Reduction of Nitrous Oxide Emissions from Urine Patches from Grazed Dairy Pastures in New Zealand: A Preliminary Assessment of ORUN® as an Alternative to the Use of Nitrification Inhibitor Dicyandiamide (DCD)

Abstract

Agriculture plays a significant role in economic development and livelihood and is a key contributor to food security and nutrition. However, global concerns regarding the sustainability of the agricultural sector (mainly environmental damage) is linked to agricultural activities such as greenhouse gas (GHG) emissions, water pollution, and loss of biodiversity. The aim of this study was to assess the effectiveness of ORUN® (a formulated agricultural chemical mixture) to reduce N2O emissions from urine patches and to improve pasture yield, pasture N uptake, and soil mineral N concentrations. The field trials were conducted during the spring of 2015 on dairy urine patches at Massey University, New Zealand. Treatments consisted of control nil urine, control nil urine + ProGibb®, urine only, urine + ProGibb®, urine + ORUN®, and urine + ORUN PLUS® replicated four times in a randomized complete block design. At 31 days after treatment (DAT), analysis of soil samples in 0–5 cm soil profiles showed that urine + ProGibb® significantly (p = 0.0041) increased the soil nitrate concentration (121.40 kgN/ha) compared with 48.15 kgN/ha from urine only. The urine + ProGib® treatment produced significantly lower herbage N recovery (35% of applied N) compared with the urine only. Throughout the trial period, the urine patches treated with ProGibb® and ORUN® produced significantly higher N2O fluxes compared with urine only and urine + ORUN PLUS®, as well as higher surface soil nitrate and mineral N concentrations.