Effect of different types of organic fertilizers on the chemical properties and enzymatic activities of an Oxisol under intensive cultivation of vegetables for 4 years

Figures & data

Table 1 Some selected chemical properties of the original soil and the soils after harvesting the final three crops

Treatment		pH (1:1)	EC (saturated)(dS m^−1)	Total C	Total N	Mehlich III extractable
						P	K	Ca	Mg
				(g kg^−1)		(mg kg^−1)
Original soil		6.7	0.2	14.0	4.42	93	127	3054	207
	CF	5.19 c	3.33 b	13.0 e	4.43 d	328 cd	265 bc	753 d	239 e
	SBM	4.30 e	1.16 d	14.8 e	2.31 e	234 e	200 e	43 f	48 f
After 24th crop	PRC	4.83 d	2.10b cd	57.4 b	8.13 b	367 bc	235 bc	384 e	430 c
	DCDC	4.96 cd	4.88 a	81.3 a	12.25 a	408 b	720 b	1278 b	667 a
	HDC	6.13 a	2.68 bc	42.0 c	6.43 c	291 de	346 de	2033 a	436 c
	CDC	6.79 a	1.79 cd	30.7 cd	4.75 d	549 a	691 a	1847 a	506 b
	SA	5.18 c	2.66 bc	40.6 d	6.46 c	346 bcd	372 bcd	948 c	332 d
	CF	5.55 d	1.05 de	11.3 f	3.79 e	282 b	292 c	983 e	181 c
	SBM	4.58 d	0.73 e	14.4 f	2.34 f	198 c	141 d	53 g	40 f
After 25th crop	PRC	4.70 cd	1.85 bc	60.9 b	7.94 b	268 b	317 bc	779 f	381 e
	DCDC	4.89 c	4.43 a	89.0 a	12.27 a	272 b	580 a	1662 c	592 a
	HDC	6.67 a	2.08 b	46.6 c	6.43 c	222 c	360 bc	3014 a	379 e
	CDC	6.90 a	1.28 d	31.6 de	5.07 d	459 a	545 a	2078 b	448 b
	SA	5.62 b	1.51 cd	40.8 cd	6.44 c	261 b	365 b	1270 d	293 d
	CF	5.40 e	2.32 c	12.3 d	4.12 f	309 cd	281 c	920 d	211 e
	SBM	4.15 f	1.74 c	14.9 d	2.32 g	258 de	172d	65 e	89 f
After 26th crop	PRC	4.96 cd	2.85 b	57.6 b	8.04 b	333 bc	539 a	1025 d	462 b
	DCDC	4.73 d	4.06 a	81.4 a	9.35 a	382 b	433 b	1509 c	183 a
	HDC	6.83 a	2.27 bc	50.3 b	5.37 d	237 e	261 cd	4463 a	396 c
	CDC	6.56 b	2.12 c	31.6 c	4.53 e	553 a	625 a	2177 b	473 ab
	SA	5.17 c	2.99 b	49.1 b	5.86 c	319 c	342 bc	1443 c	325 d
Within columns of the same crop, means followed by the same letter are not significantly different (P = 0.05) using a Duncan's multiple range test. CDC, chicken dung compost; CF, chemical fertilizer; DCDC, dairy cattle dung compost; HDC, hog dung compost; PRC, pea residue compost; SA, sequential application; SBM, soybean meal.

Table 2 Some selected heavy metal contents of the original soil and the soil after harvesting the final three crops

Treatment		Mehlich III extractable (mg kg^−1)
		Cu	Zn	Cd	Pb	Cr	Ni
Original soil		2.34	15.6	0.13	4.85	0.37	2.13
	CF	2.55 a	28.9 a	0.14 b	5.11 a	0.28 a	2.31 a
	SBM	1.95 b	11.0 e	0.06 d	1.43 b	UD	1.75 ab
After 24th crop	PRC	0.08 f	21.8 d	0.12 c	0.28 ef	0.55 a	1.55 ab
	DCDC	0.13 f	23.3 c	0.16 b	0.15 f	UD	1.43 b
	HDC	1.20 c	24.1 c	0.20 a	0.65 c	UD	1.83 ab
	CDC	1.00 d	26.8 b	0.22 a	0.33 de	UD	1.68 ab
	SA	0.58 e	23.3 c	0.15 b	0.43 d	0.28 a	2.33 a
	CF	3.14 a	26.4 bc	0.13 b	5.02 a	0.32 b	2.22 a
	SBM	2.23 b	10.8 e	0.06 c	1.80 b	0.02 c	1.30 bc
After 25th crop	PRC	0.20 d	23.4 d	0.08 c	0.38 d	0.11 c	0.98 c
	DCDC	0.30 d	25.5 c	0.15 b	0.35 d	0.13 c	1.32 bc
	HDC	1.60 c	27.5 b	0.20 a	1.10 c	1.12 a	2.00 a
	CDC	1.30 c	29.8 a	0.21 a	0.50 e	0.50 ab	1.48 b
	SA	0.58 d	25.9 c	0.17 ab	1.18 c	0.53 ab	1.25 bc
	CF	2.89 a	27.7 cd	0.18 a	4.65 a	0.25 c	2.18 a
	SBM	0.95 b	12.0 d	0.03 c	1.53 b	1.95 ab	1.22 b
After 26th crop	PRC	UD	30.5 c	0.08 bc	0.13 c	1.60 b	0.95 b
	DCDC	UD	34.8 c	0.12 b	0.48 c	0.45 c	1.30 b
	HDC	0.65 c	45.5 b	0.21 a	1.15 b	2.38 a	2.03 a
	CDC	0.38 d	57.0 a	0.20 a	0.30 c	2.00 ab	1.35 b
	SA	0.18 e	35.8 c	0.08 bc	0.23 c	2.70 a	1.20 b
Within columns of the same crop, means followed by the same letter are not significantly different (P = 0.05) using a Duncan's multiple range test. CDC, chicken dung compost; CF, chemical fertilizer; DCDC, dairy cattle dung compost; HDC, hog dung compost; PRC, pea residue compost; SA, sequential application; SBM, soybean meal, UD, under the detection limit.

Table 3 Some selected characteristics (on a dry-weight basis) of the organic fertilizers used in the experiment

Parameter	Soybean meal	Pea residue compost	Dairy cattle dung compost	Hog dung compost	Chicken dung compost
Organic matter (g kg^−1)	700 a	690 a	670 a	600 a	620 a
Total N (g kg^−1)	52.0 a	27.9 b	29.5 b	26.2 b	30.2 b
C/N	6.0 b	11.0 a	10.2 a	10.2a	9.1 ab
pH (1:5)	6.10 a	6.40 a	6.45 a	7.30 a	6.50 a
EC (dS m^−1) (1:5)	4.75 b	3.83 b	7.79 ab	3.84 b	13.08 a
Total P (g kg^−1)	9.1 b	6.7 b	10.8 ab	10.7 ab	17.1 a
Total K (g kg^−1)	21.3 b	10.3 b	19.7 b	14.4 b	37.0 a
Total Ca (g kg^−1)	3.0 b	6.5 b	13.1 b	44.5 a	46.5 a
Total Mg (g kg^−1)	2.8 b	3.2 b	5.5 b	4.5 b	8.4 a
Total Cu (mg kg^−1)	11.6 c	17.3 c	29.8 c	101.8 b	222.5 a
Total Zn (mg kg^−1)	36.7 c	78.7 c	136.8 b	228.6 a	265.2 a
Total Mn (mg kg^−1)	28.3 d	178 c	372 b	507 a	516 a
Total Cd (mg kg)	0.7 c	0.7 c	1.5 bc	3.1 a	2.5 ab
Total Ni (mg kg)	25.9 b	34.5 b	42.0 b	89.6 a	89.7 a
Total Cr (mg kg)	0.3 b	3.3 b	7.3 b	91.0 a	8.9 b
Total Pb (mg kg)	3.9 b	7.3 b	14.0 b	36.7 a	16.2 b
Within rows, means followed by the same letter are not significantly different (P = 0.05) using a Duncan's multiple range test. EC, electrical conductivity.

Figure 1  Effect of the treatments on the microbial biomass content, respiration and nitrification over 4 years of cultivation. Bars with the same letter are not significantly different at the 0.95 level of probability, according to a Duncan's Multiple Range Test. CDC, chicken dung compost; CF, chemical fertilizer; DCDC, dairy cattle dung compost; HDC, hog dung compost; PRC, pea residue compost; SA, sequential application; SBM, soybean meal.

Table 4 Linear correlation coefficients between selected chemical properties and the enzymatic activities of the soils

	Mic-C	Mic-N	pH	EC	OM	TN	EXT-P	EXT-K	EXT-Ca	EXT-Mg
Mic-C	–	0.8923**	–0.1342	0.7411**	0.9007**	0.9548**	0.1015	0.4709*	0.0995	0.7120**
Mic-N	0.8923**	–	–0.0490	0.6672**	0.8205**	0.8901**	0.1425	0.5839**	0.2047	0.7273**
CO2-resp	0.5847*	0.5317*	0.1597	0.4454*	0.7555**	0.6952**	0.1418	0.5375*	0.4277	0.6279**
dHase	0.2280	0.4539*	0.7916**	–0.0144	0.1196	0.2042	0.2427	0.4150	0.5940**	0.5941**
Gluase	0.9194**	0.8311**	–0.1470	0.5346*	0.8055**	0.8720**	0.0781	0.4156	–0.0245	0.6773**
Protease	0.8503**	0.8552**	0.2285	0.6408**	0.7587**	0.8392**	0.2054	0.6105*	0.3592	0.7743**
Urease	0.2347	0.3320	0.8353**	0.2480	0.3150	0.3095	0.5411*	0.6288**	0.8066**	0.7001**
Nitrifi	–0.2674	–0.0141	0.8874**	–0.1997	–0.1495	–0.1783	0.1543	0.4284	0.6202**	0.3480
aSase	0.0943	0.2544	0.5552**	0.2364	0.3338	0.2202	0.1889	0.3517	0.7139**	0.3750
aPase	0.7886**	0.6155**	–0.5878**	0.6091**	0.7758**	0.7816**	–0.1480	0.1364	–0.3036	0.2662
Pase	0.2744	0.4612*	0.8299**	0.2304	0.3391	0.3191	0.0616	0.4800*	0.8976**	0.7273**
Mic-C, microbial C; Mic-N, microbial N; CO2-resp, respiration rate; dHase, dehydrogenase; Gluase, β-glucosidase; Nitrifi, nitrification; aSase, arylsulphatase; aPase, acid phosphatase; Pase, alkaline phosphatase; OM, organic matter content; TN, total N content, EXT-P, Mehlich III extractable P. *P < 0.05;
**P < 0.01.

Figure 2  Effect of the treatments on soil enzymatic activities over 4 years of cultivation. Bars with the same letter are not significantly different at the 0.95 level of probability, according to a Duncan's Multiple Range Test. CDC, chicken dung compost; CF, chemical fertilizer; DCDC, dairy cattle dung compost; HDC, hog dung compost; PRC, pea residue compost; SA, sequential application; SBM, soybean meal.

Table 5 Linear correlation coefficients between the extractable heavy metal concentrations and the enzymatic activities of the soils

	Cu	Zn	Cd	Pb	Cr	Ni
Mic-C	–0.6181**	0.0374	0.1196	–0.4538*	–0.2526	–0.2784
Mic-N	–0.5287**	–0.0265	0.2735	–0.5251*	–0.3327	–0.1622
CO2-resp	–0.7271**	0.4583*	0.1166	–0.5914**	0.3962	–0.5973**
dHase	–0.0173	0.2179	0.7805**	–0.2042	–0.1838	0.2685
Gluase	–0.6277**	–0.0335	0.0436	–0.4839*	–0.2460	–0.3245
Protease	–0.4604*	0.1024	0.4801*	–0.4205	–0.3043	–0.0623
Urease	–0.2651	0.8064**	0.8087**	–0.2598	0.2816	0.1044
Nitrifi	0.1200	0.4563*	0.7410**	–0.0883	0.1204	0.2352
aSase	–0.3447	0.6307**	0.3695	–0.3365	0.5451*	–0.0469
aPase	–0.5485**	–0.2435	–0.3603	–0.2934	–0.2052	–0.3629
Pase	–0.2337	0.5209*	0.8315**	–0.3460	0.1221	0.1852
Mic-C, microbial C; Mic-N, microbial N; CO2-resp, respiration rate; dHase, dehydrogenase; Gluase, β-glucosidase; Nitrifi, nitrification; aSase, arylsulphatase; aPase, acid phosphatase; Pase, alkaline phosphatase. *P < 0.05;
**P < 0.01.