Increasing plant density improved maize yield without penalty of harvest grain moisture in extensive field trials

The harvest moisture content (MC) of maize (Zea mays L.) is an important factor affecting industrial processing and harvest quality. However, higher MC levels may escalate drying expenses during production. While augmented plant density has shown potential to enhance maize yield, limited information exists regarding its impact on plant density and MC interaction. This study amassed four year of field trial data from four primary maize ecological areas in China (Longitude: 89°E to 125°E, Latitude: 35°N to 44°N) to examine the relationship between plant density and MC of maize. Our analysis revealed that increasing plant density exerted an effect on the MC of maize. This effect stemmed from a combination of uncertain grain development and premature plant senescence due to overcrowding. We categorized the relationship between plant density and MC into six types: NC-Type (No-changing), I-Type (ever-increasing), L-Type (ever-lessening), V-Type (like the valley), P-Type (like the peak), and W-Type (like a wave). On average, a variation approximately 0.053 % in MC was observed when the plant population changed by 1000 plants/ha. Moreover, different maize varieties contributed to a more substantial variation in MC. Despite the negligible impact of MC variation caused by plant density on grain quality, subsequent harvest management, and industrial production of maize, there was a significant enhancement in maize yield with increased plant density. Thus, increasing plant density presents an opportunity to boost maize output without compromising quality or grain moisture levels.