Browsing by Author "Tindwa, H"

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    Effects of copper concentration in soil on prolife ration and survival of rhizobia, nodulation and biological nitrogen fixation in beans, cowpeas and soybeans
    (Sokoine University of Agriculture, 2010) Tindwa, H
    A study was conducted in which two strains of the fast – growing bean rhizobia- PV 1 and PV 2 and two others of the slow – growing bradyrhizobia for cowpeas and soybean- CP 1 & GM 8 , respectively, were used to test their ability to: - (a) proliferate in copper contaminated liquid media, (b) survive in copper contaminated soil, (c) nodulate respective host legumes and (d) fix nitrogen under increasing copper levels both in vitro and in vivo. Known population sizes of each of the strains were exposed to copper concentrations in the range: 0, 20, 40 60, 80 and 100 ppm in either Yeast - extract Mannitol Broth or in modified Leonard Jar assemblies or potted soil. Most Probable Number (MPN) studies were also done to estimate populations of the native strains of the fast - and slow - growing rhizobia in a Cu -contaminated soil. Results indicated that copper was more toxic to the slow – growing bradyrhizobia than to the fast – growing rhizobia. Reduction in population sizes in vitro was more significant (p = 0.05) for bradyrhizobial than for rhizobial strains. Reductions in fresh nodule volume, fresh nodule mass and total shoot nitrogen were more significant (p = 0.05) in the bradyrhizobial – than in rhizobial – legume associations. Copper depressed the populations of slow – growing strain CP 1 and GM 8 in vivo more than those of the fast – growing strains PV 1 and PV 2 . There was no statistically significant (p = 0.05) effect of 82.5 mg Cu/kg soil on numbers (MPN) of native rhizobial strains, probably due to adsorption of Cu by soil colloids. This study showed that based on the solution culture, potted soil and soil survival experiments, slow - growing rhizobia were more susceptible to Cu toxicity than were the fast - growing rhizobia.
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    Influence of bio-rock P fertilizer on nutritional composition of whole maize grains: the case of Madaba and Morogoro, Tanzania
    (An International Journal of Basic and Applied Research, 2022) Chove, B; Tindwa, H; Pela, S
    This study was designed to understand the influence of Bio-rock P fertilizer as the source of phosphorous on nutritional composition in maize grain. Bio-rock P fertilizer is a preparation made of rock phosphate and phosphate solubilizing bacteria (PSB). The experiment was laid out in randomized complete block design with three replications each receiving five rates of bio-rock phosphate fertilizer (Control, 20 kg P/ha with PSB, 40 kg P/ha with PSB, 60 kg P/ha with PSB and 80 kg P/ha with PSB). The study was carried out at two geographically different sites; Magadu in Morogoro and Madaba in Ruvuma for the duration of 90 days in the 2019 - 2021 cropping season. In both sites, the results showed that, bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. However, Bio-rock P rates had a significant effect on ash and fat contents of maize grains (p<0.05). Bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. For mineral content, there was significant difference in P, K, Mg, and Fe in Magadu and Madaba samples. Therefore, application of bio-rock phosphate increased macronutrients content (ash and fat) and some of micronutrients specifically phosphorous, potassium, magnesium and iron content and as the rates of bio-rock phosphate increased.