Analysis of Length of Growing Season in Some Agro-ecological Zones Using Non-parametric Trend Test
The ever increasing population and consequently increase in demand for food and the increasing exploitation of the land justifies the need for adequate studies on rainfall as an important factor affecting agricultural production. The date of the onset of rains is an important factor in planning agricultural operations such as land preparation and sowing. The study conducted agro-statistical analysis of rainfall characteristics over three different zones of Nigeria. Daily rainfall data were collected for the period between 1971 and 2005 for 6 stations and were subjected to standard analysis to determine trends and variations in the onset dates, cessation dates, length of rainy season, number of wet days, drought episodes. The results showed that the inter-annual variability of the onset dates is higher than that of cessation dates with a progressive shift in both onset and cessation dates. The length of rainy season varied from 77-291 days in Guinea zone, 77-243 days for Savannah and 73-155 days for the Sahel. Changes in the length of growing season ranged between -9 and -10 for Guinea zone, -21 and 11 days for Savannah zone and -28 and 20 days for the Sahel. Similarly, the numbers of wet days have declined over Nigeria. The information presented in this study are to serve as input for proper land and water resources management for productive agricultural enterprise across the three major agro-ecological zones of Nigeria.
AGRHYMET (1996). Méthodologie de suivi des zones àrisque. Bulletin de Suivi de la Campagne Agricole au Sahel 2:2. [Available from Centre Regional AGRHYMET, B.P. 11011, Niamey, Niger.]
Ajayi AE (1998). Agro-statistical analysis of rainfall data for the humid and su-humid stations of Nigeria. Unpublished M. Eng. Department of Agricultural Engineering, the Federal University of Technology, Akure Ondo-State.
Alli AA (2010). Trends and cycles of rainfall and temperature for water resources development in Nigeria. Unpublished M.Sc. Thesis. The Federal University of Technology, Akure, Nigeria.
Brazdil R (1992). Fluctuation of atmospheric precipitation in Europe. GeoJournal 27(3):275-291.
Cannarozzo M, Noto LV, Viola F (2006). Spatial distribution of rainfall trends in Sicily (1921-2000). Physics and Chemistry of the Earth 31(18):1201-1211.
Dinpashoh Y, Jhajharia D, Fakheri-Fard A, Singh VP, Kahya E (2011). Trends in reference crop evapotranspiration over Iran. Journal of Hydrology 339(3-4):422-433.
Hess TM, Stephens W, Maryah VM (1995). Rainfall trends in the North East and Zone of Nigeria (1961-1990). Agricultural and Forest Meteorology 74(1-2):87-97.
Houghton JT, Meira Filho LG, Callander BA, Harris N, Kattenberg A, Maskell K (1996). Climate change. The IPCC Second Assessment Report. Cambridge University Press. New York pp 72.
Karl TR, Knight RW, Plummer N (1995). Trends in high-frequency climate variability in the twentieth century. Nature 377(6546):217-220.
Kunkel KE, Piekler JrRA, Changnon SA (1999). Temporal fluctuation in winter and climate extremes that cause economic and human health impact: a review. Bulettin of the American Meteorological Society 80(6):1077-1098.
Oguntunde PG, Abiodun BJ, Olukunle OJ, Olufayo AA (2011). Trends and variability in pan evaporation and other climatic variables at Ibadan, Nigeria, 1973-2008. Meteorological Applications 19(4):464-472.
Oguntunde PG, Friesen J, Van de Giesen N, Savenije HHG (2006). Hydroclimatology of the Volta river Basin in West Africa. Trends and variability from 1901 to 2002. Physics and Chemistry of the Earth 31(8):1180-1188.
Salmi T (2002). Detecting trends of annual values of atmospheric pollutants by the Mann-Kendall test and Sen’s slope estimates-the Excel template application MAKESENS. Publications on Air Quality, No. 31. Helsinki, Finland.
Trenberth KE (1998). Atmospheric moisture residence times and cycling: implications for rainfall rates with climate change. Climate Change 39(4):667-694.
WMO (1985). The global climate system: a critical review of the climate system during 1982-1984. World Climate Data Programme.
Distribution - Permissions - Copyright
Papers published in Notulae Scientia Biologicae are Open-Access, distributed under the terms and conditions of the Creative Commons Attribution License.
© Articles by the authors; licensee SHST, Cluj-Napoca, Romania. The journal allow the author(s) to hold the copyright/to retain publishing rights without restriction.
Open Access Journal - the journal offers free, immediate, and unrestricted access to peer-reviewed research and scholarly work, due SHST supports to increase the visibility, accessibility and reputation of the researchers, regardless of geography and their budgets. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author.