Beneficial effect of humic acid urea on improving physiological characteristics and yield of maize (Zea mays L.)
2022
Song, Xiliang | Guo, Weixiong | Xu, Lixue | Shi, Lianhui
Descending the application of nitrogen (N) fertilizers and promoting N utilization efficiency (NUE) are the keys to alleviating environmental pollution and achieving sustainable agricultural development. Humic acid urea (HU) as a novel slow-release urea fertilizer is beneficial for the enhancement of crop nitrogenous utilization rate. However, the effect of HU on the plant growth of maize supplied with reduced N fertilizer is still unclear. In the study, pot experiments were conducted to detect the impact of N fertilizer (urea) reduction combined with HU on the physiological characteristics and grain production of maize. The results revealed that an N fertilizer reduction caused serious N deficiency, which significantly decreased the total N in all plant tissues (leaves, stems, spikes, and roots), reduced SPAD values, and suppressed the efficiency of photosynthesis, resulting in remarkable decreases in dry weight, grain yield and NUE of maize. The application of HU alleviated the negative effect of N deficiency and significantly increased the plant total N content by 20.1–28.4%, SPAD values by 5.0–24.3%, leaf photosynthetic efficiency by 10.2–37.0%, and NUE by 41.7–77.5%, respectively. At the same N application rate, HU also increased the biomass and grain yield of maize by 30.2–59.1% and 12.6–39.1%, respectively. Furthermore, the HU application with a 15% reduction in the N application rate maintained the grain production of maize with no significant reduction. Collectively, our study indicated that HU could enhance the utilization rate of urea, promote N absorption and accumulation by plants, increase biomass, and consequently, increase the crop yield of maize.
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