Table 1.
Items | CK | Opt. N*50–70% | Opt. N | Opt. N*130–150% | Con. N |
---|---|---|---|---|---|
Grain yield benefit | 1942 c | 3195 b | 3294 a | 3281 ab | 3267 ab |
N cost | 0 e | 66 d | 99 c | 132 b | 155 a |
Other costs | 1157 a | 1157 a | 1157 a | 1157 a | 1157 a |
Private profitability | 786 b | 1956 a | 2038 a | 1992 a | 1956 a |
Social cost | 74 e | 175 d | 227 c | 285 b | 336 a |
Ecosystem economic benefit (EEB) | 712 d | 1797 ab | 1811 a | 1706 bc | 1620 c |
Human Capital Losses (HCL) | 18 e | 45 d | 56 c | 68 b | 82 a |
Integrated compensation benefit (ICB) | 699 d | 1754 a | 1747 a | 1632 b | 1537 c |
Social cost-private profitability ratio (%) | 11.0 c | 9.4 c | 12.0 bc | 15.5 ab | 18.6 a |
CK, no N; Opt. N*50–70%, 50–70% of optimal N rate; Opt. N, optimal N rate; Opt. N*130–150%, 130–150% of optimal N rate; Con. N, conventional N rate. Means followed by the same lowercase letter are not significantly different among the five N treatments at p < 0.05 according to LSD.