Effects Of Ammonium Nitrogen Research Articles

Effect of ammonium nitrogen on pepper grown under soilless culture

The response of pepper (Capsicum annuum L.) to Ammonium-N was studied in a multispan greenhouse under soilless culture using coir fiber as substrate. Ammonium-N application rates were 0, 2, 4, 6 and 8 mM with a total-N concentration of 13 mM. The total content of the rest of all macronutrients in the nutrient solution was maintained from the beginning of the experiment until the end. The highest water uptake was recorded at 2 mM ammonium concentration in the nutrient solution. Compared to nitrate, ammonium nitrogen caused a decrease in nitrate absorption, but led to an increase when applying 8 mM ammonium. Despite a progressive increase in ammonium content in the nutrient solution, potassium absorption was constant below the ammonium concentration of 8 mM. Under a high N-NH4 content (from 6 to 8 mM) in the nutrient solution, high toxicity was found, deriving in the appearance of deformed or noncommercial fruits. There was a significant benefit by the use of ammonium as a component in the nutrient solution. The optimum yield ammonium concentrations were found in the range from 2 to 4 mM. Nevertheless, concentrations higher than 6 mM led into a decrease in commercial production, with the production of increasing deformed fruit, out of size and/or blossom-end rot.

Effect of ammonium nitrogen on microalgal growth, biochemical composition and photosynthetic performance in mixotrophic cultivation

To enhance microalgal growth and optimize ammonium utilization, the effect of ammonium on microalgal growth, biochemical composition and photosynthetic performance were investigated by mixotrophic cultivation of microalga Spirulina platensis comparing with autotrophic cultivation. The results indicated that elevated ammonium significantly affected the microalgal growth, but the microalga in mixotrophic cultivation showed better growth and stronger tolerance to higher ammonium. The microalgal proteins were increased by increasing nitrogen concentration. The synthesis of microalgal carbohydrates was inhibited by higher ammonium, especially in mixotrophic cultivation. The addition of ammonium decreased the microalgal lipids in autotrophic cultivation but increased microalgal lipids in mixotrophic cultivation. Ammonium negatively affected the microalgal photosynthetic performance. The inhibition was intensified by elevated ammonium, inducing stronger photosystem protection mechanism, particularly in mixotrophic cultivation. The rate of ammonium inhibition to the microalgal photosystem was quick in the early stage by decreasing electron transport rate of PS II.

Effect of different nitrogen forms and concentrations on biomass and alkaloids of Isatidis Folium

In order to provide theoretical basis of improving nitrogen utilization efficiency in Isatis indigotica, the biomass and active components in Isatidis Folium under different nitrogen forms and concentrations were analyzed. I. indigotica was cultivated by sand culture in greenhouse, and the experiment was designed with orthogonal test L25 (5(6)). As an index to the biomass and indigo, indirubin, the effects on the I. indigotica by three factors [NO3(-) -N, NH4(+) -N, CO(NH2)2] at five different levels were studied. There were significant difference of the biomass and active components by different nitrogen forms and concentrations. The effect of amide nitrogen [CO(NH2)2] on biomass of Isatidis Folium was the most apparent, and the effect of ammonium nitrogen on indirubin was more obvious. Considering the biomass and active ingredient, one combination was optimized, which was (NH4)2SO(4)-7.5 mmol x L(-1), KNO(3)-2.5 mmol x L(-1), CO(NH2)(2)- 5 mmol x L(-1). It is important to promote the growth in pre-stage of I. indigotica, and cost-effective combination of balanced nitrogen fertilizer could reasonably promote the growth, and improve the contents of active components and individual biomass.

Short-term effects of ammonium nitrogen in upland pasture soil affected or not affected by cattle

The short-term effects of excessive NH 4 + -N on selected characteristics of soil unaffected (low annual N inputs) and affected (high annual N inputs) by cattle were investigated under laboratory conditions. The major hypothesis tested was that above a theoretical upper limit of NH 4 + concentration, an excess of NH 4 + -N does not further increase NO 3 − formation rate in the soil, but only supports accumulation of NO 2 − -N and gaseous losses of N as N2O. Soils were amended with 10 to 500 μg NH 4 + -N g−1 soil. In both soils, addition of NH 4 + -N increased production of NO 3 − -N until some limit. This limit was higher in cattle-affected soil than in unaffected soil. Production of N2O increased in the whole range of amendments in both soils. At the highest level of NH 4 + -N addition, NO 2 − -N accumulated in cattle-affected soil while NO 3 − -N production decreased in cattle-unaffected soil. Despite being statistically significant, observed effects of high NH 4 + -N addition were relatively weak. Uptake of mineral N, stimulated by glucose amendment, decreased the mineral N content in both soils, but it also greatly increased production of N2O.

Stimulating effect of earthworm excreta on the mineralization of nitrogen compounds in soil

The effect of excreta of earthworm species Aporrectodea caliginosa and Eisenia fetida on the mineralization of nitrogen compounds in soils has been studied. A single application of excreta obtained from three earthworms in one day increased the formation of nitrate nitrogen compounds in the soil by 10–50%. The application of ammonium nitrogen (in the form of NH4Cl) in amounts equivalent to the ammonium nitrogen content in the daily excreta of three earthworms had the same effect on the mineralization of nitrogen compounds. The effect of earthworm excreta, as well as the effect of ammonium nitrogen, on the nitrification process was an order of magnitude higher than their contribution to the formation of nitrates due to the oxidation of the introduced ammonium. Hence, ammonium—an important component of the earthworm excreta—can exert a stimulating effect on nitrification processes in the soil and produce long-term cumulative effects that are much more significant than the direct effect of this nitrogen compound.

Effects of Ammonium Nitrogen on Lettuce Grown on Pumice in a Closed Hydroponic System

Two successive lettuce crops were grown in spring 2005 in a completely closed hydroponic system. The ratio of ammonium to total nitrogen (Nr) in the fresh nutrient solution (FNS) introduced into the closed system to compensate for plant uptake was 0, 0.1, 0.2 and 0.3 on a molar basis. In all Nr treatments, the concentrations of total N, K, Ca, Mg, P, and micronutrients in the FNS were identical, but that of SO42– increased as Nr increased, to compensate electrochemically for the enhanced NH4+ and decreased NO3– supply. The highest fresh and dry weights per plant were attained with the highest ammonium supply (Nr = 0.3) but, even when no NH4+ was included in the FNS as an N source, the plants were healthy without apparent nutritional disorders. The ammonium concentration in the drainage solution dropped to nearly zero in all treatments some days after the initiation of recycling, which implies a preferential uptake of NH4-N over NO3-N. The root zone pH, as indicated by the values measured in the drainage solution, decreased slightly as Nr increased, and ranged from 6.5 to 8.0 in all treatments. The leaf K, Ca, Mg, and Fe concentrations were not influenced, whereas those of P, Mn, Zn, and Cu were enhanced by the increasing NH4+ supply. The increased ammonium supply did not enhance the utilization of N in plant metabolism, although it reduced the nitrate concentration of the internal leaves in the early spring experiment. The leaf micronutrient concentrations were clearly more than critical levels even when NO3– was the sole N source for lettuce, whereas the P concentration approached the lowest critical level when Nr was 0 or 0.1. The stimulation of lettuce growth as Nr was increased to 0.3 may be a consequence of enhanced P uptake resulting from better control of pH in the root zone.

Dinâmica do nitrogênio no solo em razão da calagem e adubação nitrogenada, com palha na superfície

Em sistemas com semeadura direta, a calagem tem sido aplicada superficialmente, causando excesso de calcário nos primeiros centímetros do perfil do solo, onde também é aplicado o N em cobertura e a densidade de comprimento radicular é alta. O objetivo deste trabalho foi estudar a dinâmica do N e do pH do solo em razão da calagem em superfície e aplicação de N em cobertura, na presença de palha. Plantas de algodão (Gossypium hirsutum) foram cultivadas, por 60 dias, em vasos que receberam calagem superficial ou incorporada e aplicação de doses equivalentes a 0, 50, 100 e 150 kg ha-1 de N em cobertura, na forma de sulfato de amônio; os vasos apresentavam, na superfície, o equivalente a 4 t ha-1 de palha de milheto. A calagem aumentou a mineralização e a nitrificação do N no solo, independentemente do modo de aplicação de calcário, aumentando a sua disponibilidade à planta e também a possibilidade de lixiviação. A absorção de N pela planta, além de sua imobilização pela massa microbiana do solo, neutralizou o efeito do adubo nitrogenado amoniacal no pH do solo. O algodoeiro respondeu melhor à calagem incorporada do que à superficial, mas esta resposta não foi causada por diferenças na disponibilidade de nitrogênio.

Ammonium‐nitrogen assimilation and nitrogen fixation in azospirillum lipoferum and azospirillum brasilense

AbstractThe effect of ammonium nitrogen on the growth and efficiency of nitrogen fixation by A. lipoferum and A. brasilense grown under various growth conditions was investigated.

Effect of ammonium nitrogen on biochemical treatment of refinery wastewater

Effect of ammonium nitrogen on biochemical treatment of refinery wastewater

Some effects of combined nitrogen on the nodule symbioses of Casuarina and Ceanothus

1. The effect of ammonium-nitrogen on the further growth and activity in fixation of nodules already present at the commencement has been studied inCasuarina cunninghamiana growing in water culture and inCeanothus velutinus var.laevigatus in Peralite culture. 2. In Casuarina, at a low level of ammonium-nitrogen nodule growth remained similar to that in plants in nitrogen-free solution, but was stimulated in Ceanothus. In both genera nodule growth was strongly retarded at higher levels. 3. Fixation of nitrogen fell continuously in Casuarina as the level of ammonium-nitrogen was increased, while that in Ceanothus was unaffected at a low level but markedly decreased at a higher one. These effects were compounded from the changes noted in 2 and a tendency for the efficiency of nodule tissues in fixation to fall in the presence of ammonium-nitrogen, though this was not always shown. 4. In both genera but especially in Casuarina the growth of plants entirely dependent on nodule nitrogen was inferior to that of plants additionally supplied with ammonium-nitrogen. The reasons are discussed. 5. The results indicate the effects likely to be produced in the field as the soil nitrogen level rises through the action of the nodules of these species.