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The goal of this study was to evaluate the morphogenetic, physiology, and forage mass characteristics of Mavuno brachiariagrass (Urochloa brizantha × Urochloa ruziziensis) under shading. The experiment was analyzed as split-plot. Whole plots were two growing seasons (spring/summer and fall/winter) and the subplots were shade levels (0, 30, 45, and 73%). There is a linear positive effect of shade on leaf elongation rate, leaf blade lengths, canopy height, chlorophyll indices, leaf percentage, and leaf to stem ratio. Shade linearly decreased stem and inflorescence percentages and tillers number. There was a quadratic effect of shade on growing cycle length, forage mass, and photosynthesis. Regarding to seasons, spring/summer presented higher rates of leaf appearance, leaf elongation, and stem elongation compared to fall/winter. In conclusion, Mavuno brachiariagrass harvested at 95% LI presents great adaptation to shading of 30%, without impairing the forage mass although increasing leaf size, chlorophyll indices, and canopy height.

The objective of this study was to evaluate the effects of different crop arrangements and weed management in integrated crop–forage–forestry systems on weed incidence, yield of maize and forage grass, quality of total harvested and tree development. The experiment was analyzed as split-plot and as randomized complete block design. Whole plots were crop arrangements containing maize, Marandu palisadegrass, Basilisk signalgrass, Piata palisadegrass, eucalyptus and acacia, and subplots were the weed management (1.5 kg ha−1 of atrazine and 1.5 kg ha−1 of atrazine + 0.006 kg ha−1 of nicosulfuron). Planting was done under no-tillage system and herbicides were applied 22 days after maize emergence. The weeds incidence was not affected by treatments. Applying the mixture of atrazine and nicosulfuron reduced the grasses yield. However, the total dry mass harvested was not affected. The average yield of whole-plant corn in the intercropping systems was 12.9 t ha−1 of dry mass. The simultaneous establishment of the integrated crop–forage–forestry systems does not reduce the productivity and quality of whole-plant corn nor the production of the tree component at the first cultivation year. Despite the reduced grasses yield, the application of nicosulfuron and atrazine does not improve the production and quality of whole-plant corn in relation to the application of atrazine alone.

The objective of this work was to evaluate the morphogenetic, structural, physiological, and productive traits of forage peanut (Arachis pintoi) subjected to different levels of artificial shading in the field. The 'Amarillo MG-100' forage peanut was planted in April 2015, and the evaluations were carried out from May 2017 to April 2018. The treatments were: 0, 30, 45, and 75% of artificial shading. There was no significant effect of shading on the morphogenetic traits of forage peanut. Shading increased final leaf length and canopy height and decreased the leaf area index and number of stolons. Photosynthesis, transpiration rate, stomatal conductance, chlorophyll b, and leaf temperature increased quadratically as a function of shading. There was a linear positive effect on the growing cycle length and a quadratic effect on the production of dry matter mass, with the maximum at 30% shade. Forage peanut harvested at 95% light interception (11-cm height) shows adaptation to shading up to 45%, with increased leaf size, canopy height, photosynthetic rate, stomatal conductance, transpiration rate, and chlorophyll b. In addition, plants at 30% shading show a higher yield than those growing under full sun. Resumo: O objetivo deste trabalho foi avaliar as características morfogenéticas, estruturais, fisiológicas e produtivas do amendoim-forrageiro submetido a diferentes níveis de sombreamento artificial no campo. O amendoim-forrageiro 'Amarillo MG-100' foi plantado em abril de 2015, e as avaliações foram realizadas de maio de 2017 a abril de 2018. Os tratamentos foram: 0, 30, 45 e 75% de sombreamento artificial. Não houve efeito significativo do sombreamento sobre as características morfogenéticas do amendoim-forrageiro. O sombreamento aumentou o comprimento final da folha e a altura do dossel e diminuiu o índice de área foliar e o número de estolões. A fotossíntese, a taxa de transpiração, a condutância estomática, a clorofila b e a temperatura das folhas aumentaram quadraticamente em função do sombreamento. Houve efeito linear positivo sobre o tamanho do ciclo de crescimento e efeito quadrático sobre a produção de massa de matéria seca, com o máximo a 30% de sombra. O amendoim-forrageiro colhido a 95% de interceptação luminosa (11 cm de altura) apresenta adaptação ao sombreamento de até 45%, com aumento do tamanho das folhas, da altura do dossel, da taxa fotossintética, da condutância estomática, da taxa de transpiração e da clorofila b. Além disso, as plantas sob sombreamento de 30% apresentam maior rendimento do que aquelas que crescem sob a luz do sol.

Tithonia diversifolia (Tithonia) is performed as an invasive species with a high adaptive potential that can be used for several purposes, including an alternative source of forage for different animal categories. The use of Tithonia is growing rapidly as farmers recognize its high accumulation of biomass, good nutritional value and adaptation to tropical environments. However, the effects of irrigation and nitrogen on the characteristics of Tithonia have been poorly studied. In this context, the objective of this study was to identify changes in the productive characteristics and morphophysiology of Tithonia under different irrigation simulations and nitrogen fertilization rates, seeking to understand its adaptive potential in different water and nutritional scenarios, improvements in the efficiency of the use of water and nitrogen and its potential for use in a global context. Field trials was a split-plot design with three replicates. Whole plots were irrigation rate (0%, 25%, 50%, 75% and 100% of crop evapotranspiration - ETc) and the subplots were the nitrogen fertilizer rate (0, 50, 100 and 150 kg ha−1). There were significant effects of irrigation, nitrogen, and their interaction on dry biomass accumulation, nitrogen- and water-use efficiency, plant height, chlorophyll index, and photosynthetic rate. Irrigation and nitrogen rates increased the dry biomass accumulation. The highest dry biomass accumulation was 7.32 Mg ha−1 in cycle I and 10.4 Mg ha−1 in cycle II. The greatest nitrogen-use efficiency was observed at a rate of 100 kg of nitrogen ha−1, and the greatest water-use efficiency was observed at irrigation 75% ETc. Irrigation and nitrogen also increased plant height, chlorophyll index, and photosynthetic rate. Tithonia proved to be a plant adapted to the humid temperate climate and sandy-loam texture soil, presenting great dry biomass accumulation potential even without irrigation and nitrogen fertilization. However, the greatest dry biomass accumulation was obtained with water replacement of 100% of ETc, the crop evapotranspiration, and nitrogen fertilization of 150 kg ha−1.