Cai Z, Laughlin R J, Stevens R J
Institute of Soil Sciences, Chinese Academy of Sciences, Nanjing, People's Republic of China.
Chemosphere. 2001 Jan;42(2):113-21. doi: 10.1016/s0045-6535(00)00116-8.
In a laboratory study, soil amended with and without wheat straw (2.8 g kg(-1) soil) was incubated under 70% water holding capacity (WHC), continuously flooded and flooded/drained cycle conditions at 30 degrees C for 51 days. Dinitrogen and N2O evolution and ammonia volatilisation were measured during the incubation. Extractable NH4+-N and NO3--N were determined at the end of the incubation. Entrapped N2, N2O, and dissolved NH4+-N and NO3--N in drainage water were measured in the flooded/drained cycle treatment when the floodwater was drained. The results indicated that N loss through ammonia volatilisation was undetected in all treatments due to the low soil pH value (pHH2O= 5.87) and no air movement. The recovery of urea-15N as N2 was lowest in the continuously flooded treatments (0.75% and 0.96% with and without straw amendment, respectively), highest in the 70% WHC treatments (5.65% and 4.41%, respectively), and intermediate in the flooded/drained cycle treatments (1.79% and 2.65%, respectively). The recovery of urea-15N as N2O was in the same order as that of N2, negligible in the continuously flooded treatments, 0.01% and 0.07% in the flooded/drained cycle treatments, and 1.29% and 2.23% in the 70% WHC treatments, respectively. Peak N2O evolution rates were observed after the floodwater was drained but no substantial evolution was found after the soil was reflooded following drained periods. However, peak N2 evolution rates were observed after the onset of both drainage and re-flooding. Considerable quantities of N2 but no detectable N2O were entrapped in the flooded soil.
在一项实验室研究中，将添加和未添加小麦秸秆（2.8克/千克土壤）的土壤在30℃下分别置于持水量70%（WHC）、持续淹水和淹水/排水循环条件下培养51天。在培养期间测定了氮气和一氧化二氮的释放以及氨的挥发。在培养结束时测定了可提取的铵态氮和硝态氮。在淹水/排水循环处理中，当排干洪水时，测定了截留的氮气、一氧化二氮以及排水中溶解的铵态氮和硝态氮。结果表明，由于土壤pH值较低（pHH2O = 5.87）且没有空气流动，所有处理中均未检测到氨挥发造成的氮损失。以氮气形式回收的尿素-15N在持续淹水处理中最低（添加和未添加秸秆时分别为0.75%和0.96%），在持水量70%的处理中最高（分别为5.65%和4.41%），在淹水/排水循环处理中居中（分别为1.79%和2.65%）。以一氧化二氮形式回收的尿素-15N与以氮气形式回收的顺序相同，在持续淹水处理中可忽略不计，在淹水/排水循环处理中分别为0.01%和0.07%，在持水量70%的处理中分别为1.29%和2.23%。在排干洪水后观察到一氧化二氮的释放峰值，但在排水期后土壤重新淹水后未发现大量释放。然而，在排水和重新淹水开始后均观察到氮气的释放峰值。淹水土壤中截留了大量的氮气，但未检测到一氧化二氮。
