Aims: The objective of this study was to evaluate the photosynthetic activity and production of Urochloa ruziziensis when inoculated with Azospirillum brasilense in the presence and absence of drought. Study Design:  Randomized block design and factorial 2x2. Methodology: The first factor was the presence or absence of seed inoculation with A. brasilense strains AbV5 + AbV6; the second factor was the presence or absence of drought. The variables evaluated were: relative water content (RWC), soil gravimetric moisture, net assimilation rate of CO2, response in function of active photon flux density, apparent quantum efficiency, light compensation point, absolute integrity of membrane, damage to membranes, dry mass aborted leaves, and total dry mass of aerial part. Results: Results demonstrate that plants maintained in drought presented a reduction in all evaluated variables. Under conditions of drought the use of A. brasilense promoted smaller variations in RWC, net assimilation rate of CO2, apparent quantum efficiency, light compensation point, absolute integrity of membrane, and damage to membranes; no variations were observed for dry mass, aborted leaves or total dry mass of aerial part. Conclusion: The inoculation of U. ruziziensis seeds with A. brasilense mitigates drought damage in plant physiology, but it does not mitigate leaf losses or plant productivity.

In Modell‐ und Feldversuchen wurde über mehrere Jahre der Einfluß von unbehandeltem, pasteurisiertem und Gamma‐bestrahltem Klärschlamm auf die Bodenbiologie untersucht. Für die Versuche wurde Klärschlamm der westlich von München liegenden Kläranlage Geiselbullach verwendet. Die Untersuchungen wurden an 4 verschiedenen Standorten bzw. Bodenarten vorgenommen. Zusammenfassend zeigen die bisherigen Ergebnisse, daß durch Ausbringung von Klärschlamm das Bodenleben über einen längeren Zeitraum aktiviert wird und die Biomasse ansteigt, wobei Standorteinflüsse deutlich zu erkennen waren. Eine gesicherte Abhängigkeit von der Schlammbehandlung war dabei nicht feststellbar. Unter günstigen Laborbedingungen kann bei höheren Schlammgaben die Mineralisierung der in den Boden gebrachten organischen Verbindungen kurzfristig zu einem stärkeren pH‐Abfall führen. In Zusammenhang damit steht ein entsprechender Rückgang der mikrobiellen Biomasse. Erste Ergebnisse über die Beeinflussung des mikrobiellen N‐Kreislaufes ergaben, daß durch Klärschlammgaben, wie sie in der Praxis üblich sind, die Denitrifikationskapazität der Böden deutlich erhöht wird. Die Nitrifikationsgeschwindigkeit war bei den Versuchsböden nach Klärschlammausbringung ungefähr verdoppelt.

The present study aimed to evaluate the productive performance of maize crop when seed inoculated with A. brasilense, associated with different foliar doses of magnesium in the crop vegetative stages. For this, two essays were conducted in field conditions, one located in Laranjeiras do Sul-PR and the other in Entre Rios do Oeste-PR. A randomized blocks scheme was used, with a 3 × 2 factorial, being the treatments with magnesium (Mg): magnesium sulphate; magnesium oxide and without magnesium, and the presence or absence of seed inoculation with A. brasilense. The magnesium sources were supplied via foliar at the V 4 stage of the crop, using doses of 6 kg ha -1 . Evaluations were carried at R 1 determining the SPAD index and stem diameter and, at the end of the productive cycle, were evaluated production components and yield. In both sites no significant effects of foliar application with Mg were observed over the evaluated parameters. The A. brasilense inoculation provided an increase of 9.66% and 6.32% in stem diameter and of 6.8% and 6.24% in the SPAD index in Laranjeiras do Sul and Entre Rios do Oeste respectively, however, they did not increase production components and yield. It is concluded that the inoculation with A. brasilense increases of stem diameter values and SPAD index, in turn the foliar fertilization with different sources of magnesium do not interfere in the development and productivity of corn crop.

The objective of this study was to evaluate the biometric and bromatological characteristics of Urochloa ruziziensis in due to inoculation times with Azospirillum brasilense in the presence or absence of nitrogen fertilization. To do so it was used a randomized blocks design, with factorial scheme 4 × 2, where the first factor consisted the inoculation periods: control; A. brasilense in the seed; A. brasilense at tillering (aerial) and A. brasilense seed + foliar. The second factor constituted in the presence or absence of nitrogen (1000 mg dm³). Evaluations were made in the first, second and third cut, being evaluated the plant height, number of tillers per plant, leaves dry mass, culm+sheath dry mass; crude protein content, neutral detergent fiber and acid detergent fiber. The use of nitrogen fertilization increased the productive and bromatological parameters in the crop of U. ruziziensis, however, the use of A. brasilense increased only the height of plants, not influencing the other productive characteristics and the bromatological parameters. It is concluded that the use of A. brasilense, regardless the period it was made, presents inconclusive results for biometric and bromatological characteristics of plants of Urochloa ruziziensis in need of further studies, on the other hand, the nitrogen fertilization brings positive effects over the evaluated parameters on U. ruziziensis.

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