ABSTRACT: Areas affected by coal mining can be recovered by revegetation with leguminous plants associated with nitrogen-fixing bacteria. This study addressed the isolation and characterization of native nitrogen-fixing bacteria from coalmine wasteland under different vegetation restoration approaches using Macroptilium atropurpureum (DC) Urb and Vicia sativa L. as trap plants. The bacteria were characterized and identified on the basis of 16S rRNA sequences. Additionally, nitrogen-fixing strains were characterized for tolerance to high heavy metal and low pH levels, as well as […]

Mucuna species are widely used as green manure, and little information is available about rhizobia that can nodulate them. The objective of this study was to evaluate the diversity and ability of bacteria isolated from symbiotic nodules of velvet bean (Mucuna pruriens (L.) DC.) and Mucuna deeringiana (Bort.) Merr. From the nodules of either mucuna species, grown in pots with soils from an agroecological system, 80 bacteria were isolated. The selected bacteria were classified and used to assess the symbiotic […]

Nitrogen removal in soybean grains at harvest may exceed biological N2 fixation, particularly if grain yields are as high as typically achieved on “Terra Rossa” soils of Eastern Paraguay. Applying N fertilizer or coating seeds with rhizobial inoculants that enhance nodulation may represent a way of balancing the N budget. However, the effects of such treatments appear to be highly site-specific. The objective of this study was to examine the effects of N application (N) and rhizobial inoculation (I) on […]

Black wattle is the third most cultivated forest species in Brazil. Besides its economic importance, black wattle is also used to restore degraded areas, where soils are generally acid and Al levels high. This study intended to investigate the genetic diversity of indigenous rhizobia in soils in Rio Grande do Sul and to select isolates that fix N2 efficiently at low pH. Fifty Bradyrhizobium sp. isolates were obtained, which, along with the recommended strains BR 3067 and BR 3068, were […]

The effect of N, Ni, Mo, Co and S omission on the N and S leaf contents of common bean plants (Phaseolus vulgaris), grown in a greenhouse, was evaluated. The experimental design was factorial, using two soil types (Entisol and Cambisol), two inoculation levels (with and without Rhizobium), combined with six fertilization treatments: (a) Complete (N, P, K, Ni, Mo, Co and S); (b) without N; (c) without Ni; (d) without Co; (e) without Mo; (f) without S. The experimental […]

Three series of experiments were carried out. In the first, the effects of N, Mo, and rhizobium were studied at two municipalities; in the second, conducted at another municipality, a factorial with four rates of N (0, 30, 60, and 90 kg ha-1) and four rates of Mo (0, 40, 80, and 120 g ha-1) was studied; and in the third, at six municipalities, the following combinations of N at planting time (kg ha-1), N as side dressing (kg ha-1) […]