(Citrus Sinensis) Budlings As Influenced By Shade Intensity, Watering Frequency And Fertigation Nitrogen Concentration

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Jebez C B
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Jebez C B
This study was undertaken to understand the relationship between growth of potted orange budlings and varying levels of shade, nitrogen and watering. Partitioning of dry matter nitrogen, sucrose and starch to rootstock and scion stems and leaves and chlorophyll contents were determined. Budlings of 'Washington Navel ' variety scions budded onto rough lemon rootstocks were used. The experimental design was split split plot with 4 replications. The treatments consisted of 4-shade intensities (0%, 30%, 60% 90%) as main plots, 3 watering frequencies (kPa~ 40, 40< kPa ~213, kPa>213) as sub plots and 3 fertigation nitrogen concentrations (0 mg Nil, 50 mgl l, 1 OOmg Nil) as sub sub plots treatments. Results indicated that 30% shading resulted in 39% saving in water as compared to no shading. Scion stem height also increased significantly (P<0.05). 0% shading favoured increased scion stem diameter, leaf area index, chlorophyll content and relative growth rate. High watering frequency interaction with reduced shade significantly reduced scion stem height and relative growth rate while high shade and low watering frequency significantly reduced (P = 0.05) the leaf area index. 90% shade resulted in reduced dry matter in roots and rootstock stems. High fertigation nitrogen concentration favoured increased chlorophyll contents in leaves while reducing DM in roots. Highly significant interaction effects were also observed between the treatments and levels of tissue starch, nitrogen and sucrose. Increased shading favoured increased starch in roots and rootstock stems, but decreased the levels in scion stems and leaves. Increased shading up to 60% raised sucrose levels in roots and scion stems but reduced it (levels of sucrose) in rootstock stems and leaves. At 90% shade, leaves and rootstock stems had significantly high sucrose levels while roots and scion stems had the lowes