Nitrogen recovery of coated fertilizers and influence on peanut seed quality for peanut plants grown in sandy soil

ABSTRACT

Warm and high precipitation climates in most area of Japan are suitable for growing crops. However, the arable lands are limited. A small scale field experiment was conducted on a sandy soil in the Tottori sand dune to test nitrogen (N)-use efficiency from a regular N fertilizer {ammonium sulfate [(NH₄)₂SO₄]} and a mixture of resin-coated N fertilizers for peanut (Arachis hypogaea L. cv. Hanritusei) production. Nitrogen was applied at 30, 60, 90, and 120 kg N ha⁻¹ for the regular N, and at 60, 90, and 120 kg N ha⁻¹ for the mixture of coated N-phosphorous (P)-potassium (K) 80 days, NPK 140 days and ammonium nitride (NH₄NO₃) + limestone 120 days, each providing 35, 35, and 30% of N supplied. Sufficient P and K and a micronutrient fertilizer were included. Water was applied through drip irrigation. The seed yields were 81 to 137% higher with the coated N than with the equivalent amounts of regular fertilizer N. Nitrogen recovery rates were 10% to32% for the regular N and 79–94% (average 86%) for the coated N. The high recoveries obtained with the coated N were due to the fact that N release matched crop N uptake and the fertilizer placement (beneath the seeds) allowed for immediate uptake. A highly effective N fertilization management program for crop production on this sandy soil is possible. A carbon (C):N ratio of 16.9 and 13.4 in the seeds was found with the regular N and the high rates of coated N treatments, respectively, indicating the seed quality was significantly affected by N application from the different sources.

Acknowledgments

The first author was financially supported by the Japanese Society for the Promotion of Science (JSPS). The authors acknowledge the contribution from J.X. Liu, whose voluntary engagement in the field operation through the growing season was critical for the completion of the experiment. Labor supports from A. Yuya, Y. Sakaguchi, J. Hatanaka, R. Funakoshi, and J.S. Wei in the spring season, and editorial contribution from J.P. Winter are appreciated.