The objective of this study was to evaluate the effects of strains of Azospirillum brasilense, Pseudomonas fluorescens and Rhizobium tropici on the shoot dry weight (SDW) and root dry weight (RDW) yield, N uptake and nutritive value of 'Mavuno' grass inoculated with plant growth-promoting bacteria. We evaluated the effects of inoculation with the Ab-V5 and Ab-V6 strains of Azospirillum brasilense and Pseudomonas fluorescens or coinoculation with Rhizobium tropici and Ab-V6, with and without nitrogen (N) application, as well as re-inoculations. The growth promoting bacteria + N promoted increases in SDW and RDW yield, tillers dry weight, relative chlorophyll index and N uptake. There were no effects of re-inoculation by Azospirillum brasilense, Pseudomonas fluorescens and Rhizobium tropici on nutrition, nutritive value and SDW and RDW yield, demonstrating that this technique still needs further studies with 'Mavuno' grass in the form and the correct period to be performed.

Core Ideas Bermudagrass K fertilization affects forage characteristics. Bermudagrass K fertilization effects are influenced by N fertilization. K fertilization is crucial to increase belowground reserves of bermudagrass. Adequate supply of potassium (K) is an important factor that can affect bermudagrass [Cynodon dactylon (L.) Pers.] production and persistence, particularly in soils with limited nutrient holding capacity. The objectives of this study were to (i) evaluate the effects of different nitrogen (N) and K fertilization strategies on Jiggs bermudagrass herbage accumulation (HA), root–rhizome mass, and K concentration and accumulation in above‐ and belowground tissue; and (ii) identify the critical minimum tissue K concentration below which bermudagrass HA is reduced. The experiment was conducted in a greenhouse at Ona, FL, from August to December, 2014 and 2015. Treatments were a factorial combination of three N (0, 45, and 90 lb/acre) and four K2O fertilization levels (0, 18, 36, and 72 lb K2O/acre, the equivalent of 0, 15, 30, and 60 lb K/acre) after every harvest, distributed in a completely randomized design with four replicates. Herbage was harvested every 6 weeks, and root and rhizome mass determined at the end of each year. There were no effects of K fertilization on HA and root–rhizome mass when no N was applied; however, Jiggs HA and root–rhizome biomass increased linearly with increasing K fertilization levels at 45 and 90 lb N/acre. For these N levels, HA increased with tissue K concentration up to 1.4%. Root and rhizome K concentrations decreased linearly with increasing levels of N. Conversely, root–rhizome K content increased with increasing levels of N fertilization. Potassium fertilization increased HA and root–rhizome mass of Jiggs bermudagrass; however, the responses were influenced by N fertilization levels.

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Core Ideas Bahiagrass pastures on soils with low K concentration may not respond to K fertilization. Tissue K concentration in bahiagrass is variable and dependent on fertilization levels. Bahiagrass tissue K concentration of 17 g kg−1 was related to the greatest herbage accumulation in plants receiving greater levels of fertilization. Bahiagrass (Paspalum notatum Flügge) is the most utilized forage for beef cattle (Bos spp.) in Florida, but there is concern that bahiagrass pastures are declining due to insufficient K fertilization. Two studies determined the effects of K and N fertilization on bahiagrass herbage mass (HM) and nutritive value in field plots (Exp. 1), and greenhouse (Exp. 2). At two locations from May to December 2014 and 2015, Exp. 1 evaluated the combinations of three N fertilization levels (0, 50 kg N ha−1 in May, or 50 kg N ha−1 in May and August) and two levels of K fertilization (0 or 42 kg K ha−1). Potassium fertilization did not affect HM, crude protein (CP), or in vitro digestible organic matter (IVDOM); however, tissue K concentration increased from 10.6 to 11.2 g kg−1 with increasing K fertilization. Plots fertilized with N had greater HM than the control, but there was no difference between plots fertilized in May only vs. those fertilized in May and August. Experiment 2 was conducted in a greenhouse in 2014 and 2015 with a factorial combination of three levels of N fertilization (0, 50, and 100 kg N ha−1) and four levels of K fertilization (0, 16, 33, and 66 kg K ha−1). There was a quadratic relationship between tissue K concentration and herbage accumulation (HA) and maximum HA occurred with tissue K concentration of 17 g kg−1. Bahiagrass tissue K concentration and response to K fertilization are variable and can be related to fertilization levels.

RESUMO Objetivou-se avaliar a possibilidade de recuperação deumapastagem degradada, deBrachiaria decumbens, com a introdução da leguminosaStylosanthes e adubação fosfatada. O experimento constou de distintos métodos de introdução em um delineamento experimental em blocos casualizados com parcelas subdivididas (adubado com e sem fósforo), com quatro repetições e compostos pelos tratamentos: testemunha Brachiaria decumbens; dessecação parcial com 1,5L ha-1 de glifosato; dessecação total com 3,0L ha-1 de glifosato; plantio direto; escarificação do solo; gradagem rome e aração mais gradagem. Nos tratamentos gradagem rome e aração mais gradagem a semeadura da leguminosa foi feita a lanço e os demais na forma de semeadura direta. Foram realizados seis cortes para separação dos componentes morfológicos da forragem e composição botânica. Os maiores acúmulos de massa seca total foram encontrados para dessecação parcial com 1,5L ha-1 de glifosato, gradagem rome, aração mais gradagem e dessecação total com 3,0L ha-1 de glifosato em relação aos tratamentos plantio direto da leguminosa e testemunha. A composição bromatológica foi melhor na estação da primavera, PB e FDA apresentaram diferenças significativas entre todos os tratamentos (P<0,05). O adubo fosfatado teve efeito para FDA nas estações da primavera e outono. A introdução da leguminosa, por meio de gradageme aração + gradagem,promoveu a maior produtividade na biomassa total e a dessecação parcial e totalaumentaram a participação da leguminosa. A adubação fosfatada somente apresentou resultados positivos na produtividade e participação da leguminosa durante a época de verão.

Rhizoma peanut (Arachis glabrata Benth.) is a widely used warm‐season legume in Florida. Ecoturf is a rhizoma peanut germplasm with superior nutritive value; however, there is limited information about the effects of regrowth interval on this characteristic. The objective was to investigate the effects of regrowth interval on in situ crude protein (CP) and dry matter (DM) disappearance of Ecoturf compared with the predominant cultivar ‘Florigraze’. The experiment was conducted from July to October of 2014 and 2015. Treatments were a split‐plot design of Florigraze and Ecoturf (main plots) harvested at regrowth intervals of 4, 8, and 12 wk (subplots), distributed in a randomized complete block design with four replicates. Samples of each treatment were incubated in two steers (Bos spp.) for 0, 3, 6, 9, 12, 24, 48, and 72 h, and DM and CP disappearance were fit to a nonlinear model. Ecoturf had greater CP concentration than Florigraze (193 vs. 168 g kg−1). There was no effect of genotype on in situ effective disappearance of CP (715 g CP kg−1); however, there was a quadratic effect of regrowth interval. Ecoturf had greater effective disappearance of DM than Florigraze only at 4 wk of regrowth (597 vs. 563 g kg−1). Dry matter and CP disappearance parameters may differ between Ecoturf and Florigraze. Harvesting at a regrowth interval of 8 wk or less may improve rhizoma peanut nutritive value.

RESUMO. Avaliaram-se a produção e o valor nutritivo da forragem das seguintes espécies:Cynodon spp (Tifton 68, Tifton 78, Tifton 85, Florakirk, Florico e Florona), Paspalum notatum (Tifton 9), Brachiaria brizantha (Marandu) , sendo o menor valor observado no capim-Tifton 9, na estação das águas, e o maior valor no capimTifton 68, na época da seca. A diferença estacional na PMS foi mais pronunciada no capimTifton 85, que apresentou somente 9% da produção anual na estação seca. , being the lower value observed in the cv. Tifton 9 in the WS and the higher value in the cv. Tifton 68 in the DS. The seasonal difference in the production of DM was more pronounced in the cv. Tifton 85, which presented only 9% of the annual production in the DS. IntroduçãoA região Noroeste do Estado de São Paulo apresenta grande potencial de uso das gramíneas forrageiras dos gêneros Brachiaria, Cynodon, Paspalum e Panicum. No entanto, há escassez de informações sobre o comportamento, produção e manejo das gramíneas desses gêneros nas condições de clima e solos dessa região. Como conseqüência, o que se observa nas propriedades rurais é o estabelecimento desses capins em solos de baixa fertilidade e nos quais, devido a não correção e reposição de nutrientes, iniciam-se rapidamente os processos de esgotamento e degradação, caracterizando assim, um ciclo vicioso de baixa produtividade e necessidade constante de se reformar as pastagens.No Brasil, não existe registro de onde e como o gênero Cynodon foi introduzido. Acredita-se que ocorreu por iniciativa de pecuaristas e pesquisadores para avaliar o seu comportamento em condições brasileiras. As informações que se seguem, referentes aos capins do gênero Cynodon foram apresentadas recentemente por Burton e Hanna (1995) e Pedreira et al. (1998).O cultivar Tifton 68 (C. nlemfuensis) é um híbrido entre duas introduções do Quênia e

Mavuno' brachiariagrass (Brachiaria spp.) is a warm-season perennial grass cultivar released in Brazil with potential to be used as forage in subtropical regions. The objective of this study was to evaluate herbage accumulation (HA), nutritive value, and the persistence of Mavuno under different harvest frequencies. The experiment was conducted in Ona, FL, from April to November in 2016 and 2017. Treatments were the factorial arrangement of four grasses: Jiggs bermudagrass [Cynodon dactylon (L.) Pers], 'Tifton 85' bermudagrass (Cynodon spp.), 'Mulato II' brachiariagrass, and Mavuno and two regrowth intervals (3 or 6 wk), distributed in a randomized complete block design with four replicates. Mavuno and Mulato II had similar total annual HA (11.0 Mg ha −1 ), and in vitro digestible organic matter (IVDOM, 644 g kg −1), but greater total annual HA and IVDOM than Jiggs (7.8 Mg ha −1 and 500 g kg −1 ) and Tifton 85 (8.4 Mg ha −1 and 550 g kg −1 ). Mavuno had the least crude protein (CP) among all treatments (111 vs. 124 g kg −1 ), and CP and IVDOM were greater at the 3-wk regrowth interval than at the 6-wk interval (130 vs. 111 g kg −1 and 610 vs 548 g kg −1 , respectively). Root mass was greater at 3 wk than at 6 wk for Tifton 85 (9.4 vs. 5.4 Mg ha −1 ) but was not affected by regrowth interval for Jiggs, Mavuno, and Mulato II (6.5 Mg ha −1 ). Mavuno and Mulato II had superior HA and IVDOM, and Mavuno may be a viable forage source in subtropical regions.