Straw Mulching with Minimum Tillage Is the Best Method Suitable for Straw Application under Mechanical Grain Harvesting

Table 3

Dry matter accumulation, leaf area index, and SPAD value of maize under different practices of crop straw application.

CNSA	Treatments		Maize ear initiation stage (V12)			Silking stage (R1)
			Dry matter weight (t/ha)	Leaf area index (m/m)	Leaf SPAD values	Dry matter weight (t/ha)	Leaf area index (m/m)	Leaf SPAD values
1	Straw returns	SDBP	0.39 ± 0.04a	4.28 ± 0.14a	51.88 ± 2.11a	9.67 ± 0.33a	5.19 ± 0.18a	56.40 ± 0.83a
		SSBRT	0.26 ± 0.02b	3.15 ± 0.11b	47.37 ± 1.26b	6.71 ± 0.23b	4.37 ± 0.13b	53.15 ± 1.28b
		SMMT	0.25 ± 0.01b	3.12 ± 0.18b	47.53 ± 1.12b	6.34 ± 0.21c	4.29 ± 0.18b	47.38 ± 1.10c
	Cultivars	BY9	0.29 ± 0.02a	3.42 ± 0.11a	50.05 ± 1.96a	7.33 ± 0.25a	4.58 ± 0.17a	51.51 ± 1.12b
		JY99	0.30 ± 0.02a	3.61 ± 0.18a	47.79 ± 1.03b	7.80 ± 0.27a	4.64 ± 0.15a	53.11 ± 1.01a
	Interaction	BY9×SDBP	0.35 ± 0.03b	3.92 ± 0.09b	53.43 ± 2.01a	9.57 ± 0.30a	5.25 ± 0.16a	55.73 ± 0.75ab
		BY9×SSBRT	0.26 ± 0.02c	3.14 ± 0.07c	49.39 ± 2.16b	6.37 ± 0.24 cd	4.17 ± 0.15c	52.47 ± 1.48c
		BY9×SMMT	0.27 ± 0.01c	3.21 ± 0.16c	47.34 ± 1.70bc	6.06 ± 0.20d	4.33 ± 0.20bc	46.33 ± 1.14d
		JY99×SDBP	0.42 ± 0.04a	4.64 ± 0.19a	50.32 ± 2.20ab	9.76 ± 0.36a	5.12 ± 0.20a	57.07 ± 0.91a
		JY99×SSBRT	0.26 ± 0.01c	3.15 ± 0.15c	45.35 ± 0.35c	7.04 ± 0.23b	4.57 ± 0.10b	53.83 ± 1.07bc
		JY99×SMMT	0.23 ± 0.02c	3.03 ± 0.20c	47.71 ± 0.54bc	6.61 ± 0.22bc	4.24 ± 0.15c	48.43 ± 1.05d
3	Straw returns	SDBP	0.17 ± 0.01a	2.53 ± 0.15a	42.78 ± 1.00b	5.12 ± 0.18ab	4.42 ± 0.20b	53.43 ± 1.07b
		SSBRT	0.18 ± 0.01a	2.56 ± 0.15a	44.27 ± 0.87ab	4.80 ± 0.17b	4.24 ± 0.17c	53.67 ± 1.04ab
		SMMT	0.17 ± 0.01a	2.45 ± 0.11a	45.95 ± 1.10a	5.30 ± 0.12a	4.61 ± 0.19a	54.65 ± 0.83a
	Cultivars	BY9	0.18 ± 0.01a	2.60 ± 0.11a	44.63 ± 0.95a	5.20 ± 0.17a	4.49 ± 0.18a	52.94 ± 0.87b
		JY99	0.16 ± 0.01a	2.43 ± 0.16b	44.03 ± 1.03a	4.94 ± 0.13a	4.35 ± 0.18a	54.89 ± 1.09a
	Interaction	BY9×SDBP	0.19 ± 0.01a	2.86 ± 0.13a	43.33 ± 0.74 cd	5.53 ± 0.20a	4.76 ± 0.22a	52.13 ± 0.67d
		BY9×SSBRT	0.17 ± 0.01bc	2.45 ± 0.12bc	44.33 ± 0.92bc	4.65 ± 0.15c	4.12 ± 0.17 cd	53.10 ± 1.23 cd
		BY9×SMMT	0.17 ± 0.01bc	2.48 ± 0.08bc	46.23 ± 1.19a	5.41 ± 0.17a	4.60 ± 0.16ab	53.60 ± 0.71bc
		JY99×SDBP	0.14 ± 0.01d	2.20 ± 0.16c	42.23 ± 1.26d	4.70 ± 0.15c	4.07 ± 0.17d	54.73 ± 1.46ab
		JY99×SSBRT	0.18 ± 0.00ab	2.66 ± 0.18ab	44.20 ± 0.82bc	4.95 ± 0.18bc	4.36 ± 0.17bc	54.23 ± 0.85ab
		JY99×SMMT	0.16 ± 0.01c	2.42 ± 0.14bc	45.67 ± 1.01ab	5.18 ± 0.07ab	4.62 ± 0.21a	55.70 ± 0.95a

Groups labeled with different letters were significantly different (). The  ± sign is followed by the standard deviation. CNSA: cumulative number of straw returns.