The presence of trees in silvopastoral systems causes changes in the microclimate of the understory where there is the cultivation of forages. This study evaluated the forage dry mass and the structural characteristics of Piatã grass under two densities of trees in a silvopastoral system, in contrast to a treeless area in the rainy and dry seasons of the Brazilian savannah region, so called Brazilian Cerrado. The forage was Brachiaria brizantha cv. BRS Piatã and the tree species was the eucalyptus (Eucalyptus grandis  E. urophylla) planted in the North-South direction in the treatments: forage grown in treeless area (control); forage grown in eucalyptus understory with spacing between rows of 22 m (SSP22); forage grown in eucalyptus understory with spacing between rows of 12 m (SSP12). The experimental design was a randomized complete block with three replications and evaluations conducted from April 2013 to April 2014. There was a reduction in cumulative dry mass and in accumulation rate of Piatã grass in silvopastoral system in the rainy season and the Western side suffered greater interference from trees during this season. For every 1% reduction in photosynthetically active radiation occurred a decrease of 1.35% in the forage dry mass, corresponding to 42.8 kg ha À1. The structural characteristics of Piatã grass have changed in both dry and rainy seasons in silvopastoral system. The spacing between rows of Eucalyptus greater than 22 m is less damaging for pasture productivity when the trees of the silvopastoral system are planted in North-South direction. 2016 Elsevier B.V. All rights reserved.

Resumo -O objetivo deste trabalho foi avaliar a viabilidade do consórcio de milho (Zea mays) cv. BRS 1035 com braquiária (Urochloa brizantha) e guandu-anão (Cajanus cajan), no sistema de dessecação parcial. Os experimentos foram realizados na safra de verão de 2008/2009, em Santo Antônio de Goiás, GO e Ipameri, GO, em blocos completos ao acaso, com cinco repetições. Os tratamentos constituíram-se de cultivos de milho, em consórcio com braquiária e guandu-anão, com a aplicação de nitrogênio mineral em cobertura, à emergência da cultura ou aos 20 dias após esse evento, com ou sem aplicação de subdose de herbicida à braquiária não dessecada. A viabilidade do sistema de dessecação parcial é dependente do manejo da adubação nitrogenada do milho ou do controle do crescimento da braquiária nas faixas não dessecadas.Termos para indexação: Brachiaria, Zea mays, culturas intercalares, curva de crescimento, índice de área foliar, produtividade. Maize intercropped with palisadegrass and pigeon pea in partial desiccation systemAbstract -The objective of this work was to assess the viability of maize (Zea mays) cultivar BRS 1035 intercropped with palisadegrass (Urochloa brizantha) and pigeon pea (Cajanus cajan) in the partial desiccation system. The experiments were performed in the summer season of 2008/2009, in Santo Antônio de Goiás, GO and Ipameri, GO, Brazil, in a complete randomized block design, with five replicates. The treatments consisted of maize intercropped with palisadegrass and pigeon pea, with mineral nitrogen application on maize, on the day of its emergence, or 20 days after this event, with or without the application of a herbicide subdose on palisadegrass not desiccated. The viability of the partial desiccation system is dependent on the nitrogen fertilizer management of corn or on the growth control of nondesiccated palisadegrass rows.

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Jiggs bermudagrass has presented competitive production potential over other forages. However, there is a lack of information about the nutritional value of this forage with important relevance in ruminant nutrition. This study aimed to evaluate the protein and carbohydrate fractionation of Jiggs bermudagrass in different seasons of the year under intermittent grazing by Holstein cows. The experiment was conducted during one year in a completely randomized design with nine replications and treatments consisted of the effect of four seasons: fall, winter, spring and summer. The results showed that there were seasonal variations in the fractions of proteins and carbohydrate, with the exception of the protein fraction B3. The better climatic conditions in spring and summer contributed to an increase in the protein fraction A and carbohydrate A+B1. The winter had a greater fraction C of protein and carbohydrate, reflecting the nutritive value of the forage. The use of irrigation during fall and winter had a positive effect on nitrogen fractions B1 and B2 and on non-fiber carbohydrates.

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Under certain circumstances species of the Brachiaria genus, particularly B. humidicola might be able to suppress the biological nitrification in soil. This study aimed to investigate the ability of four Brachiaria species cultivated in Brazil to promote changes in the N dynamics in the soil as well as its capacity in use efficiently N under low N availability. In a greenhouse condition and using a Quartzipsamment soil, four species of Brachiaria (B. brizantha, B. decumbens, B. humidicola and B. ruziziensis) and two cut managements ("single cut" -performed at 140 days after seeding (DAS) and "cut/regrowth"-performed at 55 DAS and 85 days after the first cut (140 DAS)), plus a control treatment containing only soil were compared in a factorial design (4×2+1). The following evaluations were performed in plants: dry matter of shoots and roots, total N content, N accumulated and N use efficiency; and soil (which was split in rhizospheric and non-rhizospheric): ammonium, nitrate and total-N contents and pH value. Based on the soil inorganic-N content, there was no detectable effect of species in the soil nitrification process. Moreover, the highest ability of uptaking and using the N was observed in B. humidicola, which in the "single cut" management proved to be able to produce 201 g of shoot dry matter in response to each 1 g of N accumulated.

The Brazilian Cerrado is a highland tropical savanna considered a biodiversity hotspot with many endemic species of plants and animals. Over the years, most of the native areas of this biome became arable areas, and with inadequate management, some are nowadays at varying levels of degradation stage. Crop-livestock integrated systems (CLIS) are one option for the recovery of areas in degradation, improving the physicochemical and biological characteristics of the soil while increasing income and mitigating risks due to product diversification. Little is known about the effect of CLIS on the soil microbial community. Therefore, we perform this pilot case study to support further research on recovering degraded areas. The bacterial and fungal soil communities in the area with CLIS were compared to an area under moderate recovery (low-input recovering - LI) and native savanna (NS) area. Bacterial and fungal communities were investigated by 16S and ITS rRNA gene sequencing (deep rRNA sequencing). Ktedonobacteraceae and AD3 families were found predominantly in LI, confirming the relationship of the members of the Chloroflexi phylum in challenging environmental conditions, which can be evidenced in LI. The CLIS soil presented 63 exclusive bacterial families that were not found in LI or NS and presented a higher bacterial richness, which can be related to good land management. The NS area shared 21 and 6 families with CLIS and LI, respectively, suggesting that the intervention method used in the analyzed period brings microbial diversity closer to the conditions of the native area, demonstrating a trend of approximation between NS and CLIS even in the short term. The most abundant fungal phylum in NS treatment was Basidiomycota and Mucoromycota, whereas Ascomycota predominated in CLIS and LI. The fungal community needs more time to recover and to approximate from the native area than the bacterial community. However, according to the analysis of bacteria, the CLIS area behaved differently from the LI area, showing that this treatment induces a faster response to the increase in species richness, tending to more accelerated recovery. Results obtained herein encourage CLIS as a sustainable alternative for recovery and production in degraded areas.

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