ISSN:
1573-5036
Schlagwort(e):
Alluvial soils
;
Ammonium
;
Amino acids
;
Chernozem
;
Clay minerals
;
Electroultrafiltration
;
EUF Nitrate
;
Nmin
;
N release
;
N reserves
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Summary The determination of N fractions in the soil by means of electro-ultrafiltration (EUF) is described. The results can be summarized as follows: 1) For aqueous soils suspension the direction of NH4 + and NO3 − migration in an electric field is determined by electrical charge and water flow. Therefore the filtrates obtained at both the cathode and anode can be mixed for subsequent analysis for NH4−N and NO3−N. In order to avoid N losses the volatile NH3 is recovered in 1N HCl solution. 2) Considerable amounts of NH4−N and NO3−N as well as low-molecular organic N compounds can be determined by EUF in soil samples taken from June to September. The readily available N is extracted by EUF at 20°C and 200 V, while determinations at 80°C and 400 V also give information on N release from reserves. 3) It was demonstrated with soils from long term N and K fertilizer experiments that the EUF−NO3 contents reflect the N accumulation in the soil due to N fertilization or plant residues. In clayrich soils the EUF−NH4 contents give information on the release of fixed NH4. Moreover EUF−NH4 also gives information on N from readily mineralizable organic compounds. The EUF procedure gives improved insight into the N dynamics of a site and this should serve as a basis for N-fertilizer recommendations.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02140716
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