1. Agronomic Performance of Soybean (Glycine max (L.) Merrill) and Sunflower (Helianthus annuus L.) under Crop Rotation in the Humid Tropics

    Olowe, V.I.O1, Adejuyigbe C2

    1. Institute of Food Security, Environmental Resources and Agricultural Research (IFSERAR), Federal University of Agriculture, Abeokuta (FUNAAB), P.M.B 2240, Abeokuta, Nigeria. olowevio@funaab.edu.ng
    2. Department of Soil Science and Land Management, FUNAAB, P.M.B 2240, Abeokuta, Nigeria. adejuyigbeco@funaab.edu.ng.

    Abstract: Crop rotation is a veritable strategy to achieve one of the principles of agroecology aimed at enhancing recycling of biomass, optimizing nutrient availability and balancing nutrient flow. Consequently, a five year study was carried out between 2008 and 2012 to determine the agronomic performance of soybean, sunflower, sesame and maize in the forest – savanna transition zone of Nigeria. Three cropping systems: continuous, organic rotational and conventional systems were evaluated in a randomized complete block design (RCBD) with four replicates. The two key crops reported herein are soybean and sunflower. Data were collected on plant height, seed yield and yield attributes of sunflower and soybeans. All data collected were subjected to analysis of variance and means of significant treatment were separated using the least significant difference method. Average head diameter and weight of sunflower were significantly (p<0.05) affected by cropping system in 2009. The conventional cropping system only significantly (p<0.05) produced seed yield (1642.6 kg.ha-1) higher than the continuous (778.0 kg.ha-1) and organic rotational cropping (1262.0 kg.ha-1) systems in 2009. Thereafter, as the system stabilized, the organic rotation cropping system recorded higher seed yield than the continuous and conventional cropping systems in 2010, 2011 and 2012. Soybean grown under organic rotation cropping system produced significantly (p<0.05) higher number of branches, seeds and pods per plant than the soybean under continuous and conventional cropping systems in 2012. On average, grain yield of soybeans under organic rotational cropping system (2,445.0 – 2,758.3 kg/ha) was superior to the continuous and conventional systems (1,343.8 – 2556.3 kg/ha) as the system stabilized from 2010 – 2012. Therefore, adoption of organic rotational cropping system with the inclusion of soybean as a component crop is recommended for sustainable organic crop production system in the humid tropics.

    Keywords: agroecology; crop rotation; cropping systems; oilseeds; organic.

    Pages: 87 – 99 | Full PDF Paper

  2. The Relation between Atmospheric Teleconnection Patterns and Precipitation Extremes over Europe

    O. Kutay Mihliardic, Yurdanur S. Unal

    Department of Meteorology and Atmospheric Sciences, Istanbul Technical University, Maslak, 34469, Istanbul, Turkey.

    Abstract:

    Atmospheric correlations have profound importance for the perception of short-term and long-term variability in climate. The most important correlations are recognized as atmospheric teleconnection patterns which are instant correlations in the variations of large-scale atmospheric parameters at certain points on the Earth. These patterns may significantly lead to the variability in the climate and influence the extreme precipitation. Possible droughts and floods could originate as a consequence of excessive decrease or increase in precipitation amount and frequency.

    The main aim of this paper is to obtain a better understanding of the relation precipitation extremes in the whole European domain that are relevant to the several representative atmospheric teleconnection pattern indices by applying various statistical approaches valid for consecutive 38 winter seasons. Relations were checked by means of Pearson and Spearman correlation methods for selected winter seasons. What is more, Multiple Linear Regression method was applied to determine the inter-connection between these atmospheric teleconnection patterns and the extreme precipitation frequencies exceeding thresholds settled. Then, according to the exceeding frequencies the determined critical values, most of the regions over Europe have a high negative and positive coefficients of these atmospheric teleconnection pattern indices with the precipitation totals and their frequencies valid for winter seasons (statistically significant at the 90%, 1 mm/day, 10 mm/day threshold levels).

    Keywords: atmospheric teleconnection patterns, precipitation extremes, multiple linear regression, Europe.

    Pages: 100 – 110 | Full PDF Paper