Article Number: PRJA45760190


Vol. 4 Issue 1, pp: (1-13), November 2019.
Article Number: PRJA45760190
Copyright ©2019
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Full Length Research Paper

Change in Soil Chemistry and Rice Yield under Mineral Fertilizer and Organic Amendment as Occurring in Second Order Valley of Guinea Savanna: Evidence of Nonsymptomatic Iron Toxicity of Rice

ZADI Florent1, KOUADIO Konan-Kan Hippolyte1, BAKAYOKO Sidiky2 & BRAHIMA Koné 1*

1 Soil Science Department, UFR-STRM, Felix Houphouet-Boigny University, 22 BP 582 Abidjan 22, Cote d’Ivoire.

2 Agro Pedologie Department, UFR-Agroforesterie, Jean Lorougnon Guédé University, BP 150 Daloa Cote d’Ivoire.

Corresponding author: Brahima Koné, E-mail: kbrahima@hotmail.com

 Received: August 21, 2019  Accepted: September 25, 2019  Published: November 1, 2019

ABSTRACT

Iron toxicity is a widespread abiotic constraint limiting drastically rice production in lowland and, it is advocated to establish more reliable characteristics of this constraint overcoming the shortage of rice production. Three cropping cycles of rice were conducted as on-farm experiment (split-plot) including mineral fertilizer – MF (N. P, K. Ca, Mg and Zn) and organic amendment – OA (rice straw) treatments in order to observe rice yields (straw and grain) in relation with changes in soil chemistry. Yield decreasing (6.3 – 2.99 t ha-1 for MF and 4.2 – 2.65 t ha-1for OA) was observed subsequently with impoverishment of soil chemistry (C, N, K, Ca, Mg and ECC) against increasing of soil contents of available P and iron (421.36 ppm-614.33 ppm) as well as its acidity. Soil concentration of Fe was significantly contributing to the decreasing trend of grain yield regardless of the treatments while isomorphic substitution was observed between soil contents of K and Fe under MF treatment resulting highest yield declining (50%). This process was limited under organic amendment further releasing P for yield stabilization. In the light of these finding, iron toxicity was characterized by K deficiency while no visual symptom was observed.

Key words: Iron toxicity, rice, isomorphic substitution, potassium deficiency, phosphorus