Mulching An Arenic Hapludult In Southeastern Nigeria: Effects On Selected Soil Properties And Rhizome Yield Of Turmeric
A study was carried out over two cropping seasons at Umudike, southeastern Nigeria, to determine the type and quantity of mulch that would improve some selected physical properties of an Arenic Hapludult and optimize the rhizome yield of turmeric. Effects of mulch rate on bulk density (BD), total porosity (TP), macro-porosity (Ma. P), water stable aggregates (WSA > 0.5 mm) and mean-weight diameter (MWD) significantly depended on the type of mulch material used. Straw mulch reduced BD and increased other parameters more than wood shavings. Optimum values of WSA > 0.5 mm (23.2) and MWD (0.535) occurred at the 4 t/ha mulch rate, whereas, maximum values of TP (54.08%), Ma. P (26.55%) and minimum value of BD (1.51 g/cm3), were achieved at mulching beyond 4 t/ha. Apart from total porosity, which was found to be optimum, BD, organic carbon (OC), Ma. P and MWD explained individually between 80 and 99% of the variability in yield. Results also showed that all mulched plots out-yielded the bare plots. Rhizome yield varied with the rate of mulch application with yield increases declining in the order 8, 4 and 0 t/ha mulch rate. Increase in the rhizome yield of turmeric was dependent on the type of mulch used, with straw mulch out-yielding wood shavings by 38.4 and 76.6% in 2004 and 2005, respectively.
Keywords: Turmeric rhizomes, soil physical properties, mulching, arenic hapludult