Table 1. Nitrogen rates of chemical fertilizer, compost and straw (kg N ha−1) in winter wheat and summer maize from October 2010 to September 2013.
| Treatment# | Winter wheat |
Summer maize |
Annual |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2011 | 2012 | 2013 | Average | 2011 | 2012 | 2013 | Average | 2010–2011 | 2011–2012 | 2012–2013 | Average | |
| N0 | 0(0)§ | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) | 0(0) |
| N0+S | 0(41) | 0(32) | 0(47) | 0(40) | 0(15) | 0(23) | 0(24) | 0(21) | 0(56) | 0(54) | 0(71) | 0(61) |
| Nopt | 110(0) | 150(0) | 150(0) | 137(0) | 212(0) | 130(0) | 130(0) | 157(0) | 322(0) | 280(0) | 280(0) | 294(0) |
| Nopt+S | 107(49) | 150(44) | 150(60) | 136(51) | 159(23) | 130(52) | 130(56) | 140(44) | 266(72) | 280(96) | 280(115) | 275(94) |
| Ncon | 300(0) | 300(0) | 300(0) | 300(0) | 260(0) | 260(0) | 260(0) | 260(0) | 560(0) | 560(0) | 560(0) | 560(0) |
| Ncon+S | 300(62) | 300(47) | 300(64) | 300(58) | 260(39) | 260(56) | 260(57) | 260(50) | 560(101) | 560(103) | 560(121) | 560(108) |
| Mbal+S | 103(194) | 46(201) | 98(212) | 82(203) | 82(92) | 118(125) | 144(127) | 115(115) | 185(286) | 164(327) | 242(339) | 197(317) |
| Wbal+S | 108(155) | 138(103) | 110(198) | 119(152) | 134(82) | 157(86) | 150(119) | 147(96) | 242(237) | 295(189) | 260(317) | 266(247) |
#N0, Nopt, Ncon, Mbal and Wbal represent control, improved Nmin test, conventional farming practice, cattle manure with N balance method and waste compost with N balance method, respectively. S represents straw returning.
§The number in the brackets is the sum N of compost or/and straw N, compost N was calculated by 40% and 20% of total Kjeldahl N for winter wheat and summer maize season, respectively.