Factors affecting formation of methyl nitrite in soils

SUMMARY The formation of CH 3 ONO in 11 soils treated with HNO 2 or NaNO 2 in a closed system, was studied by measuring the concentration in the gas space above the soil and by absorbing CH 3 ONO in HI. The gaseous concentration of CH 3 ONO increased and then decreased following additions of HNO 2 or NaNO 2 , and the production of CH 3 ONO increased with increasing concentrations of HNO 2 or NaNO 2 added to soils. The amounts of CH 3 ONO trapped in HI were 13.5 to 20.4 times higher than those determined by integrating under the net production curves. The evolved CH 3 ONO amounted to 0.4 to 3.5% of added NO 2 − , and 4.2 to 50% of the gaseous forms of N absorbed by acidic KMnO 4 solution. The CH 3 ONO evolved from soils was positively correlated with the methoxy content of the soils, and inversely related to soil pH, with negligible amounts being evolved from alkaline soils. The results show that CH 3 ONO is a product of NO 2 − decomposition in soils, and indicate that small concentrations of the gas may be produced in N–fertilized soils in which NO 2 − accumulates.