Utilizing rainfall and alternate wetting and drying irrigation for high water productivity in irrigated lowland paddy rice in southern Taiwan

Figures & data

Figure 1. Daily maximum and minimum temperatures and radiation during the crop cycle.

Figure 2. Rainfall, ETc, and soil moisture content at 15 and 25 cm depths.

Figure 3. (a) Soil moisture trend at 25 cm (a) at vegetative (I), panicle initiation (II), and heading stage (III). 22 × 11 mm, (b) Soil moisture trend at15 cm (b) at vegetative (I), panicle initiation (II) and heading stage (III).

Figure 4. Mean soil moisture content during the crop cycle.

Table 1. Effects of water treatment on plant height and tiller numbers and LAI.

Treatments	Panicle initiation			Heading
	Plant height (cm)	Tiller numbers	Leaf area index	Plant height (cm)	Tiller numbers
T5	71.88^a	14.64	2.36^a	86.68^a	19.72
T4	70.12^ab	13.93	2.03^b	84.77^ab	19.82
T3	68.97^b	14.16	1.96^b	84.17^ab	19.32
T2	68.65^b	13.28	1.65^c	83.32^b	18.75
P	*	ns	*	*	ns

* Mean with columns not followed by the same letter (a,b,c) is significantly different at p < 0.05 level by Turkey’s test

ns: not significantly different.

Table 2. Effect of water treatment on dry biomass, root dry weight, root depth, and root volume at panicle initiation.

Treatments	Dry biomass (g/hill)	Root dry weight (g/hill)	Root depth (cm)	Root volume (cm^3)
T5	28.80^a	14.48^a	17.10	21.00 ^a
T4	26.71^ab	13.04^ab	16.89	20.30^ab
T3	28.85^a	10.94^ab	16.44	17.40^ab
T2	22.71^c	9.33^b	15.56	15.15^b
P	*	*	ns	*

* Mean with columns not followed by the same letter (a,b,c) is significantly different at p < 0.05 level by Turkey’s test

ns: not significantly different.

Table 3. Chlorophyll content and leaf RWC subjected to water treatments

Treatments	Panicle Initiation		Heading
	Chlorophyll content	RWC	Chlorophyll content	RWC
T5	46.85^a	70.43^a	44.50	85.77
T4	45.34^ab	65.02^ab	43.43	85.15
T3	43.92^b	62.57^b	44.16	82.93
T2	43.61^b	60.05^c	43.72	84.90
P	*	*	ns	ns

* Mean with columns not followed by the same letter (a,b,c) is significantly different at p < 0.05 level by Turkey’s test

ns: not significantly different.

Figure 5. Effects of water treatment on daily headed panicle.

Table 4. Effect of water treatment on panicle number, panicle weight and panicle length at harvest.

Treatments	Average panicle number per hill	Average panicle weight (g)	Average panicle length (cm)
T5	16.87	2.04	24.52
T4	15.74	2.01	25.35
T3	16.32	1.91	24.97
T2	15.44	1.71	24.65
P	ns	ns	ns

ns: not significantly different at p < 0.05 level by Turkey’s test.

Table 5. Effect of water treatment on grain number per panicle, grain weight per panicle, grain filling rate and 1000-grain weight.

Treatments	Grain number per panicle	Grain weight per panicle (g)	Grain filling rate%	1000-grain weight (g)
T5	109.20^ab	1.91^a	81.31^a	15.99^a
T4	112.83^a	1.99^a	79.15^a	15.70^a
T3	110.85^a	1.80^ab	74.91^b	14.80^a
T2	107.09^b	1.67^b	68.88^c	13.60^b
P	*	*	*	*

* Mean with columns not followed by the same letter (a,b) is significantly different at p < 0.05 level by Turkey’s test

ns: not significantly different.

Table 6. Effect of water treatment on biomass aboveground, grain yield, harvest index, yield losses and yield reduction.

Treatments	Biomass aboveground (ton/ha)	Grain yield(ton/ha)	Harvest index (HI)	Yield losses (kg/ha)	Yield reduction %
T5	12.09^a	5.74^a	0.48^a
T4	11.77^ab	5.65^a	0.48^a	90	1.57
T3	11.71^b	5.35^a	0.46^a	390	6.79
T2	10.98^c	4.48^b	0.41^b	1260	21.95
P	*	*	*	–	–

* Mean with columns not followed by the same letter (a,b,c) is significantly different at p < 0.05 level by Turkey’s test.

Table 7. Effect of treatments on water use efficiency.

Treatments	Rain (m^3/ha)	Irrigation (m^3/ha)	TWP (kg/m^3)	RWP (kg/m^3)	IWP (kg/m^3)	Water Savings (m^3/ha)	Irrigation water savings (%)	Water saving impact (kg/m^3)
T5	2768	8000	0.53	2.07	0.72
T4	2768	6400	0.62	2.04	0.88	1600	20	0.06
T3	2768	4800	0.71	1.93	1.11	3200	40	0.12
T2	2768	3200	0.75	1.62	1.40	4800	60	0.26