Effects of introduction of combine harvester and flatbed dryer on milling quality of three glutinous rice varieties in Lao PDR

Figures & data

Figure 1. Daily mean, maximum and minimum air temperature, rainfall and relative humidity during the dry season crop (December–May), harvesting (H), storage and time of milling (indicated by arrows) from June to December, 2016 (a) and during the crop growing season in wet season 2017 (b).

Table 1. Milling quality of two rice varieties (TDK11 and TDK8) produced in dry season 2015–2016, in response to different harvest methods, drying methods and storage duration (split–split plot design).

	BR (%)	MR (%)	HRY (%)	Broken rice (%)	MC (%)	BR (%)	MR (%)	HRY (%)	Broken rice (%)	MC (%)
Factors	TDK11					TDK8
Harvest methods (a)
Hand harvest	76.17a	59.97a	25.61b	34.37a	13.74a	78.31a	65.54a	43.95a	21.59b	13.91a
Combine harvest	76.96a	61.45a	28.75a	32.70a	13.19b	78.05a	66.16a	37.29b	28.87a	13.72a
Drying methods (b)
Sun drying	75.98b	58.98b	16.80b	42.18a	13.35a	78.04a	65.28b	34.29b	30.99a	13.90a
Forced air drying	77.14a	62.45a	37.55a	24.89b	13.58a	78.32a	66.42a	46.94a	19.47b	13.72a
Storage periods (c)
0 month	77.88a	63.78a	29.71a	34.07a	12.67c	79.1 a	66.84ab	42.95a	23.89c	13.47c
2 months	77.15ab	61.43b	27.11b	34.32a	13.79b	78.69b	67.04a	42.77a	24.27bc	13.88b
4 months	74.71c	56.97c	25.16c	31.81b	14.58a	76.47c	63.40c	38.18b	25.22b	14.58a
6 months	76.52b	60.68b	26.74b	33.94a	12.81c	78.41b	66.10b	38.56b	27.54a	13.33a
F-test
Harvest (H)	ns	ns	**	ns	*	ns	ns	**	**	ns
Drying (D)	**	**	**	**	ns	ns	**	**	**	ns
Storage (S)	**	**	**	*	**	**	**	**	**	**
H × D	ns	ns	ns	ns	ns	ns	*	**	*	**
H × S	*	ns	**	ns	ns	ns	ns	ns	ns	ns
D × S	ns	ns	*	*	ns	ns	ns	**	**	ns
H × D × S	ns	ns	ns	ns	ns	ns	ns	*	ns	**
CV (a) %	1.51	3.46	4.02	7.10	3.48	0.77	1.78	1.40	3.14	1.78
CV (b) %	1.30	3.90	7.10	10.06	2.81	0.73	1.01	5.04	8.45	2.43
CV (c) %	1.49	3.97	5.62	6.79	2.22	0.77	1.76	4.24	4.24	2.08

BR: Brown rice; MR: milled rice; HRY: head rice yield, broken rice; MC (grain moisture content).

ns: Not significant. *,**Significantly different at p ≤ 0.05 and 0.01, respectively.

Means followed by different letter(s) are significantly different by LSD at p ≤ 0.05

Figure 2. Head rice yield interactions between harvest methods and storage period of TDK11 (a) and drying methods and storage period of TDK11 (b) and between drying methods and storage period of TDK8 (c) produced in dry season 2015–2016.

Table 2. Milling quality of VTE450-2 rice produced in dry season 2015–2016 harvested by hand and its response to drying methods and storage duration.

Factors	BR (%)	MR (%)	HRY (%)	Broken rice (%)	MC (%)
Drying methods (a)
Sun drying	77.75a	63.38b	34.36b	29.02a	14.36a
Forced air drying	78.22a	65.65a	50.61a	15.04b	13.94a
Storage periods (b)
0 month	79.19a	65.60ab	44.34a	21.26b	13.89b
2 months	78.46ab	65.90a	44.28a	21.62b	14.14b
4 months	76.20c	62.29c	40.26b	22.02ab	14.79a
6 months	78.10b	64.26b	41.06b	23.20a	13.79b
F-test
Drying (D)	ns	*	**	**	ns
Storage (S)	**	**	**	*	**
D × S	ns	ns	**	**	ns
CV (a) %	1.34	2.14	5.49	8.86	4.51
CV (b) %	1.02	2.21	4.05	6.67	3.08

BR: Brown rice; MR: milled rice; HRY: head rice yield; broken rice; MC (grain moisture content).

ns: Not significant. *,**significantly different at p ≤ 0.05 and 0.01, respectively.

Means followed by different letter(s) are significantly different by LSD at p ≤ 0.0 (split plot design).

Figure 3. Interaction between drying methods and storage period on head rice yield of VTE450-2 produced in dry season 2015–2016 and stored during 2016 wet season.

Table 3. Milling quality of two rice varieties under hand (H) and combine (C) harvested and sun (S) and forced air (F) dried, after harvest in 2016 in dry season and wet season 2017 without storage.

Factors	BR (%)	MR (%)	HRY (%)	Broken rice (%)	MC (%)	BR (%)	MR (%)	HRY (%)	Broken rice (%)	MC (%)
Wet season 2017 (a)	TDK11					TDK8
Harvest methods (a)
Hand harvest	76.86a	61.13b	31.17b	29.96a	13.45a	78.06a	65.42a	43.50b	21.92a	14.03a
Combine harvest	76.29a	63.17a	37.22a	25.94b	13.36a	77.79a	65.93a	46.78a	19.14a	13.68a
Drying methods (b)
Sun drying	75.63b	61.52a	31.04b	30.48a	12.96b	77.37a	64.72a	38.42b	26.38a	13.81a
Forced air drying	77.52a	62.78a	37.35a	25.43b	13.85a	78.48a	66.62a	51.94a	14.67b	13.90a
F-test
Harvest (H)	ns	*	**	*	ns	ns	ns	*	ns^x	ns
Drying (D)	*	ns	**	**	**	ns	ns	**	**	ns
H × D	ns	ns	ns	ns	ns	ns	ns	**	ns^y	ns
CV (a) %	0.83	0.77	2.37	4.56	0.94	0.53	1.33	1.44	5.88	1.57
CV (b) %	0.98	1.43	2.74	3.85	1.8	1.3	1.94	1.53	7.84	1.74
Dry season 2015–2016 (b)	TDK11					TDK8
Harvest methods (a)
Hand harvest	77.41b	62.67b	27.50b	35.16a	12.92a	79.25a	66.54a	46.47a	20.07b	13.56a
Combine harvest	78.34a	64.89a	31.90a	32.98b	12.41b	79.05a	67.13a	39.42b	27.71a	13.37b
Drying methods (b)
Sun drying	77.68a	63.17a	19.29b	43.89a	12.46b	79.08a	66.52a	36.16b	30.35a	13.50a
Forced air drying	78.07a	64.38a	40.13a	24.25b	12.87a	79.22a	67.15a	49.73a	17.42b	13.43a
F-test
Harvest (H)	*	*	*	*	*	ns	ns	**	**	*
Drying (D)	ns	ns	**	**	**	ns	ns	**	**	ns
H × D	ns	ns	*	ns	ns	ns	*	**	*	ns
CV (a) %	0.48	2.05	5.7	3.56	1.69	0.66	1.16	3.23	6.66	0.7
CV (b) %	0.64	2.52	6.52	5.83	1.62	0.66	0.97	3.76	6.8	1.23

BR: Brown rice; MR: milled rice; HRY: head rice yield; broken rice; MC (grain moisture content).

ns: Not significant. *,**Significantly different at p ≤ 0.05 and 0.01, respectively.

Means followed by different letter(s) are significantly different by LSD at p ≤ 0.05 (split plot design).

^Xp = 0.0576; ^Yp = 0.0564.

Figure 4. Interactions between harvest methods, drying methods on head rice yield of TDK8 produced in wet season 2017 (a) and dry season 2016 (b) and DS 2016 of TDK11 (c).