Cassava-Groundnut Intercropping Under Mineral Fertilizer and Vermicomposts: Effect On Below Ground Microclimate, Nitrogen Mineralization and Cassava Foliage

The study which was aimed at evaluating the relative effects of nutrient sources, cropping density and intercropping on selected soil variables and cassava crop foliage attributes was conducted at Teaching and Research Farm of the Delta State University, Abraka (latitude 50 46’ and longitude 60 5’) July 2008 to June 2009, in the humid rainforest zone of Southern Nigeria. The experimental design was a 4x3x3 factorial experiment in RCBD pattern using three replicates, consisting of four nutrient levels, three cropping densities and three cropping patterns. The 4 nutrient levels were zero application, 200kg NPKMg 12:12:17:2, 40 tons of water hyacinth/poultry manure-based vermicompost (VPM) and 40 tons of water hyacinth/cow dung-based vermicompost (VCD). The 3 cropping densities were 50,000, 100,000, and 200,000 plants ha-1, while the three cropping patterns were sole groundnut, sole cassava and cassava-groundnut intercrop. Results showed that below ground temperature was not significantly affected by nutrient application, plant population and cropping systems. Vermicompost application significantly increased soil moisture and total soil nitrogen mineralized. Rate of leaf formation, leaf area index and stay green core of cassava were significantly increased by vermicompost application. Positive correlation was observed between soil N mineralized and soil moisture, rate of leaf formation and LAI. Keywords: cassava, leaf area index, stay green score, soil mineralization, moisture, temperature