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Browsing by Author "Mengel, D. B."

Now showing 1 - 4 of 4
  • 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