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 14 C-ZAA and 65 Zn-ZAA using water or NH 4 OH as carrier. Results showed that ZAA degraded in the soil and released CO 2 . The released CO 2 was from the acetate component of ZAA and accounted for less than 0.06% of the total applied 14 C. Using H 2 O as carrier resulted in more CO 2 release than using NH 4 OH, regardless of soil type. However, more 14 C was detected in the leachate when using NH 4 OH as a carrier than when using H 2 O. A plant uptake experiment using 14 C-ZAA and 65 Zn-ZAA indicated that four-leaf-stage corn seedlings absorbed higher amounts of 14 C in the stem and root than in the leaves. The 65 Zn 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.

Zinc ammonium acetate (ZAA), typically applied to soils in anhydrous ammonia as a carrier, has been used to improve corn (Zea mays L.) productivity. This study aimed to determine the fate of ZAA in soils as influenced by soil type (sandy, silt, and clay loam), sterilization (sterile and non-sterile), and two carriers (H 2 O and NH 4 OH). A 16 d laboratory incubation experiment with 14 C-ZAA showed that total recovery of carbon-14 ( 14 C) from 14 CO 2 trap and soil extraction by CaCl 2 ranged from 72% to 94% in the first 8 d for sterilized soils. However, <17% 14 C was found in non-sterilized soils. Most 14 C recovered in sterilized soil was associated with soil extraction, and relatively little was found in the CO 2 traps. All sterilized soils provided similar 14 C recoveries except the sandy loam. Slightly more 14 C was extracted from the soil when NH 4 OH was the ZAA carrier rather than water. Conversely, recovery of 14 CO 2 continued to increase during the 16 d incubation, but started faster when water was the ZAA carrier. Microbial activity appeared to be instrumental in the assimilation and disappearance of ZAA.