Effect of terrazole on nitrogen transformations and movement in irrigated corn

A field study was conducted on two sandy loam soils to determine the effect of Terrazole nitrification inhibitor (5-ethoxy-3-[trichloromethyl]-l,2,4-thiadiazole) on N movement and transformations. Sweet corn (Zea mays L.) was fertilized with (NH4)2SO4 twice during the growing season for a total application of 250 kg N ha. The N applied to one-half of the fertilized treatments was coated with Terrazole. Three levels of irrigation were established for each field. The treatments on Arlington (Typic Durixeralfs) sandy loam received 55.9, 69.0, and 78.1 cm infiltrated water. The Hanford (Typic Xerorthents) sandy loam treatments received 62.0, 76.7, and 88.2 cm infiltrated water. Soil samples were taken at 20, 40, 60, 80 and 90 d after planting and analyzed for NO3 and NH4. Movement of N was correlated with both the presence of Terrazole and the quantity of water applied. Soil NH4 was consistently higher in Terrazole treatments, suggesting that nitrification was reduced by the Terrazole. However, there was no significant increase in tissue N concentrations or yield due to Terrazole additions. Denitrification losses in the field were found to be 64% lower due to the presence of Terrazole. Additional Index Words: nitrification inhibition, irrigation, Zea mays L., denitrification. View complete article To view this complete article, insert Disc 4 then click button8