Fusarium populations in soil under long-term organic and chemical fertilizer treatments

Figures & data

Table I. Soil chemical characteristics of a winter wheat–summer maize rotation experiment using organic fertilizer (OF) or chemical fertilizer (CF) for 9 years (C9) and 13 years (C13) after establishment. 15 t ha⁻¹ of OF corresponding to a rate of 100.5 kg N ha⁻¹ was applied annually. CF was applied at 265.5 kg N ha⁻¹ and 39.3 kg P ha⁻¹ annually.

Experiment	Treatment	SOM (g kg^−1)	Nt (g kg^−1)	Nh (mg kg^−1)	P (mg kg^−1)	K (mg kg^−1)	pH
C9	OF	22.4a	1.4a	110.6a	54.9a	278.1a	7.2b
	CF	13.2b	0.8b	68.9b	20.1b	94.2b	7.4a
	U	12.2b	0.8b	63.3b	3.2c	98.9b	7.5a
C13	OF	20.9a	1.2a	103.7a	36.3a	161.8a	7.3b
	CF	13.7b	0.8b	68.9b	23.6a	72.8b	7.4a
	U	12.8b	0.8b	68.4b	4.1b	80.9b	7.5a
Different letters in a column for each experiment denote significant differences with three replicates (p < 0.05); U, unfertilized control; SOM, soil organic matter; Nt, total nitrogen; Nh, hydrolyzable nitrogen; P, available phosphorus; K, available potassium.

Figure 1.  Macroconidia of Fusarium species from soil in the North China Plain as produced on carnation leaf-piece agar (CLA). A: F. proliferatum; B: F. solani; C: F. equiseti; D: F. semitectum; E: F. polyphialidicum; F: F. oxysporum; and G: F. merismoides (magnification×400; bar = 25 µm).

Figure 2.  Bands on agarose (1%) gel after electrophoresis with nucleic acid-based determination of Fusarium species. Lane assignments: 1–7, F. proliferatum; 8–10, F. solani; 11, 12, F. semitectum; 13, F. merimoides; 14, 15, F. polyphialidicum; 17, 18 F. equiseti; 16, 19–21 F. oxysporum; 22, 23, F. graminearum (from one isolate). M Lanes represents molecular weight marker.

Table II. Identities of eight Fusarium species as determined by morphological and molecular characteristics.

Band code	Morphological identification	Primers	Amplicon size (bp)	Molecular identification
1–7	F. proliferatum	PRO 1/2^b	585	F. proliferatum
8–10	F. solani	ITS F/R^a	–	–
11, 12	F. semitectum	ITS F/R^a	431	Fusarium
13	F. merimoides	ITS F/R^a	–	–
14, 15	F. polyphialidicum	ITS F/R^a	431	Fusarium
16, 19–21	F. oxysporum	CLOX 1/2^b	534	F. oxysporum
17, 18	F. equiseti	FE F1/R1^b	389	F. equiseti
22, 23	F. graminearum	Fg16 F/R^b	400	F. graminearum sensu stricto
Band codes were coincided with the codes in Figure 2; ^aUniversal Fusarium primers; ^bSpecies-specific primers.

Table III. Probability levels of analysis of variance (ANOVA, p values) for population levels and diversity of Fusarium species with treatments (T), sampling times (S), and experiments (E) as factors.

Taxon	T	E	S	T×E	T×S	S×E	E×T×S
F. equiseti	0.002	0.613	0.479	0.274	0.875	0.363	0.670
F. graminearum	0.371	0.319	0.319	0.371	0.371	0.319	0.371
F. merismoides	0.628	0.274	0.274	0.468	0.468	0.639	0.162
F. oxysporum	0.478	0.519	0.019	0.192	0.478	0.519	0.192
F. polyphialidicum	0.115	0.025	0.025	0.260	0.260	0.108	0.260
F. proliferatum	0.249	0.043	<0.001	0.389	0.040	0.078	0.176
F. semitectum	0.444	0.047	<0.001	0.462	0.531	0.244	0.602
F. solani	0.039	0.023	0.542	0.796	0.927	0.361	0.717
Total	0.302	0.005	<0.001	0.743	0.336	0.811	0.967
H′	0.069	0.404	<0.001	0.454	0.401	0.438	0.446
Values in bold are significant at the p < 0.05 level; H′, Shannon-Wiener index.

Table IV. Mean of Fusarium population levels (10³ CFUs/g dry soil) from three fertilizer treatments in two experiments in samples collected in November 2006 and May 2007. For the explanation of C9 and C13, see Table I.

	C9			C13
Fusarium species	OF	CF	U	OF	CF	U
F. equiseti	0.75	0.63	0.42	0.96a	0.54a	0.08b
F. graminearum	0.42	0	0	0	0	0
F. merismoides	0.25	0.42	0.08	0	0	0.08
F. oxysporum	0.13	0	0.42	0.08	0.21	0
F. polyphialidicum	0.04	0	0	0.17	0	0.17
F. proliferatum	1.71	2.08	2.00	2.25	2.25	3.20
F. semitectum	0.50ab	0.79a	0.33b	1.00	0.83	0.79
F. solani	1.08a	0.50b	0.75ab	1.54	1.04	1.00
Total	4.67	4.29	3.63	6.04	5.17	5.38
H′	0.71	0.65	0.59	0.86	0.62	0.62
Different letters in a row for each experiment denote significant differences with three replicates (p < 0.05); C9, consecutive 9-year experiment; C13, consecutive 13-year experiment; OF, organic fertilizer; CF, chemical fertilizer; U, unfertilized control; H′, Shannon-Wiener index.

Table V. Correlation coefficient for soil chemical parameters to Fusarium population levels (10³ CFUs/g soil).

Fusarium species	SOM (g kg^−1)	Nt (g kg^−1)	Nh (mg kg^−1)	P (mg kg^−1)	K (mg kg^−1)	pH
F. equiseti	0.236**	0.214**	0.228**	0.250**	0.181*	−0.255**
F. graminearum	0.131	0.148	0.131	0.144	0.171*	−0.143
F. merismoides	0.071	0.094	0.073	0.075	0.124	−0.075
F. oxysporum	0.062	0.054	0.053	0.095	0.042	−0.084
F. polyphialidicum	0.087	0.072	0.096	0.003	0.023	−0.011
F. proliferatum	−0.097	−0.104	−0.091	−0.120	−0.119	0.123
F. semitectum	0.018	−0.012	0.019	0.020	−0.053	−0.018
F. solani	0.220**	0.196*	0.220**	0.146	0.128	−0.150
Total	0.093	0.065	0.094	0.068	0.012	−0.065
H′	0.152	0.133	0.151	0.127	0.094	−0.132
SOM, soil organic matter; Nt, total nitrogen; Nh, hydrolyzable nitrogen; P, available phosphorus; K, available potassium; H′, Shannon-Wiener index; *Correlation is significant at p=0.05 level; **Correlation is significant at p = 0.01.