Effects of Deep Tillage and Straw Returning on Soil Microorganism and Enzyme Activities

Table 1

Differences of tillage, year, soil depth, and soil texture on soil microorganism and enzyme activities.

Soil texture	Factor		Actinomycete	Bacteria	Fungi	Urease	Phosphatase	Saccharase	Catalase
Loam	Y (year)	2010	1.02	4.64^a	1.55^a	2.91^a	2.54	1.19^a	2.21^a
		2011	0.92	1.56^b	1.06^b	2.81^b	2.49	1.13^b	1.09^b
	T (tillage)	CT	0.86^b	3.17^b	1.51^b	2.89^b	2.11^b	1.21^a	1.53^c
		DT	1.31^a	3.69^a	1.73^a	3.05^a	2.65^a	1.24^a	1.58^b
		DNT	0.74^c	2.46^c	0.67^c	2.65^c	2.03^b	1.03^b	1.83^a
	D (soil depth)	0–10 cm	1.71^a	4.62^a	2.92^a	3.04^a	3.04^a	1.65^a	1.64^a
		10–20 cm	1.17^b	3.58^b	1.43^b	2.90^b	2.72^b	1.45^b	1.62^ab
		20–30 cm	0.75^c	2.97^c	0.57^c	2.82^c	1.92^c	0.97^c	1.65^ab
		30–40 cm	0.26^d	1.24^d	0.28^d	2.68^d	1.38^d	0.58^d	1.68^b
Clay	Y (year)	2010	2.33^b	2.79^b	1.88	2.65^a	2.25	1.16^a	2.51^a
		2011	2.83^a	3.36^a	1.83	2.58^b	2.28	1.07^b	1.13^b
	T (tillage)	CT	2.88^b	3.24^b	1.76^b	2.68^a	2.68^b	1.11^b	1.75^c
		DT	3.58^a	3.71^a	2.31^a	2.72^a	2.92^a	1.19^a	1.79^b
		DNT	1.29^c	2.28^c	1.50^c	2.44^b	1.93^c	1.04^c	1.93^a
	D (soil depth)	0–10 cm	4.19^a	5.46^a	3.73^a	2.96^a	3.07^a	1.26^a	1.80^b
		10–20 cm	3.76^b	3.76^b	2.09^b	2.67^b	2.52^b	1.24^a	1.79^b
		20–30 cm	1.73^c	2.27^c	1.16^c	2.52^c	2.36^c	1.05^b	1.85^a
		30–40 cm	0.64^d	0.82^d	0.45^d	2.31^d	2.10^d	0.89^c	1.85^a

Note: different small letters in the column indicated significant difference at 𝑃<0.05. Differences between 2010 and 2011 were compared by the Student 𝑡-test (2-tailed test). Differences among the different soil depths and soil tillage were determined by Duncan's test. CT represented conventional tillage, moldboard ploughed to a depth of 20 cm, and straw was returned. DT represented deep tillage moldboard ploughed to a depth of 30 cm and straw was returned. DNT represented deep tillage moldboard ploughed to a depth of 30 cm and straw was removed.