Nutritional diagnosis of nitrogen and phosphorus in Ocimum basilicum L. plants grown under macronutrient applications

The objective of this work was to assess the nutritional status of basil (Ocimum basilicum L.) plants grown under application of macronutrients, in a Typic Hapludult. The experiment was conducted in Cruz das Almas, BA, Brazil, in a greenhouse. The treatments were based on a Baconian matrix statistical arrangement, in which one of the nutrients is supplied in different quantities, whereas the other nutrients are maintained at the reference rates. Six nutrients, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) were evaluated at three different rates. Two additional treatments were used (reference rates; and without nutrient applications), totaling 20 treatments. A completely randomized experimental design with five replications was used, totaling 100 experimental units. Plant material was collected 50 days after treatment applications and dried in an oven for 72 hours. Approximately 0.1 g of dry weight of leaves, stems, and roots were subjected to acid digestion in a mixture of concentrated sulfuric acid and hydrogen peroxide. The digested material was diluted in 100 mL of distilled water to obtain the extract for nutritional diagnosis. The optimal maximum N and P accumulations in basil leaves for high plant performances were 51 and 3.0 g kg-1, respectively. The estimated rates for each nutrient to provide the optimal total N accumulation in basil plants were: N = 235.61, P =91.27, K = 175, S = 41.98 (mg dm-3), Ca = 0.97, and Mg = 0.36 (cmolc dm-3).The objective of this work was to assess the nutritional status of basil (Ocimum basilicum L.) plants grown under application of macronutrients, in a Typic Hapludult. The experiment was conducted in Cruz das Almas, BA, Brazil, in a greenhouse. The treatments were based on a Baconian matrix statistical arrangement, in which one of the nutrients is supplied in different quantities, whereas the other nutrients are maintained at the reference rates. Six nutrients, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) were evaluated at three different rates. Two additional treatments were used (reference rates; and without nutrient applications), totaling 20 treatments. A completely randomized experimental design with five replications was used, totaling 100 experimental units. Plant material was collected 50 days after treatment applications and dried in an oven for 72 hours. Approximately 0.1 g of dry weight of leaves, stems, and roots were subjected to acid digestion in a mixture of concentrated sulfuric acid and hydrogen peroxide. The digested material was diluted in 100 mL of distilled water to obtain the extract for nutritional diagnosis. The optimal maximum N and P accumulations in basil leaves for high plant performances were 51 and 3.0 g kg-1, respectively. The estimated rates for each nutrient to provide the optimal total N accumulation in basil plants were: N = 235.61, P =91.27, K = 175, S = 41.98 (mg dm-3), Ca = 0.97, and Mg = 0.36 (cmolc dm-3)

Initial development of maize plants grown with different combinations of nitrate and ammonium

Corn is one of the main commodities of Brazilian agribusiness, due to its wide use, whether for human or animal consumption or in the chemical and biofuel industries. Thus, this work was carried out to evaluate the influence of different proportions of nitrate and ammonium in the initial development of corn plants. The experiment took place in a greenhouse, by direct sowing, where the seeds were placed at a depth of 1 cm in plastic pots with a capacity of 6 dm3 containing a mixture of previously sieved and washed with vermiculite, in a 2:1 ratio. Five proportions of nitrate and ammonium ions (NO3- :NH4+) were used: T1=100:0, T2=75:25, T3=50:50, T4=25:75 and T5=0:100, through nutrient solutions. After 35 days of cultivation, the following were evaluated: plant height, number of leaves, culm diameter, chlorophyll a, b, total and a/b ratio, root length, leaf fresh matter mass, dry matter mass of leaves, culm, roots, total dry mass, and root dry mass/shoot dry mass ratio, leaf area, specific leaf area, leaf area ratio, and leaf mass ratio. Nitrate as the only source of nitrogen provided a smaller increase in the chlorophyll a index of maize plants, which is the most important chlorophyll in the capture of light in the antenna complex. It is not recommended to cultivate corn plants with only nitrate or ammonium; however, it was observed that high doses of nitrate combined with low doses of ammonium in the culture medium provided satisfactory performance for most variables

Pigmentos fotossintéticos em plantas de manjericão nutridas com cama de frango sob ambiente sombreado / Photosynthetic pigments in basil plants nutrited with chicken bed under a shadowed environment

O crescimento e teor de óleo essencial em plantas aromáticas são influenciados pela intensidade luminosa, teor de clorofila e a nutrição mineral. Neste contexto, objetivou-se avaliar a influência da cama de frango semidecomposta no incremento de teores relativos de clorofila em plantas de manjericão sob ambiente sombreado. A pesquisa foi desenvolvida em casa de vegetação da Universidade Federal do Recôncavo da Bahia, no município de Cruz das Almas-BA, Brasil. O delineamento experimental foi inteiramente casualizado constituído por três concentrações de cama de frango 0, 2,5 e 5,0 % com 8 repetições, totalizando 24 parcelas amostrais. As plantas foram aclimatizadas em ambiente sombreado, através de telado coberto por malha preta com 50% de irradiância solar. Após 60 dias de aclimatização, foram avaliados os teores relativos dos pigmentos fotossintéticos (clorofilas ‘a’, ‘b’, total e relação a/b) utilizando o medidor eletrônico de clorofila Falker modelo CFL  1030 no limbo foliar entre os horários das 6:00 ás 8:00 h. Os resultados obtidos foram submetidos a análise de variância utilizando-se o programa estatístico “R”, quanto ao efeito significativo foram estimados os modelos de regressão linear e quadrática. Concluíram-se que plantas de manjericão crescidas sob ambiente sombreado apresentaram maiores teores de clorofila a, b e total quando cultivadas na concentração de cama de aviário a 2,5 % do volume do substrato. A maior relação dos teores de clorofila a/b foi observada em plantas nutridas com 0,0% e 5,0% do fertilizante orgânico

Doses de alumínio no crescimento inicial de plantas de aboboreira em cultivo semi-hidropônico: Aluminum doses in the initial growth of squash plants in semi-hydroponic cultivation

A aboboreira (Cucurbita moschata) é uma hortaliça de grande importância econômica e apresenta potencial produtivo no Brasil. Entretanto, os solos brasileiros são ácidos e intemperizados, com elevados teores de alumínio tóxicos para o cultivo das plantas. Assim, a presença do alumínio trivalente nos solos, se torna um desafio para a agricultura brasileira, devido à toxicidade que este elemento causa, limitando a produção agrícola. Diante disto, o objetivo deste presente trabalho foi avaliar o crescimento inicial de plantas de aboboreira sob crescentes doses de alumínio, em cultivo semi-hidropônico. O experimento foi conduzido em casa de vegetação da Universidade Federal do Recôncavo da Bahia (UFRB), Cruz das Almas, Bahia. O delineamento utilizado foi o inteiramente casualizado (DIC), com cinco tratamentos: 0 (controle); 13,5; 27; 54 e 81 mg.dm-3 de cloreto de alumínio (AlCl3) com quatro repetições. Após 10 dias da aplicação, em dose única, das soluções nutritivas de Hoagland e Arnond (1950) modificadas com a adição das doses de alumínio, foram avaliados os parâmetros fisiológicos de crescimento. Os resultados foram submetidos à análise de regressão a 5% de significância. As baixas doses de alumínio promoveram o crescimento de plantas de aboboreira, enquanto as maiores doses foram tóxicas para todas as variáveis. Plantas cultivadas com doses de até 54 mg.dm-3 de Al apresentaram maiores índices de clorofilas a, b e total e acima dessas doses houve redução na produção de clorofilas. As doses 0 e 13,5 mg.dm-3 de Al foram responsáveis pelos maiores crescimentos do comprimento da raiz, altura e número de folhas. Para as produções de massa seca da raiz e massa seca da parte aérea das plantas de aboboreira, observaram-se que as menores doses de alumínio apresentaram os maiores incrementos até a dose de 13,5 mg.dm-3