Abstract: This research study assessed the use of Pueraria phaseoloides crops as cover in oil palm (Elaeis guineensis) plantations to improve the ecological function of soils under tropical conditions. The plots examined (90 palms·ha-1) were established 5, 7, 11, and 30 years ago. The results showed a high and stable specific coverage index that ranged between 52 and 87%. This enhanced soil moisture by reducing the incidence of solar radiation. It also increased competitive capacity with the complex of weeds present and improved soil nutrient averages (1.60 mg/L N and 0.42 mg/L P). Fruit bunch average yields also improved in the short term, ranging from 10.6 to 22.4 t·ha-1, with more frequent harvest events when compared to the control. It is concluded that Pueraria phaseoloides is a sustainable alternative to improve the establishment of plantations under tropical conditions.

Resumen: Esta investigación evaluó el uso de los cultivos de Pueraria phaseoloides como cobertura en plantaciones de palma aceitera (Elaeis guineensis) para mejorar el funcionamiento ecológico de los suelos en condiciones tropicales. Se examinaron parcelas de densidades de siembra de 90 palmas·ha-1 establecidos hace 5, 7, 11 y 30 años. Los resultados mostraron un índice de cobertura específico elevado y estable que osciló entre 52 y 87 %. Se observó mejor humedad del suelo con una menor incidencia de radiación solar, mayor capacidad competitiva con el complejo de malezas presentes, y mejores promedios de nutrientes (1.60 mg/L N y 0.42 mg/L P). Además, se incrementaron los rendimientos promedios de los racimos de fruta a corto plazo entre 10.6 y 22.4 t·ha-1 con eventos de cosechas más frecuentes en comparación con la estándar. Se concluye que Pueraria phaseoloides es una alternativa sostenible para mejorar el establecimiento de las plantaciones en condiciones tropicales.

Resumen Introducción. Los cultivos de cobertura compiten en sus etapas iniciales de crecimiento con las malezas, por lo que en áreas donde predominan malezas de muy rápido crecimiento es necesaria la aplicación de herbicidas para controlarlas mientras la cobertura se establece. Objetivo. Evaluar la tolerancia de las leguminosas Mucuna pruriens (L) DC cv. preta, M. pruriens cv. cinza, Vigna radiata (L.) Wilczek, Pueraria phaseoloides (Roxb) Benth. y Crotalaria spectabilis Roth a herbicidas preemergentes y posemergentes. Materiales y métodos. Se realizaron 2 estudios en un invernadero de la Universidad de Costa Rica, situado en Alajuela, Costa Rica. En el primer experimento se evaluaron los herbicidas posemergentes cletodim, fluazifop-p-butil, fomesafen y bentazon, en el 2012 y se repitió en el 2013. El segundo experimento se realizó 2 veces en el 2014 para evaluar los herbicidas preemergentes pendimetalina, oxifluorfen, alachlor y linuron. Se evaluó la altura, el grado de daño y el peso seco de las plantas sembradas en potes de 1,5 litros. El diseño experimental utilizado fue completamente aleatorio. Resultados. Todas las especies evaluadas, con excepción de P. phaseoloides, resultaron tolerantes a bentazon, cletodim y fluazifop-p-butil. Estas especies también mostraron tolerancia a alaclor, linuron y pendimetalina. P. phaseoloides fue tolerante a fomesafen y fluazifop-p-butil, pero resultó moderadamente afectado por los herbicidas preemergentes. Solamente las plantas aplicadas con oxifluorfen y fomesafen evidenciaron una reducción significativa del peso seco, con excepción de las plantas de P. phaseoloides aplicadas con fomesafen. Conclusión. Las leguminosas evaluadas resultaron tolerantes a la mayoría de los herbicidas aplicados para control de monocotiledóneas y dicotiledóneas.

Abstract Introduction. Cover crops compete during their initial growth stages with weeds, therefore in areas where the predominant weeds are fast growers it is necessary to spray herbicides to control those plants while the cover gets established. Objetive. To evaluate the tolerance of the legumes Mucuna pruriens (L) DC cv. preta, M. pruriens cv. cinza, Vigna radiata (L.) Wilczek, Pueraria phaseoloides (Roxb) Benth. and Crotalaria spectabilis Roth to pre- and postemergence herbicides. Materials and methods. Two studies were carried out in a greenhouse of the University of Costa Rica, located in Alajuela, Costa Rica. The first experiment evaluated the postemergence herbicides clethodim, fluazifop-p-butyl, fomesafen and bentazon in 2012 and was repeated in 2013. The second experiment was performed twice in 2014 to evaluate the postemergence herbicides pendimethalin, oxyfluorfen, alachlor and linuron. Plant height, injury index and dry weight of plants sowed in 1.5 liters pots was assessed. The experimental design was completely randomized. Results. All the evaluated species, except for P. phaseoloides, were tolerant to bentazon, cletodim and fluazifop-p-butil. These species were also tolerant to alachlor, linuron, and pendimethalin. P. phaseoloides was tolerant to fomesafen and fluazifop-p-butyl, but resulted moderately affected by the preemergent herbicides. Only plants treated with oxyfluorfen and fomesafen showed a significant dry weight reduction, except for P. phaseoloides plants sprayed with fomesafen. Conclusion. The evaluated legumes were tolerant to the majority of the sprayed herbicides for the control of both dicotyledonous and monocotyledonous weeds.

Resumo A Campomanesia adamantium (guavira) é nativa do Cerrado brasileiro e utilizada como alimentícia e medicinal. A planta tem sido explorada indiscriminadamente em seu hábitat, o que, somado às queimadas e ao desmatamento, levam-na ao risco de extinção. Para a preservação da espécie, é essencial seu manejo in situ e ex situ, e as práticas agroecológi-cas associadas à adubação verde são um sistema recomendado. Neste estudo, investigamos o desenvolvimento da C. adamantium cultivada com os adubos verdes Stylosanthes macrocephala, Pueraria phaseoloides, Calopogonium mucunoides e Cajanus cajan, além dos atributos químicos e microbiológicos do solo. Os adubos verdes tiveram maiores produções de massas frescas e secas no segundo corte, e as plantas de C. mucunoides, S. macrocephala e P. phaseoloidestiveram maiores concentrações de nutrientes. A massa do C. mucunoidesteve rápida decomposição e influenciou os atributos químicos do solo, havendo maior atuação dos microrganismos do solo no processo bioquímico de decomposição dos resíduos orgânicos. As plantas de C. adamantium mais bem desenvolvidas e com maiores produções e teores de nutrientes nas folhas foram cultivadas com os adubos verdes C. mucunoides e S. macrocephala. Os resultados mostraram que as plantas de C. adamantium respondem positivamente ao uso do adubo verde C. mucunoides, com aumento da produção de folhas. Este cultivo agroecológico contribui para a preservação de C. adamantium e para o uso adequado dos recursos naturais do Cerrado.

Abstract Campomanesia adamantium (guavira) is a native plant of the Brazilian Cerrado used both as food and as medicine. The plant has undergone indiscriminate overexploitation in its habitat, which, in association with fires and deforestation, puts the species at risk of extinction. To preserve the species, in situ and ex situ management actions are required and agroecological practices associated with green manuring is the recommended system. In this study, we investigated the development of C. adamantium grown with the green manures Stylosanthes macrocephala, Pueraria phaseoloides, Calopogonium mucunoides, and Cajanus cajan, as well as the chemical and microbiological properties of the soil. The green manures had the highest production of fresh and dry masses at the second cut and C. mucunoides, S. macrocephala, and P. phaseoloides presented the highest nutrient concentrations. C. mucunoides mass decomposed rapidly and influenced the chemical properties of the soil, with a greater role of soil microorganisms in the biochemical process of decomposition of the organic residues. The bestdeveloped and highest yielding plants with the highest leaf nutrient content were obtained for C. adamantium grown with the green manures C. mucunoides and S. macrocephala. The results showed that C. adamantium responded positively to the use of the green manure C. mucunoides with increased leaf production. This agroecological cultivation to contributes for the preservation of C. adamantium and the appropriate use of the natural resources of the Cerrado.

RESUMEN El experimento fue conducido para determinar los coeficientes de digestibilidad y la energía digestible de la harina de kudzu (Pueraria phaseoloides) en cuyes. Se utilizaron 10 cuyes machos de 12 semanas y 828 g de peso promedio, colocados en jaulas metabólicas. Cinco animales fueron alimentados con la dieta basal (subproducto de trigo) y los otros cinco con la dieta experimental (60% subproducto de trigo y 40% harina de kudzu). Para estas determinaciones se utilizó el método indirecto, teniendo como alimento basal al subproducto de trigo, cuyos coeficientes de digestibilidad se determinaron por el método directo. Se tuvo una fase pre-experimental de 14 días para la adaptación de los cuyes a las instalaciones y la nueva dieta. La fase experimental fue de seis días, en la cual se realizó la colección de heces. En ambas fases se midió diariamente el consumo de alimento. Los coeficientes de digestibilidad aparente obtenidos fueron: 42.90% de materia seca, 40.57% de materia orgánica, 81.07% de proteína cruda, 68.86% de extracto etéreo, 30.77% de fibra cruda, 30.55% de extracto libre de nitrógeno y 74.18% de ceniza. El valor de la energía digestible determinado por diferencia fue de 1.98 Mcal/kg de materia seca.

ABSTRACT The experiment was conducted to determine the digestibility coefficients and digestible energy of kudzu meal (Pueraria phaseoloides) in guinea pigs. Ten male guinea pigs of 12 weeks and 828 g of average weight were placed in metabolic cages. Five animals were fed the basal diet (wheat by-product) and the other five were fed with the experimental diet (60% wheat by-product and 40% kudzu meal). The indirect method was used for these determinations. The wheat by-product meal was used as a basal feed and its digestibility coefficient was determined by the direct method. There was a 14-day preexperimental phase for the adaptation of the animals to the facilities and the new diet. The experimental phase was six days, in which the stool collection was performed. In both phases, feed consumption was measured daily. The apparent digestibility coefficients obtained were: 42.90% dry matter, 40.57% organic matter, 81.07% crude protein, 68.86% ethereal extract, 30.77% crude fibre, 30.55% nitrogen free extract and 74.18% ash. The digestible energy value determined by difference was 1.98 Mcal/kg of dry matter.

Resumen Se evaluó el efecto de las coberturas Mucuna bracteata, Desmodium sp. y Pueraria phaseoloides en el crecimiento y su influencia en el estado fitosanitario de un cultivo de caucho natural de dos años de edad en la altillanura colombiana. En condiciones de libre exposición se establecieron tratamientos por cobertura con tres repeticiones y tres réplicas con un control. Las variables respuestas fueron perímetro y la altura total del árbol; se realizaron muestreos del follaje de las coberturas para identificar y cuantificar hongos presentes. Adicionalmente, se hicieron inoculaciones de Colletotrichum gloesporioides en las tres coberturas en condiciones semicontroladas. Se encontró que las tres coberturas generan un leve aumento en la materia orgánica del suelo y favorecen el desarrollo de los árboles. Los hongos más frecuentemente aislados correspondieron a Cladosporium sp., E. sorgui y Fusarium sp. Las inoculaciones mostraron que las tres coberturas son susceptibles a C. gloesporiodes.

Abstract The purpose of this research is evaluating the results of the effect of M. bracteata, Desmodium sp y P. phaseoloides cover crops in growth, and their influence in the phytosanitary conditions of a two years old natural rubber crop in the “Altillanura Colombiana”. We established treatments by cover crop with three repeats and a control crop. The development of the trees was evaluated through the measurement of perimeter and total height. Additionally, inoculations of C. gloesporioides were carried out in the three cover crops under semi-controlled conditions. It was found that the three cover crops generated a slight increase in the organic matter of the soil and have a favorable effect on the development of the trees. Also, that the most frequently isolated fungi corresponded to Cladosporium sp., E. sorgui and Fusarium sp., and that the inoculations showed that the three coverages are susceptible to C. gloesporioides.

Resumen Se determinó el efecto de aislados de rizobios tolerantes a la acidez en el crecimiento, la nodulación y el rendimiento de kudzú tropical, cultivado en condiciones de acidez. Mediante la medición del diámetro de la colonia y el número de células viables se estableció, en condiciones de acidez, la tolerancia a pH 4.5 de tres cepas de Bradyrhizobium: K2, 1_2 y 2_4. Se realizaron dos ensayos de inoculación de kudzú tropical: uno en condiciones controladas, y otro en campo. Se determinó el efecto de la acidez en la nodulación, crecimiento y rendimiento del cultivo. Se empleó un ANOVA de clasificación simple yun arreglo bifactorial en el análisis estadístico. Las tres cepas de rizobios resultaron tolerantes a pH 4.5. Esta condición no disminuyó su diseminación por la placa Petri, el diámetro de las coloniasni el número de células viables. La acidez no disminuyó la nodulación ni el crecimiento de plantas de kudzú, inoculadas con K2 y 1_2 en condiciones controladas. La inoculación de kudzú con los aislados de rizobios produjoefectividad en la fijación biológica del nitrógeno, más de90 % de los nódulos totales, más de75 % del rendimiento en masa seca aérea, y más de45 % del contenido de nitrógeno de la biomasa aérea de las plantas, en condiciones de campo. La elaboración y aplicación de inoculantes basadas en K2 y 1_2 contribuiría a disminuir el uso de fertilizantes minerales en suelos afectados por la acidez.

Abstract The effect of acid-tolerant rhizobia isolates on growth, nodulation and yield of tropical kudzu, grown under acidity conditions, was determined. By measuring the diameter of the colony and the number of viable cells, the pH tolerance of three Bradyrhizobium strains: K2, 1_2 and 2_4 was established under acidity conditions. Two inoculation tests of tropical kudzu were carried out: one under controlled conditions, and another in the field. The effect of acidity on nodulation, growth and yield of crop was determined. A simple classification ANOVA and a two-factor arrangement were used in the statistical analysis. The three strains of rhizobia were tolerant at pH 4.5. This condition did not decrease its dispersion in the Petri dish, the diameter of the colonies or the number of viable cells. The acidity did not decrease the nodulation or the growth of kudzu plants, inoculated with K2 and 1_2 under controlled conditions. The inoculation of kudzu with rhizobia isolates produced effectiveness in the biological fixation of nitrogen, more than 90 % of the total nodules, more than 75 % of the aerial dry mass yield, and more than 45 % of the nitrogen content of the aerial biomass of plants, under field conditions. The elaboration and application of inoculants based on K2 and 1_2 would contribute to reducing the use of mineral fertilizers in soils affected by acidity.

Resumen El objetivo del presente estudio fue evaluar el rendimiento de materia seca (MS), concentraciones de fibra detergente neutro y ácido (FDN y FDA), proteína cruda (PC) y digestibilidad in vitro de la MS (DIVMS) de las leguminosas forrajeras Stylosanthes guianensis (SG), Centrosema macrocarpum (CM), Pueraria phaseoloides (PP) y Arachis pintoi (AP). Durante 11 meses se realizaron seis cortes a intervalos de 56 días. La siembra de las especies se realizó en parcelas experimentales de 3 x 7 m bajo un diseño de bloques completos al azar con cuatro repeticiones. La acumulación de MS total fue mayor (P≤0.05) en SG y CM con 19,410 y 17,462 kg MS ha-1, respectivamente, en comparación a PP (14,704 kg) y AP (12,466 kg). La especie con menor cantidad (P≤0.05) de FDN y FDA fue AP con 60 y 35 %, respectivamente. Esta misma especie tuvo mayor digestibilidad (74 %) seguido de SG con 62 %, PP con 57 % y CM con 55 %. Las especies con mayor (P≤0.05) contenido de PC fueron AP y CM con 21 % seguido de SG con 19 % y PP con 17.8 %. Las especies SG y CM fueron las leguminosas con mayor producción de MS; mientras que AP fue la especie con mayor digestibilidad y proteína. No obstante, de acuerdo a su valor nutritivo y producción de MS, las cuatro leguminosas pueden ser utilizadas como fuente de proteína para rumiantes en dietas de bajo valor nutritivo.

Abstract Dry matter yield and nutritional data are needed before forage legumes can be proposed for inclusion in livestock systems. An evaluation was done of the dry matter (DM) yield, concentrations of neutral and acid detergent fiber (NDF and ADF) and crude protein (CP), and in vitro DM digestibility (IVDMD) of the forage legumes Stylosanthes guianensis (SG), Centrosema macrocarpum (CM), Pueraria phaseoloides (PP) and Arachis pintoi (AP). During an eleven-month period six cuts were made of these legumes at 56-d intervals. Experimental plots were 3 x 7 m, and analyses were done using a completely random block design with four replicates. Overall DM yield was higher (P≤0.05) in SG (19,410 kg DM ha-1) and CM (17,462 kg DM ha-1), than in PP (14,704 kg DM ha-1) and AP (12,466 kg DM ha-1). Arachis pintoi had the lowest NDF (60%) and ADF (35 %) contents (P≤0.05). Digestibility was highest in AP (74 %), followed by SG (62%), PP (57 %) and CM (55 %). Crude protein content was highest (P≤0.05) in AP and CM (21 %) followed by SG (19 %) and PP (17.8 %). Although DM yield was highest in SG and CM, and digestibility and crude protein content were highest in AP, all four forage legume species exhibited sufficiently high nutritional values and DM production to make them alternative protein sources for ruminants with low-nutrient diets.

Abstract Tectona grandis L.f. (teak) is the most cultivated precious wood forest species in the world and in Costa Rica it has been used in commercial reforestation projects. Among the silvicultural activities of these plantations are weed and the prevention and management of pests. Recently, cover crops have been used as an alternative method of weed control, however, the effect of this control on pests is unknown. A study was developed to determine the effect of the use of cover crops in the control of weeds and to evaluate the presence of herbivores and pathogens in young teak stands in the South Pacific of Costa Rica A randomized complete block design with 3 replications and 7 treatments was used: Control (without weed control), Chemical weed control, Manual weed control, Cover crop Canavalia ensiformis, Cover crop Vigna radiata, Mix between Vigna radiata and Pueraria phaseoloides and Cover crop Crotalaria juncea. Olivea tectonae (“teak rust”) and Rhabdopterus sp. (“Teak skeletonizer”) were selected as target disease and pest where 2 evaluations of the incidence and severity index were made, when the plantation was 6 and 12 months old. Despite the fact that incidence values were higher than 60% in both, the average values of severity were grouped in the minor categories. In addition, no significant differences were found among treatments and the incidence or severity of the evaluated pests, which demonstrates that the use of cover crops can be a viable alternative for the control of weeds in a teak plantation. Therefore, we recommend to continue with studies that evaluate the effect of the use of coverages in the presence and severity of teak pests in different regions of the country.

Resumen Tectona grandis L.f. (teca) es la especie forestal con fines comerciales más cultivada en Costa Rica. Dentro de las actividades de manejo de estas plantaciones se encuentran el control de arvenses y el manejo integrado de plagas y enfermedades. Recientemente se han utilizado cultivos de cobertura como método alternativo de control de arvenses, sin embargo, se desconoce la afectación de este control en las plagas. Se desarrolló una investigación para determinar el efecto de la utilización de cultivos de cobertura en el control de arvenses y evaluar la presencia de herbívoros y organismos fitopatógenos en plantaciones jóvenes de teca en el Pacífico Sur de Costa Rica. Se utilizó un diseño experimental de bloques completos al azar con 3 repeticiones y 7 tratamientos: Testigo (sin control de arvenses), Control de arvenses químico, Control de arvenses manual, Canavalia ensiformis, Vigna radiata, Mezcla entre Vigna radiata y Pueraria phaseoloides y Crotalaria juncea. Se seleccionaron como enfermdad objetivo Olivea tectonae (“roya de la teca”) y plaga objetivo Rhabdopterus sp. (“esqueletizador de la teca”) y se realizaron 2 evaluaciones de incidencia e índice promedio de severidad, cuando la plantación tenía 6 y 12 meses de edad. A pesar de que la incidencia mostró valores superiores a 60% en ambas los valores promedios de severidad se concentraron en las categorías menores. Adicionalmente en las evaluaciones realizadas no se evidenció efecto de las coberturas en el aumento de la incidencia o severidad de la enfermedad y plaga evaluadas, lo que demuestra que el uso de coberturas puede ser una alternativa viable para el control de arvenses de una plantación de teca. Por lo anterior se recomienda continuar con estudios que evalúen el efecto del uso de coberturas en la presencia y severidad de plagas en teca en distintas regiones del país.

Abstract Legume cover crops are planted to control weed, to prevent soil erosion, and to increase nitrogen in soil. The objective of this study was to evaluate the response to phosphorus fertilization of the legumes Mucuna pruriens cv. cinza, Mucuna pruriens cv. preta, Crotalaria spectabilis, Vigna radiata, and Pueraria phaseoloides, during two seasons of the year. The experiment was carried out in a greenhouse at the Agricultural Experiment Station Fabio Baudrit Moreno (EEAFBM, in Spanish), of the University of Costa Rica, Alajuela, Costa Rica, from November 2012 to January 2013, and it was replicated from April to May 2013. Doses of 0, 30, 60, and 90 kg P2O5/ha were applied on steam sterilized soil, an then it was used to fill 2 kg capacity pots. The variables assessed were plant height, number of true leaves, and dry weight 18-26 days after planting, depending on legume species. Crotalaria spectabilis, V. radiata, and P. phaseoloides achieved the highest growth when fertilized at the rate of 60 kg P2O5/ha, whereas both M. pruriens cultivars did not increase growth as a response to phosphoric fertilization. Due to the positive effect of phosphorus fertilization on growth of small seeded legumes, it is important to validate the use of this fertilizer to achieve rapid soil cover, which could decrease weed competition.

Resumen Los cultivos de cobertura de especies leguminosas son sembradas para el control de malezas, prevención de la erosión del suelo y aporte de nitrógeno al suelo. El objetivo de este estudio fue evaluar la respuesta de las leguminosas de cobertura Mucuna pruriens cv. cinza, Mucuna pruriens cv. preta, Crotalaria spectabilis, Vigna radiata y Pueraria phaseoloides a la fertilización fosfórica, en dos épocas del año. El experimento se realizó en un invernadero en la Estación Experimental Agrícola Fabio Baudrit Moreno (EEAFBM) de la Universidad de Costa Rica, en Alajuela, Costa Rica, en el periodo de noviembre del 2012 a enero del 2013, y se repitió de abril a mayo del 2013. Se aplicaron dosis de 0, 30, 60 y 90 kg P2O5/ha en suelo esterilizado con vapor y posteriormente, utilizado para llenar potes de 2 kg de capacidad. Se evaluó altura de planta, número de hojas verdaderas y peso seco luego de 18-26 días de la siembra, según la especie de leguminosa. Tuvieron un mayor crecimiento C. spectabilis Ruth, V. radiata (L) Wilczek y P. phaseoloides (Roxb), cuando fueron fertilizadas con 60 kg P2O5/ha, mientras que, los dos cultivares de M. pruriens no incrementaron su crecimiento con la fertilización fosfórica. El fósforo a la siembra de las leguminosas de semilla pequeña aceleró su crecimiento, lo que indica la importancia de validar el empleo de este fertilizante para la obtención de una rápida cobertura del suelo, lo cual podría disminuir la competencia con las malezas.

RESUMEN La altillanura colombiana es una microrregión que tipifica un tipo de producción bovina extensiva que requiere el uso de gramíneas adaptadas que respondan a la fertilización nitrogenada para mejorar el rendimiento y la calidad nutricional de las praderas, a fin de intensificar los sistemas de producción ganaderos. El estudio se desarrolló en la sede Taluma de Corpoica, ubicada a 04°34'25" Oeste y 71°20'10" Norte en el municipio de Puerto López (Meta, Colombia), en condiciones de clima y suelo representativos de la altillanura colombiana. El objetivo del estudio fue determinar el comportamiento agronómico y nutricional de los genotipos de Brachiaria brizantha CIAT 16315, 16467, 26990, 26124, 6387 y el control Mulato II manejados con fertilización nitrogenada sola y asociada con la leguminosa Kudzú (Puerariaphaseoloides). Se utilizó un diseño de bloques completos al azar con arreglo en franjas divididas, en donde la parcela correspondió a la gramínea forrajera y la franja al nivel de fertilización nitrogenada (N46, N92 y P. phaseoloides + N46). Los genotipos fueron evaluados durante 90 días, tanto en época seca, como lluviosa. Las accesiones con mayor producción de biomasa (p < 0,001) fueron B. brizantha CIAT 16315 (2.040 kgMS.ha-1), B. brizantha CIAT 16467 (1.864 kg MS.ha-1) y B. brizantha CIAT 6387 (2.033 kgMS.ha-1). El tratamiento de la gramínea + N92 (kgN.ha-1) presentó valores significativamente (p < 0,001) superiores de PC (9,55%) y degradabilidad del forraje (65,7%), y los menores contenidos de materia seca (37,05%), FDN (61,97%) y FDA (30,55%) en relación con las gramíneas fertilizadas con 46 kgN.ha-1 y las gramíneas asociadas con Kudzú y fertilizadas con 46 kgN.ha-1. Por mayor contenido de PC (p < 0,001), se destacaron los materiales B. brizantha CIAT 16315 (8,34%) y CIAT 26124 (8,06%) que no presentaron diferencias significativas con el pasto Mulato II (8,18%). Los resultados demostraron la importancia de la fertilización nitrogenada para mejorar la producción y calidad nutricional de las praderas de B. brizantha.

ABSTRACT The Colombian altillanura is a microregion that typifies a extensive cattle production system which requires the use of adapted grasses responding to nitrogen fertilization to improve yield and nutritional quality grassland to intensify livestock production systems. The study was conducted at the Taluma station of CORPOICA, located at 04°34'25" West and 71°20'10" North in the town of Puerto López (Meta, Colombia), under conditions of climate and soil of the Colombian altillanura. The objective of this study was to determine the agronomic and nutritional behavior of genotypes of Brachiaria brizantha CIAT 16315, 16467, 26990, 26124, 6387 and Mulato II as control, handled single nitrogen fertilization and associated with the legume Kudzú (Pueraria phaseoloides). Design of randomized complete block arrangement in divided stripes, where the plot corresponded to the forage grass strip and the level of nitrogen fertilization was used (N46, N92, and N46 + P. phaseoloides). Accessions with greater biomass production (p < 0.001) were B. brizantha CIAT 16315 (2040 kgDM.ha-1), B. brizantha CIAT 16467 (1864 kgDM. ha-1) and B. brizantha CIAT 6387 (2033 kgDM.ha-1). Treatment grasses + N92 (kgN.ha-1) values had significantly (p <0.001) higher in CP (9.55%) and degradability of forage (65.7%) and lower dry matter content (37.05 %%), NDF (61.97%) and FDA (30.55%) compared with the response of grasses fertilized with 46 kgN.ha-1 and grasses associated with Kudzú and fertilized with 46 kgN.ha-1. For higher CP content (p <0.001), materials B. brizantha CIAT 16315 (8.34%) and CIAT 26124 (8.06%) which did not differ significantly with grazing Mulato II (8.18%). The results demonstrated the importance of nitrogen fertilization on the production and nutritional quality pastures B. brizantha.

RESUMO Altas temperaturas e baixa precipitação caracteriza a região do semiárido Brasileiro. Este clima regional exige a adoção de práticas que aumentem a eficiência e sustentabilidade da agricultura local. O objetivo deste trabalho foi verificar o comportamento de espécies leguminosas herbáceas perenes como cobertura permanente do solo sob pomar de bananeira, no Vale do Jequitinhonha, nordeste do estado de Minas Gerais, Brasil. Para esse fim, foi avaliado as diferenças entre as leguminosas, calopogônio e cudzu tropical na capacidade de cobertura do solo, quantidade de fitomassa senescentes depositada na superfície do solo, conteúdo de nutrientes na fitomassa senescentes, bem como seus efeitos sobre a temperatura e umidade do solo em comparação com solo sem cobertura. Os resultados demonstraram que, em comparação com o cudzu tropical o calopogônio obteve maior capacidade de cobertura do solo e, devido a maior quantidade de fitomassa senescente, foi mais eficaz no incremento de nutrientes. Além disso, ambas leguminosas reduziram a temperatura e mantiveram maior umidade do solo em comparação com o solo sem cobertura. Essas espécies podem depositar níveis elevados de material senescente sobre a superfície do solo, proporcionando várias vantagens para o sistema de cultivo de bananeiras em região semiárida.

ABSTRACT High temperatures and low rainfall characterize the Brazilian semiarid regions. This regional climate demands the adoption of practices that increase the efficiency and sustainability of local farming. This study aimed to assess the ability of two perennial herbaceous leguminous species, calopo and tropical kudzu, to provide permanent soil cover in banana plantations in Jequitinhonha Valley, northeast Minas Gerais state, Brazil. To this end, we evaluated the differences of calopo and tropical kudzu in soil cover capacity and the amount of senescent phytomass deposited on the soil surface, nutrient content in senescent phytomass, as well as their effects on temperature and soil moisture, compared with bare soil in two experimental sites. The results showed that, compared with tropical kudzu, calopo had a higher soil cover capacity and was more effective at increasing organic material and nutrients in the soil owing to the relatively higher amount of senescent phytomass deposited on the soil surface. However, both calopo and tropical kudzu reduced soil temperature and increase soil moisture compared with bare soil. Overall, we concluded that these species can deposit high levels of senescence in the soil, providing several benefits to the cultivation system of banana plants in the semiarid regions.

RESUMO Objetivou-se, com este trabalho, avaliar a produtividade e a viabilidade econômica em três ciclos da bananeira cv. Prata Anã em associação com leguminosas herbáceas perenes, vegetação nativa ou comparadas com o manejo convencional. A pesquisa foi conduzida utilizando-se delineamento em blocos casualizados com parcelas subsubdivididas com quatro repetições. As parcelas foram formadas por quatro lâminas de irrigação: 50, 75, 100 e 125% da evapotranspiração da cultura e as subparcelas por plantas de cobertura (Calopogonium mucunoides, Pueraria phaseoloides e vegetação espontânea sem adição de N) ou tratamento com adubação nitrogenada sem plantas de cobertura (manejo convencional). As subsubparcelas foram representadas pelos segundo, terceiro e quarto ciclos de produção da bananeira. Foram estimadas a produtividade e a viabilidade econômica do cultivo para um período de sete anos. O manejo convencional proporcionou maior produtividade e viabilidade econômica no cultivo da bananeira Prata Anã em função da adubação nitrogenada. Manejos com plantas de cobertura leguminosas também foram viáveis economicamente mas devem ser investigados em combinação com a adubação nitrogenada e comparada com o método convencional.

ABSTRACT This research aimed to evaluate the yield and economic viability of three crop cycles of the banana cv. ‘Prata Anã’ in association with perennial herbaceous legumes, natural vegetation, or compared with the conventional management. The research was conducted using a complete randomized block design with split-split plots and four replicates. The plots were formed by four irrigation depths: 50, 75, 100 and 125% of crop evapotranspiration, and the subplots by cover crops (Calopogonium muconoides, Pueraria phaseoloides, and natural cover without N addition) or no cover crops with addition of N fertilization (conventional management). The subsubplots were formed by the second, third and fourth banana production cycles. Yield and economic viability of the cultivation were estimated for a period of seven years. The conventional management promoted greater yield and economic viability in the cultivation of ‘Prata Anã’ banana, due to the N fertilization. Managements with leguminous cover crops were also economically viable, but they should be investigated in combination with N fertilization and compared with the conventional method.

RESUMO O consórcio de milho com adubo verde perene é uma opção para promover a cobertura do solo, controlar plantas espontâneas e reciclar nutrientes do solo, em sistema orgânico. Objetivou-se avaliar as características agronômicas e produtividade de grãos e de palhada de milho orgânico em consórcio com adubos verdes perenes, semeados em diferentes estádios fenológicos do milho. Utilizou-se esquema fatorial 3 x 2 + 1, com três espécies perenes de adubos verdes - calopogônio (Calopogonium mucunoides Desv.), puerária [Pueraria phaseoloides (Roxb.) Benth] e soja-perene [Neonotonia wightii (Wight & Arn) Lackey] - e duas épocas de semeadura dos adubos verdes - estádios V4 (quatro folhas expandidas) e VT (pendoamento) do milho - mais um tratamento controle (milho em monocultivo). Utilizou-se delineamento em blocos casualizados, com quatro repetições. Avaliou-se a cobertura do solo, produção de massa seca dos adubos verdes e das plantas espontâneas e variáveis de crescimento e produção do milho. A semeadura dos adubos verdes, no estádio V4, proporcionou maior porcentagem de cobertura do solo, em relação ao VT. O calopogônio, quando comparado aos demais adubos verdes, apresentou maior porcentagem de cobertura do solo (35,63 %) e massa seca (1,0 Mg ha-1). Os adubos verdes perenes cultivados em consórcio com milho não interferiram no crescimento, produtividade de grãos e palhada do milho. Porém, não foram eficientes na supressão das plantas espontâneas.

ABSTRACT Maize intercropped with perennial green manure is an option to promote soil coverage, control weeds and recycle soil nutrients, in an organic system. This study aimed at evaluating the agronomic characteristics and yield of grains and organic maize straw intercropped with perennial green manures sown at different maize growth stages. A 3 x 2 + 1 factorial design was used, with three perennial species of green manure - calopogonium (Calopogonium mucunoides Desv.), tropical kudzu [Pueraria phaseoloides (Roxb.) Benth] and perennial soy [Neonotonia wightii (Wight & Arn) Lackey] - and two green manure sowing times - at the maize V4 (four expanded leaves) and VT (bolting) stages - plus a control treatment (maize monoculture). A randomized blocks design, with four replications, was used. Soil coverage, production of green manures dry matter and weeds, and maize growth and production variables were evaluated. The sowing of green manures at the V4 stage had a higher percentage of soil coverage, in relation to the VT stage. Calopogonium, when compared to the other green manure species, had the highest percentage of soil coverage (35.63 %) and dry matter (1.0 Mg ha-1). Perennial green manures grown intercropped with maize did not affect growth, grain yield and maize straw. However, they were not effective in suppressing weeds.

El experimento fue conducido para determinar los coeficientes de digestibilidad y la energía digestible del Arachis pintoi, Stylozanthes guianensis, Erythrina poeppigiana, Centrocema macrocarpum y Pueraria phaseoloides. Se empleo el método directo, usando el mismo forraje como único alimento. El experimento tuvo dos fases, una de adaptación y una de colección de heces, con una duración de 15 y 5 días, respectivamente. Se utilizaron 25 cuyes machos en etapa de crecimiento distribuidos de tal manera que 5 cuyes correspondieron a cada leguminosa tropical evaluada. Los coeficientes de digestibilidad de los nutrientes del Arachis pintoi (51,96, 56,80, 29,46 y 71,32 por ciento de digestibilidad de la materia seca, proteína cruda, fibra cruda y extracto libre de nitrógeno, respectivamente) fueron cuantitativamente superiores a los otros tratamientos a excepción de la ceniza. Asimismo, los valores de energía digestible (en base seca) obtenidos fueron mayores en el Arachis pintoi (2,20 Kcal/g) que los otros forrajes.

This study was carried out to determine the digestibility coefficients and digestible energy of Arachis pintoi, Stylozanthes guianensis, Erythrina poeppigiana, Centrocema macrocarpum and Pueraria phaseoloides. The direct method was used, using the same forage as the only food. The experiment had two phases, one for adaptation and one of faeces collection, with duration of 15 and 5 days, respectively. We used 25 male guinea pigs in growth stage distributed in order to get 5 guinea pigs for each tropical legume evaluated. The digestibility coefficients of nutrients were numerically higher for Arachis pintoi (51,96, 56,80, 29,46 y 71,32 percent of the dry matter, crude protein, crude fiber and nitrogen free extract digestibility, respectively) than for all the other treatments, except for the ash. Likewise, digestible energy values (in dry basis) were greater for Arachis pintoi (2,20 kcal/g) than for all other forages.

RESUMO: A banana é uma das frutas mais consumidas no mundo, sendo explorada na maioria dos países tropicais. O objetivo deste trabalho foi avaliar os principais atributos da fertilidade do solo na bananeira sob duas coberturas do solo e dois locais de crescimento das raízes. O trabalho foi conduzido em Curaçá, BA, entre outubro de 2011 e maio de 2013, no delineamento experimental de blocos casualizados, no esquema de parcelas subdivididas, com cinco repetições. Nas parcelas foram avaliadas duas coberturas vegetais (cobertura 1 - Pueraria phaseoloides e cobertura 2 - coquetel vegetal com Sorghum bicolor, Ricinus communis L, Canavalia ensiformis, Mucuna aterrima e Zea mays e nas subparcelas: local 1- Amostragem de solo entre planta na linha da bananeira e local 2 - Amostragem de solo na entrelinha da bananeira. Verificou-se efeitos significativos e independentes para o fator cobertura vegetal e local de amostragem para as variáveis M.O., Ca e P e efeitos significativo da interação cobertura vegetal com os locais de amostragens do solo para as variáveis potássio, magnésio e soma de bases trocáveis. A cobertura vegetal com o coquetel e o local da entrelinha apresentaram o maior teor de matéria orgânica. O potássio foi o nutriente que teve a maior variação negativa em relação a caracterização inicial e seu teor foliar foi abaixo do valor de referência, mesmo assim não reduziu a produtividade da cultura. O cultivo de bananeira associado à cobertura do solo no arranjo com coquetel vegetal proporcionou maior disponibilização de nutrientes no solo, comparado a cobertura com kudzu tropical.

ABSTRACT: Banana is one of the most consumed fruits in the world, which is grown in most tropical countries. The objective of this work was to evaluate the main attributes of soil fertility in a banana crop under two cover crops and two root development locations. The work was conducted in Curaçá, BA, Brazil, between October 2011 and May 2013, using a randomized block design in split plot with five repetitions. Two cover crops were assessed in the plots, the cover 1 consisting of Pueraria phaseoloides, and the cover 2 consisting of a crop mix with Sorghum bicolor, Ricinus communis L., Canavalia ensiformis, Mucuna aterrima and Zea mays, and two soil sampling locations in the subplots, between plants in the banana rows (location 1) and between the banana rows (location 2). There were significant and independent effects for the cover crop and sampling location factors for the variables organic matter, Ca and P, and significant effects for the interaction between cover crops and sampling locations for the variables potassium, magnesium and total exchangeable bases. The cover crop mix and the between-row location presented the highest organic matter content. Potassium was the nutrient with the highest negative variation from the initial content and its leaf content was below the reference value, however not reducing the crop yield. The banana crop associated with crop cover using the crop mix provided greater availability of nutrients in the soil compared to the coverage with tropical kudzu.