Physiological characteristics of high yield under cluster planting: photosynthesis and canopy microclimate of cotton

Figures & data

Figure 1. A schematic diagram showing traditional planting pattern and cluster planting pattern.

Figure 2. Leaf area index of cotton at different growth stages in traditional and cluster planting patterns in 2012. Values represent means ± SD (n = 6).

Table 1. Canopy light interception (Li) of cotton in different layers in three growths stages between traditional and cluster planting pattern in 2012.

	Full flowering stage			Full bolling stage			Boll opening stage
Treatment	Upper layer	Middle layer	Lower layer	Upper layer	Middle layer	Lower layer	Upper layer	Middle layer	Lower layer
Traditional planting	0.39 ± 0.05^a	0.70 ± 0.07^a	0.78 ± 0.07^a	0.45 ± 0.06^a	0.79 ± 0.07^a	0.84 ± 0.09^a	0.36 ± 0.04^a	0.62 ± 0.07^a	0.71 ± 0.06^a
Cluster planting	0.48 ± 0.05^b	0.83 ± 0.07^b	0.88 ± 0.07^b	0.52 ± 0.08^b	0.89 ± 0.09^b	0.93 ± 0.09^b	0.44 ± 0.04^b	0.79 ± 0.06^b	0.84 ± 0.09^b

Note. Values represent means of six replications ±SD. Different lowercase (a, b) in the same row indicates significant differences (p < 0.05).

Table 2. Canopy CO₂ concentration, temperature and relative humidity of cotton in three growth stages between traditional and cluster planting pattern in 2012.

		Full-flowering stage			Full-bolling stage			Boll-opening stage
	Treatment	Upper layer	Middle layer	Lower layer	Upper layer	Middle layer	Lower layer	Upper layer	Middle layer	Lower layer r
CO2 concentration (μmol mol^−1)	Traditional planting	366 ± 16^a	361 ± 16^a	370 ± 23^a	363 ± 17^a	358 ± 18^a	368 ± 26^a	372 ± 23^a	369 ± 18^a	375 ± 25^a
	Cluster planting	368 ± 18^a	362 ± 15^a	370 ± 25^a	365 ± 24^a	360 ± 21^a	368 ± 27^a	374 ± 25^a	370 ± 19^a	376 ± 25^a
Temperature (℃)	Traditional planting	36.1 ± 2.5^a	36.7 ± 4.1^a	36.2 ± 3.5^a	35.8 ± 3.1^a	36.3 ± 4.2^a	35.9 ± 2.9^a	33.8 ± 2.3^a	34.4 ± 3.1^a	34 ± 2.8^a
	Cluster planting	35.8 ± 2.7^a	36.5 ± 3.4^a	35.8 ± 3.2^a	35.5 ± 2.9^a	36 ± 3.6^a	35.7 ± 2.6^a	33.5 ± 2.8^a	34.1 ± 3.5^a	33.7±3.1^a
RH (%)	Traditional planting	32.1 ± 2.4^a	33.6 ± 2.8^a	34 ± 2.8^a	34.1 ± 2.6^a	35.1 ± 2.9^a	36.2 ± 3.5^a	42.1 ± 3.2^a	43.6 ± 3.2^a	44.2 ± 3.7^a
	Cluster planting	34.3 ± 2.8^b	35.4 ± 3.2^b	36 ± 3.2^b	35.8 ± 2.4^b	37.3 ± 3.2^b	38.2 ± 4.1^b	43.6 ± 3.2^b	44.7 ± 4.3^b	46 ± 4.3^b

Note. Values represent means of six replications ±SD. Different lowercase (a, b) in the same row indicates significant differences (p < 0.05).

Figure 3. Leaf chlorophyll content (SPAD) of cotton at different growth stages in traditional and cluster planting patterns in 2012 and 2013. Values represent means ± SD (n = 6). n.s.: not significant. ***p < .001.

Table 3. Leaf and canopy photosynthetic rate of cotton in three growth stages between traditional and cluster planting pattern in 2012 and 2013 (μmolCO₂ m⁻² s⁻¹).

		Treatment	Full-flowering stage	Full-bolling stage	Boll-opening stage
PN	2012	Traditional planting	26.65 ± 0.39	26.95 ± 0.28	25.26 ± 0.09
		Cluster planting	26.80 ± 0.20	28.98 ± 0.21	27.43 ± 0.13
	2013	Traditional planting	25.65 ± 0.39	26.62 ± 0.33	25.06 ± 0.14
		Cluster planting	25.90 ± 0.26	27.98 ± 0.21	26.43 ± 0.13
Planting pattern treatments			n.s.	***	***
Year			**	**	***
Planting pattern treatments × year			n.s.	n.s.	***
CAP	2012	Traditional planting	22.96 ± 0.18	24.08 ± 0.31	19.10 ± 0.25
		Cluster planting	23.15 ± 0.30	25.95 ± 0.18	21.62 ± 0.41
	2013	Traditional planting	21.96 ± 0.18	23.45 ± 0.52	18.34 ± 0.13
		Cluster planting	22.25 ± 0.12	25.22 ± 0.39	20.63 ± 0.51
Planting pattern treatments			n.s.	***	***
Year			**	*	**
Planting pattern treatments × year			n.s.	n.s.	n.s.

Values represent means of six replications ±SD. n.s.: not significant.

* p < .05;

** p < .01;

*** p < .001.

Table 4. Effect of planting pattern treatments on cotton yield and yield components in 2012 and 2013.

Year	Treatment	Lint yield	Seed cotton yield	Lint percentage	Final boll numbers	Mean boll size
		(kg ha^−1)	(kg ha^−1)	(%)	(Bolls m^−2)	(g boll^−1)
2012	Local traditional planting	3207.3 ± 97.4	8240.0 ± 111.5	38.9 ± 0.2	160 ± 5.1	5.16 ± 0.2
	Cluster planting	3910.3 ± 88.8	9876.0 ± 92.0	39.6 ± 0.4	189 ± 2.7	5.45 ± 0.2
2013	Local traditional Planting	3015.2 ± 84.3	7834.2 ± 92.1	38.5 ± 0.2	155 ± 3.2	5.05 ± 0.2
	Cluster planting	3645.2 ± 106.9	9332.1 ± 103.1	39.1 ± 0.2	179 ± 4.1	5.21 ± 0.1
	Planting pattern treatments	***	***	***	*	***
	Year	***	***	***	***	***
	Planting pattern treatments × Year	***	***	*	n.s.	*

Values represent means of six replications ±SD. n.s.: not significant.

* p < .05;

*** p < .001.