Effect of Tillage System, Herbicide Weed Management, and N-Split Application on Yield and Milling Quality of Irrigated Rice (Oryza Sativa L.) in the Guinea Savannah Zone of Ghana
Wandaat Yennumi Emmanuel,
Dzomeku Israel K,
Mahama Ahmed Rufai
In the Guinea Savannah agro-ecological zone of Ghana, rice productivity is hampered by suboptimal
tillage practices, ineffective weed management, and poor soil fertility. To address these constraints,
a field experiment was carried out in Botanga and Golinga to evaluate the effects of tillage systems,
herbicide application methods, and N-split fertilizer regimens on irrigated rice (Oryza sativa L.) yield
and milling quality. The study used a 3 x 3 x 3 factorial design arranged in a split-split-plot with
three replications. Results revealed that soils at both sites were clay loam, slightly acidic (pH 5.10),
with low total nitrogen (0.10%), available phosphorus (2.88 mg/kg), and exchangeable cations. Amon
the treatments, minimum tillage combined with pendimethalin + triclopyr significantly reduced weed
density compared to other combinations. The application of pendimethalin (0.40 kg a.i. ha⁻¹) + triclopyr
(0.03 kg a.i. ha⁻¹), coupled with 120 kg N ha⁻¹ split into four applications, enhanced tillering (19 and
17 tillers per hill at Golinga and Botanga, respectively, at 6 weeks after planting). This treatment also
produced the highest filled spikelets per panicle and maximum 1000-grain weight at both locations.
The same fertilizer and herbicide combination yielded the highest grain production, 8,487 kg/ha at
Golinga and 8,016 kg/ha at Botanga, and showed positive correlations with panicle weight, seeds per
panicle, and straw weight. Additionally, it resulted in the highest unbroken grain recovery (7.5 mm)
and benefit-to-cost ratio. The study recommends applying pendimethalin + triclopyr at 0.40 kg a.i. ha⁻¹
combined with 120 kg N ha⁻¹ split into four doses to maximize rice yield, quality, and income. Overall,
the research underscores the significance of tailored, evidence-based agronomic practices to improve
rice productivity in Ghana’s Guinea savannah zone.
