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Cocoa is a crop in increasing demand and cultivated worldwide. However, basic information concerning the movement of nutrients in leaves over time is still unknown, and methods to find an optimal time to collect a sample are still ambigu-ous. The present work focused on describing the movement of foliar nutrients (N, P, K, Ca and Mg) in productive 5-year-old cocoa clone CCN51 plants at the same dose of 114.8 kg ha-1 under different sources of nitrogen fertilization (Urea, calcium ni-trate, ammonium sulfate and a control without application). Samples were taken from the time the leaf reached 70% of its total expansion until 10 months of age. The results indicated that the contents of N, Ca and Mg increased as the leaf grew, remained stable between 116 and 158 days of shoot emergence (DSE) and then decreased at the beginning of the leaf senescence period. While the K and P con-tents decrease from the beginning of the trial until 158 DSE where they are stable until the final stage of leaf life. Around 110 to 120 DSE, the leaves of cocoa CCN51 show a more stable nutritional content, a period in which samples can be collected for leaf analysis.

<p><strong>Background</strong>. In the new global economy, cocoa is an important crop. However, far too little attention has been paid to the nutritional aspects. On the other hand, nitrogen is the most important nutrient in crop production, and mineral nitrogen fertilizers are the most widely used by farmers. Improving the efficiency of nitrogen uptake and utilization could potentially increase crop yields and quality, as well as reduce nitrogen fertilization and environmental pollution. <strong>Objective.</strong> Therefore, the objective of this study was to evaluate the effect of three nitrogen sources on morphological characteristics, yield and quality of CCN-51 cocoa, and soil chemical characteristics in the Ecuadorian Amazon. <strong>Methodology.</strong> A randomized design was established with 4 treatments with the same N dose, but varying the source (amide: urea, calcium nitrate, NC, and ammonium sulfate, SA), plus a control without N application. The investigated variables are soil chemical characteristics, shoot growth, fruit morphology, seed chemical characteristics, production and yield estimates, and agronomic efficiency of the sources. <strong>Results.</strong> NC maintained soil pH at 5.29 points compared to SA and urea, which acidified at a higher rate (4.32 and 3.96), leading to an increase of N and a decrease Ca in the soil. SA increased the fat content in the cocoa seed (54.1 %), with a higher number of fruits per plant (16.7) and, therefore, a better yield (0.799 t/ha). <strong>Implications.</strong> These results provide basic information on the nitrogen source effects and cocoa nutrition to be considered for future research. <strong>Conclusion.</strong> The findings suggested that NC conserves soil pH better than the other sources. SA increases production and fat content, so it can be considered the most efficient. </p>

As bactérias pertencentes ao gênero Bacillus sp. têm alto potencial para o controle biológico de fungos fitopatogênicos. Portanto, na presente pesquisa nos propusemos avaliar a capacidade antagônica de isolados de Bacillus sp. contra o fungo fitopatogênico Sclerotium sp. Os testes foram realizados utilizando dois métodos (dual e dual modificado), assim como cinco isolados de Bacillus sp. (LBM01, LBM02, LBM03, LBM04 e LBM06). As avaliações do crescimento micelial foram realizadas no meio de cultura BDA. Todos os experimentos foram realizados em triplicata e as placas foram incubadas sob fotoperíodo de 12 h a 28±1 ºC durante 7 dias. O crescimento radial dos patógenos foi medido nos intervalos de 24, 48, 72, 96, 120, 144 e 168 horas. A porcentagem de inibição foi calculada através da equação: I% = [(C-T)/C]x100. Todos os isolados de Bacillus sp. testados foram capazes de inibir o crescimento micelial do Sclerotium sp. em até 72 h, enquanto os isolados LBM01, LBM03 e LBM06 foram capazes de manter a inibição durante 168 h. O isolado LBM06 revelou a maior porcentagem de inibição em todos os dois métodos de cultura utilizados.

Sugarcane is an essential crop in the Brazilian economy. The adoption of techniques in the acclimatization of plants in vitro contributes to success in the field. The present work aims to evaluate the effect of Azospirillum brasilense on the acclimatization of sugarcane seedlings. The experiment was conducted with six treatments and twelve replications. There were two control treatments without inoculation, one with N fertilization and one without, and four with A. brasilense (2.0x108 CFU) at different doses (19.92mL + N fertilization, 9.84mL, 19.92mL, and 39.84mL). Evaluations were seedling height (SH), stem diameter (SD), number of shoots per tube (NS), number of leaves (NL), fresh aerial weight (AFM), root fresh weight (RFM), total chlorophyll (TC), foliar nitrogen (FN) and visual microscopic study of the roots. The results showed that the recommended dose of A. brasilense + N fertilization increased by 36% in seedling height, 29% in stem diameter, 85% in aerial fresh mass, 21% in total chlorophyll, 142% in foliar N, and also increased root hairs and the presence of microbial biofilm. Therefore, the bacterium A. brasilense can be used in association with nitrogen fertilizers or alone, where it obtained great benefits in the increase of biomass.