Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
THE INFLUENCE OF RATES AND SOURCES OF NITROGEN WITH AND WITHOUT A NITRIFICATION INHIBITOR ON CORN NUTRITION AND SOIL NITROGEN
Abstract
Greenhouse and laboratory experiments were conducted to determine the influence of N sources, N rates, nitrification inhibitor rates and their interactions on selected plant and soil parameters. Corn (Zea mays L.) (MO 17 x B 73 hybrid) was the test crop. A calcareous soil (Crofton silt loam) was selected as a growing and incubation medium. Urea, ammonium sulfate and ammonium nitrate were applied as sources of N. Nitrogen fertilizer rates were from 0 to 225 ppm in 75 ppm increments, and nitrapyrin applied at 0 to 1.0 ppm in 0.5 ppm increments. All treatments were arranged in a randomized complete-block design, complete factorial procedure with three blocks (replications). Variables measured in greenhouse experiments included: plant height, stem diameter, dry matter yield and nutrient uptake, and soil pH. Corn seedlings were harvested at 21, 42 and 63 days after seedling emergence, and then analyzed for total N, P, K, Ca, Mg, Zn, Cu, Fe and Mn. One laboratory experiment measured the influence of a nitrification inhibitor on soil NO(,3)('-)-N and soil NH(,4)('+)-N. Two greenhouse experiments similar in nature, were conducted and are referred to as experiment 1 and experiment 2. In greenhouse experiment 1, the effects of N sources in stem diameter and dry matter yield were found to be statistically significant. In greenhouse experiment 2, plant height was additionally found to be statistically significant. In both greenhouse experiments, increased N rates without nitrapyrin significantly increased all parameters tested. In contrast, nitrapyrin-treated soil significantly depressed all parameters. In general, the differences between N sources in the uptake of all nutrients were statistically significant. Ammonium sulfate (AS) resulted in higher nutrient uptake values than did urea (U), or ammonium nitrate (AN). Nitrogen fertilizer rates without nitrapyrin increased the uptake of all nutrients in both greenhouse experiments. In experiment 1, nitrapyrin-treated soil reduced uptake of total N, P, K, Ca, Mg, Zn and Cu, but it had no effect on uptake of Fe and Mn. Uptake of all nutrients including Fe and Mn was depressed by nitrapyrin in experiment 2. In both greenhouse experiments, the N sources effect was significant in lowering soil pH. Also, increasing rates of N decreased soil pH in experiment 1, but did not in experiment 2. In laboratory experiment, soil NO(,3)('-)-N and soil NH(,4)('+)-N were affected by incubation time. All measured parameters were influenced more in the first 21 days than in 42 or 63 days of incubation. The soil parameters tested were influenced more by rates than by sources of N. Nitrapyrin-treated soil did affect soil NO(,3)('-)-N and soil NH(,4)('+)-N. Increasing rates of nitrapyrin from 0.5 to 1.0 ppm, increased soil NH(,4)('+)-N, but decreased soil NO(,3)('-)-N.
Subject Area
Agronomy
Recommended Citation
AL-UQAILI, JAWAD KADUM, "THE INFLUENCE OF RATES AND SOURCES OF NITROGEN WITH AND WITHOUT A NITRIFICATION INHIBITOR ON CORN NUTRITION AND SOIL NITROGEN" (1981). ETD collection for University of Nebraska-Lincoln. AAI8127151.
https://digitalcommons.unl.edu/dissertations/AAI8127151