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Ionic Effect of Salts on Mineral Nitrogen Release in an Allophanic Soil
Author(s) -
Agarwal A. S.,
Singh B. R.,
Kanehiro Y.
Publication year - 1971
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1971.03615995003500030034x
Subject(s) - chemistry , sulfate , nitrification , inorganic chemistry , chloride , nitrogen , cation exchange capacity , ion exchange , ionic bonding , soil water , ion , organic chemistry , geology , soil science
A comparison of the effects of sulfate and chloride salts on N release and microbial activity in Akaka soil showed that only sulfate salts at low concentrations increased CO 2 evolution. The chlorides were more effective than sulfates in effecting NH 4 ‐N release in the soil. The addition of CaCl 2 ·2H 2 O resulted in the greatest NH 4 ‐N release, followed by that of KCl and NaCl. Among sulfates, K 2 SO 4 ranked first, followed by Na 2 SO 4 and CaSO 4 · 2H 2 O. The idea that certain chemical reactions and/or processes are involved in splitting NH 4 ‐N from organo‐inorganic complexes of a soil and that NH 4 + ions are subsequently exchanged with cations in the surrounding soil solution was further substantiated by results of this investigation. The exchange reaction was noted to depend on the nature and valence of the cation, concentration in the soil solution, length of reaction, and the anionic species associated with the cation. The capacity of the cations for releasing NH 4 ‐N decreased in the order Ca > K > Na for the chloride series. Unlike the NH 4 ‐N release pattern, sulfates were more effective than chlorides in promoting nitrification. In general, all salts, excepting CaSO 4 · 2H 2 O, at higher concentrations curtailed nitrification. The results indicated a real participation of anions in soil N release. Two salts containing the same cation but different anions released different magnitudes of N at an equivalent concentration. Thus, the results of this investigation provide further support for the role of cations in soil N release and, in addition, furnish reasonable evidence of the participation of anionic species. A consideration of the overall values of NH 4 ‐ and NO 3 ‐N at various salt concentrations led to the series, CaCl 2 · 2H 2 O > KCl > NaCl > K 2 SO 4 > Na 2 SO 4 > CaSO 4 · 2H 2 O, in order of decreasing N release power.