Browsing by Author "Mahama, George Y."

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    Conservation Agriculture Improves Soil Quality, Crop Yield, and Incomes of Smallholder Farmers in North Western Ghana
    Naab, Jesse B.; Mahama, George Y.; Yahaya, Iddrisu; Prasad, P. V. Vara (Frontiers Media, 2017-06-21)
    Conservation agriculture (CA) practices are being widely promoted in many areas in sub-Saharan Africa to recuperate degraded soils and improve ecosystem services. This study examined the effects of three tillage practices [conventional moldboard plowing (CT), hand hoeing (MT) and no-tillage (NT)], and three cropping systems (continuous maize, soybean–maize annual rotation, and soybean/maize intercropping) on soil quality, crop productivity, and profitability in researcher and farmer managed on-farm trials from 2010 to 2013 in northwestern Ghana. In the researcher managed mother trial, the CA practices of NT, residue retention and crop rotation/intercropping maintained higher soil organic carbon, and total soil N compared to conventional tillage practices after 4 years. Soil bulk density was higher under NT than under CT soils in the researcher managed mother trails or farmers managed baby trials after 4 years. In the researcher managed mother trial, there was no significant difference between tillage systems or cropping systems in maize or soybean yields in the first three seasons. In the fourth season, crop rotation had the greatest impact on maize yields with CT maize following soybean increasing yields by 41 and 49% compared to MT and NT maize, respectively. In the farmers’ managed trials, maize yield ranged from 520 to 2700 kg ha-1 and 300 to 2000 kg ha-1 for CT and NT, respectively, reflecting differences in experience of farmers with NT. Averaged across farmers, CT cropping systems increased maize and soybean yield ranging from 23 to 39% compared with NT cropping systems. Partial budget analysis showed that the cost of producing maize or soybean is 20–29% cheaper with NT systems and gives higher returns to labor compared to CT practice. Benefit-to-cost ratios also show that NT cropping systems are more profitable than CT systems. We conclude that with time, implementation of CA practices involving NT, crop rotation, intercropping of maize and soybean along with crop residue retention presents a win–win scenario due to improved crop yield, increased economic return, and trends of increasing soil fertility. The biggest challenge, however, remains with producing enough biomass and retaining same on the field.
  • Effect of contrasting sources of organic and inorganic fertilizers on growth and yield maize in dry agro-ecology in Northern Ghana
    Kanton, R. L.; Ahiabor, B. D. K.; Ansoba, E.; Asungre, A. P.; Lamini, S.; Mahama, George Y.; Prasad, P. V. Vara (2013)
    Declining maize yields due to a myriad of factors such as inherently poor soils, continuous cropping of cereal after cereal, high cost and unavailability of chemical fertilizers, continuous crop residue removal and soil erosion and run-off have all had their toll low soil fertility and reduced maize yields in northern Ghana. To address this negative trend a field trial was conducted at the Manga Agricultural Research Station in the Upper East Region of Ghana, which represents a Sudan Savanna agro-ecology in the country. The experiment was established as a complete block design with 4 replications with plot dimension of 4.5 m x 5 m. The experimental treatments comprised available sources of both organic and chemical fertilizers currently being used by peasant farmers in Ghana. The experimental factors studied were nitrogen fertilizer rates: 0 kg N/ha; 40 kg N/ha and 80 kg N/ha; length of tied ridges were: 2 m and 4 m wide and crop residue management practices were: total crop residue removal; 50% crop residue removal; 100% crop residue retention and 50% crop residue retention. The trial was established as a randomized complete block design with 4 replications. The results of this study revealed that the chemical fertilizers with micro nutrients such as S, Zn and Mg produced taller plants with superior stem dimensions and also produced tassels and silk significantly earlier than their counterparts. They also produced the best grain and straw yields, due to higher cob numbers, bolder grain and higher harvest indices. Poultry manure and sheep manure were the best amongst the organic sources evaluated.
  • Effects of double cropped on yield and biomass accumulation of cover crops in Kansas
    Roozeboom, K.; Mahama, George Y.; Mengel, D. B.; Prasad, P. V. Vara (2013)
    The contribution of nitrogen (N) by cover crops is an important component of sustainable agriculture and alternative source of N. Legume summer and winter cover crops can decrease inorganic N fertilizer requirements and production costs through symbiotic N2 fixation. It is also vital to make maximum use of the available land during the growing season. However, summer crop yields may be decreased due to shortened length of growing season and risk of water shortage. The objectives of this research were to (a) to evaluate the performance of doubled cropped soybean and grain sorghum yield following winter wheat, and (b) to determine total biomass production, N and carbon accumulation of various cover crops following winter wheat. Field experiments were conducted at two locations (Ashland Bottoms and North Farm both in Riley County, Kansas) in 2012. The experimental design was a randomized complete block design with four replications. Five crops, cowpea [Vigna unguiculata (L.) Walp], sunn hemp (Crotolaria juncea), pigeon pea [Cajanus cajan (L.) Millsp], soybean [Glycine max (L.) Merr.], and grain sorghum [Sorghum bicolor (L.) Moench] were randomly assigned to the experimental units. Nitrogen and carbon concentrations in the above ground parts were determined. There was a significant interaction between location and crop (P
  • Genotypic differences in yield and nitrogen use efficiency of sorghum
    Prasad, P. V. Vara; Mahama, George Y.; Mengel, D. B.; Tesso, T. T. (2012)
    Grain sorghum is an important crop in the semi-arid regions of Africa, Asia and United States. Productivity of grain sorghum is limited by soil fertility, especially nitrogen (N). Sorghum genotypes are known to vary in their response to nitrogen, however, the information on nitrogen use efficiency is limited. The objectives of this research were to (a) determine the response of sorghum genotypes (hybrids and inbred lines) to nitrogen fertilizer; and (b) quantify genotypic differences in nitrogen use efficiency (NUE). Field experiments were conducted at three locations (Hays, Ottawa and Manhattan in; Kansas) in 2010 and 2011. Six hybrids and six inbred lines of grain sorghum were grown with 0N, 45N and 90 kg N ha-1. The experimental design was a split-plot design with nitrogen regimes as main plots and genotypes as sub-plot, with four replications. Planting was done in May and June across all the locations, and nitrogen fertilizer (Urea, 46% N) was applied at emergence. Nitrogen concentrations in the grain and component of NUE were determined for Ottawa and Manhattan. There were significant effects of genotypes (P
  • Influence of nitrogen fertilizer on growth and yield of grain sorghum hybrids and inbred lines
    Mahama, George Y.; Prasad, P. V. Vara; Mengel, D. B.; Tesso, T. T. (2014)
    Grain sorghum [Sorghum bicolor (L.) Moench] is an important crop in semiarid regions of the world because of its drought tolerance. Nitrogen is one of the most limiting nutrients in crop production due to low availability and loss. We hypothesize that there are differences in physiological and yield traits among grain sorghum genotypes in response to N. The objectives of this study were to determine the responses of sorghum genotypes (hybrids and inbred lines) to N fertilizer and the relationship between their physiological and yield traits. Field experiments were conducted at two locations in Kansas for two seasons (2010 and 2011). Genotype × N regimes and year × genotype interactions were significant for leaf chlorophyll, aboveground biomass, grain yield, and seed number. Overall, the hybrids were superior to inbred lines for grain yield and total aboveground biomass, but grain yields of inbred lines TX2783 and TX7000 were comparable to hybrids. Maximum total aboveground biomass, leaf chlorophyll index, and grain yield were obtained at 90 kg N ha–1. Across years, application of 45 and 90 kg N ha–1 resulted in an increase in yield of 13 and 48% over 0 kg N ha–1, respectively. No strong relationship was detected between genotypes and leaf chlorophyll index or chlorophyll a fluorescence and grain yield, but there was a strong relationship between seed number and total aboveground biomass and grain yield. Leaf chlorophyll index and chlorophyll a fluorescence did not provide physiological basis for differences in N response among the genotypes for grain yield.
  • Nitrogen use efficiency in grain sorghum genotypes
    Prasad, P. V. Vara; Mahama, George Y.; Mengel, D. B.; Staggenborg, Scott A.; Tesso, T. T. (2011)
    Grain sorghum is an important crop in the semi-arid regions. Productivity of grain sorghum is limited by soil fertility, especially nitrogen (N). Sorghum genotypes are known to vary in their response to nitrogen, however, the information on N use efficiency (NUE) is limited. Objectives of this research were to (a) determine the response of sorghum genotypes (hybrids and inbred lines) to N; and (b) quantify genotypic differences in nitrogen use efficiency. Field experiments were conducted at three locations (Hays, Ottawa and Manhattan, Kansas) in 2010. Six hybrids and six inbred lines were grown at three N regimes; 0, 45 and 90 kg N ha-1. Experimental design was a split-plot design with N as main plots and genotypes as sub-plots, with four replications. Planting was done in May and June across all the locations, and N fertilizer (Urea, 46%N) was applied at emergence. Data on biomass was measured at vegetative, flowering and maturity, and grain yield at maturity. Concentrations of N in the grain and components of NUE were determined for Ottawa. There were significant effects (P