Optimizing Fertilization Depth for Enhanced Growth, Nutrient Uptake, and Economic Benefits in Seed Production Maize: A Case Study in Northwest China's Arid Region

Abstract

Adjusting fertilization depth is a well-known strategy for increasing crop yields. However, the precise mechanism underlying this impact, particularly regarding nutrient absorption, utilization, and the resultant increase in seed production in maize remains unclear. In this two-year (2021–2022) field study conducted in arid northwest China, we comprehensively examined the effects of varying nitrogen fertilization depths [0 cm (L0), 5 cm (L5), 15 cm (L15), and 25 cm (L25)] on maize crop growth, nutrient uptake and distribution, fertilizer use efficiencies, grain yield, and economic benefits. The findings underscore that the optimal nitrogen fertilization depth is crucial in promoting maize growth, dry matter production, and grain yield. For instance, L25 significantly (P<0.05) increased average plant height by 5.00% and 10.36% and dry matter accumulation by 2.65% and 3.39% compared to L15 and L5, respectively. Furthermore, L25 had 19.17% (P<0.05) and 7.11% higher total nutrient uptake than L5 and L15, respectively, and increased grain nutrient uptake by an average of 23.33% (P<0.05). Moreover, L25 significantly increased NUE (26.22% and 13.04%), PUE (54.51% and 19.98%), and KUE (61.10% and 21.38%) compared to L5 and L15, respectively, and facilitated the highest translocation of dry matter to grain. Structural equation modeling confirmed that deep nitrogen fertilization promotes maize growth, dry matter translocation to grain, and nutrient uptake and distribution in maize plants, significantly improving fertilizer use efficiency and yield. This research contributes valuable insights for guiding fertilization management practices to increase maize seed production in regions with climate conditions akin to the Hexi Corridor.

Keywords: Fertilization depth, Nutrient uptake, Fertilizer use efficiency, Economic benefit, Seed production maize