Vol. 10, Issue 3 (2021)

Author(s):
Sandeep Kumar Maurya, RK Singh, Brijesh Kumar, Sarvajeet and Ranvir

Abstract:
Halosulfuron methyl (HM) at 67.5, 75.0, and 150.0 g/ha recorded significantly effective in lowering the population (1.2–2.2/m²) and dry weed weight (0.45–0.49 g/m²) of C. rotundus at 60 DAT as compared to other treatments including its lower doses. Atrazine (PE) followed by 2,4-D was not effective against C. rotundus. HM at 67.5, 75.0 and 150.0 g a.i./ha gave 96.3–97.0% control of C. rotundus as against an increase in C. rotundus population (15.1%) in atrazine (PE). 2,4-D treatment and 24.4% increase in untreated check over pre-treatment population. HM at 67.5, 75.0 and 150.0 g a.i./ha recorded higher weed control efficiency (97.8–97.9%) as compared to atrazine (PE) followed by 2,4- D (8.7%) and three hoeings (48.8%). None of the doses of HM affected the dry weight of grassy as well as broadleaf weeds recorded at 60 days after treatment. HM used at 67.5, 75.0 and 150.0 g a.i./ha also recorded significantly higher cane yield as compared to its lower doses, atrazine (PE) followed by 2,4-D and weedy check. Treatment of three hoeings gave maximum cane yield whereas; lowest cane yield was recorded in untreated plots. An increase of 60.9–64.8% in cane yield over control was recorded when HM was applied at 67.5, 75.0 and 150 g a.i./ha whereas standard check (atrazine followed by 2,4-D) recorded 33.9% increase. Critical periods of weed control (CPWC) were studied in six field trials. In ratoon cane, CPWC with natural weed infestations started between 228 and 916 growing degree days (GDD), and ended between 648 and 1311 GDD, depending on the site and cane variety. These results represented a maximum CPWC of 12 to 28 weeks after harvest (WAH). In-plant cane, the CPWC started earlier (6WAP) and was longer than those in ratoon cane.