Combined application of biochar and nitrogen fertilizer promotes the activity of starch metabolism enzymes and the expression of related genes in rice in a dual cropping system

Table 2 The responses of grain yield and yield components to different levels of biochar and N fertilizers

(Kg ha^− 1)	B	PN hill^− 1	PH (cm)	TGW(g)	PL (cm)	GY (kg ha⁻¹)
Early season
Low N(135)	0	6.67d	114.33c	19.97d	19.94c	6122.5c
	10	9.67c	116.67b	21.97c	19.44bc	7122.5b
	20	10.13bc	117.50b	21.59c	21.05bc	7477.2ab
	30	11.0ab	118.40a	23.27ab	24.53a	7863.2a
High N (180)	0	11.33c	118.47b	23.74bc	24.50bc	7122.5b
	10	9.67c	116.95b	21.93c	21.42b	7243.5b
	20	11.33a	118.42a	23.58a	24.59a	7870.3
	30	11.33a	118.47a	23.74a	24.50a	7891.7a
Late season
Low N(135)	0	6.48d	111.23b	19.28d	19.24b	5481.4c
	10	9.07bc	115.30a	21.28c	19.41b	6538.4c
	20	9.67a	116.53a	20.90c	20.35b	7065.5a
	30	10.33abc	116.90a	22.58ab	23.83a	7222.2a
High N (180)	0	8.67c	115.17a	21.68bc	19.31b	6481.4c
	10	9.00bc	116.12a	21.24c	19.47b	6887.4ab
	20	9.33abc	116.92a	22.89a	23.89a	7229.3a
	30	10.00ab	116.97a	23.05a	23.80a	7250.7a
SOV		PN	PH	TGW	PL	GY
Biochar (B)		**	ns	*	**	**
Nitrogen(N)		*	ns	**	*	**
Season(S)		ns	ns	ns	ns	ns
B × N		**	**	**	**	**
B × S		ns	ns	ns	ns	ns
N × S		ns	ns	ns	ns	ns

PN panicle number, PH plant height, TGW thousand-grain weight, PL panicle length, GY grain yield. SOV-source of variation, ** indicate the significant difference P ≥ 0.01 and * indicate P = 0.01-0.05, Values followed by the same letters within a column are not significantly different at P ≤ 0.05.

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