Fate of zinc ammonia acetate in soils and its uptake by corn

Zinc ammonium acetate (ZAA) is applied to soil with anhydrous ammonia as a carrier to improve corn (Zea mays L.) productivity. To study the fate of ZAA in the soils, a laboratory leaching experiment was conducted with 14C-ZAA and 65Zn-ZAA using water or NH4OH as carrier. Results showed that ZAA degraded in the soil and released CO2. The released CO2 was from the acetate component of ZAA and accounted for less than 0.06% of the total applied 14C. Using H2O as carrier resulted in more CO2 release than using NH4OH, regardless of soil type. However, more 14C was detected in the leachate when using NH4OH as a carrier than when using H2O. A plant uptake experiment using 14C-ZAA and 65Zn-ZAA indicated that four-leaf-stage corn seedlings absorbed higher amounts of 14C in the stem and root than in the leaves. The 65Zn was detected in most tested plant parts. Our study showed that ZAA enhanced cytokinin levels in root and/or shoot tissues of corn seedlings, suggesting a secondary regulatory effect of ZAA in improving corn productivity.