Administration of dicyandiamide to dairy cows via drinking water reduces nitrogen losses from grazed pastures. (December 2014)

• Record Type: Journal Article
• Authors: Richards, Karl; Fenton, Owen; Watson, Catherine; WELTEN, B. G.; LEDGARD, S. F.; LUO, J.
• Is Part Of: Journal of agricultural science. Volume 152:Number 1(2014:Feb.)
• Page Start: 150
• Page End: 158
• Publication Date: 2014-12
• Subjects: Agriculture -- Periodicals; 630.5
• DOI: 10.1017/S0021859613000634
• Languages: English
• ISSNs: 0021-8596

Abstract

<abstract abstract-type="normal"> <title>SUMMARY</title> <p>Oral administration of the nitrification inhibitor dicyandiamide (DCD) to ruminants for excretion in urine represents a targeted mitigation strategy to reduce nitrogen (N) losses from grazed pasture. A farmlet grazing study was undertaken to examine the environmental benefits of administering DCD in trough water to non-lactating Friesian dairy cows that consecutively grazed 12 replicated plots (each 627 m<sup>2</sup> with a grazing intensity of up to 319 cows/ha/day) during two grazing rotations in the winter of 2007 in the Waikato region, New Zealand. Nitrate-N (NO<sub>3</sub><sup>−</sup>-N) leaching losses were measured using ceramic cup samplers (600 mm soil depth) and gaseous emissions of nitrous oxide (N<sub>2</sub>O) were quantified using a static chamber technique in the DCD and control treatments. Administration of DCD in trough water had no effect on daily water intake by dairy cows, which averaged 15 and 18 l/cow/day for the June and August grazing rotations, respectively. This resulted in a mean daily DCD intake of 46 and 110 g/cow/day, respectively. The DCD farmlet had significantly lower NO<sub>3</sub><sup>−</sup>-N concentrations in leachate at the last three samplings, which reduced total NO<sub>3</sub><sup>−</sup>-N leaching losses by 40% (from 32·0 to 19·2 kg N/ha). The DCD treatment reduced N<sub>2</sub>O emission rates compared to the control treatment following the August grazing, resulting in a 45% reduction in total N<sub>2</sub>O emissions relative to the control treatment (from 0·49 to 0·27 kg N<sub>2</sub>O-N/ha). This preliminary study highlights the potential for administering ruminants with DCD as an effective mitigation option for reducing N losses from agricultural systems.</p> </abstract>