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    Wyświetlanie 1-9 z 9
    Tytuł:
    Effects of Intra-Row Spacing of Pearl Millet (Pennisetum glaucum (L.) R. Br) and Cropping Systems on the Productivity of Soybean-Pearl Millet Intercropping System in a Southern Guinea Savanna Location, Nigeria. (Part I)
    Autorzy:
    Ijoyah, Michael Ojore
    Hashin, Ishaya Kunzan
    Geza, Richard Ter
    Powiązania:
    https://bibliotekanauki.pl/articles/1193958.pdf
    Data publikacji:
    2015
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Savanna
    Southern Guinea
    cropping systems
    intra-row spacing
    pearl millet
    soybean
    Opis:
    A field experiment was conducted from June to November, during the 2013 and 2014 cropping seasons at the Research Farm, University of Agriculture, Makurdi, Nigeria, to evaluate the effects of intra-row spacing of pearl millet and cropping systems on the productivity of soybean-pearl millet intercrop and to assess the yield advantages of the intercropping system. The experiment was a 3x4 factorial arrangement of treatments, fitted in a randomized complete block design (RCBD), replicated four times. The cropping systems (sole soybean, sole pearl millet and soybean-pearl millet intercrop) constituted the main plots, while the intra-row spacing of pearl millet (15 cm, 20 cm, 25 cm and 30 cm) into soybean were allocated to the subplots. Results of study showed that to maximize intercrop yields of soybean and pearl millet in a soybean-pearl millet intercrop, the optimal intra-row spacing for pearl millet is 30 cm. Intercropping soybean and pearl millet significantly (P ≤ 0.05) reduced yields of soybean (25.0 % and 22.2 % respectively, in years 2013 and 2014) and that of pearl millet (34.4 % and 33.3 % respectively, in years 2013 and 2014). Though, the highest land equivalent ratio (LER) values, highest land equivalent coefficient (LEC) values and lowest competitive ratio (CR) values were recorded for pearl millet sown into soybean at the intra-row spacing of 15 cm, however, highest aggressivity was obtained sowing pearl millet into soybean at the intra-row spacing of 25 cm, the level at which both crops dominated each other.
    Źródło:
    World Scientific News; 2015, 18; 35-48
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance of some forage rass species in the Southern Guinea Savannah agro-ecological zone in Nasarawa State of Nigeria
    Autorzy:
    Okwori, Abel Ibrahim
    Abdulsalam, Mansur
    Powiązania:
    https://bibliotekanauki.pl/articles/1179173.pdf
    Data publikacji:
    2017
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Forage species
    Nasarawa State
    Performance
    Southern Guinea Savanna
    Opis:
    The absence of improved forage grass species in Nasarawa ecological zone has prompted a study to identify improved species for use. A potted screen house study was therfore conducted using four improved forage grass species obtained from the National Animal Production Research Institute (NAPRI) Shika near Zaria, Nigeria. The four forage species were thus sown into four soil types obtained from four locations in Nasarawa State arranged in a randomized complete block design. Records were taken for percent emergence, weekly growth rate and dry matter yields. The results indicated that there was significant differences in the percent emergence, weekly growth rate and dry matter yield.
    Źródło:
    World Scientific News; 2017, 83; 92-118
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Impact of Gas Flaring from the Kaduna Refinery and Petrochemical Industry (KRPC) on Plant Diversity in Kaduna Northern Guinea Savanna Eco-Region of Nigeria
    Autorzy:
    Sodimu, A. I.
    Yilwa, V. M.
    Onwumere, G. B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1182487.pdf
    Data publikacji:
    2017
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Eco region
    Impact
    Kaduna Refinery
    Northern Guinea Savanna
    Plant diversity
    Opis:
    50m x 50m plots were laid in each of the two (2) sites, replicated three (3) times to make a total of six (6) plots in all. The plants in all the sites were grouped into four (4) growth forms (trees, shrubs, herbs and grasses) which are evaluated using line transect method. The data were analyzed using student ‘t’ test and biodiversity index was calculated using Shannon Weiner method. The result showed that the population density and biodiversity index of the plant composition in the control site are more than that of the flare site from all the growth forms assessed due to combustion of fossil fuel and the heat generated from the flaring site. The mean of the plant species at the flare site is 663.00 and the control site is 1495.00. The standard deviation for the flare site is 4.32 and that of the control site is 2.51. The paired sample ‘t’ test correlation coefficient showed that there is strongly positive correlation efficient of 0.86 between plant diversity at the flare site and those at the control site. However, from the above analysis, it is concluded that there is statistically significant difference between plant species in the flare site and the control site (p<0.05) due to gas flaring that kills and suppress the growth of plants in the flare site. It is recommended that gas should be harnessed for use as liquefied natural gas. Government and NGOs should embark on an aggressive afforestation programme. Government should also enforce law against flaring, major industrial polluters and monitor their compliance with laid down standard.
    Źródło:
    World Scientific News; 2017, 69; 168-178
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A model for random fire induced tree-grass coexistence in savannas
    Autorzy:
    Klimasara, Paweł
    Tyran-Kamińska, Marta
    Powiązania:
    https://bibliotekanauki.pl/articles/747396.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Matematyczne
    Tematy:
    savanna, ecology, fire-vegetation feedbacks, tree-grass coexistence, stochastic modelling, piecewise deterministic Markov processes
    sawanna, ekologia, sprzezenie zwrotne, koegzystencja roslin, modelowanie stochastyczne, kawałkami deterministyczne procesy M
    Opis:
    Sawanny zajmują ok. 20% lądowej powierzchni Ziemi. W tym ekosystemie korony drzew są na tyle oddzielone od siebie nawzajem, że do podłoża dociera wystarczająco dużo światła, aby utrzymywała się równomierna warstwa traw. Takie długotrwałe współistnienie traw i drzew, czyli brak konwersji do łąki lub lasu, jest możliwe dzięki różnym czynnikom. Uważa się, że najważniejsze z nich to powtarzające się pożary, obfitość pory deszczowej oraz uszczuplanie warstwy roślinnej przez roślinożerców i działalność człowieka. Większość dotychczasowych modeli koegzystencji traw i drzew jest deterministyczna, jeżeli już przyjmuje się stochastyczne występowanie pożarów lub deszczu, to zazwyczaj w bardzo uproszczonej formie, a analiza jest przeprowadzana numerycznie.W tym artykule wprowadzamy uproszczony model, składający się z układu równań różniczkowych, opisujących wzrost traw i drzew w czasie oraz procesu stochastycznego, odpowiadającego za losowe pojawianie się pożarów. Analizujemy ten proces, korzystając z metod teorii półgrup liniowych, co pozwala nam pokazać, że startując z dowolnego rozkładu początkowego biomasy traw i drzew, po odpowiednio długim czasie rozkład tych biomas się stabilizuje. Istnieje jedyny (absolutnie ciągły względem dwuwymiarowej miary Lebesgue'a) taki rozkład stacjonarny. Planujemy rozbudować zaproponowany model o~dodatkowe czynniki środowiskowe wymienione wcześniej oraz konkurencję o~zasoby pomiędzy trawami a sadzonkami drzew. Ponadto podobne uwzględnienie stochastycznej natury występowania pożarów można uwzględnić w~modelowaniu innych zjawisk przyrodniczych jak związek pomiędzy pożarami lasów a populacją żywiących się korą sosen chrząszczy.   
    Tree-grass coexistence in savanna ecosystems depends strongly on environmental disturbances out of which crucial is fire. Most modeling attempts in the literature lack stochastic approach to fire occurrences which is essential to reflect their unpredictability. Existing models that actually include stochasticity of fire are usually analyzed only numerically. We introduce minimalistic model of tree-grass coexistence where fires occur according to stochastic process. We use the tools of linear semigroup theory to provide more careful mathematical analysis of the model. Essentially we show that there exists a unique stationary distribution of tree and grass biomasses.
    Źródło:
    Mathematica Applicanda; 2018, 46, 1
    1730-2668
    2299-4009
    Pojawia się w:
    Mathematica Applicanda
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Devastating Effect of Forest Degradation in Southern Guinea Savanna of Nigeria
    Autorzy:
    Buochuama, A.
    Akande, O. A.
    Buochuama, M. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1161466.pdf
    Data publikacji:
    2018
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Nigeria
    devastating
    ecological
    forest degradation
    guinea savanna
    Opis:
    Forest degradation poses serious ecological consequences to the environment. Therefore, this research deals with the devastating effect of forest degradation in southern guineas savannah of Nigeria. In this study, about one hundred and twenty questionnaires (120) were used to collect data from a number of villages in Wawa community. Descriptive statistics was used in the data analysis. Construction, poverty, population increase, and farming were some of the sources of forest degradation in the study area. The consequences of forest degradation in the study area were erosion, desertification, wildlife habitat destruction and global warming/ climate change. The study noted that the solutions for curbing forest degradations include the following; agroforestry, creation of more forest reserves afforestation/ reforestation, implementation of forest laws and policies and public enlightenment on the consequences of forest degradation.
    Źródło:
    World Scientific News; 2018, 112; 107-117
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Assessment of Soil Based Heavy Metals from Anthropogenic Activities in Kaduna Northern Guinea Savanna of Nigeria
    Autorzy:
    Sodimu, A. I.
    Onwumere, G. B.
    Yilwa, V. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1075622.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Anthropogenic
    Assessment
    Heavy Metals
    Northern Guinea Savanna
    Soil Based
    Opis:
    Soil based heavy metals resulting from anthropogenic activities in Kaduna Northern Guinea Savanna of Nigeria was assessed. Soil samples were collected at a depth of 15m with a soil auger using 50m × 50m plots laid in each of the four sites (ST1, ST2, ST3 and ST4) replicated three (3) times to make a total of twelve (12) plots. The assessment was done in two (2) seasons (wet season and dry season). Soil based heavy metals were carried out according to AOAC using atomic absorption spectrophotometer. The data collected were analyzed with descriptive statistic as well as Anova using SPSS package. Eleven (11) soil based heavy metals; V, Cr, Mn, Zn, Co, Ni, Cu, Br, Pb, Cd and Fe were revealed in each of the selected sites. There were significant differences (P<0.05) when concentration are compared between seasons within the sites. Higher soil heavy based metals were recorded in the wet season than the dry season in all the sites. The sites behind Kaduna Refinery and Petrochemical Company (KRPC) is significantly higher (P<0.05) in concentration than all other sites while the control (Kamaku National Park) has the least concentration (P<0.05). Pearson correlation showed a significant and positive association between soil based heavy metals and automobile / farming activities in wet season (R = 0.40**) and dry season (R = 0.95**) as well as in industrial / farming activities in wet season (R = 0.88**) and dry season (R = 0.94**) at 0.01 probability level. It is concluded that variation in the assessment of soil based heavy metals in the selected sites are influenced by anthropogenic activities (mainly agriculture and fossil fuel combustion) in the sites. It is recommended that there should be provision for licensing and registration of all major industrial polluters and monitoring their compliance with laid down standard; further research into anthropogenic air pollution and farming activities which leads to increase in soil based heavy metals especially in the Northern Guinea Savanna where there are limited research should be investigated.
    Źródło:
    World Scientific News; 2019, 125; 83-93
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Revisiting the Logistic Growth with Random Disturbances
    Ponowna analiza modelu logistycznego z losowymi skokami
    Autorzy:
    Klimasara, Paweł
    Powiązania:
    https://bibliotekanauki.pl/articles/953278.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Matematyczne
    Tematy:
    population dynamics
    logistic growth
    ecological modeling
    savanna
    savanna question
    stationary density
    piecewise deterministic markov processe
    dynamika populacyjna
    równanie logistyczne
    modelowanie ekosystemów
    sawanna
    gęstość stacjonarna
    kawałkami deterministyczne procesy Markova
    Opis:
    Modele populacyjne oparte o równanie logistyczne wziaz sa popularne w modelowaniu ekosytemów i pozwalaja lepiej zrozumiec rózne zjawiska. W tym artykule rozwazamy prosty 1-wymiarowy model sawanny zaproponowany przez D’Odorico, Laio i Ridolfi’ego w pracy [5], który jest modelem współistnienia traw i drzew na sawannach indukowanego losowymi pozarami. Jednak zamiast wprowadzac ubytki biomasy spowodowane wystepowaniem pozarów bezposrednio do równan modelu, definiujemy odpowiedni proces stochastyczny. Nastepnie badamy go z wykorzystaniem teorii półgrup stochastycznych. Zasadniczym wynikiem jest twierdzenie 3.1 okreslajace, kiedy przedstawiony model moze opisywac stabilne współistnienie traw i drzew charakterystyczne dla sawann. Mianowicie przy spełnionym warunku (7) istnieje jedyny absolutnie ciagły rozkład stacjonarny biomasy drzew, do którego cały układ bedzie dazył, natomiast w sytuacji (8) taki rozkład nie istnieje. Powyzszy wynik mozna łatwo przeniesc na wyzsze wymiary i zastosowac np. w dwuwymiarowym modelu podanym w poprzedniej pracy (na ten temat) autora i Marty Tyran-Kaminskiej [7].
    The logistic growth population model still can help explain ecological phenomena. We consider a simple 1-dimensional model of savanna introduced by D’Odorico, Laio, and Ridolfi [A probabilistic analysis of fire-induced tree-grass coexistence in savannas. The American Naturalist 167, 2006] which is in fact a model of tree-grass coexistence driven by stochastic fire. We provide an appropriate stochastic process for this model and study it using the stochastic semigroup theory. Finally, we give the condition inducing the existence of a unique stationary distribution of woody biomass.
    Źródło:
    Mathematica Applicanda; 2019, 47, 2
    1730-2668
    2299-4009
    Pojawia się w:
    Mathematica Applicanda
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Diversity and trophic structure of bird’s communities in Brazilian Savanna areas of the Cuiabá River basin
    Autorzy:
    Dario, Fabio Rossano
    Sandrini, Marcos Paulo
    Powiązania:
    https://bibliotekanauki.pl/articles/1031776.pdf
    Data publikacji:
    2020
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Brazil
    Savanna
    avifauna
    bird
    ecology
    Opis:
    We analyzed the differences in composition, richness, and abundance of birds in different forest fragments of the Brazilian Savanna in the Cuiabá River basin, Mato Grosso State, Brazil, and we demonstrated the variations in richness and abundance of birds between different trophic guilds. We used point counts to characterize the avifauna. Sampling was conducted in two seasons: summer and winter of 2018 in a total of 36 hours distributed in 108 samples. A total of 743 contacts were obtained belonging to 87 bird species distributed among 17 orders and 33 families and categorized in 16 trophic guilds. The omnivorous and insectivorous birds composed most of the community. For each species, we calculated the abundance index value that showed our study site had a large number of species with low index and few species with intermediate to high index compared to the pattern observed in other surveys. Our study area was characterized by high species diversity for both periods studied. The Shannon-Weaver diversity index for our study areas was 3.90 for the summer period and 3.77 for the winter period. Equitability was high, 0.82 for the summer period and 0.79 for the winter period, suggesting the number of species registered in our study site represented the maximum capacity the areas can shelter. Our results show that despite being a secondary and fragmented forest the study area was characterized by a diverse avian community. The ciliary forest studied that follows the Cuiabá River, although fragmented and isolated by extensive degraded areas and occupied by pastures and agricultural crops, they are important natural environments to maintain bird diversity.
    Źródło:
    World News of Natural Sciences; 2020, 29, 3; 252-268
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The paleoecology of the Late Miocene mammals from the Optima Local Fauna of Oklahoma, USA
    Autorzy:
    Frederickson, Joseph A.
    Cohen, Joshua E.
    Engel, Michael H.
    Hunt, Tyler C.
    Wilbert, Greg A.
    Castaneda, Olga S.
    Czaplewski, Nicholas J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2216233.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Mammalia
    grassland
    tooth breakage
    Neogene
    North America
    mesowear
    savanna
    stable isotopes
    Opis:
    The Optima Local Fauna represents an important glimpse into the ecological transition between savannah and grassland during the late Miocene (Hemphillian) of what is now the southcentral Great Plains of North America. Though dominated by horses, herbivores from the Optima are morphologically diverse, bearing adaptations for both browsing and grazing lifestyles. Likewise, the carnivorans show similar ranges of size and presumed dietary behavior. In this study, we used carbonate isotope, mesowear, and tooth breakage and wear analyses to investigate the dietary complexity of mammals from a single site collected by the Oklahoma Museum of Natural History. Seventeen taxa were analyzed, including five perissodactyls (Teleoceras hicksi, Dinohippus interpolatus, Neohipparion eurystyle, Nannippus ingenuus, and Astro hippus ansae), four artiodactyls (Texoceros guymonensis, Pediomeryx hemphillensis, Megatylopus matthewi, and Platy gonus sp.), a single proboscidean (Mammut sp.), two rodents (Dipoides indet. and Umbogaulus monodon), and five carni vorans (Agriotherium schneideri, Amphimachairodus coloradensis, Borophagus secundus, Eucyon davisi, Pliotaxi dea cf. nevadensis). Both stable isotope analysis and dental mesowear indicate a broad dietary partitioning occurred among the Optima herbivores, where the artiodactyls were identified as mixed feeders and the perissodactyls were recovered as grazers. In the carnivorans, the large felid Amphimachairodus coloradensis was a hypercarnivore with limited tooth breakage and an enriched δ13C signature, indicating low carcass utilization and a prey preference for horses. The canids had a more generalized diet, with B. secundus showing a greater proportional consumption of carcasses through a higher tooth breakage rate. The large ursid Agriotherium schneideri is here interpreted as an omnivore based on depleted δ13 C values. Overall, we found evidence for a diversity of dietary niches in both carnivores and herbivores during the late Hemphillian in Oklahoma, likely driven by the expansion of grasslands in the region.
    Źródło:
    Acta Palaeontologica Polonica; 2022, 67, 1; 221-238
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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