Effect of slow releasing nitrogen fertilizers on nutrient status across wheat rhizosphere grown on volcanic ash
2000
Miah, M.Y. | Wang, M.K. | Chino, M. | Chiu, C.Y.
The volcanic ash of the Mount Pinatubo in Philippines was used in this study. The major drawbacks of this ash for growing agricultural crops are nitrogen (N) and iron (Fe) deficiencies with low organic matter contents. The main objective of this study is to investigate the wheat grown on the volcanic ash to and determine the nutrient status across its rhizosphere using a rhizobox system. Either oxamide or polyolefinresin-coated urea (PORCU) along with potash and phosphate fertilizers was applied to each rhizobox containing the volcanic ash. Plants were grown on the central compartment (CC) of the rhizobox. The nutrient status was examined by the assessment of distribution patterns of NH4(+)-N, NO3(-)-N, Ca2+, Mg2+, K+, Cl-, SO4(2-), PO4(3-), and associated pH. Although NH4(+)-N in both oxamide and PORCU treatments was accumulated to a somewhat considerable extent of the rhizosphere. The rhizosphere effect was more prominent in oxamide treatment. While NO3(-)-N concentrations in either of the treatment was low with a mere rhizosphere effect in PORCU treatment and a rugged distribution in oxamide treatment. Dominant anions and cations accumulated in the CC and the near by compartments of oxamide treatment were Cl-, SO4(2-) and Ca2+, respectively. In contrast, SO4(2-) and K+ were accumulated in the CC and the adjacent PORCU treated compartments. Thus the overall distribution of nutrients and pH across the wheat rhizosphere was rugged. Despite of this, it seems that with a rugged nutrient distribution and pH, the effects of slow releasing N fertilizers may well ensure the N benefit on plants while growing on the volcanic ash under circumstances of low N content.
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