Influence of soil strength on wheat (Triticum aestivum) growth under prolonged tillage

Tillage enhances soil physical condition which favors root growth and crop productivity. Though, continuous rotary tillage at same depth leads to the formation of plough pan which slowdown crop productivity. Some serious speculations have been made about rotary tillage that in long run it induces subsoil compaction. This study was conducted at farmers' field in Malhendi, Shamli (UP) to investigate the effect of prolonged use of rototilling with special attention to subsoil compaction. The experimental sites were under rotary tillage (RT) under wheat for last 15 years under rice-wheat cropping system which compared with conventional tillage (CT-cultivator harrow). The crop growth and yield was reduced under RT due high mechanical impedance and BD in deeper layer as compared to CT. In upper soil strata (5-15 cm) the cone index of RT (505kPa-2057kPa) soils are lesser than that of CT (625-2257kPa) while in subsoil layer (45 cm) it becomes severe under RT(4578 kPa) compared to CT (2468 kPa). Similar trend found in bulk density under both tillage treatments. The bulk densities observed before tillage at 0-15cm, 15-30 and 30-45 cm depth were 1.50 Mg/m(3) and 1.56 Mg/m(3),1.37 Mg/m(3) for CT 1.42 Mg/m(3) 1.67 Mg/m(3) and 1.81 Mg/m(3) for RT respectively. The grain yields were (5909 kg/ha) and (4594 kg/ha) under CT and RT tillage system respectively. The CT system well performed in plant height, no of tillers and root growth characteristics, viz. root length density, root volume than that of RT. Performing studies shows that long-term RT induced subsoil compaction which needs some amelioration tillage management.