Jeferson Klein

Características agronômicas do trigo em função de Azospirillum brasilense, ácidos húmicos e nitrogênio em casa de vegetação

The objective of this study was to investigate the effect of the combined use of Azospirillum brasilense, humic acid and different levels of nitrogen on agronomic characteristics of wheat under greenhouse conditions. The experiments were installed on May 21, 2011 and proceeded to harvest on September 13, 2011. The experimental design was a randomized complete block in a 4 x 4 factorial design with four replications. The first factor relates to the combination of strain Ab-V5 of A. brasilense with humic acids, with the following treatments: control, Ab-V5, humic acid and Ab-V5 + humic acid and the second factor refers to nitrogen levels (0, 30, 60 and 90 kg ha-1 N). Most variables in the analysis had a positive linear effect of treatments depending on nitrogen fertilization, and only for variable weight of hundred grains, the negative effect was linear. There were no significant differences between the variances in grain production. It was concluded that the combined use of Ab-V5 + humic acid promotes the production mainly of dry leaves and are not responsive to nitrogen fertilizer for other productive components under study, as well as grain yield.

Cultivares de trigo submetidas a déficit hídrico no início do florescimento, em casa de vegetação

The water restriction can damage the performance of crops, especially in the flowering period. Thus, the aim of this research was to evaluate the response of genotypes of wheat submitted to water deficit in the beginning of flowering. The experiment was conducted in greenhouse, in a completely randomized design, in factorial scheme 3 x 2, with five replications. The factors studied were: three wheat cultivars (Coodetec (CD) 105, 108 and 111) and 2 irrigation managements (with and without imposition of water deficit). During the period of water deficit imposition, gravimetric soil moisture and the relative content of water in leaf were evaluated, while at the moment of rehydration the biometric variables were determined. At the end of the crop cycle the components of production were evaluated. Reduction was found in the gravimetric soil moisture, in the relative levels of water and in all biometric variables, in function of the water deficit. The grain production showed difference only among the water regimes, in which the cultivar CD 111 is more efficient in the maintenance of the productive potential in conditions of water deficit, through the quick recovery in the relative content of water in leaves.

Qualidade fisiológica de sementes de três cultivares de trigo submetidas à inoculação e diferentes tratamentos

The objective of this study was to evaluate the physiological quality of wheat seed treated with plant growth regulators, triadimenol and Azospirillum brasilense. The experimental design was completely randomized with four replications in a 3x8factorial: three wheat cultivars and eight seed treatments. The cultivars used were CD-150, CD-116 and CD-104, and the treatments were a combination of three different substances: 150 g.L-1 triadimenol (TRI), 90 mg.L-1 kinetin + 50 mg.L-1 giberellic acid + 50 mg.L-1 indolebutyric acid (CGA) and strains Ab-V5 and Ab-V6 of A. brasilense at a concentration of 2.0 x 108 viable cells mL-1 (AZO), as follows: control, TRI, CGA, AZO, TRI+CGA, TRI+AZO, AZO+CGA and TRI+CGA+AZO. Germination and abnormal seedlings (%), shoot and hypocotyl length and the diameter, length and number of roots, dry weight of shoot and root/shoot were determined. The results showed that: the treatments did not affect seed germination; the treatments did not increases the early development of wheat seedlings and triadimenol alone or in combination with A. brasilense plant growth regulator resulted in lower values for shoot, root and hypocotyl length and root number for all the cultivars.

Synergistic action of Azospirillum brasilense combined with thiamethoxam on the physiological quality of maize seedlings

Plant growth promoting substances, either from biological or chemical origin, are widely used in modern agriculture. In this context, this study evaluated the physiological quality of maize seed treated with thiamethoxam and inoculated with Azospirillum brasilense . Initially, we tested bacterial growth on medium with increasing concentrations of thiamethoxam. We also evaluated the physiological quality of seeds through morphometric measurements, emergence speed index and chlorophyll content by SPAD through a 2x3 factorial arrangement with seed inoculation with A. brasilense (100 mL per 25 kg of seed) and three doses of thiamethoxam (0, 80 and 120 ml per 60,000 seeds). Bacterial population showed a linear reduction according to increasing doses of thiamethoxam. The dose of 120 ml thiamethoxam (42 mg active ingredient) caused a decrease in several variables, while, the inoculation proved a positive activity in seedlings physiological quality. Thus, the inoculation combined with 80 ml thiamethoxam (28 mg active ingredient) show synergistic action in early development in maize seedlings. Keywords: Thiamethoxam, inoculant, plant growth promoting bacteria African Journal of Biotechnology , Vol 13(49) 4501-4507

Phosphorus and potassium fertilization in culture of soybean plants in the Oxisol

It is recommended to use phosphorus and potassium fertilization on soybean; however it has been common to verify the absence of effect on crop productivity, especially in no-tillage system. Thus, the study aimed to evaluate the effect of doses of superphosphate and potassium chloride in the leaf tissue nutrient content and yield of soybean growing in Oxisol. The experiment was installed in October 2011 in a randomized block design in split-bands with two factors (4x4), with four replications, totaling 64 plots, being Factor 1 with doses of superphosphate (0, 136, 331 and 700 kg ha-1) at sowing and Factor 2 with doses of potassium chloride (0, 160, 320 and 800 kg ha-1) released with cultivar Vmax RR (SYN 7059RR). In the experiment, the variables evaluated were Ca, Mg, K, P, S, Cu, Zn, Mn and Fe in leaf tissue and grain yield. The fertilization with superphosphate and potassium chloride do not interfere in leaf nutrient content and yield of soybean cultivar Vmax RR (SYN 7059RR) grown on an Oxisol of clayey with levels of P and K classified as high. In these cases, it is advisable to keep only the maintenance fertilization according to the values ​​of P and K exported by grain. Key words: Chemical fertilizer, tillage systems, organic mineral fertilizer, superphosphate, potassium chloride.