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Syrediffusion och redoxpotential vid olika markvattenhalter i styv lera

Nilsson, Åsa (1988). Syrediffusion och redoxpotential vid olika markvattenhalter i styv lera. ["eprint_fieldopt_monograph_type_und_thesis" not defined]. Uppsala: (NL, NJ) > Dept. of Soil Sciences > Div. of Hydrotechnics, Sveriges lantbruksuniversitet. Avdelningsmeddelande / Sveriges lantbruksuniversitet, Institutionen för markvetenskap, Avdelningen för lantbrukets hydroteknik ; 88:2
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Abstract

The purpose of this greenhouse investigation was to test a multichannel oxygen flux meter (Fig. 7) which was first designed by Armstrong & Wright (1976). The aim was to determine values of oxygen diffusion rate (ODR) critical for the growth of summer rape in two different clay soils from the middle part of Sweden (Table 1). A further aim was to study the effects of irrigation and soil compaction on ODR and to measure redoxpotential in the two soils. Undisturbed soil samples were extracted from the soil surface in steel cylinders with a height of 10 cm and a diameter of 7.2 cm. Different soil water suctions were applied to the samples and summer rape was sown on a number of cylinders. ODR was measured with a bare platinum electrode which was forced into the soil to a depth of 1.5 cm. A reference silver electrode was also lightly but firmly pressed into the soil. The leads from the two electrodes were connected to the oxygen flux meter which maintained an effective voltage of 0.65 V across the electrodes. An electric current resulted from the reduction of oxygen at the platinum surface and was assumed to be proportional to ODR in the surrounding soil solution (lemon & Erickson, 1952). The current was allowed to flow for 4 minutes before a reading was taken. In an initial experiment (Fig. 9) it was concluded that the steel cylinder would have no measurable disturbing effect on the current. The same pair of electrodes was used to register the redoxpotential of the soil sample, but in this measurement no voltage was applied to the system. ODR values greatly varied within as well as between soil samples, probably due to the heterogenicy of soil (lemon & Erickson, 1952). Despite this, the statistical significance of an increase in ODR values with a decrease in water content was high for most samples studied (Tables 4 and 6). In general, low ODR values were obtained as a result of irrigation (Diagrams 14 - 20) and soil compaction (Diagrams 5 - 6 and 9 - 10). There was a tendency for ODR to increase with increase in redoxpotential (Diagrams 23 - 24). Despite the low ODR values of ten obtained (less than 2pmol m-2 s-l) the growth of rape was normal in all noncompacted samples (Diagrams 25 - 26). This was probably due to the high percentage of roots growing on the outer surface of the sample next to the cylinder wall, where the oxygen supply was assumed to be more adequate than inside the soil sample. Because of this, it was not possible to determine a critical ODR value for the growth of summer rape in these samples. Regarding the results obtained from this investigation, it can be Concluded that the ODR method is a good indicator of soil aeration status and a complement to other existing methods of measuring soil aeration.

Authors/Creators:Nilsson, Åsa
Title:Syrediffusion och redoxpotential vid olika markvattenhalter i styv lera
Series/Journal:Avdelningsmeddelande / Sveriges lantbruksuniversitet, Institutionen för markvetenskap, Avdelningen för lantbrukets hydroteknik (0282-6569)
Year of publishing :1988
Number:88:2
Number of Pages:56
Place of Publication:Uppsala
Publisher:Institutionen för markvetenskap, avdelningen för lantbrukets hydroteknik, Sveriges lantbruksuniversitet
ISBN for printed version:91-576-3354-1
ISSN:0282-6569
Language:Swedish
Publication Type:Report
Refereed:No
Full Text Status:Public
Subjects:Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Soil science
Keywords:syrediffusion, markens syretillstånd, ODR, syreflödesmätare, lerjordar, vårraps, syretillgång, odlingsteknik
URN:NBN:urn:nbn:se:slu:epsilon-8-722
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-8-722
ID Code:5127
Department:(NL, NJ) > Dept. of Soil Sciences > Div. of Hydrotechnics
Deposited By: Elisabeth Bölenius
Deposited On:15 Sep 2010 00:00
Metadata Last Modified:02 Dec 2014 10:37

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