Table 1. Effect of no-till on the soil environment.

• Soil physical characteristics– Increased soil water– Moderation of soil temperature– Increased bulk density

• Soil chemical characteristics– Increased soil organic matter– Decreased ph at the surface

Table 2. N immobilization of 15N fertilizer (%) (Rice & Smith, 1984)

Soil type Plowed No-till

Cavode 15 24

Maury 11 21

Tilsit 6 13

Table 3. N Mineralized From Sod (Rice et al., 1987).

Site Soil drainage Plowed No-till ug N/g 1 Well 40 92 Moderately well 73 84 Somewhat poorly 48 29 2 Moderately well 17 22 Somewhat poorly 9 12 Poorly 11 8

Table 4. Effect of tillage systems and N fertilization on N mineralization (Espinoza, Y. 1997.)

Tillage NitrogenPotential

Nmin

Actual Nmin

No tillage No nitrogen 277c 40b

Manure 490a 98a

Fertilizer 320c 70ab

Conventional tillage No nitrogen 297c 53b

Manure 431b 87a

Fertilizer 348bc 72ab

Figure 1. Effect of tillage on soil organic carbon after 10 y (0-5 cm).

0

5

10

15

20

25

mg

C/g

Control Fertilizer Manure

a

bbbcc c

Figure 2. Effect of tillage and rotation on soil organic carbon after 34 y (0-30 cm) (Dick and Durkalski, 1997).

0

2

4

6

8

10

12

Mg

C/h

a

Maize/soy Maize Maize/Oat/Hay

No-tillPlow

abb

bcc

c

Figure 3. Effect of tillage on soil nitrogen after 10 y (0-5 cm)

0

0.5

1

1.5

2

2.5

3

mg

N/g

Control Fertilizer Manure

abb bccd d

Figure 4. Effect of long-term tillage on N mineralization (Rice et al., 1986)

0

5

10

15

20

25

ug

N/g

Plowed No-till Grass

Figure 5. Effect of tillage and N source on denitrifying enzyme activity (0-5 cm) (Kocyigit, 1998).

0

50

100

150

200

250

ug

N2O

-N/g

/h

Control Fertilizer Manure

No-tillCT