Unlocking maize yield potential through exploring canopy-root interactions with nature-based nutrient management

Abstract

Context

Understanding the canopy-root interactions is the key to further improving maize yield with dense planting. However, the effects of nature-based nutrient management on these interactions in dense maize production are not yet well understood.

Objective

In this study, we attempted to unravel the interplay between above-ground canopy and below-ground root morphology and their correlation with grain yield and quality within a high-yielding maize system (HYMS) and under nature-based nutrient management.

Methods

A 2-yr field experiment at the Wuqiao Experimental Station of China Agricultural University was conducted to compare the HYMS with nature-based nutrient management, with current farmers' practices (CP) in 2021 and 2022. The variety, planting density, and fertilization for CP were based on the practices commonly used by local farmers. The HYMS included four treatments: crop-soil management (CSM), rhizosphere management with CSM (CSM+RM), microbial addition with CSM (CSM+MA), and integrated crop-soil system management (ICSM).

Results

Above-ground dry matter (AGDM) contributed 74–82 % to grain yield, with the remainder from the harvest index. At physiological maturity, the average AGDM in HYMS was 19.5 t ha⁻¹ in 2021 and 24.3 t ha⁻¹ in 2022, 14.9 % and 22.3 % higher than CP. For the canopy, HYMS exhibited a maximum leaf area index of 4.8 in 2021 and 4.9 in 2022, higher than that of CP by 0.40 and 0.39. At silking, the leaf nitrogen content in HYMS surpassed that in CP by 15.0 % with stronger ear leaf in length and thickness. The index of the leaf stay green degree in HYMS was 4.3 % higher than CP. As a result, the source supply/sink demand ratio in HYMS treatments was 0.17, exceeding that of CP by 11.2 %. For visible roots within the 0–60 cm soil depth, HYMS treatments generally had 2.9–13.1 % lower values per plant for root dry matter root nitrogen root length root average diameter root surface area, and root volume compared to CP due to higher plant density. However, the root system in HYMS showed a lower senescence rate than CP.

Conclusions

Nature-based nutrient management alleviates the reduction in individual root growth caused by high-density planting, thereby supporting the canopy and resulting in increased AGDM and grain yield.

Implications

These findings provide valuable insights for developing effective management strategies to achieve high maize yields under dense planting conditions.