Anastácia Fontanetti

Dinâmica populacional de plantas daninhas na cultura do milho em função de adubação e manejo

The aim of this work was to evaluate the weed establishing (and unwanted plant) populations during six consecutive agricultural years for maize crops. The systems studied were till, both organic and traditional, intermediated by a traditional plantation system. The experiments were carry out in the agricultural years 2003/04 until 2008/09, in the experimental area in southeast of the Minas Gerais State), which is owned by the Federal University of Vicosa. The treatments were SDT1 (till without fertilizer and herbicide application ); SDT2 (till with mineral fertilizer (300 kg ha-1 with of 8-28-16 (N-P-K) plus 100 kg ha-1 of nitrogen for side fertilization, and the herbicide application): SDT3 (till with fertilizer with organic compost in a dose of 40 m3 ha-1 and herbicide application ); SDO (organic till with organic compost in a dose of 40 m3 ha-1, and mowing). We can conclude that the herbicide application or the clearing of the ground stimulated a greater alteration in the establishing of weed (unwanted plant) communities than the type of fertilizer used.

Morfofisiologia de plantas de milho em competição com picão-preto e trapoeraba submetidas a roçada

The efficiency of using clearings to control Picao-preto (Bidens pilosa) and Trapoeraba (Commelina benghalensis) was evaluated based on the morphological and physiological characteristics of corn. An experiment under greenhouse conditions was conducted in 2009/2010. The physiological characteristics were obtained in a subdivided parcel, with four evaluations being performed throughout the corn cycle (1- before the first clearing (V3); 2- after the first clearing (V6);3- after the second clearing (V9); and 4- corn plants at the fluorescence stage), by means of Infra Red Gas Analyzer. Two clearings reduced the influence of B. pilosa and C. benghalensis weeds on the morphological characteristics of corn. The clearing did not influence the physiological aspects of the corn plants in competition with weeds. C. benghalensis caused a greater interference in the physiological characteristics of corn, reducing photosynthesis and transpiration. When not cleared, B. pilosa species had a greater capacity of interfering in corn morphology.

Shade Trees Spatial Distribution and Its Effect on Grains and Beverage Quality of Shaded Coffee Trees

Shading coffee trees has gained importance, especially among smallholders, as an option to improve the products’ quality, therefore acquiring place at the specialty coffee market, where consumers are willing to give bonus for quality. This work aims to evaluate the influence of shade trees’ spatial distribution among coffee trees’ agronomic characteristics, yield, and beans and cup quality of shaded coffee trees. The experimental design consisted of completely randomized blocks with six repetitions and four treatments: coffee trees on shade trees planting rows, distant one meter from the trunk; coffee trees on shade trees planting row, distant six meters from the trunk; and coffee plants between the rows of shade trees, parallel to the previous treatments. The parameters analyzed were plant height, canopy diameter, plagiotropic branches’ length, yield, coffee fruits’ phenological stage, ripe cherries’ Brix degree, percentage of black, unripe, and insect damaged beans, bean size, and beverage quality. Shade trees quickened coffee fruits’ phenological stage of coffee trees nearest to them. This point also showed the best beverage quality, except for overripe fruits. The remaining parameters evaluated were not affected by shade trees’ spatial distribution.

Ecological Mowing: An Option for Sustainable Weed Management in Young Citrus Orchards

The citrus yield in Brazil is not ranked among the best in the world, potentially due to inadequate management by citrus growers. The low adoption of conservation agriculture (CA) techniques and the improper application of herbicides are also well-known problems. Thus, this study evaluated the use of CA techniques, and two Urochloa species (ruzi grass and signal grass) were used as cover crops. Two different types of mowers (ecological, EM; conventional, CM) launched the mowed biomass into different positions within a young Tahiti acid lime orchard (up to four years old). In addition, the integration of glyphosate into this management system was evaluated, with (GLY) and without (NO GLY) glyphosate application. This experiment was conducted across three growing seasons (2011–2014), in Mogi Mirim, São Paulo State, Brazil. The cover crop biomass yields and the effects of the mowing treatments, weed density, vegetative growth and fruit yields of the Tahiti acid lime trees were evaluated. In terms of major results, signal grass produced higher biomass yield values (up to 64%) than ruzi grass; EM promoted higher mowed biomass values in the intra-row (up to 5.1 ton ha-1, 9.0 times higher than CM), and a higher canopy volume (up to 33% than CM). These results were enhanced when ruzi grass was associated with the EM (56% lower weed density; 126% higher fruit yield than CM) and with GLY (52% higher fruit yield than NO GLY); and EM with GLY (43% lesser weed density and 107% higher fruit yield than NO GLY). Overall, ruzi grass was a good cover crop because it provided less competition for the citrus trees, EM provided a mulch layer in the intra-row of the citrus trees, and associated with GLY, these approaches could provide options for an integrated and more sustainable weed management, primarily for young Tahiti acid lime orchards. Nomenclature: Glyphosate; signal grass, Urochloa ruziziensis (R. Germ. & C.M. Evrard) Morrone & Zuloaga; Tahiti acid lime, Citrus latifolia (Yu. Tanaka) Tanaka.

Efeito de remineralizador, vinhaça e plantas de cobertura nos atributos químicos do solo

Objetivou-se com este trabalho avaliar as alteracoes nos atributos quimicos de um Latossolo Vermelho, com pH e teores de nutrientes adequados, cultivado com feijoeiro ( Phaseolusvulgaris L.), em sucessao a plantas de cobertura e a aplicacao de vinhaca e deremineralizador (po de basalto). O ensaio foi realizado em casa de vegetacao, no delineamento experimental de blocos casualizados em esquema fatorial 4x4x2, com tres repeticoes. O primeiro fator foram doses de remineralizador (0, 2, 4 e 8 t ha -1 depo de basalto). Pousio (controle) e as plantas de cobertura crotalaria ( Crotalariajuncea L.), milheto ( Pennisetumglaucum (L.) R. Brown) e braquiaria ( Urochloa cv. ruziziensis Germain &Evrard) representaram o segundo fator. O terceiro fator foi a aplicacao ou nao de vinhaca (200 m 3 ha -1 e 0 m 3 ha -1 , respectivamente). Os atributos quimicos analisados, aos 110 dias apos incubacao do remineralizador, foram: materia orgânica do solo (MOS), pH em CaCl 2 , acidez potencial (H+Al), soma de bases (SB), capacidade de troca de cations (CTC) e saturacao por bases (V).Tratamentos com vinhaca e remineralizador, associadas amilheto e crotalaria, proporcionaram aumento do pH e de V e diminuicao de H+Al. Conclui-se que feijoeiro cultivado em sucessao a plantas de cobertura cultivadas com po de basalto e vinhaca pode viabilizar a transicao de um sistema de manejo convencional da adubacao de solo para um manejo com insumos alternativos.