O uso intensivo e inadequado dos solos acelera sua degradação, sendo necessária a intervenção por meio de práticas conservacionistas para restaurar a capacidade produtiva dos mesmos. O objetivo deste estudo foi avaliar o comportamento e desenvolvimento de diferentes leguminosas utilizadas como adubos verdes em solos de Cerrado, Alto Vale do Jequitinhonha, em Turmalina, MG. O delineamento experimental adotado foi em blocos ao acaso, com sete tratamentos e quatro repetições, sendo os tratamentos constituídos pelas leguminosas: mucuna-cinza (Mucuna nivea), mucuna-preta (Mucuna aterrima), lablabe (Dolichos lablab), feijão-de-porco (Canavalia ensiformis), Crotalaria juncea, Crotalaria spectabilis e guandu-anão (Cajanus cajan). O ciclo precoce de C . juncea, C. spectabilis e feijão-de-porco favorece a inserção destes nos sistemas de cultivo. Aos 40 dias, o feijão-de-porco e mucuna-cinza já cobriam o solo, com 67 e 63 %; já o guandu-anão e C. juncea apresentaram os maiores desenvolvimentos, nesse período. Os teores de N, P e K tendem a diminuir nas avaliações realizadas nas diferentes fases vegetativas, o que contribui para melhor escolha da época de manejo das leguminosas. Crotalaria juncea, mucuna-cinza, feijão-de-porco e mucuna-preta foram as leguminosas que se destacaram na produção de matéria seca, o que torna essas espécies promissoras para adubação verde na região. As leguminosas, em sua maioria, apresentam potencial para reciclagem dos macronutrientes e aporte de N aos sistemas de produção.

This study was carried out to evaluate the contributions to the optimization of water use in a carrot crop under different forms of mulch using Gliricidia sepium, fertilization with castor bean cakes and irrigation water depths. The experiment was conducted in Seropédica, RJ, Brazil (22º 46’ S and 43º 41’ W), from June to September 2010. The experiment was conducted using a split-split-plot scheme (5 x 3 x 2), with four replicates. The five plots had irrigation depths corresponding to 0, 43, 72, 100 and 120% of crop evapotranspiration (ETc); the three subplots contained the different forms of mulch (whole leaves (WL) and chopped leaves and branches (CLB)) and the absence of mulch (AM); and the two sub-subplots contained either the presence (PF) or absence of fertilization (AF). Using time domain reflectometry (TDR) in the irrigation management, water depths ranging from 67.8 to 285.5 mm were applied. The use of mulch in association with fertilization led to higher yields and water-use efficiency (WUE) of the carrot plants, and the mulch composed of WL performed best. The application of irrigation depths corresponding to 97% of ETc promoted the highest carrot yields, although the highest values of WUE were observed, with irrigation depths corresponding to a range from 51 to 68% of ETc.

O presente trabalho objetivou avaliar o comportamento e as potencialidades de leguminosas herbáceas perenes para o uso como cobertura permanente em solos da região da Caatinga Mineira, Médio Vale do Jequitinhonha, MG, visando a introdução dessas plantas de cobertura em áreas agrícolas. O experimento foi conduzido de dezembro de 2008 a julho de 2009. O delineamento experimental foi em blocos ao acaso, com seis tratamentos e quatro repetições. Os tratamentos foram constituídos pelas leguminosas: cudzu tropical (Pueraria phaseoloides), calopogônio (Calopogonium mucunoides), amendoim forrageiro (Arachis pintoi), soja perene (Glycine wightii), estilosantes (Stylosanthes capitata, Stylosanthes macrocephala) e pela testemunha (sem a presença de leguminosa). Foram avaliados os seguintes parâmetros: emergência das plântulas; taxa de cobertura do solo; promoção da retenção de umidade e temperatura do solo; capacidade de inibição da vegetação espontânea; potencial de deposição de folhas e de aporte de macronutrientes pela senescência de folhas; produção total de fitomassa seca e acúmulo de macronutrientes na parte aérea. A cobertura plena do solo foi alcançada pelo calopogônio, amendoim forrageiro e cudzu tropical. O calopogônio conferiu maior capacidade de retenção da umidade e inibição das plantas espontâneas. Em todos os tratamentos com leguminosas a temperatura do solo foi inferior à testemunha, a partir dos 120 dias de ciclo. Na região da Caatinga Mineira, as leguminosas perenes calopogônio e cudzu tropical, podem contribuir significativamente para o incremento de nitrogênio, aporte de outros macronutrientes (K, P, Ca e Mg) e incremento da matéria orgânica do solo. The study objective was to evaluate the performance and potential of perennial herbaceous legumes for use as permanent soil cover in the Caatinga Mineira region MG, Brazil, for the introduction of these cover crops in agricultural areas. The experimental design was in a randomized blocks with six treatments and four replications. The treatments consisted on the leguminous: Pueraria phaseoloides, Calopogonium mucunoides, Arachis pintoi, Glycine wightii e Stylosanthes capitata, Stylosanthes macrocephala and the control (without the presence of leguminous). Were evaluated: seedling emergence and rate of soil cover, promotion of moisture retention and soil temperature, ability to inhibit the spontaneous vegetation, deposition potential of leaves and intake of macronutrients by senescence of leaves, dry matter production and accumulation of nutrients in the shoot. The full coverage of the soil was reached for Calopogonium mucunoides, Arachis pintoi and Pueraria phaseoloides. The Calopogonium mucunoides created greater capacity to retain moisture and inhibiting weeds. In all the treatments with leguminous, the soil temperature was lower than in control, from the 120 day cicle. In the region of Caatinga Mineira, the perennial leguminous Calopogonium mucunoides and Pueraria phaseoloides, could contribute significantly to the increase of the nitrogen and other macronutrients (K, P, Ca and Mg) and the increase of organic matter under the soil

Coffea canephora plants have been wilting and dying in major producing regions of Brazil; however, the disease etiology is unknown. Coffee clones differ in susceptibility, and disease occurs throughout the year. The symptoms include wilting, leaf yellowing, defoliation, vascular tissue darkening, and drying and death of plagiotropic and orthotropic branches and the plant. To identify the etiological agent, vascular tissue fragments from symptomatic plants collected in the Jerônimo Monteiro municipality (20°53′28′′S, 41°25′59′′W) were surface sterilized, placed on carrot baits, and incubated at 26 °C. The resulting mycelia were transferred to potato dextrose agar (PDA) medium and incubated at 26 °C, in 12 h light/dark for 10 days. Monosporic cultures from four isolates were prepared and characterized (Booth, 1971; Summerell et al., 2013). A TEF-1α gene fragment was amplified (O’Donnell et al., 2000). The PCR products were sequenced by capillary electrophoresis (ABI3730) using POP7 polymer and BigDye v3.1 (...

An experiment was carried out in Magé, Rio de Janeiro State, Brazil, to evaluate the performance of taro (Colocasia esculenta) intercropped with sunn hemp (Crotalaria juncea), used as green manure. A randomized blocks design with four replicates was used and the soil of the field plots was classified as Haplic Gleysol. Treatments consisted of taro (1) intercropped with unpruned sunn hemp, (2) intercropped with sunn hemp cut at soil level, (3) intercropped with sunn hemp pruned at its mid-height, and (4) in monoculture. The taro was planted in double rows spaced by 1.0 m. The planting furrows had a space of 0.5 m, with rhizomes placed at every 3.0 m. The experimental plot consisted of four 3.0 m rows and the useful area corresponded to the five central plants in each of the two central rows. The sunn hemp was sown in parallel lines in the spaces between the taro double rows, 120 days after planting the taro. When the sunn hemp was cut at soil level, an accumulation of 211 kg ha-1 of N was observed. Besides this, the sunn hemp's biomass promoted the cycling of an average 17 kg ha-1 of P, 85 kg ha-1 of K, 151 kg ha-1 of Ca, and 27 kg ha-1 of Mg. Worth mentioning, it represented also a deposition of 6.85 Mg ha-1 of dry substance. Even when pruned at its mid-height, the sunn hemp still provided 60% of nutrients relatively to the treatment in which it was cut at soil level. In addition to the nutrient supply, the use of taro intercropped with sunn hemp cut at soil level or pruned at mid-height represented efficient alternatives for controlling the spontaneous vegetation and for reducing taro leaf burning by solar radiation, without compromising the yield of taro. In all intercropping systems, taro plants had a larger leaf area and were taller than plants in monoculture.