Effects of Inter-cropping and a Herbicide on Management of Striga hermonthica on Sorghum

Abstract

Aims: The present work was undertaken to determine the effects of the herbicide chlorsulfuron and intercropping sorghum (cv.Wad-Ahmed) with cowpea (T100K-901-6 cv.) on S. hermonthica incidence and sorghum growth. Study Design: Randomized Complete Block Design (RCBD) with four replicates. Place and Duration of Study: A series of laboratory and greenhouse experiments was undertaken at the College of Agricultural Studies, Sudan University of Science and Technology (SUST) at Shambat, during the season 2013/2014. Methodology: Striga free or infested soil was placed in plastic pots (9 cm i .d) with perforations at the bottoms. Pots filled with Striga free soil (0 mg) were included as control for comparison. Sorghum cultivar Wad-Ahmed was sown as sole crop or intercropped with cowpea. Chlorsulfuron at 1.3 g active ingredient (a.i)/fed was applied three weeks after sowing. Plant height and Stem diameter were measured in centimetres using a ruler and vernier caliper instrument, respectively, while weight was weighed in gram after drying using a balance. Results: At 60 and 75 days after sowing (DAS), irrespective of Striga seed bank size, cowpea intercropped with sorghum displayed significant reduction in stem diameter (19.0-56.7%). Sorghum intercropped with cowpea at Striga seed bank size of 16 mg/pot resulted in a significant reduction in sorghum dry weight (61.6%). However, at 60 and 75 DAS displayed a significant reduction in sorghum height only at the seed bank size of 16 mg/pot. Chlorsulfuron applied to Sole sorghum at Striga seed bank size of 16 mg/pot reduced sorghum dry weight by 51.9%. Sorghum intercropped with cowpea and subsequently treated with chlorsulfuron at Striga seed bank size of 16 mg/pot decreased sorghum height significantly (20.8 – 29.5%). Sorghum intercropped with cowpea and subsequently treated with chlorsulfuron, irrespective of Striga seed bank size, reduced sorghum dry weight (28.1- 47.6%). Conclusion: According to this study, Striga management requires integrated practices comprising different components. Intercropping sorghum with cowpea reduced Striga emergence. Chlorsulfuron effectively reduced germination and suppressed Striga emergence.