Márcio Voss

Rendimento e nodulação de soja em diferentes rotações de espécies anuais de inverno sob plantio direto

The different preceding crops were compared in relation to soybean yield and nodulation during four years at the Faculdade de Agronomia e Medicina Veterinaria, in Passo Fundo, State of Rio Grande do Sul, Brazil. Four production systems with annual winter pastures were tested, in which soybean was sown after different winter crops (white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat). Both in winter and summer the crops were grown under no-tillage. An experimental design of blocks at random, with three replications and plots with 500 m2, was used. No significant differences between type of preceding crop and soybean yield were found in the mean of years . After five years of no-tillage, an abundant nodulation in soybean was observed in all production systems. Soybean grown after white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat may be included, without any loss, in the different systems studied.

Nodulação e fixação biológica de nitrogênio de Adesmia latifolia e Lotus corniculatus em vasos de Leonard

Adesmia latifolia is a forage legume native from Southern Brazil which is outstanding due to stoloniferous growth habit and for forage production during the cool season. The Lotus corniculatus (birdsfoot trefoil) is a forage usually utilized as cool season species in subtropical and temperate regions. For both species, however, there is a reduced number of scientific works related to the nodule type and biological nitrogen fixation (BNF). This work had the purpose to analyze such processes in these species and also to compare their morphological development under different nitrogen sources: mineral-N (ammonium nitrate - 5%), symbiotic-N (inoculation) and without nitrogen (control). The experiment was carried out in greenhouse conditions, utilizing Leonard Jars with nutritive solution; the substrate consisted of mixture of sand, vermiculite and charcoal. It was a randomized complete design with four replications. At the end of 65 days the plants were harvested and evaluated for length and volume of roots, number and weight of nodules, dry matter (DM) accumulation and BNF. A. latifolia stand out for the character number of nodules (126/jar) and total nodule weight (82.22 mg DM/jar) as compared to birdsfoot trefoil with 82 nodules/jar and 20.25 mg DM/jar. The BNF was more effective in A. latifolia, whose inoculated plants produced an average of 37% of DM that was obtained by plants supplied with mineral-N, while birdsfoot reached only 15% of DM production with BNF. The amount of symbiotic fixed nitrogen was 43.12 mg N/jar in Adesmia and 9.92 mg in birdsfoot trefoil.

Sorção de cobre e manganês por bactérias rizosféricas do trigo

The metals bioaccumulation in microganisms is mainly a result of superficial phenomena, occurring adsoption, in a stoychometric way, with the anionic radicals of cellular walls followed or not by precipitation of metals. To study the sorption of metals by live bacteria, the Cu2+ and Mn2+ taken up by a Bacillus sp. and a Pseudomonas sp., were quantified isolated from weath rizosphere, from a cloride solution of metals resting in the supernatant, after centrifugation. A completely randomized experimental design was used, with 3 repetitions. The effect of Cu2+ and Mn2+ contents, pH and time of bacterial growth were tested. Bacillus sorbed more Cu2+ and Mn2+ than Pseudomonas in all concentrations of those metals. Cu2+ sorption by both bacteria showed more increase than Mn2+ with rising those metals content in the solution. Alteration of pH from 5,0 to 3,0 reduced the metal sorption. With 90 hour cultivation time, Pseudomonas showed more Cu2+ and Mn2+ sorption than with 16 hour cultivation time. The results agree with the colloids cations exchange phenomena.

Soybean yield and nodulation in different annual winter crops under no-tillage

The different preceding crops were compared in relation to soybean yield and nodulation during four years at the Faculdade de Agronomia e Medicina Veterinaria, in Passo Fundo, State of Rio Grande do Sul, Brazil. Four production systems with annual winter pastures were tested, in which soybean was sown after different winter crops (white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat). Both in winter and summer the crops were grown under no-tillage. An experimental design of blocks at random, with three replications and plots with 500 m2, was used. No significant differences between type of preceding crop and soybean yield were found in the mean of years . After five years of no-tillage, an abundant nodulation in soybean was observed in all production systems. Soybean grown after white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat may be included, without any loss, in the different systems studied.

Adubação com molibdênio em soja, na presença ou ausência de calcário aplicado na superfície do solo, em plantio direto

An experiment was carried out in 1997/1998 on Dark Red Latosol (Haplorthox), in Passo Fundo, with pH (H2O) 4.9 and 41.2mmolc de Al3+dm-3, to study the effects of lime, applied on the surface of the soil, and molybdenum, on soybean yields. The residual effect of lime and the reapplication of Mo was studied at the same location, in 1998/1999. The experimental design was the complete randomized block, with four replications. The treatments consisted of: 1) lime + Mo applied on the seeds; 2) lime + foliar application of Mo; 3) lime; 4) Mo applied on soybean seeds; 5) Mo applied on soybean leaves and 6) no lime and no Mo. Lime was applied at a rate of 2t ha-1, at the surface of soil. Molybdenum was applied at the rate of 12g ha-1, on the seeds, and 30g ha-1, when foliar applied, 30-33 days after emergency. Soybean responded to applied Mo, even in the treatments with lime, in both seasons. The results of the two experiments indicated that the superficial application of lime did not release enough Mo for the development of no-tillage soybean in the acid soil used. The fertilization of molybdenum on the seeds or foliar way had the same efficiency.

Yield and nodulation of soyabeans in rotations with different annual winter crops in a no-tillage system.

The different preceding crops were compared in relation to soybean yield and nodulation during four years at the Faculdade de Agronomia e Medicina Veterinaria, in Passo Fundo, State of Rio Grande do Sul, Brazil. Four production systems with annual winter pastures were tested, in which soybean was sown after different winter crops (white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat). Both in winter and summer the crops were grown under no-tillage. An experimental design of blocks at random, with three replications and plots with 500 m2, was used. No significant differences between type of preceding crop and soybean yield were found in the mean of years . After five years of no-tillage, an abundant nodulation in soybean was observed in all production systems. Soybean grown after white oats, grazed black oats, grazed black oats + grazed common vetch, and wheat may be included, without any loss, in the different systems studied.