Potential of Controlled Irrigation and Drainage for Reducing Nitrogen Emission from Rice Paddies in Southern China

Table 2

The change of the concentration of -N, -N, and TN after fertilization at tillering stage in 2010.

Form of N	Sample site	Measure time
		8.6	8.9	8.11	8.13
-N (mg/L)	Surface	1.55	2.01	1.10	1.53
	Underground	0.74	0.56	2.09	0.77
-N (mg/L)	Surface	0.28	0.41	0.28	0.25
	Underground	0.29	0.19	0.31	0.17
TN (mg/L)	Surface	2.64	2.92	3.77	2.41
	Underground	2.62	2.39	2.46	2.84