Table 1. Seasonal and annual total (Mean ± 1SE, n = 3) of N2O and NO emissions and vegetable yield (fresh weight) in greenhouse vegetable cropping systems.
Measurement period | Treatment | N fertilizer | N2O-N | NO-N | NO-N/N2O-N ratio | Yield (t ha−1) |
---|---|---|---|---|---|---|
(kg N ha−1) | ||||||
Tomato (24 Aug 2013~3 Mar 2014, 190 days) | Control | 0 | 1.09 ± 0.17d | 0.63 ± 0.09fgh | 0.61 ± 0.14abcd | 112.40 ± 5.38a |
F−L | 260 | 4.97 ± 0.32abc | 3.69 ± 0.28b | 0.74 ± 0.04abc | 120.67 ± 5.46a | |
F−M | 400 | 5.20 ± 0.34abc | 5.08 ± 0.40a | 0.98 ± 0.17a | 123.07 ± 5.73a | |
F−H | 520 | 6.60 ± 0.48a | 5.95 ± 0.26a | 0.91 ± 0.08ab | 122.40 ± 9.83a | |
Chinese cabbage (4 Mar~7 May 2014, 65 days) | Control | 0 | 0.62 ± 0.02d | 0.21 ± 0.12h | 0.33 ± 0.03cd | 71.41 ± 8.57b |
F−L | 100 | 1.78 ± 0.23cd | 1.25 ± 0.43efgh | 0.72 ± 0.11abc | 79.84 ± 6.50b | |
F−M | 150 | 2.09 ± 0.26cd | 1.55 ± 0.71defg | 0.76 ± 0.16abc | 73.17 ± 4.52b | |
F−H | 200 | 2.70 ± 0.48bcd | 1.89 ± 0.34cdef | 0.73 ± 0.07abc | 69.16 ± 4.72b | |
Green soybean (8 May~13 Aug 2014, 98 days) | Control | 0 | 2.71 ± 0.26bcd | 0.42 ± 0.16gh | 0.16 ± 0.02d | 8.39 ± 1.07c |
F−L | 60 | 5.71 ± 0.72ab | 2.00 ± 0.57cde | 0.38 ± 0.10cd | 10.25 ± 1.36c | |
F−M | 90 | 6.79 ± 0.82a | 2.62 ± 0.91bcd | 0.43 ± 0.09bcd | 9.26 ± 0.92c | |
F−H | 120 | 7.17 ± 1.08a | 2.97 ± 0.61bc | 0.43 ± 0.05bcd | 9.94 ± 0.57c | |
Annual cycle (24 Aug 2013~13 Aug 2014, 353 days) | Control | 0 | 4.41 ± 0.45 | 1.26 ± 0.37 | 0.28 ± 0.03 | 192.20 ± 15.01 |
F−L | 420 | 12.45 ± 1.27 | 6.94 ± 1.28 | 0.57 ± 0.09 | 210.76 ± 13.31 | |
F−M | 640 | 14.07 ± 1.42 | 9.25 ± 2.02 | 0.69 ± 0.14 | 205.50 ± 11.17 | |
F−H | 840 | 16.47 ± 2.04 | 10.81 ± 1.21 | 0.66 ± 0.04 | 201.51 ± 15.13 |
Data shown are means ± standard errors of three replicates. The flux measurements period includes the vegetable-growing season and the following fallow period. Different letters within the same column indicate significant differences among treatments at p < 0.05 level.