Evaluation of the productivity, content and nutrient use efficiency in genotypes of Eucalyptus spp. in Jequitinhonha valley, MG

A hibrida\ue7\ue3o de esp\ue9cies de eucalipto possibilita a obten\ue7\ue3o de h\uedbridos mais produtivos e com alta efici\ueancia de absor\ue7\ue3o e/ou utiliza\ue7\ue3o de nutrientes, dependendo das esp\ue9cies combinadas. Neste contexto, o presente trabalho, conduzido na regi\ue3o do Vale do Jequitinhonha, Minas Gerais, teve por objetivos: determinar a produtividade, o conte\ufado e a efici\ueancia de utiliza\ue7\ue3o de N, P, K, Ca e Mg de h\uedbridos interespec\uedficos de Eucalyptus spp. Para tanto, mediu-se o di\ue2metro \ue0 altura do peito (DAP) de todas as \ue1rvores presentes em cada parcela, e abateram-se tr\ueas \ue1rvores com di\ue2metro correspondente ao da \ue1rvore m\ue9dia. Procedeu-se \ue0 cubagem das \ue1rvores pelo m\ue9todo de Smallian, utilizando a altura, o di\ue2metro e a espessura de casca na base e a 25, 50, 75 e 100 % da altura comercial. O peso de material fresco do lenho, da casca, das folhas e dos galhos foi determinado no campo, e desses componentes se coletaram amostras para determina\ue7\ue3o do peso da mat\ue9ria seca. As amostras do tronco consistiram de discos coletados, com casca, na base e a 25, 50, 75 e 100% da altura comercial. As amostras de tecido vegetal foram analisadas para: N, P, K, Ca e Mg. Os resultados obtidos n\ue3o indicaram diferen\ue7as significativas para a produ\ue7\ue3o de biomassa de copa entre os h\uedbridos de eucalipto em conseq\ufc\ueancia de apresentarem mesma idade. Entretanto, a produ\ue7\ue3o de biomassa de tronco apresentou diferen\ue7as significativas sendo os h\uedbridos de Eucalyptus urophylla S. T. Blake proveniente de poliniza\ue7\ue3o natural mais produtivo em 50 e 69% em compara\ue7\ue3o aos h\uedbridos de Eucalyptus urophylla W. Hill. Ex Maiden com Eucalyptus grandis Dehnh.e de Eucalyptus urophylla com descendentes do cruzamento de Eucalyptus camaldulensis com Eucalyptus grandis respectivamente. Al\ue9m disso, aqueles h\uedbridos foram os que alocaram maior quantidade de biomassa no tronco (92,3%) em rela\ue7\ue3o \ue0 copa (7,7%), e ainda foram os mais eficientes na absor\ue7\ue3o e utiliza\ue7\ue3o de N, P, K, Ca e Mg. Concluiu-se que: 1) h\uedbridos de Eucalyptus urophylla provenientes de poliniza\ue7\ue3o natural ou controlada n\ue3o apresentam diferen\ue7a na produ\ue7\ue3o de biomassa de copa quando avaliados numa mesma idade; 2) a poliniza\ue7\ue3o controlada de Eucalyptus urophylla com Eucalyptus grandis e com descendentes do cruzamento de Eucalyptus camaldulensis com Eucalyptus grandis reduz a produ\ue7\ue3o de biomassa de tronco; 3) h\uedbridos de Eucalyptus urophylla provenientes de poliniza\ue7\ue3o natural s\ue3o mais produtivos e mais eficientes na absor\ue7\ue3o e utiliza\ue7\ue3o de N, P, K, Ca e Mg e 4) h\uedbridos de Eucalyptus urophylla provenientes de descendentes do cruzamento de Eucalyptus camaldulensis com Eucalyptus grandis s\ue3o menos produtivos e menos eficientes na absor\ue7\ue3o e utiliza\ue7\ue3o de N, P, K, Ca e Mg.The hybridization of eucalyptus species can provide more productive hybrids and with a high efficiency of nutrient absorption and, or, nutrient use, depending on the combined species. In this context, the present work was undertaken in the Jequitinhonha Valley region, Minas Gerais, and its objectives were: to determine the productivity, content and use efficiency of N, P, K, Ca and Mg in interspecific hybrids of Eucalyptus spp. In each plot, the diameters were measured at breast height (DBH) in all the trees, and three trees with diameter similar to the average mean were felled. The volume of the trees was estimated by the Smallian method, using the height, diameter and the bark thickness at the base and at 25, 50, 75 and 100 % of the commercial height. The fresh weight of the wood, bark, leaves and branches was determined in the field, and samples from them were collected for the determination of dry matter. The log samples consisted of collected disks with bark, from the base and at 25, 50, 75 and 100 % of the commercial height. The samples of vegetable tissues were analyzed for: N, P, K, Ca and Mg. The results obtained did not show significant differences for the production of crown biomass between the eucalyptus hybrids of the same age. However, the production of log biomass presented significant differences and the naturally pollinated hybrids of Eucalyptus urophylla were 50.0 % and 69.0 % more productive compared with the hybrids of Eucalyptus urophylla with Eucalyptus grandis and Eucalyptus urophylla with descendants of the crossing of Eucalyptus camaldulensis with Eucalyptus grandis, respectively. Also, these hybrids allocated larger amount of biomass in the log (92.3 %) in relation to the crown (7.7 %), and they were more efficient in the absorption and use of N, P, K, Ca and Mg. The conclusions were that: 1) same aged hybrids of Eucalyptus urophylla from natural or controlled pollinations did not differ in their crown biomass; 2) log biomass was reduced in the hybrids from controlled pollination between Eucalyptus urophylla with Eucalyptus grandis and Eucalyptus urophylla with descendants of the crossing of Eucalyptus camaldulensis with Eucalyptus grandis; 3) hybrids of Eucalyptus urophylla from natural pollination were more productive and more efficient in the absorption and efficiency of use of N, P, K, Ca and Mg and 4) hybrids of Eucalyptus urophylla with descendants of the crossing of Eucalyptus camaldulensis with Eucalyptus grandis are less productive and less efficient in the absorption and use of N, P, K, Ca and Mg

PARAMETERIZATION OF THE 3-PG MODEL FOR EUCALYPT IN THE REGION OF CERRADO IN MINAS GERAIS STATE

O modelo 3-PG \ue9 uma ferramenta eficaz para determina\ue7\ue3o do potencial produtivo de florestas de eucalipto. No entanto, as parametriza\ue7\uf5es deste modelo, hoje dispon \uedveis, produzem resultados subestimados quando aplicadas \ue0 regi\ue3o do Cerrado de Minas Gerais. Dessa forma, o objetivo deste trabalho foi parametrizar o modelo 3-PG para plantios de eucalipto localizados na regi\ue3o do Cerrado de Minas Gerais. Para isso, foram utilizados dados de povoamentos de h\uedbridos clonais de Eucalyptus grandis x Eucalyptus urophylla , com idades entre 3 e 84 meses, localizados nas regi\uf5es de Curvelo e Itacambira \u2013 MG. As estimativas de crescimento obtidas pelo modelo 3-PG foram comparadas com dados de crescimento de povoamentos florestais medidos nas duas regi\uf5es, at \ue9 a idade de 84 meses. O conjunto de valores de par \ue2metros e vari\ue1veis obtidos neste trabalho permitiu simular com acur\ue1cia, em termos das vari\ue1veis produzidas pelo modelo, os padr\uf5es de crescimento de povoamentos florestais presentes na regi\ue3o do Cerrado mineiro. Dessa forma, conclui-se que a parametriza\ue7\ue3o promoveu melhorias no desempenho do modelo que resultaram em estimativas acuradas de crescimento.The 3-PG model is an effective tool for determining the productive productivity of eucalypt plantations. However, the model parameterizations available today produce underestimated results when they are applied to Cerrado region of Minas Gerais state. Thus, in this paper we aimed to parameterize the 3-PG model for fast-growing eucalypt clonal plantations in the Cerrado region of Minas Gerais state, Brazil. To perform the parameterization, there were collected data from stands of Eucalyptus grandis x Eucalyptus urophylla clonal hybrid, throughout an age range, from very young stands (about 3 months old) until adult stands (about 7 years old), in two regions (Curvelo and Itacambira \u2013 MG). The growth estimates obtained by 3-PG were compared with data from forest inventory in both regions, until 84 months old. The application of 3-PG model using the set of parameter and variable values determined in the study allowed to describe, accurately, the growth patterns of forests stands in the Cerrado region of Minas Gerais state. Thus, it follows that the parameterization upgraded the performance of the model that resulted in accurate estimates of growth

NUTRI\uc7\uc3O E CRESCIMENTO DA ERVA-MATE SUBMETIDA \uc0 CALAGEM

Mate tea trees are native of south Brazil, growing on acid soils. However, small farmers intercrop this species with agricultural crops, which usually require liming to reduce the soil acidity. Therefore, this study aimed to verify the liming effect on Mate tea seedling growth and nutritional status. Samples of an acidic soil (pH = 4.2, Al3+ = 3.9 cmolc dm-3) were incubated with increased rates (0.0, 0.7, 1.8, 2.5, 3.4, 4.3 and 5.2 g dm-3) of a liming material for 21 days. Then mate tea seedlings were transplanted to the pots containing 3 dm3 of soil, grown for 210 days. At the end of this period, seedlings were harvested, split into leaf plants, stem, and roots for determining the foliar area, root length and volume, dry matter production and levels of N, P, K, Ca, Mg, Fe, Cu, Zn, Mn and Al as well as the efficiency of the usage of Ca and Mg by the plant. The soil was analyzed chemically. Calcareous elevated the values of Ca, Mg and K in the soil and stimulated a little increase in the aerial parts of the plants. Seedling maximum dry matter production was obtained at low rates of liming and drastically decreased at high liming rates. Micronutrients and Al seedling decreased with lime rate. Calcium and Mg utilization efficiency reduced with increasing availability of these nutrients in the soil. It can be concluded that mate tea plants are tolerant to soil acidity and the lime is needed only to supply Ca and Mg nutritional requirements.A erva-mate ocorre naturalmente em solos \ue1cidos, mas \ue9 comumente cultivada em cons\uf3rcio com culturas anuais que requerem corre\ue7\ue3o da acidez. Contudo, pouco se conhece sobre seu comportamento frente \ue0 calagem. O objetivo desse estudo foi verificar a influ\ueancia do calc\ue1rio no crescimento e estado nutricional de plantas jovens de erva-mate. Para isso, incubou-se o solo com 0,0, 0,7, 1,8, 2,5, 3,4, 4,3 e 5,2 g dm-3 de calc\ue1rio. Ap\uf3s 21 dias de incuba\ue7\ue3o, mudas de erva-mate foram transplantadas para vasos com 3 dm3 de solo. Ap\uf3s 210 dias determinou-se o crescimento em altura e di\ue2metro, posteriormente separou-se as plantas em folha, caule e raiz para determina\ue7\ue3o da \ue1rea foliar, comprimento e volume de ra\uedzes, produ\ue7\ue3o de mat\ue9ria seca e teor de N, P, K, Ca, Mg, Fe, Cu, Zn, Mn e Al, al\ue9m da efici\ueancia de utiliza\ue7\ue3o de Ca e Mg pela planta. O solo foi analisado quimicamente. O calc\ue1rio elevou os teores de Ca, Mg e K do solo e estimulou um pequeno aumento no crescimento da parte a\ue9rea das plantas, o que n\ue3o ocorreu para o sistema radicular. O m\ue1ximo crescimento e produ\ue7\ue3o de mat\ue9ria seca da parte a\ue9rea da erva-mate ocorreu em pequenas doses de calc\ue1rio, quando o teor de Ca e Mg no solo se situava, respectivamente, na faixa de 3,3 a 3,4 e 1,1 a 1,4 cmolc dm-3. Nas maiores doses de calc\ue1rio os teores foliares de Cu, Zn, Mn e Fe e o crescimento das plantas foram fortemente reduzidos. A efici\ueancia de utiliza\ue7\ue3o de Ca e Mg pela planta reduziu com o aumento da disponibilidade dos mesmos no solo. A erva-mate mostrou ser pouco responsiva \ue0 calagem e muito tolerante ao Al. Desta forma, a aplica\ue7\ue3o de calc\ue1rio deve visar o suprimento de Ca e Mg para as plantas e n\ue3o a corre\ue7\ue3o da acidez do solo no intuito de neutralizar o Al troc\ue1vel

NUTRI\uc7\uc3O E CRESCIMENTO DA ERVA-MATE SUBMETIDA \uc0 CALAGEM

Mate tea trees are native of south Brazil, growing on acid soils. However, small farmers intercrop this species with agricultural crops, which usually require liming to reduce the soil acidity. Therefore, this study aimed to verify the liming effect on Mate tea seedling growth and nutritional status. Samples of an acidic soil (pH = 4.2, Al3+ = 3.9 cmolc dm-3) were incubated with increased rates (0.0, 0.7, 1.8, 2.5, 3.4, 4.3 and 5.2 g dm-3) of a liming material for 21 days. Then mate tea seedlings were transplanted to the pots containing 3 dm3 of soil, grown for 210 days. At the end of this period, seedlings were harvested, split into leaf plants, stem, and roots for determining the foliar area, root length and volume, dry matter production and levels of N, P, K, Ca, Mg, Fe, Cu, Zn, Mn and Al as well as the efficiency of the usage of Ca and Mg by the plant. The soil was analyzed chemically. Calcareous elevated the values of Ca, Mg and K in the soil and stimulated a little increase in the aerial parts of the plants. Seedling maximum dry matter production was obtained at low rates of liming and drastically decreased at high liming rates. Micronutrients and Al seedling decreased with lime rate. Calcium and Mg utilization efficiency reduced with increasing availability of these nutrients in the soil. It can be concluded that mate tea plants are tolerant to soil acidity and the lime is needed only to supply Ca and Mg nutritional requirements.A erva-mate ocorre naturalmente em solos \ue1cidos, mas \ue9 comumente cultivada em cons\uf3rcio com culturas anuais que requerem corre\ue7\ue3o da acidez. Contudo, pouco se conhece sobre seu comportamento frente \ue0 calagem. O objetivo desse estudo foi verificar a influ\ueancia do calc\ue1rio no crescimento e estado nutricional de plantas jovens de erva-mate. Para isso, incubou-se o solo com 0,0, 0,7, 1,8, 2,5, 3,4, 4,3 e 5,2 g dm-3 de calc\ue1rio. Ap\uf3s 21 dias de incuba\ue7\ue3o, mudas de erva-mate foram transplantadas para vasos com 3 dm3 de solo. Ap\uf3s 210 dias determinou-se o crescimento em altura e di\ue2metro, posteriormente separou-se as plantas em folha, caule e raiz para determina\ue7\ue3o da \ue1rea foliar, comprimento e volume de ra\uedzes, produ\ue7\ue3o de mat\ue9ria seca e teor de N, P, K, Ca, Mg, Fe, Cu, Zn, Mn e Al, al\ue9m da efici\ueancia de utiliza\ue7\ue3o de Ca e Mg pela planta. O solo foi analisado quimicamente. O calc\ue1rio elevou os teores de Ca, Mg e K do solo e estimulou um pequeno aumento no crescimento da parte a\ue9rea das plantas, o que n\ue3o ocorreu para o sistema radicular. O m\ue1ximo crescimento e produ\ue7\ue3o de mat\ue9ria seca da parte a\ue9rea da erva-mate ocorreu em pequenas doses de calc\ue1rio, quando o teor de Ca e Mg no solo se situava, respectivamente, na faixa de 3,3 a 3,4 e 1,1 a 1,4 cmolc dm-3. Nas maiores doses de calc\ue1rio os teores foliares de Cu, Zn, Mn e Fe e o crescimento das plantas foram fortemente reduzidos. A efici\ueancia de utiliza\ue7\ue3o de Ca e Mg pela planta reduziu com o aumento da disponibilidade dos mesmos no solo. A erva-mate mostrou ser pouco responsiva \ue0 calagem e muito tolerante ao Al. Desta forma, a aplica\ue7\ue3o de calc\ue1rio deve visar o suprimento de Ca e Mg para as plantas e n\ue3o a corre\ue7\ue3o da acidez do solo no intuito de neutralizar o Al troc\ue1vel

CRESCIMENTO E NUTRI\u106\uc3O DE ERVA-MATE INFLUENCIADOS PELA ADUBA\u106\uc3O NITROGENADA, FOSFATADA E POT\uc1SSICA

Ilex paraguariensis is considered a low P-requiring species because it grows naturally in soils with low P content, although no much information is also available for N and K requirements. This trial aimed to evaluate the effect of increasing P rates, combined with N and K rates on Ilex paraguariensis growth and its mineral composition. Phosphorus rates of 0, 100, 200, 400 e 600 mg dm-3 of P2O5 were combined with 0, 50 e 100 mg dm-3 of N e K2O. The fertilizers were mixed with the soil and placed in plastic pots of 2.9 dm3. Seedlings of Ilex were transplanted to the pots and grown for 120 days. Ilex seedling growth was affected by the interaction of P and NK rates. The best P rate was between 18.5 and 28.6 mg dm-3and the highest growth was obtained when P was combined with 100 mg dm-3of N and K2O. Iron deficiency symptoms appeared at the P rates of 400 and 600 mg dm-3 of P2O5. It can be concluded that Ilex responds to increasing P rates, as long as plant N, K and Ca requirement is met.A ocorr\ueancia natural da erva-mate em solos \ue1cidos e com baixa fertilidade natural, levou essa esp\ue9cie a ser considerada de baixa exig\ueancia nutricional, principalmente em rela\ue7\ue3o ao f\uf3sforo, embora pouco se conhe\ue7a tamb\ue9m sobre a exig\ueancia de N e K. Diante disto, o objetivo deste trabalho foi avaliar o crescimento, teor de nutrientes no solo e em plantas jovens de erva-mate submetidas a doses de P combinadas com NK. Aplicou-se 0, 100, 200, 400 e 600 mg dm-3 de P2O5 combinados com 0, 50 e 100 mg dm-3 de N e K2O a um Latossolo Vermelho distr\uf3fico. Tr\ueas mudas de erva-mate foram transplantadas para vasos com 2,9 dm3 de solo. Aos 120 dias determinaram-se a altura, di\ue2metro do caule, comprimento e volume radicular e produ\ue7\ue3o de mat\ue9ria seca da parte a\ue9rea e radicular das mudas. Determinaram-se os teores de N, P, K, Ca, Mg, Fe, Cu, Zn, Mn e Al das folhas e ra\uedzes, al\ue9m do conte\ufado de N, P, K, Ca e Mg. Amostras de solo foram submetidas \ue0 an\ue1lise qu\uedmica. O crescimento da erva-mate foi afetado pela intera\ue7\ue3o entre P e NK, demonstrando melhor crescimento quando o teor de P no solo estava entre 18,5 a 28,6 mg dm-3 combinado com 100 mg dm-3 de N e K2O. Em doses superiores a 400 mg dm-3 de P2O5, as folhas passaram a apresentar clorose internerval, sintoma t\uedpico de defici\ueancia de Fe. A ordem dos macronutrientes mais exigidos e que mais contribu\uedram para o crescimento da erva-mate foi P, N, K, Mg e Ca. A erva-mate cresce bem em solos com altos teores de P, mas depende da boa disponibilidade de N, K e Ca