Use of the new Nitrogen Index tier zero to assess the effects of nitrogen fertilizer on N2O emissions from cropping systems in Mexico

High N fertilizer application to irrigated wheat in Northern Mexico for conventionally tilled and permanent raised beds: Effects on N balance and short term N dynamics

“…According to the N Index Model applied to crosscheck measured INNOVA emission data, volatilization losses were estimated to be 6 kg N ha −1 and denitrification losses were 18 kg N ha −1 . Work from Saynes et al (), using the N Index Model for Mexico, yielded average values of 5.3 kg N 2 O‐N ha −1 y −1 which is much lower than average values measured in the present study based on INNOVA (20 kg N 2 O‐N kg ha −1 season −1 ). Irrigation events and high soil NO 3 ‐N (or NH 4 ‐N, which was nitrified later to NO 3 ‐N) may have enhanced denitrification processes due to anaerobic soil conditions that in these soils and climates can last up to one week after irrigation.…”

Examining the impact of conservation agriculture on environmental efficiency among maize farmers in Zambia

“…In economies such as Zambia there are no standard national nutrient management tools, soil nutrients testing is beyond the reach of many subsistence farmers, and soil testing laboratories are either of lower standards or non-existent. The current study differs from other studies in the generation of farm-level nitrogen balance sheets by using the Nitrogen Index Tier Zero tool (NITZ; developed and validated by Saynes et al, 2014). 3 Over the past two decades, numerous studies have analyzed technical efficiency (TE) and allocative efficiency of farmers in SSA (for example, Abdulai and Huffman, 2000).…”

“…We therefore examine household EE with respect to nitrogen efficiency, using nitrogen balance scores from the NITZ tool in a stochastic production frontier (SPF) framework. Figure A1, available in the online appendix at (https://doi.org/ 10.1017/S1355770X16000309), displays quantitative and qualitative results of the NITZ (see Saynes et al, 2014 for details on the implementation of the NITZ). 4 In empirical analysis of EE, the potential environmentally detrimental element is either considered an input, with input-orientation strategies (for example, Reinhard et al, 1999Reinhard et al, , 2002 or an output, and efficiency estimates follow an output orientation (for example, Färe, 1989;Cuesta et al, 2009).…”

“…Here, the NITZ tool is used in generating the nitrogen balance. Saynes et al (2014) are the first to use it in their study of N 2 O emissions from N fertilizer in Mexico based only on nutrient management practices. In this study, we argue that, beyond nutrient management practices, other farm and household confounding factors may influence household nitrogen use efficiency.…”

“…Hence, some studies account for nitrogen surplus using weights such as the International Panel on Climate Change (IPCC) default value of 1 per cent of N applied or N released through mineralization of organic matter in mineral soils (e.g., the eutrophication power of 1 adopted by Coelli et al, 2007). 2 However, in their recent study on Mexico, Saynes et al (2014) demonstrate that this approach underestimates nitrogen emission by more than two-fold. Some other related literature employs National Farm Accountancy Data (for example, Reinhard et al, 1999Reinhard et al, , 2002, while others have used national nutrient management tools (for example, Ramilan et al, 2009).…”