Effects of Controlled Irrigation and Drainage on Nitrogen and Phosphorus Concentrations in Paddy Water

Table 3

Mean TP, -N, and -N concentrations in percolation water at different stages during the time of flooding and drought.

Form of N and P (mg⋅L^−1)	Treatments	Time
		Tillering stage (stage I)		Jointing-booting stage (stage II)		Panicle initiation stage (stage III)		Milky stage (stage IV)
		Flooding	Drought	Flooding	Drought	Flooding	Drought	Flooding	Drought
-N	FFTD	5.17	4.01	1.24	0.83	2.34	0.88	0.92	0.77
	FDTF	6.18	3.83	1.69	1.07	3.01	1.60	1.10	0.61
-N	FFTD	1.72	1.17	0.83	0.39	1.33	0.79	0.51	0.34
	FDTF	2.43	1.53	1.10	0.86	1.78	1.35	0.57	0.26
TP	FFTD	0.088	0.056	0.055	0.038	0.046	0.036	0.032	0.035
	FDTF	0.106	0.066	0.101	0.034	0.064	0.034	0.039	0.040

Note: mean values in the same row followed by the same letter show nonsignificant difference. FDTF indicates first drought and then flooding; FFTD indicates first flooding and then drought.