Effects of optimized nitrogen fertilizer management on the yield, nitrogen uptake, and ammonia volatilization of direct‐seeded rice

Abstract

BACKGROUND Direct‐seeded rice has been developed rapidly because of labor savings. Changes in rice cultivation methods put forward new requirements for nitrogen (N) fertilizer management practices. Field experiments with five different fertilizer ratios of basal, tillering and panicle fertilizer, namely N1 (10:0:0), N2 (6:2:2), N3 (4:3:3), N4 (2:4:4) and N5 (0:5:5), were conducted to investigate the effects of different N fertilizer management practices on yield formation, N uptakes, and ammonia (NH3) volatilization from paddy fields in direct‐seeded rice. RESULTS The results showed that the N4 treatment improved grain yield by 5.1% while decreasing NH3 volatilization by 20.4% compared with that of conventional fertilizer treatment (N2). The panicle number per unit area was the key factor to determine the yield of direct‐seeded rice (72%). Excessive N application of basal fertilizer (N1) reduced seedling emergence, N use efficiency, and yield by 45.3%, 160.6%, and 6.9% respectively and increased NH3 volatilization by 28.1% compared with that of the N4 treatment. Removal of basal N fertilizer (N5) N reduced spike number and yield by 13.0% and 6.9% respectively, minimizing NH3 volatilization while affecting the construction of high‐yielding populations compared with that of the N4 treatment. CONCLUSION Optimized N fertilizer management achieved delayed senescence (maintenance of higher leaf Soil Plant Analysis Development meter values in late reproduction), higher canopy photoassimilation (suitable leaf area), higher N fertilizer use efficiency, and less N loss (lower cumulative NH3 volatilization). © 2023 Society of Chemical Industry.

Early harvesting and increasing stubble-cutting height enhance ratoon rice yield

“…Ma et al. (1992) found that the main source of nitrogen in the regenerating tillers was the transfer of nitrogen from rice stubble, and the nitrogen contribution of the main crop bud-promoting fertilizer was small. Lin et al.…”

“…Due to the decline in root function during the grainfilling stage of rice, the efficiency of nitrogen absorption and utilization is often low . Ma et al (1992) found that the main source of nitrogen in the regenerating tillers was the transfer of nitrogen from rice stubble, and the nitrogen contribution of the main crop budpromoting fertilizer was small. Lin et al (2015) found that the export percentage and apparent conversion rate of nitrogen from the stem and sheaths of the main crop to the ratoon crop were 37%-49% and 29%-54%, respectively.…”

Dry direct‐seeded rice has higher energy and carbon production efficiencies without reducing economic benefits

“…Globally, the rice planting area is approximately 162 million hectares, accounting for 11% of the world's arable land, and approximately 758 million tons of rice are produced annually 4 . However, with social and economic development, labor and water resource shortages and environmental deterioration have posed great challenges to traditional transplanted rice production methods 5 . The development of resource‐saving, environment‐friendly, and lightly simplified rice production methods is an inevitable trend in current rice production 6 …”

“…4 However, with social and economic development, labor and water resource shortages and environmental deterioration have posed great challenges to traditional transplanted rice production methods. 5 The development of resource-saving, environmentfriendly, and lightly simplified rice production methods is an inevitable trend in current rice production. 6 At present, there are two main methods of rice cultivation: transplanted and direct-seeded, with direct-seeded rice being divided into dry direct-seeded rice (DSR) and wet direct-seeded rice (WSR) according to the moisture condition of the land at the time of sowing.…”

Enhancing Rice Yield and Nitrogen Utilization Efficiency through Optimal Planting Density and Reduced Nitrogen Rates

“…Excessive nitrogen fertilizer leads to the absorption of excess nitrogen by rice, resulting in nitrogen waste in the soil [6]. On the other hand, insufficient nitrogen fertilizer affects rice photosynthesis, which results in reduced yield [7,8]. While higher nitrogen fertilizer input can help to increase rice yield, it reduces nitrogen use efficiency, adversely affecting biodiversity, human health, and climate and posing a significant challenge to the nitrogen cycle [9,10].…”