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Chloride and Liming Effects on Soil Nitrogen Form and Take‐all of Wheat 1
Author(s) -
Christensen N. W.,
Brett Marcia
Publication year - 1985
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1985.00021962007700010036x
Subject(s) - chemistry , sowing , ammonium , nitrogen , chloride , nitrate , ammonium chloride , ammonium nitrate , agronomy , zoology , soil ph , horticulture , soil water , biology , organic chemistry , ecology
Little is known about how chloride (Cl) functions in suppressing take‐all root rot of wheat ( Triticum aestivum L.). A field experiment was conducted to determine the effects of liming and CI application on ammonium (NH + 4 and nitrate (NO − 3 ‐N) concentrations in soil as they correlate with development of the disease. ‘Hill 81’ soft white winter wheat was grown on a limed (pH 6.6) and unlimed (pH 5.5) Aquultic Argixeroll fertilized with a factorial combination of 30 kg N ha −1 as NH 4 NO 3 , (NH 4 ) 2 SO 4 , or NH 4 Cl banded at planting and 140 kg N ha −1 as Ca(NO 3 ) 2 , (NH 4 ) 2 SO 4 , or NH 4 Cl topdressed in the spring. Soil was sampled to 10 and 20 cm depths and analyzed for NH + 4 ‐N, NO − 3 ‐N, Cl, and pH at weekly intervals for 10 weeks following spring application of N. Take‐all was assessed at 0, 6, and 11 weeks after spring fertilization. Take‐all severity, NH + 4 ‐N and NO − 3 ‐N concentrations, NH + 4 ‐N:NO − 3 ‐N ratios, and grain yield were all influenced by a highly significant interaction between liming and spring‐topdressed Cl. Liming hastened disappearance of NH + 4 ‐N and increased appearance of NO − 3 ‐N in soil. Chloride slowed disappearance of NH + 4 ‐N and appearance of NO − 3 ‐N in unlimed soil but not in limed soil. A “critical” NH + 4 ‐N:NO − 3 ‐N ratio for take‐all suppression of 3:1 was estimated from data in the literature. Takeall severity was negatively correlated (r 2 =0.84) with the length of time the NH + 4 ‐N:NO − 3 ‐N ratio remained above the estimated critical ratio. Chloride increased grain yield from 3.5 to 4.7 Mg ha −1 on the unlimed soil but had no effect on yield on the limed soil. Results suggest that Cl may reduce take‐all severity and increase grain yield on moderately acid soils in western Oregon by reducing nitrification and maintaining a favorable NH + 4 ‐N:NO − 3 ‐N ratio for disease suppression.