Beans (Phase()las valgtais L.) often respond to N fertilization; however, N fertilization is not practiced for maximum seed production in southern Idaho. This suggests that the symbiotic relationship and/or soil N sources can provide most of the N needed by this legume. Our objective was to evaluate the relative contribution of the symbiotic-nonsymbiotic N sources by studying the effects of N f...

The effect of different cropping systems on CO2 fixation by soil microorganisms was studied by comparing soils from three exemplary cropping systems after 10 years of agricultural practice. Studied cropping systems included: continuous cropping of paddy rice (rice-rice), rotation of paddy rice and rapeseed (rice-rapeseed), and rotated cropping of rapeseed and corn (rapeseed-corn). Soils from di...

Compatible rhizobia strains are essential for nodulation and biological nitrogen fixation (BNF) of hairy vetch (Vicia villosa Roth, HV). We evaluated how past HV cultivation affected nodulation and BNF across host genotypes. Five groups of similar HV genotypes were inoculated with soil dilutions from six paired fields, three with 10-year HV cultivation history (HV+) and three with no history (H...

In the tropics, cowpea is often intercropped with maize. Little is known about the effect of the intercropped maize on N2-fixation by cowpea or how intercropping affects nitrogen fertilizer use efficiency or soil N-uptake of both crops. Cowpea and maize were grown as a monocrop at row spacings of 40, 50, 60, 80, and 120 cm and intercropped at row spacing of 40, 50, and 60 cm. Plots were fertili...

Plants can acquire carbon from sources other than atmospheric carbon dioxide (CO(2)), including soil-dissolved inorganic carbon (DIC). Although the net flux of CO(2) is out of the root, soil DIC can be taken up by the root, transported within the plant, and fixed either photosynthetically or anaplerotically by plant tissues. We tested the ability of Pinus taeda L. seedlings exposed to (13)C-lab...

The soil particles can be gathered through physical and/or chemical processes in association with the biological activity, leading to formation of aggregates. Soil aggregates has several functions soil, increasing macroporosity and water circulation – consequently reducing erosion mechanical resistance root growth, contributing greater fixation plants absorption nutrients, protection intra-aggr...

Increased belowground labile C inputs under elevated [CO2] could stimulate nonsymbiotic N2 fixation, thereby enhancing growth responses of vegetation to elevated [CO2] on nutrient-poor sites. To test this hypothesis, nonsymbiotic N2 fixation rates in soils planted with 3-year-old Jeffrey pine (Pinus jeffreyi Grev. & Balf.) trees grown under 365 and 700 μL·L–1 atmospheric [CO2] were measured by ...

The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding ...