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Fertiliser Recommendations for HorticulturCrops <br /> _ i I _ --- - - -- - <br /> 4 <br /> Of $oysenberries, Youngberries and Blackberries <br /> Although the bramble group (Rubus hybrids) constitutes a significant proportion of the national berryfruit area, <br /> surprisingly little is known about their nutritional requirements. Virtually no controlled work has been carried out in <br /> New Zealand on either application, responses, or leaf tissue analysis for brambles and the overseas literature in this area <br /> is frequently inconsistent. <br /> PLANT ANALYSIS <br /> Samples for leaf analysis should be collected from primocanes during January and February. Each sample should <br /> contain approximately 50 youngest mature leaves (including petiole) selected at random from 10 or more canes. There <br /> is little published information on chemical analysis of leaf tissue for these crops. The data presented for boysenberries <br /> (Table 1) is based on a compilation of results recorded at the Soil Fertility Service plant analysis laboratory at Ruakura <br /> over a number of years,hence is only an indication of the sorts of concentrations anticipated. <br /> Values for youngberries are not considered to differ markedly from those of boysenberries. <br /> Table 1: Typical concentrations for foliar analysis of <br /> boysenberries. <br /> Element Range <br /> Macronutrients (%) <br /> Nitrogen 2.8 - 3.7 <br /> Phosphorus 0.17 - 0.34 <br /> Potassium 1.39 - 1.89 <br /> Calcium 0.65 - 1.37 <br /> Magnesium 0.22 - 0.46 <br /> Sulphur 0.18 - 0.32 <br /> Micronutrients(ppm) <br /> Manganese 134 - 304 <br /> Zinc 28 - 60 <br /> Copper 8 -29% <br /> Boron 38 - 57 <br /> FERTILISER REQUIREMENTS <br /> to date fertiliser applications in New Zealand have been made to ensure adequacy,rather than based on crop data or <br /> dant needs. No nutrient removal figures are available for this group, and fertiliser recommendations from various <br /> ;ources are widely divergent. NPK rates for example range between 28-160 kg N/ha, 35-112 kg P/ha and 28-160 kg <br /> C/ha. Despite the variation, these rates are still considerably less than those many New Zealand growers are presently <br /> ipplying. Boysenberries in California and Oregon have shown little yield response to the level or timing of fertiliser <br /> applications. This suggests New Zealand growers could,with careful monitoring,reduce the rates being used here. <br /> or this group of crops applications of N should be based on plant vigour, soil type and rainfall, with P, K, and Mg <br /> application based on soil test levels (Table 2). A pH range of 5.8 - 6.5 is considered satisfactory. Where Ca, or pH <br /> evels are below those suggested,lime should be applied in autumn or early winter. If this is coupled with low Mg <br /> evels, lime and magnesium oxide(which is less expensive), or dolomite should be used. <br /> Table 2: Suggested annual fertiliser application for established bramble crops. <br /> Element MAF Soil Quick Test Level Application Rate(kg/ha) <br /> Nitrogen <br /> - 75 - 100 <br /> Potassium <br /> 13 -20 0 <br />