RESPONSES OF TOMATO VAR. TINY TOM TO APPLICATION OF COPPER AND ZINC FERTILIZERS IN THREE LIMED TROPICAL PEAT SOILS OF SARAWAK |
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Authors: | Margaret Abat Michael J. McLaughlin Samuel P. Stacey Jason K. Kirby |
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Affiliation: | 1. Soil Science, School of Agriculture, Food and Wine , University of Adelaide , Glen Osmond , Australia;2. Soil Science, School of Agriculture, Food and Wine , University of Adelaide , Glen Osmond , Australia;3. CSIRO Sustainable Agriculture Flagship , Glen Osmond , Australia;4. CSIRO Sustainable Agriculture Flagship , Glen Osmond , Australia |
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Abstract: | We assessed the response of the tomato variety “Tiny Tom” to the application of copper (Cu) and zinc (Zn) fertilizers in three tropical peat soils of Sarawak: mixed swamp forest, Alan forest and Padang Alan forest. Limed soils were used because peat soils in their natural condition are unsuitable to sustain healthy growth of most crops. Yield responses were correlated with added Cu and Zn using Mitscherlich model. Adequate levels of applied Cu and Zn were calculated as those which resulted in 90% of the maximum obtainable shoot dry weight. Application of Cu and Zn significantly (P ≤ 0.05) increased the shoot dry weight and the shoot Cu and Zn concentrations of tomato. Application of the equivalent of 8.3 kg Cu and 5.2 kg Zn per ha was required to achieve 90% of the maximum shoot dry weight. In tomato shoots, the critical concentration for Cu was 18 mg/kg and for Zn, 92 mg/kg. The corresponding concentrations for diethylenetriaminepentaaceticacid (DTPA) extractable Cu and Zn in the soils were 2.3 mg Cu kg ?1 and 3.6 mg Zn kg ?1 . However, the addition of Cu fertilizer also increased Zn uptake by tomato plant, probably by displacing native Zn that was weakly sorbed to the soil solid phase. |
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Keywords: | copper zinc tomato tropical peat soils Mitscherlich model |
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