Nitrite Toxicity to Plants
O. L. OKE
O. L. OKE
Department of Chemistry, University of Ife, Ibadan Branch, Ibadan, Nigeria.
IT is generally believed that nitrite is an intermediate product in the conversion of ammonium to nitrate in the soil where the conversion of nitrite to nitrate is important since relatively small quantities may have toxic effects on plant growth. Nitrite is not a stable intermediate and few cases of nitrite accumulation in soils are reported. Greaves et al. 1 found that the maximum concentration of nitrite in an irrigated field in Utah did not exceed 17 lb. per acre; Feher and Vigi2 found 0.27–1.14 mg nitrite per kg in Hungarian alkaline soils, and Janssen and Metzger3 found 0.25 p.p.m. in Arizona rice fields. Sokloff and Klotz4 reported as much as 70 p.p.m. of nitrite accumulated on Romana clay loam in California after a large application of organic matter and nitrogen in the form of nitrate. Nitrite only accumulated in neutral or alkaline soils, probably because its conversion to nitrate is inhibited more than the conversion of ammonia to nitrite. Fraps and Sterges5 found that nitrites accumulated in certain soils when calcium or magnesium carbonate was added.
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