FAO SOILS BULLETIN 48 micron utrients and the nutrient status of SOUS: a global study by mikko sillanpAl FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS FAO SOILS BULLETIN 48 micronutrients and the nutrient status of soils: a global study by mikko sillanpäd sponsored by the government of finland executed at the institute of soil science agricultural research centre jokioinen, finland and soil resources, management and conservation service land and water development division FAO FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIO-NS Rome 1982 The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization oftheUnitedNations concerningthelegal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. M-52 ISBN 92-5-101193-1 Allrights reserved. No part ofthispublication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic,mechanical, photocopyingor otherwise, without theprior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme diCaracalla, 00100 Rome, Italy. C) FAO 1982 Printed in Finland by Werner Söderström Osakeyhtiö. Foreword During the last two decades, the increasing use of mineral fertilizers and organic manures of different types has led to impressive yield incrcases in developing countries. Major emphasis was given to the supply of the main macronutrients, nitrogen, phosphate and potash. For a long time it was felt that under the existing farming systems and fertilizing practices the level of micronutrients was adequate and that the problem of micronutrient deficiencies was not a serious one. However, indications from developing countries show that micronutrient problems are becoming more and more frequent. In the early 1970s the Government of Finland, through its Institute of Soil Science and FAO embarked on a system of investigation of microelement deficiencies in developing countries. In 1974, the project -Trace Element Study, TF/129/FIN" started under the FAO/ Finland Cooperative Programme, with the financial support of the Government of Finland, and with the cooperation of the staff of the Institute of Soil Science, under the direction of Prof. M. Sillanpää. The facilitiesof theInstitute were made available to the project. This programme involved a worldwide study on micro- nutrients, in cooperation with 30 countries. The study, which is presented in this document, shows that the undertaking was very timely. It appears that micronutrients are becoming deficient in developing countries and that remedial measuring will need to be taken to ensure full soil and plant productivity. The study also gives guidance for the investigation of micronutrient deficiencies, which should be dealt with at the country level. FAO expresses its appreciation to the Government of Finland for its generous support of the study and for its excellent cooperation throughout. F.W. Hauck Chief, Soil Resources, Management and Conservation Service V CONTENTS page PREFACE PART I 1 PART I SOIL AND PLANT DATA, IvIETHODOLOGY AND INTERPRETATION 3 1 MATERIALS AND METHODS 3 1.1 Collection of original plant and soil samples 3 1.2 Indicator plants 3 1.2.1 General 3 1.2.2 Sampling time 4 1.2.3 Contamination 4 1.2.4 Plant varieties 6 1.2.5 Need for better grounds for comparing plant data 6 1.2.6 Growing new indicator plants in pots 7 1.3 Analytical methods 8 1.3.1 Methods of soil analyses 9 1.3.2 Methods of plant analyses 11 1.3.3 Statistical methods 12 1.4 Expression of analytical data 13 1.4.1 Soils 13 1.4.2 Plants 14 1.4.3 Regression graphs 14 2 RESULTS AND DISCUSSION 17 2.1 General properties of soils and their mutual relations 17 2.2 Macronutrients 21 2.2.1 General aspects 21 2.2.2 Comparison of the two original indicator plants 21 2.2.3 Comparison of macronutrient status in different countries 21 2.2.4 Macronutrient contents of plants and soils in relation to four soil characteristics 28 2.3 Micronutrients 33 2.3.1 Plant analysis versus soil analysis 33 2.3.2 Molybdenum 35 2.3.2.1 General aspects 35 2.3.2.2 Soil factors affecting the molybdenum contents of plants and soils 36 2.3.3 Boron 46 2.13.1 General aspects 46 2.3.3.2 Soil factors affecting the boron contents of plants and soils 48 2.3.4 Copper 54 2.3.4.1 General aspects 54 2.3.4.2 Soils factors affecting the copper contents of plants and soils 55 2.3.5 Iron 61 2.3.5.1 General aspects 61 2.3.5.2 Soil factors affecting the iron contents of plants and soils 61 2.3.6 Manganese 64 2.3.6.1 General aspects 64 2.3.6.2 Soil factors affecting the manganese contents of plants and soils 66 2.3.7 Zinc 75 2.3.7.1 General aspects 75 2.3.7.2 Soil factors affecting the zinc contents of plants and soils 75 VI page 2.4 Mutual relations between micronutrients 83 2.5 Micronutrient contents of plants and soils in relation to yields with special reference to the "concentratiim-dilution" phenomenon 86 2.6 Suitability of plant and soil analyses for large scale operations 90 2.7 Estimation of critical micronutrient Hants 90 2.8 Plant and soil micronutrieents and other soil data in relation to FAO/Unesco soil units 96 3 SUMMARY FOR PART I 97 PART II 101 PART II NUTRIENT STATUS BY COUNTRIES 103 4 INTRODUCTION 103 5 EUROPE AND OCEANIA 105 5.1 Belgium 105 5.2 Finland 117 5.3 Hungary 128 5.4 Italy 139 5.5 Malta 150 5.6 New Zealand 158 6 LATIN AMERICA 169 6.1 Argentina 169 6.2 Brazil 180 6.3 Ecuador 190 6.4 Mexico 194 6.5 Peru 207 7 FAR EAST 219 7.1 India 219 7.2 Korea, Republic of 232 7.3 Nepal 242 7.4 Pakistan 251 7.5 Philippines 262 7.6 Sri Lanka 271 7.7 Thailand 280 8 NEAR EAST 289 8.1 Egypt 289 8.2 Iraq 300 8.3 Lebanon 313 8.4 Syria 322 8.5 Turkey 332 9 AFRICA 343 9.1 Ethiopia 343 9.2 Ghana 355 9.3 Malawi 363 9.4 Nigeria 372 9,5 Sierra Leone 383 9.6 Tanzania 392 9.7 Zambia 401 VII page 10 SUMMARY FOR PART II 411 REFERENCES 417 APPENDIXES 1Instructions for taking plant and soil samples 421 2 National mean values of basic analytica/ data on origina/ wheat plants and respective soils 422 3 National mean values of basic analytical data on original maize plants and respective soils 428 4 National mean v-alues of basic analytical data on pot-grown wheat plants and respective soils 434 5 Indicative data on fertilizer application to the original indicator crops 440 6 Average soil properties and macronutrient contents of soils classified by FAO/Unesco soil units 441 7 Average micronutrient contents of soils and respective pot-grown wheats for FAO/Unesco soil units 442 LIST OF TABLES Page Table 1. Comparison of nutrient content of two soils expressed on weight and volume bases. 13 Table 2. Numerical products of plant content x soil content along the lines dividing the regression graphs into five zones. 15 Table 3. Mean macronutrient contents of the two original indicator plants, of the respective soils and the mean amounts of N, P, and K applied in fertilizers to each crop. 21 Table 4. Regressions of pooled plant N, P, K, Ca, and Mg contents on respective soil macronutrients. 28 Table 5. Plant and soil macronutrients as functions of four soil characteristics in the whole international material. 28 Table 6. Directions (+ or symbols) of regressions of plant and soil macronutrient contents on four soil characteristics. 32 Table 7. Equations and correlation coefficients for regressions of A0-0A extractable soil Mo (uncorrected and pH-corrected) and plant Mo on six soil characteristics. 39 Table 8. Correlations between plant Mo and A0-0A extractable soil Mo in various countries. Soil Mo analyses are both uncorrected and corrected for pH and texture. 45 Table 9. Correlations between plant B and hot water extractable soil B in various countries. Soil B analyses are both uncorrected and corrected for cation exchange capacity. 51 Table 10.Equations and correlation coefficients for regressions of hot water soluble soil B (un- corrected and CEC-corrected) and plant B on various soil factors. 53 Table 11 Correlations between plant Cu and AAAc-EDTA extractable soil Cu in various countries. Soil Cu analyses are both uncorrected and corrected for soil organic carbon contents. 58 VIII page Table 12.. Equations and correlation coefficients for regressions of AAAc-EDTA extractable soil Cu (uncorrected and org. C-corrected) and plant Cu on various soil factors. 60 Table 13.Equations and correlation coefficients for regressions of AAAc-EDTA extractable soil Fe and plant Fe on various soil factors. 64 Table 14.Correlations between plant Mn and DTPA extractable soil Mn in various countries. Soil Mn analyses are both uncorrected and corrected for pH(CaC12). 69 Table 15.Equations and correlation coefficients for regressions of DTPA extractable soil Mn (un- corrected and pH-corrected) and plant Mn on various soil factors. 71 Table 16.Correlations between plant Mn content and AAAc-EDTA extractable soil Mn in various countries.