Maria do Carmo Lana

Inoculation with Azospirillum, associated with nitrogen fertilization in maize

The biological nitrogen fixation is an alternative to supply the nitrogen needed for maize. The objective of this study was to evaluate the development and yield of maize in response to inoculation with Azospirillum associated with nitrogen fertilization. We conducted two field experiments in the summer harvest, the first in the 2000/2001 crop year in the region of Marechal Cândido Rondon, under conventional tillage, and second in the 2002/2003 agricultural year in the region of Cascavel, under no tillage. The experimental design in both experiments was a randomized complete block, with four replications, 2x2x2 factorial, with two levels of nitrogen at sowing (zero and 20 kg ha-1), two levels of inoculum (zero and 200 g ha-1) and two levels of nitrogen in topdressing (zero and 100 kg ha-1). There was evaluated the height of ear insertion, total plant height, leaf N content, shoot dry biomass and grain yield. The height of ear insertion and total plant height were not influenced by the factors under study. Nitrogen fertilization at sowing increased the leaf N content, causing the opposite effect when combined with inoculation. Inoculation with Azospirillum in the absence of nitrogen, provide productivity increases of 15.4% and 7.4% for 2000/2001 and 2002/2003 crops, respectively. The inoculation provided productivity similar to that obtained with 100 kg ha-1 in topdressing in crop 2000/2001, while in association with the topdressing, reduced productivity and shoot dry biomass in crop 2002/2003.

Phosphorus loss by surface runoff in no-till system under mineral and organic fertilization

The no-till system has been intensively used in the state of Parana, Brazil, and it has increased the nutrients level at the soil surface. This has contributed for nutrient losses via runoff and consequently, off-site water pollution. The objective of this study was to evaluate phosphorus loss in surface runoff by simulated rainfall on an Oxisol, under no-till system following application of mineral fertilizer and liquid swine manure. Nitrogen, soil and water losses from the same study are reported in a separated paper. The application of liquid swine manure, compared with mineral fertilization, increased runoff concentration of total P, particulate P and dissolved reactive P by 193%, 111% and 506%, respectively, averaged for all rainfall intensities. Independently on the fertilizer source, the highest rainfall intensity provided the greatest concentration and loads of P in runoff.

Atributos químicos de solo e resposta do trigo e da soja ao gesso em sistema semeadura direta

A aplicacao de gesso para tornar o Al indisponivel, assim como para suprir nutrientes do solo para as plantas, pode proporcionar condicoes para a obtencao de elevada produtividade das culturas. Este trabalho teve como objetivo avaliar o efeito do gesso (0, 1.000, 2.000, 3.000, 4.000 e 5.000 kg ha-1) nas caracteristicas quimicas de duas areas com Latossolo Vermelho eutroferrico de textura argilosa, com ou sem Al trocavel, e na nutricao mineral e produtividade das culturas de trigo e soja em sistema semeadura direta. As doses de gesso foram aplicadas em superficie seis meses apos a calagem. Aos seis e 12 meses apos a aplicacao do gesso, foram coletadas amostras de solo nas profundidades de 0-0,10; 0,10-0,20 e 0,20-0,40 m. O uso de ate 5.000 kg ha-1 de gesso resultou em aumento dos teores de Ca2+ e SO42- e lixiviacao de K+ ate 0,20 m e Mg2+ ate 0,40 m de profundidade, um ano apos a aplicacao, sendo a dose de 3.000 kg ha-1 a que proporcionou maior reducao do Al trocavel. A aplicacao de gesso implicou aumento dos teores foliares de Ca e Mg na cultura da soja, reducao dos teores de Ca e Mg na cultura do trigo e aumento no teor de S em ambas as culturas, enquanto o teor de K aumentou ate a dose de 3.170 kg ha-1 de gesso na cultura da soja. A utilizacao do gesso eleva a produtividade do trigo, cultivar CD 104, em solo com presenca de Al trocavel, mas nao influencia a produtividade da soja em ambas os solos, com ou sem Al.

Effect of pH on boron adsorption in some soils of Paraná, Brazil

Temporary B deficiency can be triggered by liming of acid soils because of increased B adsorption at higher soil pH. Plants respond directly to the activity of B in soil solution and only indirectly to B adsorbed on soil constituents. Because the range between deficient and toxic B concentration is relatively narrow, this poses difficulty in maintaining appropriate B levels in soil solution. Thus, knowledge of the chemical behavior of B in the soil is particularly important. The present study investigated the effect of soil pH on B adsorption in four soils of Parana State, and to correlate these values with the physical and chemical properties of the soils. Surface samples were taken from a Rhodic Hapludox, Arenic Hapludalf, Arenic Hapludult, and one Typic Usthorthent. To evaluate the effect of pH on B adsorption, subsamples soil received the application of increasing rates of calcium carbonate. Boron adsorption was accomplished by shaking 2.0 g soil, for 24 h, with 20 mL of 0.01 mol L-1 NaCl solution containing different concentrations (0.0, 0.1, 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, and 4.0 mg B L-1). Sorption was fitted to non-linear form of the Langmuir adsorption isotherm. Boron adsorption increased as concentration increased. Boron adsorption was dependent on soil pH, increasing as a function of pH in the range between 4.6 and 7.4, although the bonding energy has decreased. Maximum adsorption capacity (MAC) of B was observed in the Arenic Hapludalf (49.8 mg B kg-1 soil) followed by Arenic Hapludult (22.5 mg kg-1), Rhodic Hapludox (17.4 mg kg-1), and Typic Usthorthent (7.0 mg kg-1). The organic matter content, clay content, and aluminum oxide content (Al2O3) were the soils properties that affecting the B adsorption on Parana soils.

Espaçamento e adubação nitrogenada e potássica em cobertura na cultura do milho

This work had the objective of evaluate the effect of row spacing reduction and nitrogen and potassium fertilization in covering, in the efficiency of absorption of nutrients, in the grain yield and components of the production and other agronomic traits of maize single-cross hybrid. The experiment was installed in Cascavel, State of Parana, in the agricultural year of 2004/05. It was studied three row spacings (0.45; 0.67 and 0.90m), with a population of 55000 plants ha -1 . The experiment design used was that of randomized blocks with four repetitions, in a split plot scheme. It was used 13 combinations of seven nitrogen doses (8; 20; 40; 80; 120; 140 e 152 kg ha -1 of N) with seven potassium doses (3; 7.5; 15; 30; 45; 52.5 e 57 kg ha -1 of K 2 O), adding 39 treatments. The reduction of interlineations spacing of 0.90 m to 0.45 m maintaining the same population in each area caused the increase of whole dry biomass production, more efficiency in the nitrogen and potassium absorption and also more efficiency in using N and K in the grain. The grain productivity was statistically the same in the three spacings studied. It was verified a linear increase in the productivity and of the dry biomass production in the aerial part until the doses of 152 kg ha -1 of N in covering. The fertilization with potassium proportioned an increase of dry biomass production in the aerial part, but does not influenced in the productivity. Over 80 kg ha -1 doses of N and 30 kg ha -1 of K 2 O resulted in a smaller efficiency in using nitrogen and potassium fertilization.

Growth and yield of corn hybrids in response to association with Azospirillum brasilense and nitrogen fertilization

There is a growing interest in optimizing the positive effects of the association between Azospirillum bacteria and corn crop in order to reduce the use of nitrogen fertilizers. This study aimed to evaluate the inoculation efficiency of an A. brasilense-based commercial product in association with different rates of nitrogen fertilization in two corn genotypes. The experiment was arranged in a 2 x 2 x 5 factorial randomized block design, with four replications. The treatments consisted of two corn hybrids (30F53 and CD386); with and without inoculation with a commercial product based on A. brasilense and five nitrogen rates (0, 40, 80, 120 and 160 kg ha-1). The variables plant height, basal stem diameter, leaf area, shoot dry matter, leaf nitrogen content, length and diameter of the cob, weight of 100 grains and grain yield were evaluated. Inoculation with A. brasilense provided increases of 11 and 12% in leaf area and shoot dry matter, respectively. There were differences in the response of the corn hybrids for most variables and the increase in nitrogen supply provided increments in the growth and yield of corn.

Plant density and nitrogen fertilization in Swiss chard

An experiment was conducted to evaluate the effect of plant spacing and nitrogen fertilization on Swiss chards yield, from September to November 2009. The experimental design was of randomized blocks in split plot with four replications. In the plots were allocated the two plant spacings (0.30 and 0.50 m) and in the subplots the five doses of nitrogen (0, 40, 80, 120 and 160 kg ha-1). The crop was harvested 90 days after transplanting. The plant spacing of 0.50 m provided increased production of total fresh weight of shoot (961.7 g plant-1) and marketable (873.1 g plant-1). However, the highest total yield (77.8 t ha-1) and marketable (64.5 t ha-1) was achieved with the smaller spacing between plants (0.30 m). The N rates applied in coverage until 160 kg ha-1 increased in a linear form the total and marketable production of fresh mass of shoots, the total and marketable yield, the N content and the N accumulation in the shoots of Swiss chard plants on the evaluated plant spacings.

CARACTERÍSTICAS AGRONÔMICAS E RENDIMENTO DE SEMENTES DE SOJA NA SEMEADURA REALIZADA NO PERÍODO DE SAFRINHA (1)

ABSTRACT AGRONOMIC TRAITS AND SEED PARAMETERS OF SOYBEAN CULTIVARSAS AFFECTED BY DELAYED SOWINGS Sowing date is one of the most important factors affecting soybean yielding potential. The mainaim of this research work was to evaluate the effects of delayed sowings on soybean ( Glycine max (L.)Merril) cultivar agronomic traits and seed yields. Experimental trials were carried out during the 1998/1999 and 1999/2000 growing seasons, using three sowing dates (November 15 th , January 15 ; and February15 th ) and five soybean cultivars with different seed maturation periods (BRS-132: very early; BRS-133:early; BR-16: early; BRS-134: intermediate and FT-Estrela: late). A randomized complete block design,with three replications, was set up for each sowing date, the November sowing date considered as thereference. The following agronomic traits were scored: number of days from sowing to seedling emergence,full blooming and seed maturation; first pod insertion height; plant height and degree of laid-downplants as well as the seed parameters overall seed yields, number of pods per plant and mass of thousand

Assessment of micronutrient extractants from soils of Paraná, Brazil

In Brazil, plant-available micronutrients in the soil can be determined by several chemical extractants, the most common of which are dilute acid and chelating solutions. The purpose of this study was to assess the extractants 0.1 mol L-1 HCl, Mehlich-1, Mehlich-3 and DTPA for analysis of the micronutrients Cu, Zn, Fe, and Mn in soils from the state of Parana. In samples from 12 soils (0-20 cm layer), wheat was planted (Triticum aestivum), grown for 42 days after emergence, and then bean (Phaseolus vulgaris) for 38 days. At the end of each planting period, the soil was sampled again. All extractants tested to assess the availability of Cu, Zn, Fe, and Mn correlated with each other. The efficiency of the extractants HCl, Mehlich-3 and DTPA in assessing plant-available Cu was similar, unlike Mehlich-1, which proved less efficient. The extractants HCl, Mehlich-1 and Mehlich-3 were less efficient in estimating plant-available Zn and Fe, and the most indicated extractant is DTPA. The efficiency of the extractants HCl, Mehlich-1, Mehlich-3 and DTPA in assessing plant-available Mn in soils from Parana was similar.

Eficiência de adubos fosfatados associados ao enxofre elementar na cultura do milho

The agronomic efficiency of phosphate fertilizers may be affected by phosphorus sources, soil properties, application methods and plant species. The objective of this work was to compare the efficiency of natural reactive phosphate (NRP) and triple super-phosphate (TSP) associated with elemental sulfur applied in the planting furrow of corn. The experiment was conducted in an Oxisol, in the city of Toledo-PR. The treatments were arranged in a randomized block design, in a factorial scheme 2x4x2, with two P sources (TSP and FNR), three fertilizer doses (100, 200 and 300 kg ha-1 P2O5), a control for each source, with or without addition of elemental sulfur (0 and 30 kg ha-1 S) applied at planting, with four replications. The plots consisted of four rows (6 m in length) spaced 0,90 meters. The plot usable area was formed by the center two rows, with 50 cm on each end of the plot left as border. N and K fertilization and the treatments with P and S were done by hand in the furrow and the hybrid Agroceres 8021 was sown subsequently. TSP provided the highest yields compared with NRP in the first year of cultivation. The agronomic efficiency of the NRP was 43 % and 33 % with and without S, respectively. The phosphorus content in leaf tissue was lower with NRP. The elemental S at 30 kg ha-1 did not interfere on the soil pH, but the efficiency of the phosphate fertilization was higher with the sulfur application.