Odaci Fernandes de Oliveira

Weed control via intercropping with Gliricidia. II. corn crop

A grande maioria do algodoeiro cultivado comercialmente no mundo possui fibra branca, porem atualmente existe crescente interesse em diversos paises, inclusive no Brasil, pelo algodao de fibra colorida. O uso de fibras naturalmente coloridas reduz a poluicao quimica, por dispensar o uso de corantes. O objetivo deste trabalho foi avaliar o rendimento de fibras de cultivares de algodoeiro em resposta ao controle de plantas daninhas por meio da consorciacao com a gliricidia (Gliricidia sepium). Os cultivares BRS-Verde (fibras esverdeadas), BRS-Rubi (fibras marrons avermelhadas), BRS-Safira (fibras amarronzadas) e BRS-187 8H (fibras brancas) foram submetidos aos seguintes tratamentos: sem capinas, duas capinas (aos 20 e 40 dias apos o transplantio) e consorciacao do algodoeiro com a gliricidia. Na consorciacao, a gliricidia foi plantada entre as fileiras do algodoeiro, usando-se uma plântula por cova, em covas espacadas por 0,50 m. Doze especies de plantas daninhas ocorreram no experimento, a maioria delas pertencente a familia Poaceae. As plantas daninhas ocorreram com diferentes frequencias, distribuidas desuniformemente na area experimental. Os cultivares nao influenciaram a materia seca das plantas daninhas. A consorciacao com a gliricidia reduziu a materia seca das plantas daninhas, mas nao evitou reducoes nos rendimentos de algodao em fibra e em caroco, que foram maiores nas parcelas que receberam capinas. O cultivar BRS-Safira apresentou o maior rendimento de fibras, porem nao houve diferencas entre cultivares quanto ao rendimento de algodao em caroco.

Growth and yield of corn grain and green ear in competition with weeds

Studies on plant growth are interesting because they provide explanations for the factors that influence yield in various crops. The objective of this work was to evaluate growth and yield in corn cultivar AG1051, when in competition with weeds. Cultivar AG 1051 was submitted to two groups of treatments: weed control, and sampling periods for dry biomass evaluation. The weed control treatments consisted of hoeing (two hoeings performed at 20 and 40 days after sowing) and no hoeing. Sampling periods consisted of collecting the above-ground part and roots of corn every fifteen days, until 105 days after sowing (DAS); the first sampling was performed 30 DAS. A completely randomized block design with ten replicates was used. For the characteristics evaluated in a single season, statistical analyses were carried out as a random block experiment. For the characteristics evaluated in several periods, statistical analyses were carried out as random blocks with split-plots (weed control assigned to plots). Fourteen weed species, unevenly distributed throughout the experimental area, were the most important. The growth observed for the above-ground part and root system of corn was 30% smaller in the non-hoed plots, compared to the hoed plots. Lack of weed control increased dry matter of the above-ground part of the weeds and reduced the number of unhusked and husked marketable green ears by 23% and 49%, respectively. Grain yield reduction caused by lack of weed control reached 38%.

Potencial de vida útil pós-colheita de quatro genótipos de melão tipo Galia

Avaliou-se o potencial de vida util pos-colheita de meloes (Cucumis melo L.) tipo Galia (genotipos Primal, Solarking, Total e Vicar). Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 4 (genotipos) x 4 (tempos de armazenamento: 0, 3, 6 e 9 dias), com tres repeticoes. Os frutos foram colhidos no estadio de maturacao IV (predominantemente amarelo) e armazenados a temperatura de 20 ± 1oC e umidade relativa de 50 ± 2%. O genotipo Solarking apresentou uma firmeza media de polpa superior aos demais, do inicio ao final do periodo de armazenamento. Em todos os genotipos, os valores de solidos soluveis no inicio do armazenamento encontraram-se dentro da faixa aceitavel para comercializacao no mercado externo, havendo pouca variacao com o decorrer do periodo de armazenamento. A aparencia interna limitou o tempo de vida util pos-colheita do genotipo Total em apenas seis dias. Os genotipos Solarking, Vicar e Primal apresentaram maior potencial na conservacao pos-colheita, principalmente o hibrido Solarking, que chegou aos nove dias de armazenamento com boa aparencia interna.

Distribuição do teor de sólidos solúveis totais no melão

The total soluble solids content (TSSC) in different portions of the fruit of yellow melon (Cucumis melo L.) cultivars. Two experiments were carried out with cultivars (AF-646, Gold Mine, Gold Pride, Rochedo and Goldex), in two periods. In the first experiment, the TSSC was determined in the basal (near the peduncle), median and apical portions. In the second experiment, the TSSC was evaluated in the ventral (facing and touching soil), lateral, and dorsal portions. The experimental design was of randomized complete blocks in a splitplot scheme with three replications. The cultivars were assigned to plots and fruit fractions assigned to sub-plots. Three fruits of each plot were fractioned in the mentioned portions, peeled, and the pulp was homogenized in a blender, filtered in nylon and three readings in the digital refractometer were made. In the first experiment, there was only the effect of different portions. TSSC in basal portion (8.66oB) was lower than in the median (9.53oB) and in the apical (9.48oB) portion, which did not differ from each other. In the second experiment, there was the effect for cultivars (C) and portions (P), without interaction for C x P. The Goldex cultivar presented the highest TSSC (10.03oB) and the AF-646 the lowest (8.11oB). TSSC in ventral (8.94oB) and dorsal (9.07oB) portions did not differ from each other and was higher than in lateral fractions (8.69oB).

List of angiosperm species of the riparian vegetation of the Apodi-Mossoró River, Rio Grande do Norte, Brazil

This article describes the riparian vegetation of a river in the Rio Grande do Norte state for the first time. This is a seasonal river in the semiarid region of the Caatinga biome. The study is based on data from herbarium collections and new expeditions from July 2007 to October 2008. Two hundred and forty seven taxa were recorded and of these, 116 are herbs and three of which are epiphytes, 25 sub-shrubs, 77 shrubs or trees, 26 lianas, one parasite, and two palms. This list of species of riparian vegetation in the river Apodi-Mossoro was compared with only two available lists from rivers in the northeast with similar environmental characteristics and showed a low similarity. This study points to the need for preservation of the species and remnants of riparian vegetation of the river Apodi-Mossoro and to increase efforts in the study of this vegetation type.

Planting density of gliricidia when intercropped with corn for weed control

A reducao do uso de herbicidas, em razao dos problemas de poluicao ambiental, e de grande interesse da agricultura moderna. A cobertura do solo com ramos de gliricidia (Gliricidia sepium) nao tem efeito alelopatico no milho, mas diminui a populacao de plantas daninhas. O objetivo deste trabalho foi avaliar os efeitos da densidade de plantio da gliricidia, em consorciacao, sobre o controle de plantas daninhas e sobre os rendimentos do milho. Utilizou-se o delineamento de blocos casualizados com parcelas subdivididas e dez repeticoes. Os cultivares de milho AG 1051 e BM 3061 foram cultivados sem capinas, com duas capinas (aos 24 e 44 dias apos o plantio) e consorciados com a gliricidia (plantada por ocasiao do plantio do milho, entre as fileiras da graminea, usando-se duas mudas/cova, distanciadas de 30, 40 ou 50 cm). Vinte e uma especies de plantas daninhas ocorreram na area experimental. O aumento da densidade de plantio da gliricidia reduziu a biomassa das plantas daninhas, porem nao houve diferenca entre biomassa de plantas daninhas dos consorcios e biomassa de plantas daninhas do milho nao capinado. Na maioria das caracteristicas avaliadoras do rendimento de milho-verde, a consorciacao com a gliricidia, plantada no espacamento de 30 cm, nao diferiu significativamente do milho capinado, embora as medias tenham sido menores. No numero e peso de espigas verdes comercializaveis, as reducoes com essa consorciacao foram de 5% e 13%, respectivamente. No rendimento de graos, a consorciacao referida causou reducao de 17%, diminuindo em mais da metade as perdas (36%) observadas no milho nao capinado. Os maiores rendimentos de espigas verdes e de graos foram obtidos com duas capinas, e os menores, quando o milho nao foi capinado. Os cultivares nao diferiram quanto ao rendimento de espigas verdes e de graos.

Weeds under the canopies of tree species submitted to different planting densities and intercropping

Assessing the growth and floristic composition of species that grow under the canopy of trees is important for weed control (WC). The objective of this study was to assess two experiments (E1 and E2), when the trees were two years and one year of age, respectively. In E1, sabia (S) and gliricidia (G) were submitted to planting densities from 400 to 1.200 plants ha-1. In E2, growing systems consisting of S, G, and neem (N) combinations were compared: SSS, GGG, NNN, GSG, NSN, SGS, NGN, SNS, and GNG (each letter represents a row of plants). A random block design was adopted, with three (E1) and four (E2) replicates. In E1, treatments were arranged as split-plots (species in plots). In E2, the degrees of freedom for treatments (8) were partitioned into growing systems (treatments that involved the same species) and between growing system groups (2). Twenty-one weed species were found in E1. Gliricidia attained greater plant height than sabia, but these species did not differ in canopy diameter, number of weed species per plot, and weed green and dry biomass of the shoot. Higher planting densities resulted in the reduction of all those traits. Twenty-six weed species were found in E2. Growing systems that included gliricidia showed canopies with greater diameters than growing systems that included neem. There were no differences between growing systems for number of weed species per plot and for weed green and dry biomass of the shoot.

Planting density and initial growth of two tree species adapted to the semi-arid region

Planting densities influence several aspects of forest formation, including management practices, timber yield, quality, and extraction, and consequently its production costs. The objective of this study was to evaluate Mimosa caesalpiinifolia and Gliricidia sepium growth as a function of planting density (400, 600, 800, 1000, and 1200 plants ha -1 ) and plant age. The species were evaluated every 90 days for plant height (PH), crown diameter (CD) and root collar diameter (RCD) (10 cm above the ground), with the first evaluation performed at 90 days and the last at 720 days. When plants were one year of age and beyond, evaluations were conducted also for stem diameter at breast height (DBH) (1.30 m above the ground). A randomized block design with split-plots and three replicates was adopted. Species were assigned to plots, planting densities were assigned to subplots, and evaluation ages were assigned to subsubplots. The four traits in both species had their values decreased as planting density increased, but continually increased as plant age increased. For PH and RCD there was an alternation between species superiority, with gliricidia being superior to sabia at some ages, while the opposite occurred at other ages. As to CD the species only differed in the last measurement, gliricidia being superior. With regard to DBH, gliricidia was superior starting from the second measurement. There was an effect of the species × ages interaction for the four traits and also an effect of the densities × ages interaction for CD and DBH.