Nitrogen fertilization affects maize grain yield through regulating nitrogen uptake, radiation and water use efficiency, photosynthesis and root distribution

Abstract

High external nitrogen (N) inputs can maximize maize yield but can cause a subsequent reduction in N use efficiency (NUE). Thus, it is necessary to identify the minimum effective N fertilizer input that does not affect maize grain yield (GY) and to investigate the photosynthetic and root system consequences of this optimal dose. We conducted a 4-year field experiment from 2014 to 2017 with four N application rates: 300 (N300), 225 (N225), 150 (N150), and 0 Kg ha−1 (N0) in the Northwest of China. GY was assessed by measuring the photosynthetic capacity and root system (root volume, surface area, length density and distribution). Grain yield decreased by −3%, 7.7%, and 21.9% when the N application rates decreased by 25%, 50%, and 100% from 300 Kg ha−1. We found that yield reduction driven by N reduction was primarily due to decreased radiation use efficiency (RUE) and WUE instead of intercepted photosynthetically active radiation and evapotranspiration. In the N225 treatment, GY, WUE, and RUE were not significantly reduced, or in some cases, were greater than those of the N300 treatment. This pattern was also observed with relevant photosynthetic and root attributes (i.e., high net photosynthetic rate, stomatal conductance, and root weight, as well as deep root distribution). Our results suggest that application of N at 225 Kg ha−1 can increased yield by improving the RUE, WUE, and NUE in semi-arid regions.

Effects of Different Nitrogen Forms and Competitive Treatments on the Growth and Antioxidant System of Wedelia trilobata and Wedelia chinensis Under High Nitrogen Concentrations

“…Some studies also reported higher photosynthetic rates when N was applied in the form of AN than that of NN ( Song et al, 2007 ). However, some studies have suggested that higher rates of NN may inhibit the photosynthetic rates to a certain extent ( Su et al, 2020 ), while some have found lower photosynthesis when the riparian plant was grown under AN than that of NN ( Cai et al, 2021 ). In recent years, most studies have proposed that N application in the form of ammonium nitrate was more conducive to improving the photosynthetic rates and plant growth, which is consistent with the results of this experiment ( Abbas et al, 2019 ).…”

Optimizing plant density and balancing NPK inputs in combination with innovative fertilizer product for sustainable maize production in North China Plain

“…Despite the largest N inputs from FP (350 kg ha −1 ), there was a statistically similar yield between FP and CK. Overuse of N fertilizer has adverse effects on crops by minimizing N use efficiency (NUE) and increasing nitrate leaching losses as well as contamination of groundwater 35 , 36 . Furthermore, long-term application of ammonia-based N fertilization like urea increases soil acidity which adversely affects soil fertility where crops fail to respond with more application of N fertilizers 37 .…”

Nitrogen level impact on the production of double row fodder of maize

“…Excessive nitrogen fertilizer application, on the other hand, has negative effects on crops and maize in particular, reduces nitrogen use efficiency and causes significant nitrate leaching losses because it is the primary source of nitrous oxide (N2O). As a result, nitrogen must be used in ways that meet both economic and environmental goals, which is critical for sustainable agriculture [16,17]. According to Portillo Vázquez, Pérez Soto [18], optimal fertilization is when the maximum yield: average nitrogen fertilization ratio is reached.…”