Analysis of weed management options on weed infestation and cane yield of sugarcane

A field study was conducted in a sugarcane field in the southern Guinea savanna ecology of Nigeria to document the influence of weed management methods on the pattern of weed seedlings emergence and cane yield of sugarcane across 3 crop cycles. The experiment which had 6 weed management strategies (weedy check; pre-terbutylazine at 2.0 kg a.i/ ha + supplementary hand hoeing (SHH) at 4, 10 and 16 weeks after planting (WAP); postametryn at 3.0 kg a.i/ha + SHH at 10 & 16 WAP; post-dicamba at 0.5 kg a.i/ha+ SHH at 10 and 16 WAP; pre-terbutylazine at 2.0 kg a.i/ha + post- 2, 4-D at 3.0 kg a.i/ ha; and monthly hand hoeing) was laid out in a randomized complete block design and replicated three times during 2014, 2015 and 2016 growing seasons. Weed seedlings emergence was monitored in 0.5m² quadrats continuously at 1, 2, 4, 6, 8 and 12 months after planting (MAP). The result shows that, the weed spectrum comprised 57-62% grasses, 23-29% broadleaves and 13% were sedges. Dactyloctenium aegyptium had 12.05% relative abundance, Digitaria horizontalis (10.84%), Cynodon dactylon (8.0%), and Tephrosia linearis (8.80%) Eclipta alba (7.50%), Echinochloa obstusiflora (7.17) were the top dominant weed species identified in plant and ratoon crops, respectively. Weed seedling emergence peaks occurred at 1 and 4 MAP across weed control options and crop cycles. Pre-terbutylazine at 2.0 kg a.i/ha + post 2, 4-D at 3.0 kg a.i/ ha was adjourned to minimized weeds emergence which translated into higher cane yields across crop cycles. This study concludes that pre-emergence application of terbutylazine at 2.0 kg a.i/ha + post-emergence of 2,4-D at 3.0 kg a.i/ ha prior to peak periods of weed emergence is the most stable and ideal weed management option for sugarcane estates in the southern Guinea savanna ecology of Nigeria.