Field tests of fertilizer action on soil aldehydes

In a two years' field test vanillin and salicylic aldehyde proved harmful to cowpeas in a silty clay loam at the Arlington Farm, Va. The action of both vanillin and salicylic aldehyde was modified by fertilizers. The harmful effect of vanillin was lessened by sodium nitrate fertilizer and the effect of salicylic aldehyde was lessened by acid phosphate. The effects of both vanillin and salicylic aldehyde were overcome by liming the soil. These field results are in harmony with the effect of fertilizer salts on the behavior of these compounds in water culture solution. Vanillin and salicylic aldehyde were found in this Arlington soil several months after they were applied and after the end of the crop season. On the plots fertilized with sodium nitrate the vanillin had been changed or destroyed and did not remain as such to have its effect on the crop. Neither vanillin nor salicylic aldehyde was found to remain in the limed soil. The oxidizing power of the Arlington soil was checked by both vanillin and salicylic aldehyde and this lessened oxidation was increased by fertilizers and by lime. Vanillin and salicylic aldehyde had only a slight harmful effect on a productive Hagerstown loam at the Pennsylvania Experiment Station, State College, Pa. Again the harmfulness of vanillin was ameliorated by sodium nitrate and that of salicylic aldehyde by acid phosphate, and on limes soil the aldehyde compounds had no, or only slight, harmful effects. When these State College soils were examined at the end of the growing season to determine if the added aldehydes remained in the soil, none was found in any of the plots, which would seem to show that organic substances of this nature do not persist in this soil and consequently could have little or no effect on crop growth. This experiment demonstrates that such organic substances as aldehydes can exist in one soil and have their effect on growth, while in another soil they are destroyed by oxidation or other life processes of the soil and do not remain to have an influence on soil productivity.