Bracken fern Pteridium aquilinium invasion of agricultural fields, seed germination and soil properties in Tanzania

Abstract

Climate change and land use changes exert profound effects on the dynamics of flora in ecosystems.Invasion of bracken fern [Pteridium aquilinium [L.]. Kuhn in crop fields in a field survey in Tumbi Agricultural Research Institute, Tabora, Tanzania. A total number of 66 fields were surveyed .The infestation of bracken fern was found in sweet potato, cassava, banana, maize, beans, and oil palm. Germination tests of certified seeds of maize [TAN 250], beans[Lyamungo 90]. Groundnut [Pendo] and soyabean [Uyole] were carried out using three treatments [a] rain water [control], [b] 10% aqueous root extract of p. Aquilinium [c] 10% aqueous extract of the rhizospherric soil. The growth media in plastic pots was a 2kg composition of clay, sand, and forest soil in the ratio of 1;1;1. Pots were initially watered to field capacity with subsequent  watering of 100ml twice a day for 14 days.Ten certified seeds of each variety were planted in a pot and replicated three times.The germination pecentage of the tested seeds was presented graphicaly.Soil analysis data show that P.aquilinium grows on very acidic soils. Results show that the 10% aqueous extract of P. aquilinium roots reduced the germination of maize, groundnut and soybean by 50%, 69%, 100%  respectively. The 10% rhizospheric soil aqueous extract of P. aquilinium reduced the germination of maize, and soybean between 17%-34%, 10-20% respectively. The 10%  queous extract of rhizospheric soil caused an inhibition of root growth and elongation inhibition of Pendo groundnut seedlings. This might likely be associated with Al toxicity in soil. This study confirms the toxicological effects of P. aquilinium on certified seeds. There is a need for soil acidity amelioration to improve crop productivity and the toxicological effects of P.aquilinium on legume crops.