Influence of Organic Substrates and Weeding on Weeds and Rice Production in Lowland Rice Cultivation in Western Burkina Faso.

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Résumé

Weeds have a significant impact on yields in lowland rice cultivation, hence the need to implement effective management methods. The objectives of this study
were to evaluate the effect of organic substrate types and weeding methods on weed management. Four types of fertilization as the main factor and four weed
ing methods as the secondary factor were tested using a split-plot design. The results showed the highest dry biomass with biochar and rotary hoe weeding
(1.86 g/0.5m2), biochar and chemical weeding (12.01 g/0.5m2), and biochar and rotary hoe weeding (10.10 g/0.5m2). In terms of pH, the most acidic levels
were recorded for chemical weed control treatments. The highest nitrogen content was recorded for biochar with chemical weed control (0.11%). In terms of
total phosphorus, the highest content was recorded for biochar with rotary hoe weeding (256.56 mg/kg), while the highest assimilable phosphorus content
was obtained for biochar with chemical weeding (27.59 mg/kg). The highest total and assimilable potassium contents were obtained with biochar without
weeding (1484.31 mg/kg) and chemical weeding with biochar (74.32 mg/kg). The highest yields were obtained with manual weeding combined with com
post (3208.89 kg/ha). Phytosociological analysis identified six plant groups characteristic of weeding methods and types of fertilization. However, only two are
significantly dependent on weeds. The Cyperus diformis L. group, consisting of three indicator species, namely Cynodon dactylon (L.) Pers, Cyperus di
formis L., and Passiflora foetida L., is characterized by the influence of rotary hoe weeding (100%), biochar (50%), and compost (50%). The Ammannia Pri
eureana group consists of three indicator species, Ammannia Prieureana Guill., Bacopa floribunda (R.Br.) Wettst. and Cyperus diformis L., and is character
ized by the influence of manual weeding (100%), compost (30%), and chemical fertilizer (30%), as well as sugarcane bagasse (20%) and biochar (20%). In
light of these results, it should be noted that fertilization is only effective when accompanied by a good weed management method.

Mots-clés

Weeding, Organic Substrates, Weeds, Rice Cultivation