concerns about nitrate pollution in groundwater and downstream systems cause development of surface water management system to reduce losses of agricultural drainage water nitrate in subsurface drainage using subsurface irrigation from existing drainage lines, drainage water during the growing season and out of season is controlled. the overall objective of this study was to evaluate the effect...

This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass...

Iodine biofortification of vegetables can become an alternative (to iodized salt) method of introducing this element into human diet. Development of agronomic rules concerning its application requires detailed evaluation of iodine influence on plant physiological and biological processes including mineral nutrition and quality of yield. The aim of the study was to determine the effect of iodine...

Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (K(m), 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (K(m), 5-25 mm) and a higher (3- to 5-fold)...

Soybean (Glycine max [L.] Merr.) seeds were imbibed and germinated with or without NO(3) (-), tungstate, and norflurazon (San 9789). Norflurazon is a herbicide which causes photobleaching of chlorophyll by inhibiting carotenoid synthesis and which impairs normal chloroplast development. After 3 days in the dark, seedlings were placed in white light to induce extractable nitrate reductase activi...

The short-term responses of soil microbial processes and community structure to perturbation constitute one aspect of soil quality. Such responses are often associated with an increase in the emissions of greenhouse gases (i.e., CO2, NO, or N2O) and the accumulation and potential loss of nitrate by leaching. Here we describe our recent work on responses of soil carbon and nitrogen dynamics, mic...

Tropical forests are renowned for their high diversity, yet in many sites a single tree species accounts for the majority of the individuals in a stand. An explanation for these monodominant forests remains elusive, but may be linked to mycorrhizal symbioses. We tested three hypotheses by which ectomycorrhizas might facilitate the dominance of the tree, Oreomunnea mexicana, in montane tropical ...

Organic farming avoids the use of synthetic fertilizers and promises food production with minimal environmental impact, however this farming practice does not often result in the same productivity as conventional farming. In recent years, biochar has received increasing attention as an agricultural amendment and by coating it with minerals to form biochar-mineral complex (BMC) carbon retention ...

The aim of this work was to couple a nitrogen (N) sub-model to already existent hydrological lumped (LU4N) and semi-distributed (LU4-R-N and SD4-R-N) conceptual models, to improve our understanding of the factors and processes controlling nitrogen cycling and losses in Mediterranean catchments. The N model adopted provides a simplified conceptualization of the soil nitrogen cycle considering mi...