Nitrogen effect on weed management in rice in a tropical forest-savanna transition zone of Nigeria

From rice-like plants to plants liking rice: A review of research on weeds and their management in African rice systems

“…In upland rice, split application of organic fertilisers (cattle manure) combined with weeding interventions, minimises weed interference and improves yields (Dada et al, 2017). Mineral nitrogen fertiliser application can increase weed infestation, which in turn diminishes the fertiliser effect on yield, but when fertiliser application is combined with one (early) post-emergence herbicide application (butachlor) and a manual weeding intervention, the yield is similar to that of a weed-free crop (Kolo et al, 2021). It is evident from all these studies, that weed growth can be stimulated by fertiliser applications, and thereby completely cancel out any yield advantage that one would expect from fertilization.…”

“…With the exception of a fairly recent study that explicitly compared effectiveness of different herbicides (Saleh and Oyinbo, 2017), none of the recent studies focussed on herbicide effectiveness or innovations in terms of formulations or applications. Herbicides were included in on-farm experiments to test integrated crop management (Toure et al, 2009;Senthilkumar et al, 2018) or improve fertiliser use efficiency (Kolo et al, 2021), as additional weed control intervention in water saving production approaches (de Vries et al, 2010;Krupnik et al, 2012b) or as benchmark to test the labour-saving potential of mechanical weeders (Rodenburg et al, 2015c). In a recent continent-wide survey, a number of herbicide products have been observed that were not reported before in the literature on African rice production systems (Table 5), but these do not comprise newly developed formulations.…”