Global evaluation of key factors influencing nitrogen fertilization efficiency in wheat: a recent meta-analysis (2000-2022)

Abstract

Improving nitrogen use efficiency (NUE) without compromising yield remains a crucial agroecological challenge in theory and practice. Some meta-analyses conducted in recent years investigated the impact of nitrogen (N) fertilizer on crop yield and gaseous emissions, but most are region-specific and focused on N sources and application methods. However, various factors affecting yield and N fertilizer efficiency in wheat crops on a global scale are not extensively studied, thus highlighting the need for a comprehensive meta-analysis. Using 109 peer-reviewed research studies (published between 2000 and 2022) from 156 experimental sites (covering 36.8, 38.6 and 24.6% of coarse, medium, and fine texture soils, respectively), we conducted a global meta-analysis to elucidate suitable N management practices and the key factors influencing N fertilization efficiency in wheat as a function of yield and recovery efficiency and also explained future perspectives for efficient N management in wheat crop. Overall, N fertilization had a significant impact on wheat yield. A curvilinear relationship was found between N rates and grain yield, whereas maximum yield improvement was illustrated at 150-300 kg N ha-1. In addition, N increased yield by 92.18% under direct soil incorporation, 87.55% under combined chemical and organic fertilizers application, and 72.86% under split application. Site-specific covariates (climatic conditions and soil properties) had a pronounced impact on N fertilization efficiency. A significantly higher yield response was observed in regions with MAP > 800 mm, and where MAT remained < 15 °C. Additionally, the highest yield response was observed with initial AN, AP and AK concentrations at < 20, < 10 and 100-150 mg kg-1, respectively, and yield response considerably declined with increasing these threshold values. Nevertheless, regression analysis revealed a declining trend in N recovery efficiency (REN) and the addition of N in already fertile soils may affect plant uptake and RE. Global REN in wheat remained at 49.78% and followed a negative trend with the further increase of N supply and improvement in soil properties. Finally, an advanced N management approach such as “root zone targeted fertilization” is suggested to reduce fertilizer application rate and save time and labor costs while achieving high yield and NUE.

Effects of urea topdressing time on yield, nitrogen utilization, and quality of mechanical direct-seeding hybrid indica rice under slow-mixed fertilizer base application

“…Nitrification and denitrification are significant contributors to low NUE (Chen et al, 2022). To address these issues, measures such as the 4R nutrient stewardship concept (right source, right rate, right time, right place) (IPNI, 2012) promoted by the International Plant Nutrition Institute (IPNI), N fertilizer management (Yokamo et al, 2023;Sun et al, 2023a;Sun et al, 2023b), soil testing and formulated fertilizer application (Chen et al, 2021), and leaf color diagnosis of SPAD meter (Peng et al, 1996) have been implemented by numerous scholars, resulting in positive outcomes. It is crucial to adopt practices to ensure that the N release rate aligns with the crop fertilizer requirements.…”