Localized phosphorus application via P-dipping is more effective for improving initial rice growth in lower temperature conditions

Figures & data

Figure 1. Rice shoot biomass (a) and shoot P uptake (b) at around cumulative growing degree days of 672°C after transplanting as affected by different temperatures (Low T, high T, Elev. T) and P₂O₅ concentrations in the slurry (0%, 2.3%, and 4.4% for P0, P1, and P2, respectively). Data are shown as mean values of 0 h and 2 h dipping durations. Different letters indicate that mean values were significantly different among the treatments at 5% according to Tukey’s HSD test. Day/night temperature; 28°/20°C in Low T, 33°/25°C in High T, 36°/27°C in Elev. T.

Table 1. Levels of significance in F statistics for the effect and interaction of temperature, P₂O₅ concentration in slurry, and dipping duration on the measured variables.

	Shoot biomass	Shoot P uptake	withered % of 3^rd leaf	withered % of 4^th leaf	Leaf age	Tiller number	Root biomass	Total root length
Temperature (T)	***	**	***	***	*	***	***	***
P2O5 conc. (P)	***	***	***	***	***	***	***	***
Dipping duration (D)	ns	*	ns	ns	ns	ns	ns	*
T × P	***	***	***	***	**	***	***	***
T × D	***	ns	ns	ns	ns	ns	**	ns
P × D	ns	ns	*	*	ns	ns	ns	ns
T × P × D	ns	ns	***	ns	ns	ns	ns	ns

* P < 0.05, ** P < 0.01, *** P < 0.001, ns not significant at 5% level.

Figure 2. Percentages of withered portions of the 4^th (a) and 3^rd leaves (b) at six days after transplanting as affected by different temperatures (Low T, High T, Elev. T) and P₂O₅ concentrations in the slurry (0%, 2.3%, and 4.4% for P0, P1, and P2, respectively). Data are shown as mean values of 0 h and 2 h dipping durations. Different letters indicate that mean values were significantly different among the treatments at 5% according to Tukey’s HSD test. Day/night temperature; 28°/20°C in Low T, 33°/25°C in High T, 36°/27°C in Elev. T.

Figure 3. Number of tillers (a) and leaf age (b) at around cumulative growing degree days of 672°C after transplanting as affected by different temperatures (Low T, High T, Elev. T) and P₂O₅ concentrations in the slurry (0%, 2.3%, and 4.4% for P0, P1, and P2, respectively). Data are shown as mean values of 0 h and 2 h dipping durations. Different letters indicate that mean values were significantly different among the treatments at 5% according to Tukey’s HSD test. Day/night temperature; 28°/20°C in Low T, 33°/25°C in High T, 36°/27°C in Elev. T.

Figure 4. Root biomass (a) and total root length (b) at around cumulative growing degree days of 672°C after transplanting as affected by different temperatures (Low T, High T, Elev. T) and P₂O₅ concentrations in the slurry (0%, 2.3%, and 4.4% for P0, P1, and P2, respectively). Data are shown as mean values of 0 h and 2 h dipping durations. Different letters indicate that mean values were significantly different among the treatments at 5% according to Tukey’s HSD test. Day/night temperature; 28°/20°C in Low T, 33°/25°C in High T, 36°/27°C in Elev. T.

Data availability statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.