Effect of tillage sequence and weed management on weed dynamics and productivity of dry-seeded rice (Oryza sativa)-wheat (Triticum aestivum) system Mishra J.S.1, Principal Scientist, Singh V.P., Principal Scientist Directorate of Weed Science Research, Maharajpur, Jabalpur, Madhya Pradesh 482 004 1Directorate of Sorghum Research, Hyderabad *Corresponding author Email: jsmishra31@gmail.com
Online published on 10 April, 2012. Abstract A field experiment was conducted during 2006–07 to 2008–09 at Jabalpur to study the effect of four tillage sequences [zero-till planting of both the crops (ZT-ZT), conventional planting in both the crops (CT-CT), and two rotational tillage sequences that altered between zero-till and conventional tillage (ZT-CT and CT-ZT)] and three weed control treatments (weedy check, herbicide alone, and herbicide + 1 hand weeding at 35 days after sowing) on weed dynamics, tillage economy and productivity of dry-seeded rice (Oryza sativa L.)-wheat [(Triticum aestivum (L.) emend Fiori & Paol)] system on a clay-loam soil. Results revealed that continuous zero tillage increased the population density of Echinochloa colona (L.) Link (jungle rice) and Cyperus iria L. (rice flat sedge), the most dominant weeds of rice. In subsequent wheat crop, zero tillage reduced the population of Avena ludoviciana (L.) Dur. (wild oats) and Chenopodium album L. (common lambsquarters) but increased the density of Medicago hispida Gaertn. (burclover) as compared to other tillage systems. Rotational tillage systems had variable effects on weed density in rice and wheat. Pendimethalin (1.0 kg/ha) fb 2, 4-D (0.50 kg/ha) significantly reduced the population density of E. colona, C. iria and Alternanthera sessilis (L.) D.C. (sessile joyweed) but failed to control Caesulia axillaris Roxb. (pink node flower) in rice. In subsequent wheat, clodinafop propargyl alone significantly reduced the population of A. ludoviciana, but M. hispida was unaffected even with integration of herbicide with 1 hand weeding. Continuous zero tillage yielded 25.1 and 15.4% higher grain yields of rice and wheat respectively, than that of conventional tillage regardless to weed control methods. Continuous zero tillage with recommended herbicide + 1 hand weeding recorded the maximum net returns ( 73.87 × 103/ha) and B: C ratio (3.81) in direct-seeded rice-wheat system. Top Keywords Economics, Herbicides, Rice-wheat system, Tillage, Weeds, Yield. Top |