E. Udensi

Cogongrass suppression by intercropping cover crops in corn/cassava systems

Abstract Cogongrass is a difficult weed to control in small-scale farming systems and often causes significant crop yield reduction. Field experiments were conducted from 1996 to 1999 at three sites located in the forest/savanna transition zone of Nigeria to determine the influence of intercropping cover crops on cogongrass, corn, and cassava growth. Total cogongrass biomass (shoots and rhizomes) at the onset of the study was highest at Ijaiye (889 g m−2), followed by Umumba (445 g m−2), and least in Ezillo (138 g m−2). Velvetbean had the highest percent ground cover at Umumba and Ijaiye (67 to 89%) 10 wk after planting and shaded the ground longer at all locations. Twelve months after planting, plots with cover crops had 66, 71, and 52% lower cogongrass biomass than the weedy control without cover crops at Ijaiye, Umumba, and Ezillo, respectively. Velvetbean at all locations, L. purpureus at Ijaiye, and tropical kudzu at Umumba and Ezillo were the cover crops most effective in reducing rhizome biomass of cogongrass. Annual weeds dominated the plots sown to cover crops after 2 to 3 yr. At Ijaiye and Umumba, cogongrass competition affected the yield of cassava more than the yield of corn. At all locations, cover crops and weeded control treatments had 27 to 52% more corn grain yield than the weedy control. At Ijaiye, corn grain yields from velvetbean and L. purpureus plots were similar to that from the weeded control plot. At Umumba, all plots with cover crops had corn grain yields similar to that of the weeded control. At all locations, almost all cover crop treatments had cassava root yields higher than the weedy control. Except at Ijaiye, root yields from weeded control plots were 17 to 88% higher than in cover-cropped treatments, suggesting competition between cover crops and cassava. Nomenclature: Cassava, Manihot esculenta Crantz ‘TMS 30572’; cogongrass, Imperata cylindrica (L.) Beauv. IMPCY; corn, Zea mays L. ‘SUWAN 1 SR’; Lablab purpureus (L.); tropical kudzu, Pueraria phaseoloides (Roxb.) Benth.; velvetbean, Mucuna cochinchinensis (Lour.) A. Chev.

Options for Cogongrass (Imperata cylindrica) Control in White Guinea Yam (Dioscorea rotundata) and Cassava (Manihot esculenta)

Cogongrass is a serious weed in small-scale farms in the lowland humid zone of West Africa. This study evaluated the response of cogongrass to herbicides and the legume cover crop velvetbean in cassava and white Guinea yam. In 2001/2002, cassava tuber yields and gross returns in treatments that received glyphosate alone were higher than in plots that received fluazifop-P-butyl once. In 2002/2003, treatments that received fluazifop-P-butyl once, glyphosate alone, glyphosate integrated with sowing velvetbean, or hoeing only, had higher cassava tuber yields than other treatments. Gross returns were higher in treatments that received glyphosate followed by sowing velvetbean or those hoed only than in other treatments. Fluazifop-P-butyl applied twice, glyphosate alone, or glyphosate followed by sowing velvetbean reduced cogongrass shoot biomass more than other treatments. Rhizome biomass was lower in plots that received glyphosate alone than in all fluazifop-P-butyl treatments. In 2002, white Guinea yam tuber yields were highest in plots that received glyphosate alone and lowest in plots where fluazifop-P-butyl was applied alone or followed by sowing velvetbean. The highest gross return was obtained in plots that received glyphosate alone while the lowest was obtained in plots that received fluazifop-P-butyl once followed by sowing velvetbean. In 2003, the highest tuber yields and gross returns were from plots that received glyphosate alone, fluazifop-P-butyl alone, or those hoed only. The hoed-only plots had 14 times higher cogongrass shoot biomass and 7 times higher rhizome biomass than other treatments. In both crops, hoeing alone or followed by sowing velvetbean was more costly than chemical control. The highest margin over hoeing was obtained from plots that received glyphosate alone. Sensitivity analysis showed that using glyphosate was more cost effective than fluazifop-P-butyl, even if the cost of the herbicide increased by 100% or the cost of labor decreased by 30%. Nomenclature: Fluazifop-P-butyl; gyphosate; cogongrass, Imperata cylindrica L. (Beauv.) #3 IMPCY; cassava, Manihot esculenta Crantz ‘TMS30572’; white Guinea yam, Dioscorea rotundata Poir ‘Dan-Anacha TDr 93-31’; velvetbean, Mucuna cochinchinensis (Lour.) A. Chev. MUCCO. Additional index words: Chemical control, cover crop, sensitivity analysis, weed management cost. Abbreviations: MAP, months after planting; WAP, weeks after planting.

Rimsulfuron for Postemergence Weed Control in Corn in Humid Tropical Environments of Nigeria

Cogongrass and guineagrass are serious perennial weeds in small-scale farms in lowland subhumid zones of West Africa. Field studies were conducted in 2002 and 2003 at two sites in Ibadan, Nigeria [Ijaye and the International Institute of Tropical Agriculture (IITA)], to evaluate the effect of rimsulfuron on weed communities dominated by cogongrass and guineagrass in corn. At both sites, treatments were rimsulfuron dosages of 0 (nontreated control), 10, 20, 30, 40, 50, 60, 70, and 80 g ai/ha. Rimsulfuron did not cause any visible phytotoxicity on the corn at any dosage at either site. There was a rapid increase in weed control as the dosage of rimsulfuron increased from 0 to 20 g/ha. Weed control was not improved at rates higher than 20 g/ha. Rimsulfuron was very effective against sedges, Ipomoea involucrata, Bengal dayflower, gulf leafflower, old-world diamond-flower, and wild jute providing more than 80% control at dosages between 10 and 20 g/ha at Ijaye. Rimsulfuron was less effective for cogongrass, with a maximum of only 38% control observed. At IITA, the herbicide was very effective against guineagrass, Bengal dayflower, nodeweed, coat buttons, redfruit passionflower, and waterleaf; all of which were controlled more than 70% with any rate of rimsulfuron. Regression analysis showed that the dosage of rimsulfuron required to reduce shoot dry biomass by 70% was 5 g/ha for guineagrass and 35 g/ha for cogongrass at 3 wk after treatment (WAT). At crop maturity, the dosage of rimsulfuron required to reduce shoot dry biomass by 70% was 43 g/ha for guineagrass and 200 g/ha for cogongrass. The dry biomass of cogongrass and guineagrass was higher at crop harvest than at 2 WAT regardless of herbicide dosage. Corn grain yield was 1.8 times higher at IITA than at Ijaye. At both sites, corn grain yield increased with increased herbicide dosage. Maximum corn grain yields were obtained at a rimsulfuron dosage of 20 g/ha. Nomenclature: Rimsulfuron; coat buttons, Tridax procumbens L. TRQPR; cogongrass, Imperata cylindrica (L.) Beauv. IMPCY; old-world diamond-flower, Oldenlandia corymbosa L. OLDCO; guineagrass, Panicum maximum Jacq. PANMA; gulf leafflower, Phyllanthus amarus Schum. & Thonn. PYLAM; nodeweed, Synedrella nodiflora (L.) Gaertn SYDNO; redfruit passionflower, Passiflora foetida L. PAQFO; sedges, Cyperus, Mariscus, and Kyllinga spp; Bengal dayflower, Commelina benghalensis L. COMBE; waterleaf, Talinum triangulare (Jacq.) Willd TALTR; wild jute, Corchorus tridens L. CRGTR; corn, Zea mays L. ‘TZL Comp 4W’.

Evaluation of Lumax® for preemergence weed control in maize in Nigeria

The efficacy of various herbicides against weeds of maize was studied in field trials at Ibadan, Nigeria in 2003 and 2004. The formulations were atrazine (Gesaprim® 90 WDG at 3.5 kg a.i. ha−1 and Rhonazine® 80 WP at 3.0 kg a.i. ha−1), a mixture of atrazine and metolachlor (Primextra® Gold™ 660 SC at 4.0 kg a.i. ha−1 and Primextra® 500 FW at 2.5 kg a.i. ha−1), and a mixture of mesotrione, S-metolachlor and atrazine (Lumax® at five rates: 1.88–2.96 kg a.i. ha−1). Unweeded and hoe-weeded treatments were controls. Lumax® at all rates, Rhonazine® at 3.0 kg a.i. ha−1, and Primextra® at 2.5 kg a.i. ha−1 controlled sedges, Commelina benghalensis, and Pueraria phaseoloides as effectively as the weeded control (95–100%). Weed density and biomass were significantly reduced and maize yield increased by 12–22%. The highest yield was in treatments with 2.15 − 2.96 kg a.i. ha−1 of Lumax® and 3.5 kg a.i. ha−1 of Gesaprim®, and the weeded control. Lumax® is more effective for weed control at lower rates than the previously used formulations.

Managing Nigeria’s Aquatic Resources

Abstract Ecosystem services are ecological goods and services that come from a healthy ecosystem, categorized into four broad groups: provisioning, regulating, supporting, and cultural. Nigeria’s aquatic resources have limited data, and available information on exploitation is dismal. This chapter gives an insight into the aquatic resources of Nigeria and their contribution to the economy. There are water, plants, fish, and other aquatic vertebrates resources that are used for food. Aquatic resources have contributed to the development of agriculture and tourism and provided basic and transitional materials for industries, shelter, and breeding sites for game birds and other avian migrants. Conservation practices recommended include rainwater harvesting, prevention of water pollution, use of gray water, and tree planting. Some efforts of Nigerian wetland conservation are policy based. Ecosystem services seem not to be organized in Nigeria in terms of valuation, measurement, exploitation, management, payment systems, conservation, and growth.

Effect of Seed Size on Yield and Yield Parameters of Four Tropical Soybean (Glycine max L. Merrill) Varieties in Nsukka, South-Eastern Nigeria

Field studies were conducted to determine the growth response of soybean to seed size at the Teaching and Research Farm of the Department of Crop Science, Faculty of Agriculture, University of Nigeria, Nsukka, Nigeria during the cropping season, June, 2008 to June, 2009. In this study, four soya bean varieties (TGX 14482 E, TGX 1455-2 E, TGX 1458-2 E and TGX 1497-ID) were used. The micrometre screw gauge was used to sort out the seeds of each of these varieties into three sizes of small (9.6 g /100seeds), medium 13.3 g/100 seeds and large (16.3g/100seeds) on the basis of seed weight and mean diameter. The experiment was laid out as a split-plot in randomized complete block design (RCBD) with three replicates. The four soybean varieties represented the main plot, while the seed sizes represented the subplots. Our result shows that with the exception of plant height at maturity, seed size was important in the performance of the varietal attributes measured. Plant establishment was ≥ 60% for plants that grew from medium and large seed sizes while small seed size plants had ≤ 55% establishment. Days to 50% flowering and Original Research Article Agahiu and Udensi; IJPSS, 5(2): 90-99, 2015; Article no.IJPSS.2015.063 91 50 % maturity were 55 days and 122 days for small seed size plants and 50 days and 113days for medium and large seed size plants. Number of nodules /plant averaged 12 nodules for plants that grew from small size seeds, and 15 and 18 nodules for medium and large seed size plants respectively. Number of pods/plant was significantly higher in medium and large seed size plants (43pods/plant) compared to small seed size plants (37pods/plant). An average number of seeds per pod were two seeds for medium and large seed size plants and one seed for small seed size plants. Seed weight per 100 seeds was 10 grams for small seed size plants and 12 and 16 grams for medium and large seed size plants respectively. Seed yield averaged one ton per hectare for medium and large seed size plants and less than one ton (600 kilograms) for small seed size plants. In conclusion, seed size accounted for more than 80 % performance of all the varietal attributes measured in this study. Therefore, in selecting planting material consideration should be given not only to variety but seed size of the planting material.

Effect of Tillage on the Growth and Yield of Cowpea Varieties in Sudan Savanna Agroecology of Northern Nigeria

Field study was conducted during the rainy seasons (July-November) of 2007, 2008, 2009 and 2010 at the Research Farm of the International Institute of Tropical Agriculture (IITA) Minjibir, Kano State, Nigeria; to compare responses of six cowpea varieties to tillage. The treatments consisted of tillage systems (zero tillage, flat tillage and ridge tillage) as the main plot and cowpea varieties (IT89KD-391, IT90K-277-2, IT97K-461-4, IT97K-499-35, IT98K-131-2, and IT98K-506-1) as the sub-plot. The treatments were arranged as split plot laid out in a randomized complete block design with four replications. Zero tillage was significantly superior in influencing days to maturity, canopy height, intercepted Original Research Article Ewansiha et al.; ARRB, 5(3): 275-284, 2015; Article no.ARRB.2015.030 276 photosynthetic active radiation (IPAR) and leaf area index but not total dry matter and grain yield of cowpea. A positive and significant association was recorded for days to physiological maturity and canopy height across the tillage systems with a correlation coefficient of ≤ 40% for days to maturity and ≥50% for canopy height. Though flat tillage showed a positive correlation with intercepted photosynthetic active radiation (IPAR) and leaf area (LAI), but this association was not significant. However, ridge tillage showed a positive and significant correlation with IPAR and LAI (r =0.378*** and 0.384***). All the tillage systems showed a high and significant positive correlation with cowpea dry matter and fodder yield (r= 0.54*** to 0.77***). Across varieties, grain yield was better with flat tillage than zero and ridge tillage systems, with 10% yield advantage over the two. Zero and ridge tillage were similar in their effects on grain yield. Except for IPAR, LAI and total dry matter (TDM), the interaction effect of cowpea varieties and tillage systems was significant. Our result point to the fact that extensive soil tillage (especially, conventional tillage) may not be necessary for cowpea production in this agro-ecology with a high percentage of sand and a sandy loam as soil textural class. Following our result, we may recommended varieties for the different tillage systems as follows: IT98K-131-2, IT97K-461-4, IT90K-277-2, IT98K-506-1 (grain) and IT89KD-391/IT97K-4614 (best for fodder) for zero tillage system; IT90K-277-2, IT97K-499-35, IT98K-131-2 and IT98K506-1(grain) and IT89KD-391/IT97K-499-35 (best for fodder) for flat-tillage; IT98K-131-2, IT90K277-2, IT98K-506-1 and IT97K-464-4(grain) and IT90K-277-2/ IT89KD-391 (best for fodder) for ridge tillage).