FIELD AND LABORATORY STUDIES COMPARING NUTRISPHERE-NITROGEN UREA WITH UREA IN NORTH DAKOTA, ARKANSAS, AND MISSISSIPPI

Abstract

Nitrification and ammonia volatility are two important impediments to nitrogen (N) use efficiency and crop uptake around the world. Nutrisphere® is a relatively new product whose manufacturer claims both nitrification and urea volatilization inhibiting properties. Urea coated with Nutrisphere is and the resulting fertilizer is called Nutrisphere®-N urea, or Nutrisphere-N (NSN). Eight field studies on spring (Triticum aestivum L.) or durum [T. turgidum L. subsp duram (Desf.) Husn.] wheat in North Dakota, three field studies in Mississippi/Arkansas on rice (Oryza sativa L.), four laboratory experiments in North Dakota and one in Arkansas were conducted to determine the nitrification and urea volatilization inhibiting ability of NSN compared with urea alone. Results of field and laboratory experiments revealed that the product has no nitrification or urea volatilization inhibiting properties at the recommended rates and spring wheat and rice did not benefit from the application of NSN to urea.

Keywords:

• nitrogen
• rice
• wheat
• fertilizers
• soil fertility

Notes

*V = Valley City; H = Hazelton; W = Wishek; D = Dickinson; L = Langdon; C = Cavalier; W1 = Williston site 1; W2 = Williston site 2.

^†Soil nitrate-N from 15-cm depth soil sample. Procedure from Gelderman and Beegle, 1998.

^‡P and OM from 15-cm depth soil sample. Olsen P procedure from Frank et al., 1998; OM loss on ignition (Combs and Nathan, 1998).

^†Texture by hydrometer method, organic matter by weight loss by ignition, CaCO₃ by pressure calcimetry, pH and conductivity of a 1:1 soil:water suspension, CEC by the sodium oxalate method, Olsen P (Frank et al., 1998), and available K (Warncke and Brown, 1998).

^†Site abbreviations: DREC = Delta Research and Extension Center near Stoneville, MS; LHRF = Lake Hogue Research Farm near Waldenburg, AR; and RREC = Rice Research and Extension Center near Stuttgart, AR.

*34-U = 34 kg ha⁻¹ N as urea; 34-NSN = 34 kg ha⁻¹ N as NSN; 67-U = 67 kg ha⁻¹ N as urea; 67-NSN = 67 kg ha⁻¹ N as NSN; 101-U = 101 kg ha⁻¹ N as urea; 101-NSN = 101 kg ha⁻¹ N as NSN.

*urea-ammonium nitrate 28-0-0 solution.

^†SE = standard error.

FIGURE 1 Urea remaining in an Overly soil, as influenced by time of incubation, and application of urea, urea plus Nutrisphere-N for granular fertilizers (NSGR), and urea plus Nutrisphere-N for liquid fertilizers (NSLF). North Dakota laboratory experiment 1.

FIGURE 2 Ammonium and nitrate extracted from an Overly soil, as influenced by time of incubation, and application of urea, urea plus Nutrisphere-N for granular fertilizers (NSGR), and urea plus Nutrisphere-N for liquid fertilizers (NSLF). North Dakota laboratory experiment 1.

^†NSN = Nutrisphere-N.

^‡NS = not significant at the 0.05 probability level.

^†NBPT = N-(n-butyl)thiophosphoric triamide.

^‡LSD to compare means between N sources within the same sampling time.

^§LSD to compare means between sampling time within the same N source.