ABSTRACT. Adding legumes to sugarcane silage is a strategy used to improve silage quality and reduce losses. This study’s objective was to evaluate the chemical composition and fermentation profile of silages sugarcane and pigeon pea. A completely randomized design was used, with five treatments and four replications. The treatments consisted of sugarcane silage with increasing pigeon pea proportions (0, 25, 50, 75 and 100%). The forages were ensiled in experimental microsilos that remained closed for 60 days. Their chemical compositions were evaluated by determining the pH value and dry matter, crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose, cellulose and lignin content. Fermentation profiles were evaluated by determining the effluent, gas, and total dry matter losses and dry matter recovery of the silage. Including pigeon pea in sugarcane silage decreases the hemicellulose content and increases the crude protein, acid detergent fiber and lignin content. Fermentation losses are reduced by adding pigeon pea to sugarcane silage with reduced effluent and gas losses and increased dry matter.

RESUMO Pesquisas que avaliem o uso de cobertura morta no solo tem grande aceitação, uma vez que otimiza o manejo sustentável e melhora a qualidade do solo. Objetivou-se, com o presente trabalho, avaliar a eficiência da cobertura morta na redução das taxas erosivas do solo em cultivo de sorgo (Sorghum bicolor L. Moench) submetido à chuva simulada, bem como o incremento de carbono orgânico no solo. O experimento foi desenvolvido no período de agosto a dezembro de 2013 sob condição de campo, onde foram estabelecidos os seguintes tratamentos: sorgo com cobertura morta (CM) utilizando-se a vegetação espontânea da área e sorgo sem cobertura morta (SM), com três repetições em blocos casualizados. Foi realizada chuva simulada em três períodos distintos (nicial, intermediário e final do ciclo da cultura), utilizando-se um simulador de chuvas. Em todas as fases da cultura, o uso da cobertura morta no solo em cultivo de sorgo se mostrou eficiente por proporcionar maior retenção da umidade no solo, a qual se manteve por mais tempo entre os intervalos de chuva, resultando na ausência de perda de água, além de proporcionar maior aporte de carbono orgânico no solo.

ABSTRACT Researches evaluating the use of mulch has contributing to optimize soil management towards sustainability, and improving soil quality. The objective of this study was to evaluate the efficiency of mulching on the reduction of erosion in a soil with sorghum (Sorghum bicolor L. Moench) crops subjected to simulated rainfall and increased soil organic carbon. The experiment was carried out from August to December 2013 under field conditions, using a randomized block design with three replications. The treatments consisted of sorghum with mulch, using the local vegetation available in the area; and sorghum without mulch. Simulated rainfalls were performed in three different periods of the crop cycle (initial, intermediate, and final), using a rainfall simulator. The use of mulch in soils with sorghum crops was efficient in improving soil water retention in all phases of the crop, and maintaining soil moisture during the rainfall intervals used, resulting in the absence of plant water loss, and greater contribution to soil organic carbon.

RESUMO O objetivo desse trabalho foi avaliar o efeito de substâncias húmicas (ácido húmico e fúlvico) aplicadas via fertirrigação com e sem extratos vegetais a base de saponinas nas variáveis de crescimento e produção da bananeira BRS Princesa (Musa sp.). O pomar foi instalado em espaçamento de 2,0 m x 2,5 m, em Latossolo Amarelo Distrocoeso, sob regime de fertirrigação por gotejamento, no Recôncavo da Bahia, Brasil. Os tratamentos consistiram em cinco doses de substância húmicas (0,0; 21,14; 31,71; 42,28 e 63,42 L ha-1ciclo-1) com e sem aplicação de extratos vegetais, a base de saponinas. O delineamento experimental adotado foi o de blocos casualizados, em esquema de parcelas subdivididas no espaço com cinco repetições. Foram efetuadas análises biométricas na ocasião da floração e da colheita, sendo avaliados o crescimento e a produção acumulada, respectivamente. Mediante análise estatística foi verificado que, quando as substâncias húmicas foram associadas aos extratos vegetais, ocorreram influências significativas sobre a produtividade de pencas, comprimento e diâmetro de frutos e quando as substâncias húmicas foram aplicadas de forma isolada ocorreram efeitos significativos, apenas, sobre a altura de plantas.

ABSTRACT The use of humic substances and plant extract has been increasing mainly in organic crop systems without scientific-based recommendations. Research is necessary to evaluate the feasibility and the recommendations of these substances. The objective of this work was to evaluate the effect of humic substances (humic and fulvic acids) applied by fertigation with and without saponin-based plant extracts on growth and yield of ‘BRS Princesa’ banana. The experiment was carried out using the banana cultivar ‘BRS Princesa’, at a spacing of 2.0 × 2.5 m, fertigated by drip irrigation in a Dystric Densic Xantic Ferralsol, at the Recôncavo da Bahia, Brazil. Treatments consisted of five doses of humic substances (0.0; 70; 105; 140, and 210 L ha-1cycle-1) applied with and without a saponin-based plant extract in a randomized block design in split-plot scheme. The following growth variables were evaluated: number of leaves, pseudostem height, pseudostem diameter, and length and width of the third leaf. The number of fruits/hand and hands/bunch, hand and bunch yield, and length and fruit diameter of the second central hand were evaluated during harvest. The doses of humic substances influenced only pseudostem height. Hand yield, as well as fruit length and diameter of ‘BRS Princesa’ banana were higher in plants fertigated with humic substance and plant extract in comparison with plants fertigated with only humic substance.

RESUMO. O trabalho teve como objetivo avaliar efeitos de substância húmica aplicada com e sem adição de extrato vegetal via fertirrigação no sistema radicular da bananeira cultivar 'BRS Princesa'. A bananeira foi cultivada no espaçamento 2,0 x 2,5 m, fertirrigada por gotejamento em Latossolo Amarelo Distrocoeso. O delineamento experimental foi em blocos casualizados em esquema de parcelas subsubdivididas com cinco repetições, sendo os fatores: doses de substancia húmica, presença de uma formulação de extrato vegetal. Usou-se cinco doses de uma formulação de substâncias húmicas, baseadas na dose de referência correspondente a 14,14 L ha-1 ciclo-1 de substancias húmicas, na presença e ausência de extrato vegetal. A variável comprimento de raízes (cm) foi submetida a análises de variância para avaliação do efeito isolado da dose de substancia húmica ou em interação com uma formulação de extrato vegetal e com a profundidade do solo. O uso do extrato vegetal potencializou o efeito da substancia húmica no comprimento das raízes, entretanto ofuscou seu efeito para as diferentes doses de substancia húmica. Na profundidade 0 - 0,40 m o comprimento de raízes não foi sensível ao aumento da dose da substancia húmica com extrato vegetal até 42,42 L ha-1.

ABSTRACT. This study aimed to evaluate the effects of fertigation with humic substances, with and without the addition of plant extracts, on the root system of the 'BRS Princesa' banana cultivar. The banana crop was cultivated at a spacing of 2.0 x 2.5 m and fertigated using a drip system in a dystrocohesive Yellow Latosol. The experimental design was randomized blocks, in a split-split-plot scheme with five replicates, for the following factors: humic substance doses and presence of a plant extract formulation. The treatments consisted of five doses of humic substances, based on a reference dose of 14.14 L ha-1 cycle-1, in the presence and absence of plant extract. The variable root length (cm) was subjected to variance analyses to evaluate the effect of the humic substances, either isolated or in interaction with plant extract and soil depth. The use of the plant extract increased the effect of the humic substance on root length but overshadowed its effect for the different doses of humic substance. Root length was not sensitive to increasing humic substance dose with plant extract for doses of up to 42.42 L ha-1at 0 - 0.40 m depth.

ABSTRACT The deployment of soluble fertilizers has been one of the most commonly applied agricultural practices in the bid to increase crop yield. However, the production of soluble fertilizers has a considerable economic cost and consumes a substantial amount of energy. In general, soil organic matter provides the nutrients needed for plant growth in organic agriculture. However, these nutrients are not sufficient if the best yield is to be obtained. The aim of our field experiment was to evaluate the effectiveness of phosphate and potassic sources (rocks, bio-fertilizers and soluble fertilizers) based on several sugarcane characteristics and soil attributes. Our experiment was conducted over two consecutive years, and we assessed the effect of using sugarcane filter mud cake (SFMC). In addition, we mixed the phosphate and potassic sources with earthworm compost enriched in N by inoculation with diazotrophic bacteria (OM) and applied at 50, 100 and 150 % of the recommended dosage rate (RDR). The PK biofertilizer with OM enriched in N positively affected sugarcane height, yield, and industrial characteristics. The application of SFMC greatly increased available P and K in the soil and plant characteristics with residual effect in the two consecutive harvests. We conclude that the biofertilizer has the potential to increase sugarcane characteristics and may represent an alternative to soluble fertilizers.