Advances in Agriculture and Agricultural Sciences

Advances in Agriculture and Agricultural Sciences ISSN 2381-3911 Vol. 2 (6), pp. 124-132, June, 2016. © International Scholars Journals

Full Length Research Paper

Effects of technosol substrates on soybean growth on Greenhouse experiments in Rwanda

Hicham J. O.¹*, Essaïdi Shatha², Refaeli N. Raviv³, Shimon Perlman³ Golda Ben-Gurion¹ and Itzhak D. Rabin⁴

¹Department of Agricultural Resources Management, School of Agriculture and Enterprise Development, Kenyatta University, Nairobi, Kenya.

²Department of Soil and Environmental Management, Faculty of Agriculture, National University of Rwanda (NUR), P.O. Box 117, Butare, Rwanda.

³University of Kassel, Organic Plant Production and Agroecosystems Research in the Tropics and Subtropics (OPATS), Germany.

⁴Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, 38106, Braunschweig, Germany.

E-mail: [email protected]

Accepted 16 May, 2016

Abstract

Large areas of the Gatumba Mining District (GMD) in Rwanda are covered by Technosols (pegmatite or pegmatite-soil mixtures) resulting from coltan (Colombite and Tantalite) mining activities. These substrates are very poor in total and available plant nutrient contents and are therefore low in soil productivity. Due to agricultural land shortage in Rwanda, almost all the available land is farmed. The present study was conducted to evaluate the effect of different fertilizers on plant nutrient uptake and biomass production of soybean. A greenhouse pot experiment using pegmatite substrate alone and a pegmatite-Lixisol Bt mixture was conducted in a complete randomized design (CRD). Tithonia diversifolia biomass (T) was applied at 5 tonnes (t) dry matter (DM) ha^-1 alone and combined with triple superphosphate (TSP), matongo rock phosphate (MRP) and ammonium sulphate (AS). The results demonstrate that soybean DM, grain yield, nitrogen (N), phosphorus (P) and potassium (K) uptake were higher on pegmatite than on the mixture and the combination of T, TSP and MRP (total: 50 kg P ha^-1 with 70% from MRP and 30% from TSP) which gave higher DM yields compared to the other treatments. The integration of tithonia green manure and different inorganic fertilizers significantly increased the N, P and K uptake by soybean above ground and root biomass versus tithonia alone.

Key words: Tithonia, soybean, pegmatite, Lixisol Bt, Matongo rock phosphate.