Nitrogênio de potássio para meloeiro cultivado em fibra de coco, sem drenagem

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crescimento e acúmulo de nutrientes em caramboleiras nas fases de hipobioto, muda e plantas em formação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interferência de Digitaria insularis em Coffea arabica e respostas destas espécies ao glyphosate

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características de substratos e concentrações de soluções nutritivas para o cultivo do crisântemo em vaso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fontes e modos de aplicação do nitrogênio na cultura do milho

Pós-graduação em Agronomia - FEIS

Accumulation of dry mass and macronutrients by sourgrass plants

The experiment was carried out aiming to analyze the dry mass production and distribution and the content and accumulation of macronutrients in sourgrass (Digitaria insularis) plants cultivated under mineral nutrition standard conditions. Plants grew in 7-liter pots filled with sand substrate and daily irrigated with nutrient solution, being maintained under greenhouse conditions. Treatments consisted of times of evaluation (21, 35, 49, 63, 77, 91, 105, 119, and 133 days after emergence - DAE) and were arranged in a completely randomized design with four replicates. Sourgrass showed small accumulation of dry mass (0.3 g per plant) and macronutrients (3.7 mg of N per plant, 0.4 mg of P per plant, 5.6 mg of K per plant, 0.9 mg of Ca per plant, 0.7 mg of Mg per plant, and 0.3 mg of S per plant) at vegetative growth stage (< 49 DAE). Those accumulations increased mainly after 77 DAE, reaching the maximum theoretical value at 143, 135, 141, 129, 125, 120, and 128 DAE, for dry mass (12.4 g per plant), N (163.2 mg per plant), P (27.1 mg per plant), K (260.5 mg per plant), Ca (47.6 mg per plant), Mg (30.9 mg per plant), and S (13.7 mg per plant), respectively. K and N were found with higher rates and, as a consequence, they were required and accumulated in greater amounts in plant tissues of sourgrass.

Adubação com fósforo e potássio para produção e qualidade de sementes de soja

O objetivo deste trabalho foi avaliar os efeitos da adubação com fósforo e potássio na produção e na qualidade de sementes de soja. Foram realizados experimentos em dois anos agrícolas, em delineamento de blocos ao acaso, em arranjo fatorial 5x3, com cinco doses de fósforo (0, 40, 80, 120 e 160 kg ha‑1 de P2O5 como superfosfato triplo), três de potássio (0, 50 e 100 kg ha‑1 de K2O como cloreto de potássio) e quatro repetições. Foram avaliados: produtividade, número de sementes por planta, número de vagens por planta, peso de mil sementes, germinação, vigor (envelhecimento acelerado, condutividade elétrica e lixiviação de potássio), e teores de P e K na folha e na semente. A produtividade, o peso de mil sementes e a produção de vagens e de grãos por planta aumentaram linearmente com a adubação fosfatada. O aumento na produtividade foi de 17,6%, no primeiro ano, e de 39,7% no segundo. As doses de P, no entanto, não interferiram na germinação e no vigor das sementes. A adubação potássica não altera a produtividade nem a concentração de K nas sementes, mas pode melhorar a germinação, sem interferir no vigor.

Adubação fosfatada no crescimento inicial e na nutrição de mudas de pinhão-manso

Physic nut (Jatropha curcas L.) is a perennial oilseed species that has aroused economic interest for biodiesel production. Among other factors, it is essential to determine the nutritional demands of this species to facilitate raising it as a crop. This study aimed to evaluate the early growth and mineral nutrition of physic nut, as well as soil fertility, as affected by phosphorus fertilization. The study was carried out in a plastic greenhouse in a completely randomized block experimental design with four replicates. The plants were grown in plastic pots filled with 50 dm³ of Latossolo Vermelho (Rhodic Hapludox). Application rates of 0, 50, 100, 150 and 200 mg dm-3 of P were tested, plus a control. Evaluations of plant height and root collar diameter were performed monthly. The experiment was ended 150 days after transplant of the seedlings, at which time leaf area, dry weight, leaf contents and total accumulation of macro- (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) were performed, and soil chemical properties were analyzed. We concluded that absence of P fertilization alone is as limiting to early growth of physic nut as simultaneous absence of soil amendment and fertilization. The rate of 57 mg dm-3 of P may be recommended for initial growth of physic nut. The total accumulation of nutrients in physic nut seedlings exhibited the following order: K>N>Mg>Ca>P>S>Fe>Mn>B>Zn>Cu. Phosphorus fertilization resulted in increased soil cation exchange capacity (CEC).

Teores foliares de macro e micronutrientes em milho tolerante ao glyphosate submetido à herbicidas

A serial of factors related to development of glyphosate-tolerant corn should be approached and best studied. This work was developed to evaluate foliar levels of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn, besides the grain yield of glyphosate-tolerant corn (DKB390 RR hybrid). An experiment was carried out under field conditions, during the crop year of 2010/2011. A randomized complete block design with four repetitions was used to distribute the treatments in the field. Twelve herbicide treatments were studied: glyphosate (720, 1200 and sequential application of 960 plus 720 g ha(-1) of the acid glyphosate equivalent), atrazine (2500 g ha(-1)), nicosulfuron (60 g ha(-1)), mesotrione (192 g ha(-1)), tembotrione (100,8 g ha(-1)), atrazine plus glyphosate (1000 + 960 g ha(-1)), atrazine plus nicosulfuron (1000 + 20 g ha(-1)), atrazine plus mesotrione (1000 + 144 g ha(-1)) and atrazine plus tembotrione (1000 + 75,6 g ha(-1)) and one control treatment without herbicide. The glyphosate and mesotrione alone did not cause no visible injury to corn. The other herbicides caused intoxication symptoms classified as light (<5%). The treatments studied did not affect foliar levels of N, P, K, Ca, Mg, S, B, Mn and Zn in the corn plants. But, the plants treated with atrazine plus nicosulfuron had more leaf Fe content, and the plants sprayed with glyphosate (in the three doses) and atrazine, more accumulation of Cu in the leaf. The Grain yield of corn was reduced with application single of glyphosate (1200 g ha(-1)), nicosulfuron, tembotrione and with the mixture atrazine plus nicosulfuron.

Growth and flowering of miltonia flavescens lindl. var. stellata regel orchid under different doses of a slow release fertilizer

The Orchidaceae is one of the most numerous and diversified families in the Plant Kingdom. Miltonia flavescens Lindl. is a native orchid to the southern region of Brazil. Studies related to the nutrition and fertilization of orchids are scarce, specific and existent only for few species. The objective of this work was to evaluate the effect of different doses of a slow release fertilizer (Osmocote (R) 9/15/12 + micro) on the development of M. flavescens var. stellata Regel cultivated in pots with pine bark and coconut fiber (1:1, v:v) as the substrate. The treatments consisted of: no fertilizer application (control), application of 2.5 g, 5 g and 10 g of fertilizer per liter of substrate. The experimental design was set in randomized blocks, with five replications and three plants per plot. The experiment was carried out along 25 months and the fertilizer was applied every five months. The evaluated plant parameters were: length of the longest pseudobulb, number of pseudobulbs, diameter of pseudobulbs, number of shoots, number of leaves and flowering. There was a significant increment on all evaluated characteristics with the increase of the fertilizer dose. The highest dose provided a more profuse flowering, with a larger number of flower stems and flowers, in addition to bigger flower stems and flowers. These results show that the supply of nutrients in an appropriate amount is of a great importance for the development and flowering of M. flavescens.

Applying boron to coconut palm plants: effects on the soil, on the plant nutritional status and on productivity boron to coconut palm trees

Boron, one of the micronutrients frequently found in low levels in tropical soils affects nutrition and productivity of coconut palm trees essentially cultivated in tropical climates. The objective of this research study was to evaluate the effect of boron on the nutritional status of the plant and its productivity when artificially applied to the culture soil. The experiment was carried out in a four year old, artificially irrigated, dwarf coconut palm orchard in Brazil, between January, 2005 and October, 2006. The soil was a red yellow Latosol (B: 0.18 mg dm(-3)). The treatments consisted in the application of five boron dosages: zero, 1, 2, 4, and 6 kg ha(-1). In the field, the treatments were arranged according to a completely randomized block design, with four replications. Boron (borax) dosages were applied in equal halves directly into the soil in the months of January and February of 2005. Boron concentration in the soil and plant and plant productivity were evaluated. The higher palm tree production was associated to levels of 0.6mg dm(-3) of B in the soil and 23.5mg kg(-1) in leaves. Ninety five percent of palm trees maximum production was obtained with the use of a boron dosage of 2,1kg ha(-1).

Leaf application of silicic acid to upland rice and corn

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gesso aplicado na superfície do solo no desenvolvimento do arroz de terras altas sob plantio direto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of rootstocks and pruning times on yield and on nutrient content and extraction in 'Niagara Rosada' grapevine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resposta diferencial de cultivares de algodão ao manganês em solução nutritiva

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)