scholarly journals Comparative studies on physiological and ecological characteristics of solanaceous fruit vegetables. (9). Influence of concentration ratios of nitrate nitrogen to ammonium nitrogen on growth, fruit development and nutrients absorption at different night temperatures.

1989 ◽  
Vol 27 (1) ◽  
pp. 31-36
Author(s):  
Toru KATO ◽  
Lingfeng ZHONG
1959 ◽  
Vol 31 (1) ◽  
pp. 268-281
Author(s):  
Jaakko Kivekäs ◽  
Erkki Kivinen

60 peat samples from northern Finland representing different types of peat were incubated in a laboratory at a temperature of 17—18° C. The ammonium nitrogen, the nitrate nitrogen and the pH in the samples were determined after one month of incubation as well as after three months of incubation. The results were compared to results from determinations made before incubation. An attempt was made to elucidate the factors that influence the mobilization of nitrogen. On the basis of the above results it is evident that the differences between the various peat types as mobilizers of nitrogen are under these circumstances not very distinct, nor do these differences seem to be dependent on the types of peat. The following facts can, however, be established: In the amounts of ammonium nitrogen an increase takes place in most groups of samples during the first month. This increase is fairly big in the Sphagnum-dominated peats. The increase in ammonium nitrogen continues in the unlimed samples in most peat groups during all three months of incubation. After three months of incubation the amount of ammonium nitrogen in the limed samples is smaller than in the unlimed samples, although it is usually bigger than in the original samples. After the first month of incubation the amounts of nitrate nitrogen in all types of peat have decreased compared to the amounts in the original samples. In the limed samples the decrease is not as great as in the unlimed ones. After three months of incubation the amount of nitrate nitrogen has considerably increased as compared to the amount after one month of incubation. In the limed samples it might to some extent exceed the original amount of nitrate nitrogen, however, this is seldom the case in the unlimed samples. If the results are calculated on the basis of weight unit, it can be stated that the ability to mobilize nitrogen is greater in the Sphagnum peats than in the other peat groups. Working out the results in kg per ha it will be noted that somewhat more nitrogen is mobilized in the Carex-dominated than in the Sphagnum-dominated peats. The results obtained by experiments in the laboratory are not directly applicable to conditions in the field.


1936 ◽  
Vol 26 (2) ◽  
pp. 249-257 ◽  
Author(s):  
A. H. Lewis

The results show clearly a more rapid and greater uptake of ammonium than of nitrate nitrogen by perennial rye grass grown in a sand-bentonite medium of pH 7·61. The extent to which the extra uptake with added ammonia was reflected in increased yields was dependent upon the age of the grass.Except in the very early stages the percentage nitrogen content of the herbage was higher where nitrate nitrogen was applied than where ammonium nitrogen was applied. This indicates that any nitrate absorbed by the plant was less, efficient in increasing yields than was ammonium nitrogen.The percentage P205 content of the grass was higher where the nitrogen was applied in the ammoniacal form than where it was applied as nitrate, and it appears that this greater P205 uptake with ammonium nitrogen resulted in increased growth.


2018 ◽  
Vol 781 ◽  
pp. 195-199
Author(s):  
Sergey Novoselov

The article discusses the photochemical effects of sunlight on the soil. Under the influence of light energy the amount of mineral and easy hydrolysable nitrogen, as well as labile humus substances increased in the soil. The photochemical destruction of humus substances was accompanied by an increase in their mobility and loss of colour. The article shows that the process of mineral nitrogen formation in the soil during the photochemical destruction of humus substances has two stages. The first stage includes photochemical reactions with the formation of ammonium nitrogen. The second stage is the microbiological oxidation of ammonium nitrogen to the nitrate nitrogen.


2001 ◽  
Vol 44 (7) ◽  
pp. 151-156 ◽  
Author(s):  
S. Umemoto ◽  
Y. Komai ◽  
T. Inoue

Nutrients and other pollutant runoffs from streams in artificial forest areas in central Hyogo Prefecture in southwest Japan have been investigated to estimate pollutant loads since 1995. The orthophosphate and ammonium nitrogen contents were usually low and constant during the investigation. When the flowrates of the streams were normal, the concentrations of suspended solids, CODMn, TOC and total phosphorus were very low, and did not change much. However, when stream flows were increased by rainstorms or other precipitation, higher concentrations of these parameters occurred. Otherwise, the average concentrations of nitrate nitrogen and total nitrogen were 0.26 mg/l and 0.31 mg/l, respectively, and they were often increased by precipitation events. They changed at the same time because the ratio of nitrate nitrogen per total nitrogen was high, about 80%. The fluctuation of concentrations of total phosphorus was similar to SS concentrations, which suggested that phosphorus was discharged in the types of suspended solids from forest areas. The specific loads of the nutrients and some other pollutants did not differ among the three watersheds investigated. However, the difference among them between fine days and rainy days was fairly large. It was presumed that pollutant runoff from forest areas is strongly dependent on precipitation events.


Atmosphere ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
Baoling Mei ◽  
Hongyu Yue ◽  
Xunhua Zheng ◽  
William McDowell ◽  
Qingshan Zhao ◽  
...  

The establishment of sown pasture is an important agricultural practice in many landscapes. Although both native grassland and sown pasture play a key role in the global carbon cycle, due to lack of data and field experiments, our understanding of grassland CH4 fluxes and CO2 emissions remains limited, especially when it comes to sown pasture. We measured ecosystem respiration and CH4 fluxes in response to a variety of potential drivers (soil temperature, soil moisture, ammonium nitrogen, nitrate nitrogen and dissolved organic carbon) in CG (continuous grazing), RG (rotational grazing) and UG (ungrazed) plots in sown grassland for one year in Inner Mongolia. Fluxes of CH4 and ecosystem respiration were measured using static opaque chambers and gas chromatography. Grazing significantly reduced ecosystem respiration (p < 0.01), and grazing pattern significantly influenced respiration in CG and RG plots (p < 0.01). We find that the sown grassland is a net sink for atmospheric CH4. No influence of grazing pattern was observed on CH4 flux in CG, RG and UG (p > 0.05). Soil temperature is the most important factor influencing ecosystem respiration and CH4 flux in the sown grassland, with soil moisture playing a secondary role to soil temperature. Variation in levels of ammonium nitrogen, nitrate nitrogen and dissolved organic carbon had little influence on ecosystem respiration or CH4 flux (except in UG plots). The values obtained for ecosystem respiration of grasslands have a large uncertainty range, which may be due to spatial variability as well as differences in research methods. Mean CH4 fluxes measured only during the growing season were much higher than the annual mean CH4 fluxes.


2015 ◽  
Vol 25 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Piotr Wesołowski ◽  
Adam Brysiewicz

Abstract Due to poor ecological status of Lake Starzyc, lake restoration measures were undertaken in 2003 to improve aerobic conditions of near-bottom waters and to decrease phosphorus concentrations. To do this, a wind-driven pulverising aerator was installed in the lake. The aim of this study was to analyse variability of oxygen and nitrogen concentrations in lake water near the aerator in the third year of its operation and later on in the three-year-long period of the years 2008–2010. It was found that concentrations of ammonium-nitrogen, nitrate-nitrogen and dissolved oxygen near the aerator did not differ from those in sites 4 and 5, which evidenced similar abiotic conditions in analysed waters. Higher concentrations of dissolved oxygen and lower concentrations of nitrate-nitrogen were found in the years 2008–2010 than in 2005.


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