![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
The recovery of 15N‐labelled nitrogen (N) by perennial ryegrass can be significantly increased by mixing gypsum (CaSO4 · 2H2O) into soil rooting medium at rates equivalent to 0.7 t ha−1. Similar improvements in fertilizer N efficiency might be achieved, at less cost and more conveniently, by applying smaller amounts of CaSO4 anhydrite more strategically to fertilizer microsites as a fertilizer filler or diluting agent, in calcium ammonium nitrate (CAN), in place of CaCO3. With this in mind, two complementary pot experiments were conducted under simulated spring conditions in a controlled environment chamber. Use of CaSO4 as diluting agent, in place of CaCO3, appreciably enhanced (>30%) the uptake of labeled N by perennial ryegrass plants within the second week of regrowth, but thereafter, because losses of 15N‐labeled NO3 −‐N from pots by denitrification or leaching had been minimal, plants in both treatments eventually recovered equal amounts of this N form from the soil.
Acknowledgments
The authors thank Peter Scullion and staff in the Soil and Plant Nutrition Laboratory for analytical support and for assistance with experimental harvests, Michael Nicholson and Tony Poland in the Agricultural and Environmental Science Division for 15N and mineral N analyses, respectively, Alan Gordon and Erica Chisholm of Biometrics Division for assistance with statistical analyses, and the Department of Agriculture and Rural Development for Northern Ireland for awarding Trevor Kirkpatrick a postgraduate studentship, enabling him to conduct the research.