Tillage effects on growth performance of Hevea seedling rootstock and some fertility indices of sandy acid soil in the humid forest area of Nigeria
Journal of Rubber Research
Rubber Research Institute of Nigeria, P. M. B 1049, Benin City, Nigeria; Department of Agronomy, University of Ibadan, Nigeria
Vast amount of resources are devoted annually for the establishment of Hevea seedling rootstock nursery through conventional tillage, despite global disposition of conservative tillage. A field experiment was carried out to evaluate the effect of tillage methods, namely, plough+harrow, plough only, bed and without tillage on the growth performance of Hevea brasiliensis (natural rubber) seedling rootstock and the nutrient status of sandy acid soil in a forest area (Benin) of Nigeria for two years. In both cropping years (2003/2004 and 2004/2005), the effect of tillage methods on seedling height and stem girth did not differ significantly (P ≥ 0.05). However, seedling dry matter and budding success (69.8 g/tree and 78% on the average, respectively) were significantly higher in the ploughed plots. The plots with no tillage, followed by raised seedbed treatments, had significantly higher values of organic C, available P and exchangeable bases with low levels of Al3+ and H + at 0 cm-15 cm depth. Having recorded no significant difference in crop performance between the nil-tillage and plough+harrow plots, but higher soil nutrient levels in the treatments without tillage for two years; it could be predicted that land preparation without tillage, in addition to ploughing only or raised seed-bed was a better alternative to plough+harrow which often caused soil degradation in the sandy acid soil of high rainfall areas.