-The assessment of the nutritional status of plants by leaf diagnosis such as the Diagnosis and Recommendation Integrated System (DRIS) has stood out among traditional methods of interpreting the results of plant tissue analysis. For coconut, nutritional monitoring through foliar analysis has been pointed as an efficient method for fertilizer recommendation, and the results have been traditionally interpreted using the critical level of sufficiency ranges criteria. The aim of this study was to evaluate the nutritional status and establish nutritional standards for the cultivation of hybrid coconut in the municipality of Moju, Pará, using DRIS. The leaf analysis and productivity results of 134 observations for the period 2001-2011 were used to form the database. The most common deficiencies found were lack of K, and possibly excess of Mg. The order of nutrient limitation was K> P> Ca> Fe> N> O> B> Zn> Cu> Mn> Mg. Ca, Fe and K nutrients are more likely to positively respond to fertilization, since Mg, Cu and Mn were diagnosed as having the greatest likelihood of negative response to fertilization. It was also found that N and P are elements that are in the best nutritional balance condition. Regression equations for the relationship between nutrient content in hybrid coconut leaves and its DRIS indexes were adjusted, which allowed establishing nutrient reference values based on DRIS.

ABSTRACT:The use of fire to prepare agricultural areas is a technique still used by small farmers in eastern Amazon. This type of management changes the dynamics of soil nutrients, especially phosphorus, which constitutes the most limiting nutrient for crop production in tropical soils. This study was carried out to evaluate changes in phosphorus forms in an Argissolo Amarelo Distrófico (Ultisol) submitted to burning and trituration of secondary forest in eastern Amazon. The evaluated systems were: slashand-burn of vegetation; slash-and-mulch of vegetation; and secondary vegetation. The labile, moderately labile, moderately recalcitrant, available and total phosphorus fractions were assessed at the soil depths of 0.00-0.05, 0.05-0.10 and 0.10-0.20 m. The results showed a predominance of soluble P in acid (moderately labile P) over other forms in all management systems. The management systems influence the content and distribution of the forms of P, where the slash-and-mulch system presented the prevalence of the labile fraction, and the slash-and-burn system contained less labile forms. The slashand-mulch system favored the accumulation of labile P and total organic P.

Commercial pesticides were selected, mixed and applied in coconut stems (Cocos nucifera Linn.) by endotherapy with various adjuvants. Tissue samples from the coconut stem were collected at different heights and days, and subjected to extraction and analysis by modified QuEChERS (“Quick, Easy, Cheap, Effective, Rugged and Safe") and UHPLC-MS/MS (ultra-high-performance liquid chromatography–tandem mass spectrometry). The translocations of 3-hydroxy-carbofuran, carbendazim, carbofuran, difenoconazole, imidacloprid, thiabendazole, thiamethoxam, thiophanate-methyl and spirodiclofen, using salts, citric acid and organosilicones as adjuvants, were evaluated and compared 2 and 30 days after the applications. The results showed that each pesticide had a different translocation profile, modified by the presence of the adjuvants. The most significant modifications were obtained using organosilicones, which enhanced the translocation process by 40% for most pesticides, followed by acidification (30%) and the addition of salts (22%).

Alternative techniques for applying agricultural products, such as pressurized endotherapy, have shown promise in pest and disease control in coconut palms (Cocos nucifera Linn.).