Combined application of N-fixing PGPB and rice straw mulch compensates N immobilization by straw, improving crop growth

Chemical and Biological Technologies in Agriculture

Table 4 Mean values ± SE of the respiration rate, temperature and soil water content obtained in microcosm conditions at the indicated sampling dates for the factors inoculation and the presence of mulching (in the case of temperature and soil water content only for the factor mulching)

Factor	Treatment	Soil respiration rate (mg CO2 m⁻² h⁻¹)		Temperature			Water content (%)
		Soil respiration rate (mg CO2 m⁻² h⁻¹)		Average	Maximum	Minimum	Water content (%)
		April sampling	September sampling	September2020	September 2021	Sampling	September sampling
Inoculation	Non-inoculated control	259.1 ± 15.1	181.28 ± 4.43
	Azotobacter chroococcum SM199	298.6 ± 11.7 ns	196.12 ± 3.35 ns
	Azotobacter chroococcum SM232	312.5 ± 10.8**	181.92 ± 9.92 ns
	Azotobacter salinestris SM662	319.4 ± 4.8**	202.57 ± 9.87***
	Azotobacter chroococcum SM700	309.7 ± 5.9*	192.25 ± 5.63 ns
	Azospirillum brasilense Az39	306.9 ± 18.7*	189.02 ± 7.66 ns
Mulch	Non-mulching control	291.4 ± 8.8	178.48 ± 3.31	14.82 ± 0.24	24.42 ± 0.34	8.40 ± 0.25	26.29 ± 0.22
	Mulching	310.7 ± 6.7*	202.57 ± 3.12***	14.87 ± 0.23 ns	22.51 ± 0.30***	8.95 ± 0.24 ns	24.89 ± 0.62*

Asterisks indicate the level of significance of the difference between the mean values of each treatment and its corresponding control, according to Dunnett’s test. Significance levels: ***p < 0.001; **0.001 < p < 0.01; *0.01 < p < 0.05; ns, not significant.