Nutrient status of cocoa (Theobromae cacao) in Papua New Guinea: results from a survey

Nelson, Paul N., Fidelis, Chris, Webb, Michael J., Berthelsen, Suzanne, and Yinil, David (2010) Nutrient status of cocoa (Theobromae cacao) in Papua New Guinea: results from a survey. In: Proceedings of the 19th World Congress of Soil Science. pp. 71-74. From: 19th World Congress of Soil Science, 1-6 August 2010, Brisbane, QLD, Australia.

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Cocoa is the primary cash crop in most coastal areas of Papua New Guinea (PNG), supporting an estimated 150,000 households. Smallholders produce most of the crop, but their yields are low, at about 10% of the maximum. Low yields have been attributed to many factors, but the possibility of nutrition-related limitations to productivity has not been examined in detail. Here we report on a survey of 63 cocoa blocks across the country. Based on leaf analyses, N and Fe deficiencies appear to be very widespread, with 95 % of sampled blocks falling below the critical level for N and 89 % for Fe. P deficiencies were encountered in ~25% of the blocks sampled. Leaf Mg concentrations were adequate in most blocks in most provinces, except East New Britain, where 64 % of the blocks sampled were deficient. Deficiencies of K, Ca, Mn, B, Cu and Zn were encountered in 2 -15 % of sampled blocks. There were significant relationships between leaf and soil contents of K, Ca, Mg and P. There is a clear need to further examine nutrition-related limitations to productivity in PNG, including establishment of more reliable critical levels for leaf nutrient concentrations.

Item ID: 11748
Item Type: Conference Item (Research - E1)
ISBN: 978-0-646-53783-2
Keywords: critical level; deficiency; leaf nutrient content; nutrient cycling; soil fertility; tree crop
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Date Deposited: 25 Aug 2010 00:31
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0703 Crop and Pasture Production > 070306 Crop and Pasture Nutrition @ 50%
05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050304 Soil Chemistry (excl Carbon Sequestration Science) @ 50%
SEO Codes: 82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8203 Industrial Crops > 820399 Industrial Crops not elsewhere classified @ 50%
96 ENVIRONMENT > 9609 Land and Water Management > 960904 Farmland, Arable Cropland and Permanent Cropland Land Management @ 50%
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