POTENTIAL AGROFORESTRY SYSTEMS FOR SEMIARID REGIONS

The objective of this work was to evaluate the potential of agroforestry systems in the semiarid, and to evaluate the productivity of eucalyptus in three planting spacing, in single cultivation in agroforestry systems. The comparison of the systems was in a randomized block design with four systems (monoculture; peanut systems; castor bean; cassava) and three eucalyptus spacing (10 m x 2 m, 10 m x 3 m and 10 m x 4 m). Monocultures and other characteristics were compared by randomized block design. Peanut productivity was evaluated at three and a half months, castor productivity at five and eight months and cassava productivity at 21 months. Eucalyptus productivity was measured at 13 and 21 months of age. The results showed that the wood production was greater in the 10 m x 2 m spacing and in the system with castor and single cultivation. The castor yield was higher in the system, in the 10 m x 3 m spacing, while the cassava productivity was higher in monoculture. The area equivalence index of the systems was higher than that of monocultures. Therefore, eucalyptus agroforestry systems intercropped with castor and cassava are suitable for the semiarid region. The 10 m x 2 m spacing provided a larger volume of wood (m³ ha-1). Castor yield was higher in the 10 m x 3 m spacing. For cassava, the highest yield was obtained in monoculture and in the system with 10 m x 3 m or 10 m x 4 m spacing

Methods of preparing propagules for tropical woody bamboo species

The production of seminal bamboo seedlings is considered not viable, being this the biggest limiting factor. The tissue culture and minicutting are efficient, but very costly techniques, which makes it necessary to search for alternative techniques, such as propagation through culm sections. In this context, the objective of this study was to evaluate the efficiency of three methods of vegetative propagation with segments of the culm of the species Bambusa vulgaris, B. variabilis, B. tuldoides and Dendrocalamus giganteus. The experiment was carried out in a randomized block design, factorial scheme of four (4) species (Bambusa vulgaris, B. variabilis, B. tuldoides and Dendrocalamus giganteus) and three (3) methods of preparing the propagule (a single node, binodal propagule, and binodal propagule + H 2 O), with four replicates and plots of five propagules. The propagules were deposited in shallow pits kept in field conditions. At 45 days, the percentage of shoots was measured and analyzes of variance and Tukey were performed at 5% error probability. For D. giganteus, none of the methods of preparing the propagules proved to be efficient for their propagation. The species B. vulgaris, B. variabilis and B. tuldoides showed higher percentages of sprouting. The method of preparing propagules with a single node was more efficient for B. variabilis, B. vulgaris and B. tuldoides

BASE FERTILIZATION COMPENSATION AS A METHODOLOGY FOR COMPARISON OF CONTAINERS VOLUMES

The current methodology for comparing the volumetric capacity of containers does not make it possible to differentiate the effects caused by the higher concentration of fertilizers, available by volume of container, from the real effect of the growth space and fertilization. The fertilization compensation aims to correct the effect of the concentration of fertilizers, guaranteeing the same proportion of fertilization in different volumetric capacities of containers, making it possible to be a new methodology for the production of forest seedlings. The methodological proposal was applied to the production of Handroanthus ochraceus seedlings, testing two volumetric capacities, 55 and 115 cm³, of containers, of the tube type and six doses of controlled release fertilizer, namely: 0.19; 0.24; 0.30; 0.40; 0.51, and 0.63 g / tube in a completely randomized design with four replications. The height and diameter of the collection were evaluated biweekly up to 150 days after sowing and the dry matter of the aerial and root parts. The results demonstrate that regardless of the volumetric capacity of the container, the highest doses of fertilizer resulted in greater morphological characteristics. Therefore, the effect responsible for the differential growth between the volumetric capacity of the containers, normally attributed to the greater space available for root development, is actually attributed to the greater availability of nutrients, which the fertilization compensation aims to keep constant. It was concluded that the use of basic fertilization compensation proved to be efficient for comparisons between volumetric container capacities

Initial growth of Eremanthus erythropappus (DC.) Macleish in function of planting and topdressing fertilization

Growing demand for alpha-bisabolol oil extracted from Eremanthus erythropappus (DC.) Macleish, a Brazilian native tree, justifies its commercial plantations. However, its silviculture is relatively new and lacks information, especially about its nutritional aspects. It is the first study to focus on the field response of E. erythropappus to fertilization. We aimed to assess the effect of planting fertilization and topdressing on its initial growth. The experiment, conducted in Lavras, Brazil, consisted of six different fertilization treatments using different doses of nitrogen (N), phosphorus (P), and potassium (K), with the quantities based on soil analysis results and recommendations for other forest species. We designed the experiment in four randomized blocks using or not P at planting and application or not of N and K on top dressing, with the increase until 3X P dose when using N and K. Over 20 months, we evaluate the height (H) and base diameter (BD) and processed the data by ANOVA and Scott-Knott test (p<0.07). There was no response to any dose of phosphorus, while there was a positive response to the application of nitrogen and potassium, even without the application of phosphorus. The results indicate topdressing on E. erythropappus to maximize its growth and production

SEEDLINGS OF TREE SPECIES PRODUCED IN SUBSTRATES BASED ON ORGANIC COMPOSTS

The quality of the seedling produced is directly related to substrate composition, so it is essential to select constituents with adequate characteristics. The objective of this study was to evaluate Eucalyptus urophylla, Peltophorum dubium and Eremanthus erythropappus seedlings and to relate the physical and chemical characteristics of the formulated substrates to their quality. For each species, an experiment was carried out in a completely randomized design (CRD), consisting of five treatments, five replicates, and plots composed of 20 seedlings. In order to evaluate the quality of the seedlings, the biometric variables were measured and, as a qualitative analysis, the ease to remove the seedlings from the tubes (ERT) and root aggregation to the substrate (AGGR) were evaluated. Seedlings produced in the substrates formulated with alternative constituents showed higher values when compared to seedlings produced with commercial substrate, for most of the analyzed variables. Coffee husk can be applied in the production of seedlings of P. dubium and E. urophylla. For the formation of E. erythropappus seedlings, none of the formulations tested are recommended

Genetic characterization of Zeyheria tuberculosa progenies and evaluation for formation of a seed orchard

Zeyheria tuberculosa, a native species of Brazil known for its significant potential in silviculture and genetic improvement, holds prominence among various species. In this study, our objective was to assess the diversity, genetic structure, and feasibility of establishing a seedling seed orchard (SSO) for this species. A total of 71 progenies were collected from different locations and were used in our experiment in Ijaci - MG. We genotyped 92 individuals (nine families with eight individuals, two families with seven individuals, and one family with six individuals), specifically selecting those with the highest predicted genetic values, using ten ISSR primers. The molecular markers employed effectively detected polymorphism (PIC = 0.44). The population exhibited moderate to high genetic diversity, as evidenced by observed (AO = 2.00) and effective alleles (AE = 1.61), Nei's diversity index (H* = 0.35), and Shannon's diversity index (I* = 0.52). Molecular variance analysis indicated significant genetic differentiation between the progenies (Φst = 0.19), yet the majority of the variation was observed within them (80.1%). Employing a Bayesian approach, we identified the formation of two distinct genetic groups, further confirming the non-genetic structure of the population. These findings affirm the potential of the Z. tuberculosa progenies to contribute to the establishment of a seedling seed orchard, supporting genetic improvement strategies and the conservation of the species' genetic diversity

Variabilidade espacial da sazonalidade da chuva no semiárido brasileiro

A chuva é um dos principais reguladores dos processos biogeoquímicos de uma região e o entendimento da sua variabilidade espacial e da sua sazonalidade ao longo ano, é fundamental para o gerenciamento dos recursos hídricos e planejamento agrícola do Semiárido brasileiro. Foi avaliada a variabilidade sazonal da chuva no Semiárido brasileiro sob três condições: i) a média mensal das séries temporais, ii) ano considerado mais chuvoso (2009) e o ano considerado mais seco (2012). Informações diárias de chuva foram obtidos da base de dados da Agência Nacional de Águas (ANA) e a partir deles, foram calculadas os valores totais precipitados nos meses e no ano, a entropia relativa (Dk), o índice de sazonalidade (Sk), o tempo característico da chuva (Ck) e a duração da estação chuvosa (Zk). Essas variáveis foram espacializadas para toda a região semiárida de modo à possibilitar a interpretação da variabilidade espacial a partir de técnicas de geoestatística. A magnitude do coeficiente de variação das variáveis foram semelhantes entre a média das séries temporais, o ano mais chuvoso e o ano mais seco, exceto para o Ck e a Zk no ano mais seco. O modelo de semivariograma esférico foi quem melhor representou a variabilidade espacial da maioria das variáveis estudadas. Na parte central do semiárido, mesmo no ano mais chuvoso, ocorreram os menores valores anuais de chuva. As medidas estatísticas de sazonalidade e variabilidade interanual da chuva utilizadas neste estudo mostraram um desempenho satisfatório na caracterização do comportamento das chuvas na região semiárida do Brasil

Crescimento inicial e nutrição mineral de espécies florestais com potencial econômico sob omissão de nutrientes

Nutritional management is one of the most limiting barriers to forestry development. In this context, the present work aims to establish the effect of liming and omissions of macro and micronutrients on plants development and nutritional status of Leucaena leucocephala, Cordia trichotoma, and Astronium graveolens. The experiment was carried out in a greenhouse with five dm³ pots in a randomized block design with single plant plots, with 12 treatments consisting of omission of N; P; K; S; B; Zn; Ca; Mg, without fertilization and complete fertilization. Nutrients omission and exclusion of liming limited plant growth in height, collar diameter, biomass accumulation, and reduced seedling quality. Liming is beneficial for Cordia trichotoma and Astronium graveolens. The nutrients importance order is N > K > P, Zn > Ca, Mg, B, S for L. leucocephala, N, P, K, Ca and Zn > Mg, B, S for C. trichotoma and, N, P, B, Ca > K, Zn > S for A. graveolens.O manejo nutricional caracteriza-se como uma das mais limitantes barreiras no desenvolvimento da silvicultura. Dentro deste contexto o presente trabalho visa estabelecer o efeito da calagem e das omissões de macro e micronutrientes sobre o desenvolvimento e o estado nutricional de plantas de Leucaena leucocephala, Cordia trichotoma e Astronium graveolens. O experimento foi conduzido em casa de vegetação com vasos de 5 dm³ em delineamento de blocos casusalizados com parcelas de plantas únicas, sendo testados 12 tratamentos, compostos de combinações de omissão de N; P; K; S; B; Zn; Ca; Mg, sem adubação e adubações completas. A omissão de nutrientes e exclusão da calagem limitou o crescimento das espécies florestais em altura, diâmetro do coleto, acúmulo de biomassa e reduziu a qualidade das mudas. Conclui-se que a calagem foi benéfica para o crescimento da Cordia trhichotoma e Astronium graveolens e a ordem de importância dos nutrientes é N > K > P, Zn > Ca, Mg, B, S para L. leucocephala, N, P, K, Ca e Zn > Mg, B, S para C. trichotoma e N, P, B, Ca > K, Zn > S para A. graveolens

Growth and genetic parameters of progenies of Cordia trichotoma in the juvenile phase

Increasing the productive potential of native species is a challenge for forest genetic improvement. Progeny tests are efficient tools to determine the reproductive capacity of individuals and to assist with the selection of superior genotypes. Cordia trichotoma (Vell.) Arrab. ex Steud, is a native species of commercial interest due to its high potential for sawn wood. The performance of seedling production from different progenies was the objective of this work. Seeds were collected from 34 matrices selected phenotypically and georeferenced in the region of Lavras - MG. The experiment was conducted in a completely randomized design with 4 replications of 12 plants. Germination after 70 days of sowing, survival and height at 170 days after germination were evaluated. Height and genetic parameters were estimated according to mixed REML / BLUP models using the Selegen software model 82. Progeny 104 (70.8%) was superior in germination and progenies 86 (35.42%), 92 (35.42%) and 111 (43.75%) had the highest survival rates. Height shows high values for the individual additive genetic variation coefficient (49.18%) and genotypic variation coefficient between progenies (24.59%) and moderate values of heritability in the restricted individual sense (0.45) and heritability within progenies (0.38). Due to high values for the coefficient of genotypic variation and moderate values of heritability, there is a potential for height improvements. Progenies 104 stand out in the germination and the progenies 86, 92 and 111 in the seedlings survival). Regarding height, progeny 95 is the only one that stands out negatively