Effect of soil contamination and additives on fermentative profile, microbial community and iron bioaccessibility of alfalfa silage

Chemical and Biological Technologies in Agriculture

Table 1 The fermentation characteristics of alfalfa silage

Item	Soil level (%)	Additives			SEM	Significance
Item	Soil level (%)	Con	LP	MLP	SEM	S	A	S × A
pH values	0	5.93^a ± 0.05	4.95^bB ± 0.04	4.71^bB ± 0.19	0.018	< 0.001	< 0.001	0.071
	1.5	5.91^a ± 0.08	4.94^bB ± 0.01	4.82^cAB ± 0.02
	7.5	5.95^a ± 0.01	5.18^bA ± 0.04	5.06^bA ± 0.07
LA (g kg⁻¹ DM)	0	17.3^bAB ± 1.47	39.4^abA ± 1.29	46.8^a ± 9.75	1.641	0.548	< 0.001	0.952
	1.5	20.1^bA ± 0.60	37.3^aAB ± 0.16	41.8^a ± 5.95
	7.5	14.2^bB ± 0.25	35.6^aB ± 0.63	40.6^a ± 3.18
AA (g kg⁻¹ DM)	0	14.1^a ± 0.58	10.4^bA ± 0.08	12.9^a ± 0.24	0.433	0.094	< 0.001	0.485
	1.5	14.6^a ± 1.18	7.2^bB ± 0.80	14.2^ab ± 2.52
	7.5	12.2^a ± 0.93	6.5^bB ± 0.42	11.7^a ± 0.58
PA (g kg⁻¹ DM)	0	8.3^bA ± 0.41	8.6^bA ± 0.15	16.4^aA ± 0.46	0.183	< 0.001	< 0.001	0.045
	1.5	5.7^cB ± 0.13	6.7^bB ± 0.27	15.8^aA ± 0.01
	7.5	4.6^bB ± 0.30	4.5^bC ± 0.58	11.0^aB ± 0.94
BA (g kg⁻¹ DM)	0	1.0^aB ± 0.07	0.3^bC ± 0.05	ND^c ± 0.01	0.057	< 0.001	< 0.001	0.004
	1.5	0.6^aB ± 0.01	0.4^bB ± 0.07	ND^c ± 0.01
	7.5	2.2^aA ± 0.39	0.9^bA ± 0.03	0.1^b ± 0.08
AN (g kg⁻¹ TN)	0	111.3^aB ± 2.35	51.4^cC ± 0.40	59.4^bB ± 0.19	0.724	< 0.001	< 0.001	< 0.001
	1.5	118.0^aB ± 3.64	50.0^bB ± 1.67	55.6^bC ± 0.23
	7.5	156.4^aA ± 1.05	65.6^cA ± 1.83	74.9^bA ± 1.45

DM, dry matter; TN, total nitrogen
LA, lactic acid; AA, acetic acid; PA, propionic acid, BA, butyric acid; AN, ammonia nitrogen
Con, control; LP, Lactobacillus plantarum inoculant alone; MLP, combination addition of molasses and Lactobacillus plantarum inoculant
SEM, error of the means; S, soil contamination levels; A, additives; S × A, interaction between soil contamination levels and additives. Means within the same row (a, b) or within the same column (A, B) with different superscript differ significantly from each other (P < 0.05)