Search results for "organic nitrogen"

Nitrogen Type and Availability Drive Mycorrhizal Effects on Wheat Performance, Nitrogen Uptake and Recovery, and Production Sustainability

2020

Plant performance is strongly dependent on nitrogen (N), and thus increasing N nutrition is of great relevance for the productivity of agroecosystems. The effects of arbuscular mycorrhizal (AM) fungi on plant N acquisition are debated because contradictory results have been reported. Using 15N-labeled fertilizers as a tracer, we evaluated the effects of AM fungi on N uptake and recovery from mineral or organic sources in durum wheat. Under sufficient N availability, AM fungi had no effects on plant biomass but increased N concentrations in plant tissue, plant N uptake, and total N recovered from the fertilizer. In N-deficient soil, AM fungi led to decreased aboveground biomass, which sugges…

"Role of Arbuscular Mycorrhizal Fungi in Nutrient Uptake and Growth of Durum Wheat"

Soil microbiome is involved at different levels in the food web, in bio-geochemical nutrient cycles and in several interactions with plants. Based on its key role in the agro-ecosystem processes, the soil microbiome has been identified as one of the principal factors in an agriculture addressed to the ecological intensification. Among the several relationships established between plants and soil microorganisms, arbuscular mycorrhizal (AM) symbiosis is the most widespread. Two out of three of all plant taxa (among others the main crops) are involved in the AM symbiosis which takes place between the plant root system and arbuscular mycorrhizal fungi (AMF), a monophyletic group of fungi belong…

Nitrogen and phosphorus budgets in experimental grasslands of variable diversity.

2007

Previous research has shown that plant diversity influences N and P cycles. However, the effect of plant diversity on complete ecosystem N and P budgets has not yet been assessed. For 20 plots of artificially established grassland mixtures differing in plant diversity, we determined N and P inputs by bulk and dry deposition and N and P losses by mowing (and subsequent removal of the biomass) and leaching from April 2003 to March 2004. Total deposition of N and P was 2.3 +/- 0.1 and 0.2 +/- 0.01 g m(-2) yr(-1), respectively. Mowing was the main N and P loss. The net N and P budgets were negative (-6.3 +/- 1.1 g N and -1.9 +/- 0.2 g P m(-2) yr(-1)). For N, this included a conservative estimat…

Shared effects of organic microcontaminants and environmental stressors on biofilms and invertebrates in impaired rivers

2016

Land use type, physical and chemical stressors, and organic microcontaminants were investigated for their effects on the biological communities (biofilms and invertebrates) in several Mediterranean rivers. The diversity of invertebrates, and the scores of the first principal component of a PCA performed with the diatom communities were the best descriptors of the distribution patterns of the biological communities against the river stressors. These two metrics decreased according to the progressive site impairment (associated to higher area of agricultural and urban-industrial, high water conductivity, higher dissolved organic carbon and dissolved inorganic nitrogen concentrations, and high…

Simulating soil freeze/thaw cycles typical of winter alpine conditions: Implications for N and P availability

2007

Abstract Seasonally snow-covered alpine soils may be subjected to freeze/thaw cycles, particularly during years having little snow and during the late winter and early spring periods. Freeze/thaw cycles can stimulate soil mineralization and could therefore be one factor regulating nitrogen (N) and phosphorus (P) availability and cycling. In this study laboratory incubation experiments using four soils having contrasting properties have been used to characterize the change in N and P forms (microbial and soluble inorganic/organic) that occur after simulated freeze/thaw cycles. Soil samples were collected from locations representing extreme examples of either direct human management (grazed m…

KOSMOS 2017 Peru Side Experiment: nutrients, phytoplankton abundances, enzyme rates, photophysiology

2022

This data was collected during an short-term incubation experiment in March 2017 that investigated the response of a surface plankton community to upwelling. This experiment was carried in the framework of the SFB754-funded KOSMOS mesocosm study that took place in La Punta, Callao, Peru between February-April 2017. A total of six different treatments were used to disentangle chemical and biological characteristics of deep water that influence surface plankton blooms: 2 different deep water sources with different nutrient concentrations; 3 treatments to distinguish the effects of inorganic nutrients, organic nutrients and deep water microbial populations. Measured variables include inorganic…

Rapid change in forms of inorganic nitrogen in soil and moderate weed invasion following translocation of wet meadows to reclaimed post‐industrial la…

2019

Anthropogenic expansion and loss of natural environments calls for the more sustainable use of resources, including land. To combine the conservation of highly valuable meadow habitat with reclamation of post‐industrial land, 1.3 ha of turf were translocated from an urban area to basins constructed near an abandoned quarry. In contrast to the usual method of choosing similar habitats as salvage sites, the selected quarry possessed different environmental properties to the meadows, challenging their acclimatisation. To evaluate the project, we monitored three meadows (Molinion caeruleae alliance) for three seasons: immediately before the transfer and for 2 years afterwards. We recorded veget…

Labile nitrogen, carbon, and phosphorus pools and nitrogen mineralization and immobilization rates at low temperatures in seasonally snow-covered soi…

2006

Surface mineral horizons from four ecosystems sampled in the northwestern Italian Alps were incubated at −3 and +3°C to simulate subnivial and early thaw period temperatures for a seasonally snow-covered area. The soil profiles at these sites represent extreme examples of management, grazed meadow (site M) and extensive grazing beneath larch (site L) or naturally disturbed by avalanche and colonized by alder (site A) and the expected forest climax vegetation beneath fir (site F). Changes in labile pools of nitrogen (N) and phosphorus (P) were active at all sites at both temperatures during 14 days of laboratory incubation. Ammonium was the dominant inorganic form of total dissolved N (TDN),…