Measurement of the maximum amount of water-extractable phosphorus in animal manure compost by continuous and sequential water extraction

Figures & data

Figure 1 Schematic diagram of the apparatus used for the continuous water (H₂O) extraction.

Table 1 Chemical properties of the animal manure composts used in this study

						Unit					Ca/P
Livestock	Compost †	N	C	P	K	mg g^−1 ‡	Mg	Fe	Al	C/N	(mol mol^−1)
Cattle	CMC 1	27.5	333	11.2	47.6	17.3	8.0	2.6	1.1	12.1	1.2
	CMC 2	23.9	376	14.1	44.3	18.0	8.3	2.3	1.5	15.8	1.0
	CMC 3	22.1	412	14.6	32.5	22.8	10.9	1.7	0.80	18.6	1.2
	CMC 4	12.4	282	9.61	14.0	68.7	9.4	5.0	37.1	22.7	5.5
	Mean §	21.5b	351a	12.4b	34.6a	31.7b	9.1a	2.9a	10.1a	17.3a	2.2ab
Swine	SMC 1	46.3	303	52.8	36.5	80.0	21.5	7.5	0.80	6.5	1.2
	SMC 2	29.8	367	29.2	33.4	47.5	13.1	15.8	1.3	12.3	1.3
	SMC 3	53.9	389	33.6	33.1	44.8	14.6	3.4	0.74	7.2	1.0
	SMC 4	56.2	364	37.5	27.5	51.4	13.5	5.7	1.1	6.5	1.1
	SMC 5	41.8	362	26.6	27.7	69.8	10.5	3.1	0.67	8.7	2.0
	Mean	45.6a	357a	36.0a	31.7a	58.7b	14.6a	7.1a	0.92a	8.2b	1.3b
Layer	LMC 1	28.3	248	27.6	37.4	139	11.4	3.5	1.3	8.8	3.9
	LMC 2	29.0	242	41.9	47.5	154	16.1	2.4	1.3	8.3	2.8
	LMC 3	26.7	224	25.6	32.8	214	9.2	2.9	1.0	8.4	6.5
	LMC 4	35.1	277	27.9	33.9	142	8.5	3.4	0.54	7.9	3.9
	LMC 5	44.3	304	21.6	25.4	123	6.8	1.1	0.28	6.9	4.4
	Mean	32.7ab	259b	28.9a	35.4a	155a	10.4a	2.7a	0.88a	8.0b	4.3a
Broiler	BLC 1	34.1	398	21.1	40.8	51.3	9.4	2.8	0.70	11.7	1.9
	BLC 2	28.9	414	12.5	31.5	41.2	7.0	0.69	0.22	14.3	2.5
	Mean	31.5ab	406a	16.8ab	36.1a	46.2b	8.2a	1.7a	0.46a	13.0ab	2.2ab

N, nitrogen; C, carbon; P, phosphorus; K, potassium; Ca, calcium; Mg, magnesium; Fe, iron; Al, aluminum.†CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost. ‡Nutrient contents: dry matter basis. §Means for a given element followed by the same letter do not differ significantly (p < 0.05).

Table 2 The fractionation of phosphorus (P) in the animal manure composts by sequential chemical extraction

		Concentrations of P in each fraction						Ratios of P in each fractions to total P
Livestock	Compost †	Total	H2O	NaHCO3	NaOH	HCl	Residual	H2O	NaHCO3	NaOH	HCl	Residual
				mg P g^−1 ‡						%
Cattle	CMC 1	11.2	6.03	3.18	0.24	0.31	1.43	53.9	28.5	2.11	2.73	12.8
	CMC 2	14.1	5.85	3.13	0.66	1.94	2.57	41.4	22.1	4.69	13.7	18.1
	CMC 3	14.6	4.63	6.72	0.40	1.95	0.89	31.7	46.1	2.72	13.4	6.1
	CMC 4	9.61	1.63	4.05	0.27	3.15	0.51	17.0	42.2	2.77	32.8	5.3
	Mean §	12.4b	4.53b	4.27ab	0.39a	1.84b	1.35c	36.0a	34.7a	3.07a	15.6b	10.6b
Swine	SMC 1	52.8	9.52	12.8	3.14	24.8	2.54	18.0	24.3	5.94	46.9	4.8
	SMC 2	29.2	8.21	5.63	1.87	12.2	1.32	28.1	19.3	6.40	41.7	4.5
	SMC 3	33.6	11.9	9.13	0.89	9.61	2.12	35.3	27.1	2.65	28.6	6.3
	SMC 4	37.5	10.6	4.54	0.35	20.0	2.09	28.2	12.1	0.94	53.2	5.6
	SMC 5	26.6	7.90	4.21	0.88	10.4	3.16	29.7	15.8	3.30	39.2	11.9
	Mean	36.0a	9.62a	7.27a	1.43a	15.4a	2.25bc	27.9a	19.7b	3.85a	41.9a	6.62b
Layer	LMC 1	27.6	5.46	2.67	0.43	13.7	5.38	19.8	9.67	1.55	49.5	19.5
	LMC 2	41.9	7.86	6.29	0.05	25.5	2.22	18.8	15.0	0.13	60.8	5.3
	LMC 3	25.6	6.38	2.06	0.71	12.1	4.44	24.9	8.02	2.76	47.0	17.3
	LMC 4	27.9	6.11	1.59	0.16	12.0	8.13	21.9	5.67	0.56	42.8	29.1
	LMC 5	21.6	3.54	2.52	0.55	6.11	8.89	16.4	11.7	2.55	28.3	41.1
	Mean	28.9ab	5.87b	3.02 ab	0.38a	13.9a	5.81a	20.3a	10.0b	1.51a	45.7a	22.5ab
Broiler	BLC 1	21.1	4.50	1.40	0.29	9.13	5.82	21.3	6.61	1.38	43.2	27.5
	BLC 2	12.5	2.14	0.38	0.16	2.85	7.01	17.1	3.03	1.25	22.7	55.9
	Mean	16.8ab	3.32b	0.89b	0.22a	5.99b	6.41ab	19.2a	4.82b	1.32a	32.9ab	41.7a

H₂O, water; NaHCO₃, sodium bicarbonate; NaOH, sodium hydroxide; HCl, hydrochloric acid.†CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost. ‡P concentrations: dry matter basis. §Means for a given fraction followed by the same letter do not differ significantly (p < 0.05).

Figure 2 The dissolution patterns of phosphorus (P) as a function of the cumulative water volume in the continuous water extraction. Curves represent the first-order and second-order regression equations; the best-fit models and the regression parameters are summarized in Table 3. CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost.

Figure 3 The dissolution patterns of calcium (Ca) as a function of cumulative water volume in the continuous water extraction. Curves represent the first-order and second-order regression equations; the best-fit models and the regression parameters are summarized in Table 3. CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost.

Figure 4 The dissolution patterns of magnesium (Mg) as a function of cumulative water volume in the continuous water extraction. Curves represent the first-order and second-order regression equations; the best-fit models and the regression parameters are summarized in Table 3. CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost.

Table 3 Fitted values of the parameters used to model the phosphorus (P), calcium (Ca), magnesium (Mg) and potassium (K) release patterns, and the associated coefficient of determination (R²)

	P				Ca				Mg
Compost †	Fitted model	WEPmax (µmol g^−1)	k1 or k2 (gL^−1, g^2µmol^−1L^−1)	R^2	Fitted model	WECamax (µmol g^−1)	k1 or k2 (gL^−1, g^2µmol^−1L^−1)	R^2	Fitted model	WEMgmax (µmol g^−1)	k1 or k2 (gL^−1,g^2µmol^−1L^−1)	R^2
CMC1	II	315	6.52 × 10^−3	0.995	I	268	5.78	0.991	I	290	5.81	0.994
CMC2	II	314	7.69 × 10^−3	0.997	II	334	3.33 × 10^−4	0.998	II	311	3.69 × 10^−4	0.999
CMC3	II	327	3.85 × 10^−3	0.991	I	614	9.35	0.996	I	385	4.93	1.000
CMC4	II	189	4.33 × 10^−3	0.999	II	6.75 × 10^8	2.10 × 10^−16	1.000	II	234	2.37 × 10^−3	1.000
SMC1	I	661	5.54 × 10^−1	0.997	I	731	11.2	0.992	II	782	7.30 × 10^−4	0.999
SMC2	II	451	4.75 × 10^−3	0.992	I	2132	52.6	1.000	II	447	1.50 × 10^−3	0.998
SMC3	I	615	3.86 × 10^−1	0.996	II	935	1.08 × 10^−4	0.999	II	628	2.43 × 10^−3	0.995
SMC4	I	518	4.26 × 10^−1	0.998	II	322	8.59 × 10^−4	0.999	I	407	8.10 × 10^−1	0.998
SMC5	II	362	7.98 × 10^−3	0.994	I	847	8.47	0.999	II	395	2.32 × 10^−3	0.999
LMC1	II	241	1.69 × 10^−2	0.992	II	2.58 × 10^12	1.33 × 10^−23	0.999	II	353	2.01 × 10^−3	0.999
LMC2	I	421	3.55 × 10^−1	0.996	II	8.05 × 10^10	8.57 × 10^−21	0.979	II	584	1.19 × 10^−3	0.999
LMC3	I	275	4.48 × 10^−1	0.994	I	1800	13.9	0.999	I	288	1.04	0.998
LMC4	II	272	1.29 × 10^−2	0.996	I	1983	13.9	1.000	II	307	3.46 × 10^−3	0.999
LMC5	II	190	1.39 × 10^−2	0.995	I	881	6.29	1.000	II	253	3.13 × 10^−3	1.000
BLC1	II	201	1.48 × 10^−2	0.985	II	709	3.01 × 10^−4	0.998	II	300	4.20 × 10^−3	0.998
BLC2	I	68	2.15 × 10^−1	0.998	II	408	2.71 × 10^−3	0.992	II	245	1.11 × 10^−2	0.997

WEP_max, maximum water-extractable phosphorus; k₁, k₂, constants; WECa_max, maximum water-extractable calcium; WEMg_max, maximum water-extractable magnesium.†CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost.

Figure 5 The relationships between the H₂O-P (open symbols) or H₂O-P + NaHCO₃-P (filled symbols) and the maximum water-extractable P (WEP_max). H₂O-P and NaHCO₃-P is water- and sodium bicarbonate (NaHCO₃-) extractable P using the modified Hedley sequential extraction method. CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost. The dashed line represents y = x. ***, significant at P < 0.001.

Figure 6 The relationships between WEP_max and (left) the amount of extractable calcium (Ca) at 4.0 L g⁻¹ or (right) WEMg_max. WEP_max, maximum amount of water-extractable phosphorus determined by means of non-linear regression; WEMg_max, maximum amount of water-extractable magnesium determined by means of non-linear regression. CMC, cattle manure compost; SMC, swine manure compost; LMC, layer (chicken) manure compost; BLC, broiler (chicken) litter compost. *, significant at P < 0.05; **, significant at P < 0.01.