Influence of Land use Intensity and Weed Management Practice on Field Emergence, Characterization and Growth of Weeds in Southern Guinea Savanna of Nigeria

The effects of land use intensity and weed management practice on weed seedling emergence, growth and characterization of weed species were examined at Ilorin, in the southern Guinea savanna of Nigeria. The study was conducted on three pieces of land with known cropping history, laid out as randomized complete block design with split-plot arrangement and three replicates. The main plots consisted of two cropping systems (sole maize and no cropping in continuously cultivated maize field, sole cowpea and no cropping in continuously cultivated cowpea field and sole maize, sole cowpea and no cropping in natural fallow field) while the sub plots consisted of three weed control methods (chemical weed control, hand hoeing at 3 and 6 weeks after planting and no weed control). Annual broadleaf weeds were most prevalent across the trial fields and constituted above 60 % of the total weed population. Cleome vicosa L., Euphorbia heterophylla L., Passiflora foetida L., Tridax procumbens L., Fimbristylis littoralis Gaudet and Rottboellia cochinchinensis (Lour.)Clayton were prevalent at continuously cultivated fields, Pycereus lanceolatus (poir) C.B.Cl, Phyllantus amarus Schum & Thonn. and Mariscus alternifolus Vahl had high frequency of occurrence at the natural fallow fields while Cyprus tuberosus Rotth was prevalent in all the sampled fields. In all, the frequency of occurrence of weeds was high at the continuously cultivated fields. Land use showed a pattern of increasing weed density in response to increasing land use intensity. These results show that intensive land use increases weed problems on farmers’ fields. The implication of the result on weed management is discussed.Keywords: Land use, weed emergence, sole maize, sole cowpea, follo