Challenges of weed management in rice for food security in Africa: A review

Abstract

Rice is one of the most important crops for food security in Africa. However, there is a large gap between its present demand and supply. Weed competition is basically one of the major constraints in rice systems in Africa, leading to 48–100% yield reduction and sometimes complete crop failure, thereby threatening food security. Weed control methods currently employed to avoid such losses are predominantly hoe-weeding and herbicide application. Hoe weeding is tedious, inefficient, time consuming, associated with high labour demands and often too expensive for the average farmer to afford. Herbicide use on the other hand, does not provide season-long weed control. Moreover, there are not many herbicides that can control different kinds of weeds with one application. Thus, to optimise yield, financial, social and environmental costs and benefits, integrated and ecological weed management approaches are advocated. Future weed research should therefore be focused on delivering information for the implementation of these approaches. This would require improved knowledge of weed biology and ecology, prioritization of problematic weed species, development of competitive rice cultivars and timely weed control. To address the diversity of weed problems in rice systems in Africa, however, research innovations must take full account of farmer’s local conditions using farmers’ participatory approaches. This review suggests that knowledge-based integrated novel approaches must be developed to assist farmers in coping with the challenges of weed management for sustainable rice production.

Evaluating the effects of manual hoeing and selective herbicides on maize (Zea mays L.) productivity and profitability

“…However species such as Cynodon dactylon , Imperata cylindrica and Commelina benghalensis found in our study ( Fig. 3 ) are more difficult to weed manually, and require more energy to destroy their dispersal organs including: rhizomes, stolons, and stems [ 43 ], which would have stressed the maize by disturbing the architecture of its root system, thus reducing its ability to take up water and nutrient from the soil [ 44 ], thus reducing yield. Similar phenomena have been reported in the same crop in the Czech Republic [ 45 ] and more recently in Italy [ 46 ].…”

Weed management in rainfed lowland rice ecology in Nigeria – challenges and opportunities

“…Crop competitiveness with weeds can be improved by varying seed rates or seeding methods of rice (Hay and Walker 1989;Zimdahl 2004). For instance, low seeding rates of rice using productive cultivars ensures the establishment of Bakare et al 2008aBakare et al , 2008bBakare et al , 2008cDaramola et al 2020;Enyinnia 1993;Evbuomwan 1992;Gbanguba et al 2011;Imeokparia 1994Imeokparia , 1989Imeokparia and Okusanya 1997;Imeokparia et al 1992 vigorous, competitive, and highly productive tillers that are capable of suppressing weeds at reduced seeding costs (Chauhan 2012;Gopal et al 2010;Hay and Walker 1989). Crops are also known to gain more competitiveness over weeds when established in high densities (Danmaigoro et al 2016).…”

Pengaruh Dosis Herbisida Campuran Penoksulam Dan Pretilaklor Terhadap Gulma, Pertumbuhan Dan Hasil Padi Sawah

“…Rata-rata berat gabah kering giling menunjukkan bahwa seluruh perlakuan dosis herbisida campuran tidak berbeda nyata terhadap penyiangan manual. Hal ini sejalan dengan penelitian Daramola et al (2020) bahwa aplikasi herbisida campuran Pretilaklor + Dimethametrin sebanyak 2,5 kg bahan aktif/ha dapat mengendalikan gulma dengan efektif dan memberikan pertumbuhan tanaman padi yang lebih baik serta hasil gabah yang hampir sama dengan penyiangan manual. Disamping itu, seluruh perlakuan dosis herbisida campuran mampu meningkatkan berat gabah kering giling yang berbeda nyata dibandingkan dengan kontrol.…”