Table 3. Content of NO₃⁻−N, NH₄⁺–N, and Available P and K in the 0–20 cm Soil Layer from Different Treatments in 2016–2018 at Maturity^a.

year	treatment	NO3−−N (mg kg–1)	NH4+–N (mg kg–1)	available P (mg kg–1)	available K (mg kg–1)
2016	CK	19.1c	10.5c	27.4a	200.0a
	CFF	25.0b	12.8bc	28.1a	216.8a
	CP0	34.2a	16.3a	28.3a	210.1a
	CP1	36.5a	17.1a	28.2a	198.3a
	CP2	34.6a	17.2a	32.5a	200.0a
	CP3	36.5a	14.9ab	32.9a	186.5a
2017	CK	13.6b	16.3b	30.8a	161.6a
	CFF	16.8b	18.2b	26.8a	169.6a
	CP0	23.4a	23.8a	31.0a	161.6a
	CP1	23.5a	24.0a	30.1a	156.8a
	CP2	23.1a	23.0a	28.8a	145.5a
	CP3	26.1a	26.2a	27.5a	155.2a
2018	CK	16.1b	10.3b	23.3a	189.3a
	CFF	20.9b	11.4b	23.0a	174.6a
	CP0	27.4a	16.9a	27.2a	165.5a
	CP1	27.0a	17.4a	23.6a	177.8a
	CP2	28.0a	17.9a	21.6a	172.0a
	CP3	30.1a	16.0a	23.0a	157.7a

^aNote: Means followed by the same lowercase letter within each column in the same year were not significantly different (p > 0.05) based on analysis by one-way ANOVAs followed by Duncan multiple range tests.