Maintenance of soil physical health at its optimum level is essential for sustainable crop production and rational use of natural resources without jeopardizing their quality. The ongoing conventional tillage practices for crop production using intensive ploughing and removal of crop residue from the field have resulted in an increase in surface crusting, soil compaction, soil erosion, decrease in water infiltration and ultimately aggravation of the overall soil physical health deterioration. Conservation tillage can improve soil physical structure and water storage, protect moisture, and increase crop yield. However, the long-term adoption of a single tillage method may have some adverse effects on soil and ecological environment, although crop yields have increased. Through informed allocation of soil tillage techniques, the combination and configuration of soil tillage measures, such as rotary tillage, sub-soiling, and no tillage may reduce the shortcomings of traditional long-term farming. Throughout the world, degradation of soil has become an environmental problem which limits the sustainability of agriculture and decreases soil productivity. The main reason of degradation is either over cultivation or the utilization of improper tillage methods. Therefore, tillage practices play a crucial role in chemical, biological and physical properties of agricultural soils. This role was determined often by using indicators of soil quality such as bulk density, aggregate stability, plant available water, organic carbon content, soil compaction and other properties.
The NT treatment had the highest effect at 0–10cm depth, while the effect for the ST treatment was highest at 0–30cm. SOC storage decreased with soil depth, with a significant accumulation at 0-20cm depth. Tillage system change influenced SOC content, NT, ST, and BT showed higher values of SOC content and increased 8.34, 7.83, and 1.64 MgCha−1, respectively, compared with CT. Across treatments, aggregate-associated C at a depth of 0–10cm was higher in the NT and ST treatments than in the MP and CT treatments. The advantage of the NT treatment weakened with soil depth, while the amount of aggregate-associated C remained higher for the ST treatment. There were more macro-aggregates in the ST and NT treatments than in the MP and CT treatments, while the MP and CT treatments had more micro-aggregates. The sum of macro-aggregate contributing rates for soil organic C (SOC) was significantly superior to that of the micro-aggregates. However, bulk density (Db) of the 10- to 20-cm soil layer was highest under puddled treatments (1.74–1.77 Mg m−3) and lowest under ZT treatments (1.66–1.71 Mg m−3). Likewise, soil penetration resistance (SPR) was highest at the 20-cm depth in puddled treatments (3.46−3.72 MPa) and lowest in ZT treatments (2.51–2.82 MPa). Furthermore, it has been found that porosity decreased in the order disc harrow tillage (49.90%) follow by disc plough tillage (42.62%) and zero tillage (41.17%) respectively. Meanwhile, infiltration capacity increased in the order zero tillage (24.40 cm/hr) follow by disc plough tillage (32.30 cm/hr) and disc harrow tillage (39.40 cm/hr). On the basis of conservation tillage to maintain an adequate amount of crop residue on the soil surface, less traffic and less manipulation of the land might be the benefits. However, rotary tillage can effectively improved soil structure and reduced soil bulk density, where N ↔ S treatment soil bulk density is low and in 0–60 cm soil layer averaged 1.31 g/cm3. Different tillage treatments could be used during the fallow period to store additional soil moisture: the N ↔ S treatment showed good water storage effect.