Tillage and Fertilizer Effects on Maize Production in Northern Guinea Savanna of Ghana

Maize (Zea mays L.) is a major food crop in Ghana but grain yield is often constrained by low soil fertility and water deficits during grain fill. Response of maize to tillage and fertilizer treatments was evaluated in a field experiment from 2000 through 2002 on a sandy loam soil (Typic-plinthic Paleustalf) in Wa in the northern Guinea savanna of Ghana Tied-ridging at 4wk after planting on the flat was compared with planting on a flat soil surface without ridging and with a traditional ridging practice 4 wk after planting on the flat in combination with four fertilizer treatments (F1 = no fertilizer; F2 = 45-19-19; F3 = 64-38-38 and F4 = 90-38-38) as kg N, P O and K O ha-1. Tillage-induced differences in maize growth and yield were not 2 5 2 significant in any season. Over the years fertilizer increased maize growth and yield but this was independent of the tillage treatment. Mean grain yields with the F2, F3 and F4 treatments were 208-234, 304-413 and 391-567% greater than with no fertilizer treatment, respectively. Mean stover yield was 74-85, 147-158 and 131-141% greater respectively, with F2, F3 and F4 than with no fertilizer treatment. Economic analyses showed that the marginal rate of return in applying fertilizer ranged from 97 to 107%. The MRR for F3 was greater than that of F4 but F4 had greater net returns Further studies may be needed to establish appropriate time of tied-ridging and optimum fertilizer level for maize in the Guinea savanna of Ghana.Keywords: Maize, fertilizer, tied-ridging, savanna zone, net returns

Quality Protein Maize Response to Nitrogen Rate and Plant Density in the Guinea Savanna Zone of Ghana

Field experiments were conducted in the Guinea savanna ecology of Ghana to evaluate yield response of quality protein maize (Zea mays L.) hybrid to plant density and nitrogen (N) fertilizer. The experiments were conducted at four locations on 16 farmers’ fields in 2002 and 2003. Three N rates (0, 90 and 135 kg/ha) were combined with three plant densities (50 000, 62 500 and 71 400 plants/ha) to constitute nine treatments which were tested in a randomized complete block design. Optimal N rate was not affected by plant density. There was no yield response to plant density. However, grain yield had a linear and quadratic response to N at all sites. Grain yield increases as a result of 90 kg N/ha applied over the farmers’ practice (0 kg N/ha) at Tumu, Jirapa, Kpongu and Wa were 39%, 85%, 101% and 303% in 2002, respectively. Grain yield increases for the same rate and sites in 2003 were 31%, 83%, 63% and 51%, respectively. Marginal rate of return (MMR) to 90 kg N/ha combined with 62 600 plants/ha was the highest (5564%). Increasing N rate beyond 90 kg/ha did not result in corresponding increase in yield nor net benefit to merit the extra cost that may be incurred. From the study, application of 90 kg N/ha to hybrid maize would give economic yield response and acceptable returns at low risk to farmers, regardless of plant density

Sources of Pod Yield Losses in Groundnut in the Northern Savanna Zone of Ghana

Groundnut (Arachis hypogaea L.) has gained prominence as a food and cash crop due to its increasing importance, both in the domestic and export markets. Its products, such as oil and cake, are for both domestic and industrial uses. However, farm level yields in Ghana have remained as low as 800 kg/ha compared to developed countries of more than 3,000 kg/ha. Variation in the yield of the groundnut crop has been found to be a genetic trait influenced by environment or the interaction of both. In order to identify the sources responsible for these low yields on farmers’ fields, and to be able to advise them to increase their yields, a field experiment was conducted in 2007 and 2008 on a savanna soil at Nyankpala, involving three groundnut varieties, in a split-plot design replicated four times. The varieties (Chinese, Manipinta and Nkatie-Sari) were the main factor and three harvesting stages (at maturity of each variety, 1 week after and 2 weeks after the first harvest) were the sub-plots. Pod yields were between 2,500 kg/ha and 3,100 kg/ha for the three varieties in both years at physiological maturity, which were higher than yields from the subsequent harvest dates. The decline in pod yield when harvesting was delayed beyond physiological maturity was attributed to insect infestation of the pods, sprouting of the nuts in the soil and difficulties in harvesting, resulting in most of the nuts either not harvested or physically damaged. The Chinese variety had more sprouted nuts as well as nuts left not harvested in the soil probably due to its spreading nature compared to Manipinta and Nkatie-Sari, which can be described as the bunch types. Nkatie-Sari significantly gave the highest pod yield at each stage of harvest than the other varieties. It is advisable that farmers plant improved varieties, making sure they harvest at physiological maturity, before the onset of the dry season, in order to obtain optimum pod yields of the groundnut

Participatory evaluation of drought tolerant maize varieties in the Guinea Savanna of Ghana using mother and baby trial design

Maize (Zea mays) is a major food crop in Ghana but grain yields are low as a result of drought and low soil fertility. This study evaluated drought tolerant maize varieties in 2008 and 2009 in the Guinea savanna of Ghana using researcher-managed mother and farmer-managed baby trial design. Mean grain yields ranged between 2574 and 3462 kg/ha for the mother trials and 1460 and 2328 kg/ha for baby trials. Several improved varieties performed better than the best local varieties, but two preferred varieties, TZEE Y POP STR QPM C0 and EVDT W 99 STR QPM CO which produced 35-52% more grain than the best local varieties of similar maturity rating were released in 2010. Farmers have multiple criteria for evaluating maize varieties apart from yield, though yield, larger cob and grain size were the three key criteria used by farmers to select and rank varieties. Researchers should incorporate farmers’ preferences in selecting varieties in the breeding process in order to increase likelihood of adoption of the varieties.Keywords: Drought-tolerant maize, farmer preference, mother and baby, participator

Farmer Assessment, Conservation and Utilization of Endangered Sorghum Landraces in the Upper West Region of Ghana

Grain sorghum (Sorghum bicolor (L.) Moench) is an important staple food crop in the savanna zone of Ghana. Surveys to determine farmers’ perception, crop management strategies and variety maintenance of neglected sorghum landraces were conducted in the Upper West Region of Ghana in 2004. Fifty-nine samples of the neglected landraces were collected from farmers and screened in an observation nursery in 2005 and 2006. Local landraces cultivated by subsistence farmers were 3–4.5 m tall and required 90–180 days to mature. Farmers classified them into three maturity groups: early medium and late-maturing varieties. Early maturing landraces were found in drier northwestern areas of the region and took about 90–115 days to mature. The intermediate ones matured in about 120–135 days. The late maturing landraces were found in the wetter south and are typically more than 4 m tall, requiring 140–180 days to mature. Most of the neglected sorghum landraces are either late maturing, have low yield potential, or are no longer adapted to the climatic and environmental conditions of the Region. The study showed a possible duplication among the landraces collected. Farmer preference criteria for local sorghum are based largely on food quality (overall ability to give good tuo), stable grain yield, brewing quality, earliness, grain quality and drought tolerance. Further improvement of sorghum must take these selection criteria and differences into account. It is clear that indigenous sorghum genetic material is being eroded and, therefore, measures must be taken to conserve existing landraces