2.1.1 Experimental design
Field experiments for rice (Oryza sativa L., cv. Nanjing 46) were
conducted at Chongming, Shanghai, China for two years (2019-2020). Basic
soil information was collected before the experimentation (Table 1). The
meteorological records of the closest weather station from our
experimental site (ca. 5.7 km away) were downloaded from the website of
the China meteorological data service centre (http://data.cma.cn).
The weather variables include daily solar radiation, minimum and maximum
temperatures, precipitation, vapour pressure, and wind speed. The mean
air temperature and precipitation at the experimental site for the
studied years are shown in Fig. S1, illustrating the typical weather
conditions for rice cultivation in Yangtze River Delta.
Details about the field experiment were given previously (Wang et al.,
2023). There were six treatments with varied N application amounts from
0 to 320 kg N ha-1 per season in a complete randomized
block design and three and four blocks in 2019 and 2020, respectively,
in which each plot occupied an area of 180 m2. Rice
was sown with a row spacing of 20 cm and a within-row seed spacing of
2-3 cm on 14-Jun and 4-Jun in 2019 and 2020, respectively. The
application time and amount of N were split according to the schedule in
Table 2. Based on the local practice, sufficient phosphate (112.5 kg
P2O5 ha-1) and potash
(112.5 kg K2O ha-1) fertilizers were
applied per season to prevent phosphorus and potassium deficiencies.
Other field managements were the same in each plot following local
standard practices, including irrigation, and pest, weed and disease
control.