Concurrent Improvement in Maize Yield and Nitrogen Use Efficiency with Integrated Agronomic Management Strategies

Abstract

Low nitrogen use efficiency (NUE) and productivity with excessive use of N fertilizer in maize (Zea mays L.) is a common issue for smallholder farm systems. A 2-yr field study was conducted to assess the impacts of integrated agronomic management strategies (MT) on pre-and post-silking N uptake, dry matter (DM) production dynamics, and their relationships to yield and NUE components. Three MTs were compared with the regional conventional farming practices (FP). We found that biomass yields differed significantly with similar harvest index (HI) among the MT treatments. While OPT-1 produced 21% greater DM but only 4% greater grain yield, OPT-2 had 27% higher yield, and 200% greater NUE, compared to FP. Our results showed the possibility of simultaneously achieving high yield and high NUE with optimized MT. In OPT-2, 13% greater DM production and 12% more N uptake after anthesis contributed 5% more to grain yield and 18% more to grain N. In HY, excessive N input did not improve the stay-green trait nor did it enhance grain yield. These results imply a better balance between improving total biomass and achieving more DM accumulation in the post-silking period with gradually optimized agronomic management practices than other MT. The enhanced NUE observed in OPT-2 primarily originated from the improved N recovery efficiency, which was associated with larger root biomass at silking and greater post-silking N uptake. Further NUE improvement in maize could be anticipated through enhanced N internal efficiency by balancing DM and N accumulation between vegetative and reproductive periods.

Corn Era Hybrid Response to Nitrogen Fertilization

“…Compared to the oldest era studied (1960), there was a large increase in NUE with the most recent era (2000). This indicates a considerable advancement in corn hybrid ability to use applied N to produce plant biomass and grain, which is consistent with results reported by other studies (Moll et al, 1982;McCullough et al, 1994;Coque and Gallais, 2007;Wang et al, 2014). The mean apparent NRE across N rates was 0.71 for the 2000 era, however, NRE was not greatly different and not highest for the most recent eras at the N rate near the AONR for each era (NRE mean 0.48 ∆kg kg -1 across eras at the NRE nearest the AONR for each era).…”

Integrated nutrient management (INM) for sustaining crop productivity and reducing environmental impact: A review

“…Smil (2002) estimated that N-based fertilizer has contributed by approximately 40% to the increases in production of main crops in the past 50 years but that large increase in inorganic fertilizer inputs without a correspondingly large increase in yields further decreased the already low agronomic nutrient use efficiency (ratio of grain harvested to applied fertilizer), especially in developing countries ( Fig. 3; Peng et al, 2010;Chen et al, 2011;Wang et al, 2014). In recent years, it has been estimated that twice as much inorganic fertilizer N and P are applied than recovered in crops, and this nutrient imbalance contributes to environmental pollution, which is becoming increasingly severe in rapidly developing countries (Zhang et al, 2012).…”

Relationship between plant nitrogen and phosphorus accumulations in a canola crop as affected by nitrogen management under ample phosphorus supply conditions

“…The apparent periodic contribution was calculated by dividing the DM, N or P accumulated during each specific period by the total DM, N or P in plant shoots (the term "shoots" refers here in a botanical sense to the entire aerial portion of the plants) at PM. Nitrogen and P utilization parameters, including N partial factor productivity (PFPn), P harvest index (PHI), and P utilization efficiency (PutE), were calculated according to a similar method described in Chamorro et al (2002) and Wang et al (2014):…”

“…Some studies showed significant increases in both DM and yield with split N application as compared with equivalent preplant applications (Hocking and Mason 1993;Hocking et al 1997;Ma et al 2015), while others (Tayor et al 1991;Cheema et al 2001) reported that split applications of N with a portion at seeding and another at the rosette stage were no more effective in DM and yield than all N applied at seeding. Given the high N rate is usually accompanied with low NUE and not necessarily a high seed yield (Grant and Bailey 1993; Ma and Herath 2016), plus contradictory findings with split N application, a better understanding of the underlying changes in seasonal DM and N accumulation and utilization in grain formation is important to concurrently improve seed yields and NUE (Hocking et al 1997;Ma and Dwyer 1998;Wang et al 2014). However, almost all of such studies on canola have been done on western Canada prairie soils.…”