The purpose of this guideline is to assist operators to achieve compliance with regulatory
requirements for labelling of colostrum products

Many things can cause a BACC application to require rework. This document is designed to assist our clients by highlighting some of the more common problems we encounter.

∙ N2O emissions are highly variable, and sampling strategy can affect cumulative emissions.
∙ Addressing gaps within sampling is required, as sampling limitations can affect emissions.
∙ There is a need to update methodologies within soil N2O research to improve gap-filling.

∙ Models are used for different purposes, which affects the choice of model used.
∙ We review several commonly used N2Omodels.
∙ Model uncertainty, fitting, sensitivity analysis,and upscaling are also discussed.

∙ N2O chamber measurements are often used for estimating N2O emission factors (EFs).
∙ Accurately determining EFs is challenging due to the inherently variable nature of N2O fluxes.
∙ We provide guidance on statistical analysis and EF calculation of N2O chamber measurements.
∙ Accurate reporting of data ensures the robustness of N2O results can be reliably evaluated.
∙ Authors should adhere to minimum requirements for reporting of experimental and metadata.

∙ Different flux calculation schemes can produce different flux estimates.
∙ Nonlinear schemes tend to increase accuracy but also can decrease precision.
∙ Theoretical and practical aspects of the most common flux calculation schemes are described.
∙ A gold standard approach is presented, as are alternative approaches.
∙ Error analysis can quantify performance based on both accuracy and precision.

∙ High-temporal-frequency N2O measurements improve the accuracy of inventories.
∙ A range of analytical options now exists for direct and rapid N2O analysis in the field.
∙ Automated systems are robust and proven for field deployment.

∙ Inert pre-evacuated septum-sealed vials are recommended for air sample collection fromchambers.
∙ Adequate flushing and overpressuring gas in the vial helps to maintain sample integrity.
∙ Short storage times and concurrent storage of standards is important for quality assurance.
∙ Standard gas chromatography methods are summarized along with alternative detectors.
∙ Traceable gas standards enable accurate and intercomparable gas concentration estimates.

∙ Account for spatial variation in site selection and chamber placement and coverage.
∙ Account for temporal variability with strategic sampling over a sufficient duration.
∙ Allocate resources to minimize the overall uncertainty of N2O fluxes.

∙ Chamber construction and design are critical for accurate soil gas flux determination.
∙ Ecosystem, soil conditions, and experimental aims dictate design.
∙ Understanding possible plant effects on N2O fluxes requires sophisticated design.
∙ Data on the potential artifacts of headspace mixing using fans are still needed.