Rodolfo Godoy

Resposta da Aveia Branca à Adubação em Latossolo Vermelho-Amarelo em Dois Sistemas de Plantio

Two field experiments were carried out on a Red Yellow Latosol (Hapludox), at Sao Carlos, SP in order to determine the rates of N, P, and K to obtain maximum economic return per area of forage yield for the oat line UPF 87111 grown in two planting systems: conventional tillage and mulch-covered. The experimental design was a fractionated factorial type (1/2)4 3 , with two blocks. The treatments consisted of four rates of N and K 2 O (0, 70, 140, and 210 kg ha -1 ), using urea and potassium chloride, and four rates of P 2 O 5 (0, 60, 120 and 180 kg ha -1 ), using triple superphosphate. The N, P, and K rates for maximum profit were, in kg ha -1 for conventional tillage: N = 160, P 2 O 5 = 180, K 2 O = 180; and for mulch-covered: N = 200, P 2 O 5 = 120, K 2 O = 95 resulting in forage yields of, respectively, 7,398 and 8,111 kg ha -1 of dry matter. In both planting systems, the use of nitrogen resulted in higher forage yield per unit of applied fertilizer.

Caracterização preliminar e seleção de germoplasma do gênero Paspalum para produção de forragem

ABSTRACT - With the objective to increase the germoplasm availability for forage production, 215 accessions of the genus Paspalum collected in different regions and introduced at the Embrapa Southeast - Cattle Research Center, located at the central region of the Sao Paulo state. These accessions were evaluated and selected based on their yields in the first year, of dry matter from the vegetative development throughout the year and during the period of high and low rain preciptation. The accesses were evaluated in three experiments using a randomized blocks desing with two replicates. Dry matter production was obtained and analyzed from four cuts during the year (DMYEAR), which were representative of the development during the spring/summer (DMRAINY) and autumn/winter (DMDRY) seasons. The individual analyses, per experiment, showed variability among the accessions for the evaluated characteristics. The analyses as a set for the experiments was analyzed by the methodology of total analyses of the experiments in a randomized blocks desing with a common treatments (controls - Brachiaria decumbens and Andropogon gayanus cv. Baeti). Due to the significant variance interaction among common treatments by experiments, the selection was done for each experiment by choosing the accesses that presented yields at least equivalent to the worst control. Fifty-eight accessions were selected (27%), which demonstrated the possibility of obtaining cultivars with dry matter yields equal or better than the controls.ABSTRACT – With the objective to increase the germoplasm availability for forage production, 215 accessions of the genus Paspalum collected in different regions and introduced at the Embrapa Southeast – Cattle Research Center, located at the central region of the Sao Paulo state. These accessions were evaluated and selected based on their yields in the first year, of dry matter from the vegetative development throughout the year and during the period of high and low rain preciptation. The accesses were [...]

Extração de nutrientes e eficiência nutricional de cultivares de aveia, em relação ao nitrogênio e à intensidades de corte

The objective of this experiment was to study the effect of nitrogen levels (0, 40, 80, 160, 320 kg ha-1 N) and forage cutting intensities (none, one and two cuts) on nutrient uptake and nutritional efficiency of oats (Avena byzantina / Avena sativa). The potential mineral uptake by forage and grains and their cycling through their straw, were also evaluated. This experiment was conducted on a Hapludox soil, in a split-plot design with complete randomized blocks and four replications, using the Sao Carlos and UPF 3 oat cultivars. Increasing levels of N affected both, the extraction of S and N in the first forage cut of Sao Carlos, influenced the K assimilation of both cultivars in the second cut, and S uptake, in both cultivars and cuts. In addition P uptake by straw of both cultivars, and Zn, Cu and Mn by Sao Carlos, were altered. The K concentration and extraction decreased from the first to the second cut. Potassium uptake was higher when oats were used as forage, at a level of 145 kg ha-1. Straw assimiliation of K was about 60 kg ha-1, which returned to the soil, while grain uptake was about 6 kg ha-1. Potassium, N, Fe and Mn were the nutrients of highest demand by both cultivars, which had similar nutritional efficiency and produced the same amount of forage dry matter. For grain production and use of nutrients, UPF 3 was more efficient than Sao Carlos.

Caracterização de Linhagens Puras Selecionadas de Guandu (Cajanus cajan (L.) Millsp) (1)

The purpose of this work was to characterize morphologically seventeen previously selected pigeon-pea lines that went, after selection, through processes of self pollination, selection and multiplication, to obtain pure lines. It also had the objectives of checking the efficiency of the descriptors and describing its vegetative cycle. It was possible to perform the description and to conclude that the seventeen lines have distinct characteristics and can easily be identified by these traits. The used descriptors could properly perform this task and it was concluded that they can be simplified. The seeds of the commercial lines used in this work had mechanical mixture.

Adubação de aveia em dois sistemas de plantio

The objective of this work was to determine the best rates of N, P, and K to obtain maximum economic return per area of forage yield for the oat line UPF 87111 grown in two planting systems i.e conventional tillage and with a corn-residue mulch. The experiments were carried out in a Dark-Red Latosol (Hapludox). The experimental design was a incomplete (1/2)4 3 factorial, with two randomized blocks, with a total of 32 plots, without replication. The treatments comprised four rates of N and K2O (0, 70, 140, and 210 kg ha -1 ), using urea and potassium chloride, respectively, and four rates of P2O5 (0, 60, 120 and 180 kg ha -1 ), using triple superphosphate. The N, P, K rates for maximum profit were, in kg ha -1 for conventional tillage: N = 165, P2O5 = 50, K2O = 53; and for mulch-covered field: N = 210, P2O5 = 90, resulting in forage yields of, respectively, 6,641 and 7,322 kg ha -1 of dry matter. In both planting systems there was response only to N, and its use resulted in higher forage yield per unit of applied fertilizer.

Efeito do pastejo restringido em aveia sobre a produção de leite

The objective of this research was to evaluate the effect of oat (Avena sp.) restricted grazing on milk production. Twelve crossbred dairy cows (holstein-zebu) were used in a complete randomized block design. The cows were allocated to two treatments: A. restricted grazing on oat (3 hours day-1) plus 10 kg of corn silage; B. corn silage ad libitum as the only forage. All animals received 5.0 kg of concentrate head-1 day-1 with 19% crude protein (CP) and 75% total digestible nutrientes (TDN). There was no statistical difference (P > 0.05) between A and B treatments in milk production (14.6 vs. 13.3 kg cow-1 day-1). Difference was found (P < 0.05) in fat content (3.4 vs 3.8%), but this did not affect (P < 0.05) 4% milk corrected production. Difference was found also in weight gain (P < 0.08). The cows that had access to restricted grazing on oat gained 0.53 kg day-1 and the cows that received corn silage as the only forage gained 0.25 kg day-1. It was concluded that restricted grazing on Sao Carlos oat cultivar allow high milk production with crossbred cows.

Adubação e produção de Paspalum em dois níveis de fertilidade de Latossolo Vermelho-Amarelo: estabelecimento e manutenção

The goal of this work was to determine the best rates of N, P2O5, and K2O to get maximum forage yield of Paspalum regnellii Bra 019186 grown in two soil fertility levels: low and medium in P and K. The experiments were set up in a typical Red-yellow latosol (Hapludox), in Sao Carlos, SP, Brazil. Experimental design was an incomplete (1/2)43 factorial with a total of 32 plots, in two randomized blocks, without replication. Treatments were four rates of N and K2O (0, 100, 200, and 300 kg ha-1 in the first and second year), using urea and potassium chloride, and four rates of P2O5 ( 0, 80, 160, 240 kg ha-1 in the first year and 70, 140, 210 kg ha-1 in the second year), using triple superphosphate. Cuttings were done, mainly each 35 days, in the rain season. The N, P, K rates for maximum yield in the first year were, in kg ha-1 with low fertility: N = 210, P2O5 = 240 , K2O = 190; and with medium fertility: N = 250 , P2O5 = 240, K2O = 180, and in the second year: N = 300, P2O5 = 210, K2O = 300, in soil with low fertility, and N = 300 , P2O5 = 190, K2O = 290 in soil with medium fertility, resulting in forage yields of, respectively, 5,428 and 7,789 kg ha-1 of dry matter in the first year, and of 13,084 e 10,468 kg ha-1 in the second year.

Caracterização de onze linhagens puras de guandu selecionadas em São Carlos, SP

The purpose of this work was to morphologically characterize and describe the vegetative cycle of eleven previously selected pigeon-pea lines submitted to self pollination, selection and multiplication, to obtain pure lines. All descriptions were accomplished through the use of internationally accepted descriptors for the species and it was concluded that all eleven lines can be easily distinguished by means of their morphological traits.

Avaliação do comportamento de sementes de algodoeiro (Gossypium hirsutum L.) durante o armazenamento

Sementes de algodoeiro, variedade IAC 13-1, foram armazenadas em câmara seca e em condicoes normais de ambiente, durante oito meses. Periodicamente, com intervalos bimestrais, foi avaliado o comportamento das sementes das duas porcoes, atraves de testes de germinacao e de vigor (envelhecimento rapido e irradiacao de sementes), no Laboratorio de Sementes do Departamento de Agricultura e Horticultura, ESALQ, USP. As analises dos dados e a interpretacao dos resultados permitiram concluir que: a) As sementes conservaram-se melhor em câmara seca. b) Ha possibilidade do emprego de irradiacao para avaliar o vigor de sementes, obtendo-se resultados comparaveis aos do envelhecimento rapido, dependendo da dosagem utilizada.

Avaliação agronômica de linhagens selecionadas de guandu (Cajanus cajan (L.) Millsp)

With the purpose of re-evaluating seventeen pigeon-pea lines originated from accessions previously selected for favorable agronomic characteristics, experiments were installed in five locations of the State of Sao Paulo. The confirmation of those characteristics was necessary because the original accessions presented various degrees of mechanical mixtures and segregation and were submitted to purification process in pollination controlled conditions. In those trials, the lines were cut in several occasions to evaluate forage yield. Each time, it was determined the number of plants in each parcel and its average height. Also it was determined their crude protein and tannins contents. Among the tested lines, g58-95 e g127-97 confirmed to have low plants, g94, g167-97 and g29b-94, confirmed to offer good forage yields, while line g146-97 presented good initial forage yields.