Weed Flora Dynamics in Maize (Zea mays L.) Field as Influenced by Cover Crop Types and Planting Densities at Jalingo, Northeast, Nigeria

Abstract

Aim: Competition from weeds is an obstacle to profitable maize production. Knowledge of weed species limiting productivity is essential for sustainable management. A two years field experiment was conducted to evaluate the effect of a leguminous cover crop, akidi (Vigna unquiculata sub-sp sequipedalis) and two non-leguminous cover crops (melon and sweet potato) planted at three densities on weed flora composition and shift in maize at Jalingo, North-eastern Nigeria.
 Study Design: There were 11 treatments replicated three times in a randomized complete block design.
 Methodology: Low, moderate and high densities (20,000, 30,000 and 40,000 stands/ha respectively) of Akidi, Melon and Sweet potato (A1, A2, A3, M1, M2, M3, S1, S2, S3) with weeded (C1) and unweeded (C2) checks constituted the treatments laid out in a randomized complete block design replicated three times. Weed flora abundance, percentage density, percentage frequency, frequency index and percentage contributions were determined from a 50cm x 50cm quadrat thrown twice per plot at various phases of maize growth.
 Results: Thirteen weed families made up of 11 broad leaves, one grass and one sedge were identified. The abundance was in the order Broad leaf > Grass > Sedges. The most abundant weed species were: Imperata cylindrica L (3.8), Mucuna utilis (3.0), Oldenlandia herbacea L. (2.6) Sida acuta Burm F, Tridax procumbens L. (2.5 each), Leucas martinicensis, Pennisetum pedicellatum (2.3 each). Commelina benghalensis, Cyperus difformis (3.5), Digitaria horizontalis, Fimbristylis littoralis (2.8 each). The influence of selected cover crops on individual weed percentage the contribution shows: Commelina benghalensis ( C2<C1 < M <S< A), Euphorbia hyssopifolia (C2<M/S < A<C1), Euphorbia heterophylla (M<S<A), Leucasmartinicensis (C1<C2<M<A<S), Mucunautilis (S<M<C1<C2<A) and Sida acuta (M<S<A<C2<C1) while grassy weeds, Imperata cylindrical (A<C2<S<M), Pennisetum pedicellatum (A<C2), Digitaria horizontalis (C1/ C2< A < M <S), Kyllinga squamulata (M/S <C2<A <C1). Commelina spp. increased in status from an accessory (21.2%) to abundance (66.7%) while others increased from rare to accessory (from 0.0 to 20-40%).
 Conclusion: Akidi was more effective on broad-leaved weeds while melon and sweet potato were more effective on grasses and Commelina benghalensis need to be monitored.

Influence of different population densities of Bambara groundnut intercrop and weeding frequency on maize (<i>Zea mays</i> L.) performance

“…At least two hand weedings within the first six weeks after sowing are required to reduce weed competition and ensure enhanced maize yield in Nigeria (Amosun et al, 2016). However, the drudgery, high cost of labour and delay in initiation of hand weeding has resulted in shifts to integrating manual weeding with other ecofriendly, cost-effective weed management strategies, such as intercropping with compatible smother and food crops (Tijani-Eniola et al, 2003;Nwagwu & Udo, 2019;Michael et al, 2021). In addition, when cereal and grain legumes such as cowpea, soybean and groundnut are intercropped, soil fertility is improved because significant amount of nitrogen (80-350 kg /hectare) accumulate in the soil by the action of symbiotic bacteria inhabiting the root nodules of the legumes (Mobasser et al, 2014).…”