Table 1.

Differences in the production techniques for three main crops across various primary production areas in China.

Crop	Region	Sample	Nitrogen fertiliser input	Diesel consumption	Electricity consumption for irrigation	Proportion of households applying manure	Proportion of households utilising no-till techniques	Proportion of households practicing straw returning	Proportion of households practicing straw burning
			kg N2O/ha	kg/ha	kW h/ha	%	%	%	%
Maize	I 101	50	253 ± 113 ab	326 ± 137 ab	127 ± 470 a	78 ± 42 c	12 ± 33 a	45 ± 48 b	31 ± 43 c
	I 103	40	232 ± 117 ab	317 ± 144 ab	159 ± 522 a	83 ± 38 c	18 ± 38 ab	46 ± 48 b	21 ± 37 c
	III 102	32	208 ± 79 a	518 ± 153 c	339 ± 460 ab	6 ± 25 a	0 ± 0 a	41 ± 42 b	17 ± 31 bc
	IV 102	703	214 ± 101 a	419 ± 195 bc	1888 ± 1262 c	4 ± 20 a	43 ± 49 b	78 ± 38 c	4 ± 15 ab
	V 101	16	328 ± 139 c	655 ± 210 d	1495 ± 2105 c	81 ± 40 c	0 ± 0 a	0 ± 0 a	0 ± 0 a
	VI 101	128	287 ± 118 bc	668 ± 220 d	1334 ± 3662 c	37 ± 48 b	0 ± 0 a	37 ± 47 b	3 ± 17 ab
	VI 102	85	246 ± 87 ab	500 ± 197 c	1205 ± 1486 bc	6 ± 24 a	21 ± 41 ab	84 ± 37 c	2 ± 11 a
	VII 101	195	231 ± 70 ab	292 ± 168 a	10 ± 83 a	14 ± 35 a	7 ± 26 a	1 ± 10 a	28 ± 42 c
Wheat	II 201	16	180 ± 48 a	379 ± 304 a	180 ± 347 a	19 ± 40 a	13 ± 34 b	19 ± 40 a	81 ± 40 c
	III 201	162	209 ± 71 ab	532 ± 183 b	14 ± 110 a	7 ± 25 a	1 ± 8 a	82 ± 37 b	11 ± 31 b
	IV 201	800	254 ± 102 b	635 ± 230 bc	3904 ± 3092 b	10 ± 30 a	0 ± 0 a	94 ± 23 b	2 ± 13 a
	VI 201	111	210 ± 83 ab	708 ± 222 c	1267 ± 2046 a	23 ± 42 a	0 ± 0 a	87 ± 33 b	1 ± 9 a
Rice	I 301	30	178 ± 44 b	417 ± 129 b	0 ± 0 a	37 ± 49 cd	0 ± 0	89 ± 30 bc	10 ± 30 ab
	I 302	104	185 ± 79 b	316 ± 203 a	16 ± 117 a	32 ± 47 cd	0 ± 0	80 ± 39 bc	19 ± 39 abc
	I 303	105	188 ± 84 b	320 ± 202 a	13 ± 114 a	24 ± 43 bc	0 ± 0	79 ± 40 bc	20 ± 40 abc
	II 301	142	154 ± 51 b	444 ± 181 bc	138 ± 540 a	50 ± 50 d	0 ± 0	72 ± 44 b	31 ± 46 bc
	II 302	88	154 ± 50 b	515 ± 145 cd	64 ± 200 a	25 ± 44 bc	0 ± 0	43 ± 49 a	56 ± 49 de
	II 303	91	156 ± 54 b	502 ± 142 bcd	61 ± 196 a	20 ± 40 abc	0 ± 0	45 ± 50 a	57 ± 49 de
	III 301	206	251 ± 108 c	549 ± 202 d	300 ± 958 a	8 ± 27 ab	0 ± 0	87 ± 32 bc	35 ± 47 cd
	IV 301	51	304 ± 102 d	586 ± 133 d	218 ± 545 a	20 ± 40 abc	0 ± 0	99 ± 0 c	0 ± 0 a
	VII 301	85	114 ± 35 a	766 ± 173 e	2157 ± 1074 b	1 ± 11 a	0 ± 0	29 ± 45 a	70 ± 45 e

Note: Mean ± SD. Different letters indicate significant differences among different regions of the same crop at P < 0.05 (ANOVA). Crop codes: 101 = spring maize; 102 = summer maize; 103 = autumn maize; 201 = winter wheat; 301 = single-crop rice; 302 = double-cropped early rice; 303 = double-cropped late rice. Area codes: I = triple-cropping area in South China, II = double-cropping rice area in South China, III = lower basin of the Yangtze River (paddy–upland rotation area), IV = North China Plain, V = irrigated area in Northwest China; VI = arid area in Northwest China, VII = single crop area in Northeast China.