ABSTRACT The pressing of green coconut shell, aiming at the production of powder or fiber, used as raw material by the industry, generates large amounts of the green coconut shell liquid (GCSL), whose incorrect disposal results in environmental impacts. This study evaluated the potential use of GCSL as a source of potassium for young dwarf coconut plants. The experiment was carried out in pots, in a completely randomized design, applying seven treatments, comprising five doses of GCSL, which corresponded to 0% (G0), 50% (G50), 100% (G100), 150% (G150) and 200% (G200) of the need for K2O of the plants, a treatment with mineral fertilizer, corresponding to 100% of K2O supplied as KCl (K100), and another containing 50% of K2O as KCl and 50% as GCSL (G50 + K50), with five replicates. One hundred and twenty days after transplanting the seedlings, soil chemical attributes as well as growth and nutritional status of dwarf coconut plants were evaluated. Increase in GCSL doses altered soil fertility and reduced the percentage of live leaves of dwarf coconut. The G50 + K50 treatment did not differ from K100 for all variables of growth, except for % of live leaves, indicating the possibility of replacing 50% of the K2O dose recommended for the first year of dwarf coconut cultivation with GCSL.

ABSTRACT Sugarcane seedling quality is strongly influenced by the substrate used. Currently, alternative substrate sources from the sugarcane industry itself have been used; however, there is no specific substrate to produce pre-sprouted seedlings. This study aimed to evaluate the quality of pre-sprouted sugarcane using substrates with different proportions of carnauba bagana (0, 20, 40, 60, 80 and 100 %) plus soil. The experimental design was completely randomized, with six treatments and five replicates. Pre-sprouted seedlings cultivated using substrate composed by 80 % of carnauba bagana showed the best response for number of leaves, diameter, shoot length, shoot, root and total dry mass, and Dickson Quality Index, owing to the improvement in the substrate physical and chemical characteristics.

RESUMO A qualidade de mudas de cana-de-açúcar é fortemente influenciada pelo substrato utilizado. Atualmente, fontes alternativas de substrato oriundas da própria indústria canavieira têm sido empregadas; no entanto, não existe substrato específico para produção de mudas pré-brotadas. Objetivou-se avaliar a qualidade de mudas pré-brotadas de cana-de-açúcar cultivadas em substratos com diferentes proporções de bagana de carnaúba (0, 20, 40, 60, 80 e 100 %) acrescida de solo. O delineamento experimental foi inteiramente casualizado, com seis tratamentos e cinco repetições. As mudas pré-brotadas cultivadas em substrato composto por 80 % de bagana de carnaúba obtiveram melhor resposta para número de folhas, diâmetro, comprimento do broto, massa seca da parte aérea, radicular e total, e Índice de Qualidade de Dickson, em decorrência da melhoria nas características físicas e químicas do substrato.

ABSTRACT The aim was to evaluate the productive performance and nutrient export of maize intercropped with drought-tolerant forage grasses. The experimental design was a randomized blocks in a 2x2x2+1 factorial scheme (two forage grasses species – Massai and Buffel; two forage sowing methods - in the furrow and broadcast; and two forage sowing times - anticipated and simultaneous; and monoculture maize as an additional control), with three replicates. The maize+forage intercropping promoted greater competition for resources, especially water, limiting N uptake, chlorophyll synthesis, and biomass production by maize under semiarid conditions. Early sowing gave forage plants a competitive advantage, favoring forage establishment before or immediately after the sowing of maize. Thus, the simultaneous sowing of forage grasses in a semiarid environment is a more appropriate option considering the importance of high levels of chlorophyll to ensure high photosynthetic activity in maize plants and greater capacity of biomass synthesis. Massai intercropped with maize exhibits a greaterpotential for biomass production than Buffel under semiarid conditions. Maize+Buffel result in highest macronutrient export by maize, while maize+Massai result in highest macronutrient exports by total forage biomass under a semiarid environment. The choice of the forage species and its sowing time in relation to maize are the main determinants of successful intercropping systems under semiarid conditions.

RESUMO O objetivo foi avaliar o desempenho produtivo e a exportação de nutrientes do consórcio de milho com gramíneas forrageiras tolerantes ao estresse hídrico. O experimento foi delineado em blocos casualizados em esquema fatorial 2x2x2+1 (duas espécies de gramíneas forrageiras – Massai e Buffel; dois métodos de semeadura – no sulco e a lanço; e duas épocas de semeadura – antecipada e simultânea; e monocultivo de milho como um controle adicional), com três repetições. O consórcio milho+forragem promoveu maior competição por recursos, principalmente água, limitando a absorção de N, síntese de clorofila e produção de biomassa pelo milho para condições semiáridas. A semeadura precoce deu vantagem competitiva às plantas forrageiras, favorecendo seu estabelecimento antes ou imediatamente após a semeadura do milho. Assim, a semeadura simultânea de gramíneas forrageiras em ambiente semiárido é uma opção mais adequada, considerando a importância de garantir altos teores de clorofila e, consequentemente, alta atividade fotossintética nas plantas de milho para garantir a capacidade de síntese de biomassa.Massai consorciado com milho apresenta maior potencial para produção de biomassa do que Buffel em condições semiáridas.Milho+Buffel resulta em maior exportação de macronutrientes pelo milho, enquanto milho+Massai resulta em maior exportação de macronutrientes pela biomassa forrageira total em ambiente semiárido.A escolha da espécie forrageira e sua época de semeadura em relação ao milho são os principais determinantes do sucesso do consórcio no semiárido.

Abstract In Maranhão babassu forest, the decomposed babassu biomass (DBB) has been used empirically by several farmers for the production of Jacaranda mimosifolia seedlings. This study aimed to evaluate the potential of DBB as a substrate. The substrate compositions were S1: 100% soil (control); S2: 20% DBB; S3: 40% DBB; S4: 60% DBB; S5: 80% DBB and S6: 100% DBB. The experiment was carried out from October to December 2019 at Federal University of Maranhão, Chapadinha, Maranhão, Brazil. It was observed the use of DBB enhances the emergency speed index and germination percentage, besides resulted in the development of the aerial part and the root development. Thus, DBB may be used as an alternative substrate for the production of Jacaranda mimosifolia seedlings. It is recommended to include 40% babassu biomass with 60% soil in the composition of the substrate to improve the morphological development of Jacaranda mimosifolia seedlings.