Table 3.
Linear regression parameters for the relationships between nitrous oxide (N2O) emission and TNU, NRE and NNB when management focused on rate and source, rate and timing, and rate, source and timing combinations, based on individual observations.
| Nitrogen management | TNU | NRE | NNB(TNU) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N | Reg. model | R2 | P < F | N | Reg. model | R2 | F < F | N | Reg. model | R2 | P < F | |
| Rate and source | 20 | y = −0.00x+1.47 | 0.00 | 0.972 | 16 | y = 0.032x−0.09 | 0.21 | 0.076 | 20 | y = 0.015x+1.52 | 0.34 | 0.006 |
| Rate and timing | 30 | y = −0.003x+2.13 | 0.01 | 0.552 | 26 | y = −0.017x+2.71 | 0.33 | 0.002 | 30 | y = 0.009x+2.13 | 0.26 | 0.004 |
| Rate, source and timing | 24 | y = 0.021x−1.17 | 0.46 | 0.001 | 16 | y = 0.024x+0.97 | 0.14 | 0.144 | 24 | y = 0.014x+1.86 | 0.14 | 0.066 |
N, Number of individual points; TNU, total nitrogen uptake; NRE, N recovery efficiency; NNB, net N balance. Data for rate+source from experiments conducted in Indiana, USA; rate+timing data from experiments conducted in Indiana and Minnesota (USA) and New Brunswick, Canada; and rate+source+timing data obtained from experiments in Indiana, USA.