Nitrification of ammonia (NH4) is a critical component for improved systems of animal wastewater treatment. One of the most effective processes uses nitrifying microorganisms encapsulated in polymer resins. It is used in Japan in municipal wastewater treatment plants for higher nitrification rates, shorter hydraulic retention times (HRT), and lower aeration treatment cost. We evaluated whether ...

Understanding the preference of a crop for forms nitrogen (N) is important to ensure efficient use N-sources in agriculture. A study was conducted assess nutrient uptake and dry matter yield six vegetable crops under different ratios ammonium- N (NH4+-N) nitrate-N (NO3–-N) growth medium. Seedlings cabbage, carrot, capsicum, knolkhol, lettuce, tomato, were supplied with five N-treatments (NH4+-N...

Plants mainly utilize inorganic forms of nitrogen (N), such as nitrate (NO3-) and ammonium (NH4+). However, the composition of the N source is important, because excess of NH4+ promotes morphological disorders. Plants cultured on NH4+ as the sole N source exhibit serious growth inhibition, commonly referred to as "ammonium toxicity syndrome." NH4+-mediated suppression of growth may be attributa...

A large proportion of the nitrogen (N) in soil is in the form of proteinaceous material. Its breakdown requires the activity of extracellular proteases and other decomposing enzymes. The goal of our study was to better understand how carbon (C) and N availability affect soil protease activity. Several aerobic incubations were carried out with ammonium (NH4 þ) and proteins as N sources and cellu...

Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems of the Ili River Valley, a representative aquatic ecosystem of Central Asia. The N leaching and overall...

Blossom-end rot (BER) is one of the major physiological disorders of greenhouse bell pepper (Capsicum annuum L.). The objective of the present work was to study the effects of the solution N concentration and N-NO3 : N-NH4 ratio on fruit yield and the incidence of BER and other fruit-quality traits of greenhouse-grown bell pepper in a Mediterranean climate. Three experiments were conducted: Exp...

To investigate N metabolism of two contrasting Populus species in acclimation to low N availability, saplings of slow-growing species (Populus popularis, Pp) and a fast-growing species (Populus alba × Populus glandulosa, Pg) were exposed to 10, 100, or 1000 μM NH4NO3. Despite greater root biomass and fine root surface area in Pp, lower net influxes of NH4(+) and NO3(-) at the root surface were ...

The experiment was carried out in two SBR reactors differing in ammonia load (reactor RI--ammonia load of 130 mg N-NH4 x d(-1), reactor R2--ammonia load of 250 mg N-NH4 x d(-1)). Feeding conditions in the reactors were switched from favoring autotrophic nitrification through favoring heterotrophic processes and back to autotrophic conditions. Observations of ammonia-oxidizing bacteria (AOB) com...