativas entre as médias dos vários tratamentos, detectadas pela análise de variância, foram comparadas através do teste Tukey. Os seguintes contrastes puderam ser observados : a) Pelo menos uma árvore dentre as cinco, diferiu das demais quanto à concentração relativa de cada um dos nutrientes considerados . b) Em todas as árvores estudadas, com exceção da pertencente à espécie Aleurites moluccana (nogueira de Iguape), os nutrientes constatados em maior concentração foram o N e o Ca, enquanto que, na nogueira detectou-se maior concentração de N e K. c) Piptadenia rígida (angico branco) e Cariniana estrellensis (jequitibá branco) mostraram concentrações particularmente elevadas de Fe. d) Genericamente, as folhas novas das essências observadas apresentaram tendência de possuírem maiores concentrações de N, R, K e Cu, enquanto as folhas velhas mostraram maiores concentrações de Ca e Mn

Potassium, calcium and magnesium nutritional requirements of sweet sorghum

Com os objetivos de avaliar as exigências do sorgo sacarino (Sorghum bicolor L.) em K, Ca e Mg, suas distribuições nos vários órgãos da planta, "consumo de luxo" em potássio e efeito conjugado da adubação potássica/extração pela cultura sobre o K "disponível" do solo foi conduzido um experimento no ano agrícola 82/83. Foram testadas quatro doses de K2O (zero, 50, 100 e 150 kg/ha, como KCl). Todas as parcelas foram submetidas a uma adubação com 120 kg/ha de N (uréia) e 100 kg/ha de P2O5 (superfosfato triplo) e uma calagem (1/2 SMP) com 2 t/ha de corretivo da acidez. Foi utilizada a cultivar BR-501, ajustando-se uma população de 140.000 plantas por hectare. Por ocasião da colheita amostraram-se cinco plantas por parcela, as quais foram desmembradas em folhas, colmos, panículas e órgãos residuais, sendo secadas, pesadas e procedidas determinações de K, Ca e Mg. Foi concluído que: para produzir 60,4 t/ha de colmos frescos não desfolhados, são exigidos 116 kg K/ha, 54 kg Ca/ha e 91 kg Mg/ha; o K acumula-se em maior quantidade nos colmos, enquanto que o Ca e o Mg nas folhas; o K, dependendo da dose, exerce efeitos sinergísticos sobre as quantidades de Ca e Mg das folhas; há um acentuado "consumo de luxo" em K, sendo o colmo o principal órgão acumulador; para se evitar um esgotamento do K do solo, as folhas devem ser deixadas na lavoura ou, então, o vinhoto deve ser adicionado às áreas exploradas. A field experiment was conducted in Pelotas (1983/84), RS, Brazil, with the following objectives: (a) evaluate potassium, calcium and magnesium, mineral nutrition requirements of sweet sorghum, (b) distribution of these elements in the plant, (c) luxury consumption of K, and (d) to verify the combined effect of potassium fertilization/absorption by the crop on the available K in the soil. Four treatments of K2O (zero, 50, 100 and 150 kg/ha) were used. All plots received 120 kg/ha of N, 100 kg/ha of P2O5 and 2 t/ha of limestone at seeding time. The cultivar used was BR-501 with a stand of 140,000 plants/ha and the crop was harvested 127 days after emergence. Plants were separated into the following components: leaves, stalks, panicles and plant residues. Potassium, calcium and magnesium were determined in the samples. The following conclusions were reached: (a) to produce 60.4 t/ha of fresh stalks + leaves, 116 kg/ha of K, 54 kg/ha of Ca and 91 kg/ha of Mg are needed; (b) content of K is higher in stalks, while Ca and Mg were higher in leaves; (c) K, depending on the K2O rate, (produces) synergistic or antagonistic effects on the Ca and Mg; (d) high luxury consumption of K occurs, accumulating mainly in stalks and finally, (e) to avoid K deficiency in soil, sorghum leaves should be left in the field or incorporation of vinasse (rich in K) is recommended.

Diagnosis of foliar potassium in saccharine sorghum: identification of the best plant organs and growth stage for sampling

Com o objetivo de selecionar em plantas de sorgo sacarino os melhores órgãos e o estádio fenológico da amostragem visando à diagnose do potássio, foi conduzido um experimento de campo em solo da Unidade de Mapeamento Pelotas (Planosol) no ano agrícola 82/83. O delineamento experimental utilizado foi o de blocos ao acaso com parcelas subdivididas, três repetições, com as doses de K2O (zero, 50, 100 e 150 kg/ha) nas parcelas e as épocas (emborrachamento-E5, florescimento-E6 e entre grãos, massa mole e massa dura E7/8) de coletas de plantas nas subparcelas. A cultivar de sorgo sacarino testada foi a BR-501. As plantas foram desmembradas em folhas, internódios, inflorescência e restos. Os resultados permitiram concluir que os melhores órgãos para a amostragem foram as folhas 5, 6, 7, 8, 9, 10, 11 e 12 e os internódios 3, 8, 9, 10, 11 e 12 e a melhor época de amostragem foi o emborrachamento.This experiment was carried out in field conditions during the agricultural year of 1982/83 at the Unidade de Execução de Pesquisa de Ambito Estadual of EMBRAPA, in Pelotas, RS, in a Pelotas soil unit, for the purpose of identifying the best parts and growth for sampling saccharine sorghum cv. BR-501, in order to make potassium diagnosis. The experimental design was a complete randomized block design with split plots, and three replications, with levels of potassium (0, 50,100 and 150 kg/ha) in the plots, and sampling times (boot stage, half-bloom, and between soft-dought and hard-dought) in the split plots. The plants were dissected into individual leaves, inflorescences, internodes and rests. The evaluations indicated that the best samples were leaves 5, 6, 7, 8, 9, 10, 11 and 12, and internodes 3, 8, 9, 10, 11 and 12 both when harvested at booting stage

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora