SPECIAL PUBLICATION POTASSIUM IN INDIAN AGRICULTURE International Symposium on Importance of Potassium in Nutrient Management for Sustainable Crop Production in India 3 -5 December, 2001 New Delhi N.S. Pasricha & 5 K. Bansal POTASH RESEARCH INSTITUTE OF INDIA SINTERNATIONAL POTASH INSTITUTE SPECIAL PUBLICATION POTASSIUM IN INDIAN AGRICULTURE International Symposium on Importance of Potassium in Nutrient Management for Sustainable Crop Production in India 3 - 5 December, 2001 New Delhi N.S. Pasricha & S.K. Bansal POTASH RESEARCH INSTITUTE OF INDIA W INTERNATIONAL POTASH INSTITUTE Correct Citation: Pasricha, N.S. and Bansal, S.K. 2001. Potassium in Indian Agriculture, Special Publication, Potash Research Institute of India, Gurgaon, Haryana, India. Published by the Potash Research Institute of India, Sector 19, Dundahera, Delhi-Gurgaon Road, Gurgaon-122001, Haryana, India First printed 2001 Responsibility for the information in this publication rests with the individual authors. Printed at Rakmo Press Pvt. Ltd., C-95, Okhla Industrial Area Phase-I, New Delhi-110020. Phone: 6814886, 6816282, Telefax: 6810424. Contents I. Foreword 5 2. Preface 7 3. Kinetics of Potassium Release and Fixation in Soils 9 S.K. Sanyal and K. Majumdar 4. Potassium Availability in Relation to Soil Mineralogy in the Indo-Gangetic Plains 33 S.S. Mukhopadhyay and S.C. Dutta 5. Mineralogy and Dynamics of Potassium in Soils of Arid and Semi-Arid Regions of India 45 A.V Shanwal and S.P. Singh 6. Distribution and Availability of Potassium in Lateritic Soils of India 75 T.C. Baruah, K. Borakakati and H.C. Baruah 7. Distribution and Availability of Potassium in Red Soils of India 89 N.B. Prakash and R. Siddaramappa 8. Potassium Availability and Crops Response to Fertiliser Potassium in Hill and Mountain Soils of India 109 Patiram 9. Assessing Potassium Availability in Indian Soils 125 A. Subba Rao, TR. Rupa and S. Srivastava 10. Interaction of Potassium with Other Nutrients 159 A.N. Ganeshamurthy and Ch. Srinivasa Rao 11. Potassium Management in Rice-Wheat Cropping Systems in South Asia 175 Yadvinder Singh and Bijay Singh 12. Potassium Nutrition Management for Improving Yield and Processing Quality of Potato 195 J.P. Singh, S.P Trehan and R.C. Sharma 13. Potassium Nutrition of Sugarcane in Relation to Yield, Quality and Abiotic Stress Tolerance 217 R.S Dwivedi 3 14. Potassium Fertility in Cotton Growing Soils of India and Its Influence on Yield and Quality of Cotton 241 M.S. Brar 15. Role of Potassium Fertilization in Improving Productivity of Pulse Crops 261 Masood Ali and Ch. Srinivasa Rao 16. Potassium Nutrition Management for Yield and Quality of Citrus in India 279 A.K. Srivastava and Shyam Singh 17. Influence of Potassium in Balanced Fertilization on the Yield and Quality of Vegetable Crops 321 Pritam K. Sharma, S.P. Dixit, S.K. Bhardwaj and S.K. Sharma 18. Potassium Nutrition Management for Improving Yield and Quality of Flue-cured Tobacco 357 V Krishnamurthy; B.V Ramakrishnayya and K.D. Singh 19. Potassium Nutrition Management of Oil Seed Crops 379 B.A. Golakiya and M.S. Patel Foreword Crop production in India has made a remarkable step forward in the last decades enabling to feed its steadily increasing population although the area of arable land remained almost the same. One of the driving forces behind the increased productivity of the available land is the use of mineral fertilizers. Consumption of mineral fertilizers almost doubled every decade reaching currently some 18 million tons of nutrients. Concomitantly, food grain production doubled in the last three decades to currently about 200 million tons, which not only kept the food production in line with the population growth but also increased the per capita output. However, declining growth rates in crop yield raise concern on the efficiency of fertilizer use. A rather wide nutrient ratio in fertilizer use, as practised in India, fuelled the doubts. State-wide investigations showed indeed that, irrespective to the region, nutrient supply with mineral fertilizers and other sources is progressively less in balance with the nutrient removal by the harvested crops. This refers to potassium in particular. Negative K balances are widespread, the deficit tends to increase. Continuous negative K balances mean soil K mining and ultimately loss in soil fertility and sustainability of the productivity of the cultivated land. This restricts full utilization of the genetic potential of the crops, which hinders income generation and prevents further rural development. The far-reaching consequences of unbalanced fertilization are enough reasons to bring the subject to the public knowledge. The Special Publication, which is issued on the occasion of the International Symposium on the "Importance of potassium in nutrient management for sustainable crop production in India", December 3-5, 2001 in New Delhi will address the public. Based on profound research, eminent scientists report on the behaviour of potassium in soils, its assessment, and the effect of balanced fertilization with potassium on yield and quality of crops and cropping systems. With this publication, the decision-makers should be aware of the long-term consequences of unbalanced fertilization, consequences for food security, resource management, environment and the rural development. On the other hand, the consumer should also know that judicious and balanced use of mineral fertilizers, potassium in particular, contributes not only to produce high quality crops but safe food at the same time. Appreciatively, the Potash Research Institute of India, PRII, took the initiative to encourage and convince concerned scientists to collect the results and to prepare the manuscripts. Dr. Pasricha and his colleagues deserve our thanks and gratitude for issuing this Special Publication. November, 2001 (Adolf Krauss) Director, IPI 5 Preface This special publication on "Potassium in Indian Agriculture" released at the occasion of International Symposium on "'Importance of Potassium in Nutrient Management for Sustainable Crop Production in India" is a compilation of specific contributions from the scientists who have been working on one or the other aspects of potassium as a plant nutrient. Future food production will be increasingly dependent on supplementing plant nutrients obtained from soil with mineral fertilizers. Mineral fertilizers have now become indispensable for ensuring sufficient food production and checking decline in soil productivity through nutrient depletion. The rapidly increasing population and consequent rise in food demand have rendered mineral fertilizers an integral part of our food supply chain. In a developing country like India, with increasing population and consequent decrease in per capita arable land, there is no alternative to a matching growth in food production as well. The challenge, therefore, is to sustain growth in food production whilst maintaining soil fertility and taking care of natural resources and environment. Balanced fertilizer application is, therefore, a must. Balanced fertilization entails supplying plants with precise and adequate amounts of nutrients needed for their optimal growth and development. Consideration of size and readability have limited the amount of detail that can be presented on each aspect related to potassium nutrition, but it is our hope that this publication will contribute to improve our understanding of the complexities of potassium in soil, its role in plant nutrition and provide a basis for future research. With the introduction of high yielding fertilizer responsive crop cultivars grown under intensive conditions, depletion of soil nutrients, like potassium, is taking place at an alarming rate without sufficient replenishment. Such a compendium on this vital plant nutrient is necessary since much new knowledge has accumulated in the recent time. Dr. Adolf Krauss's generous contribution in writing the Foreword is gratefully acknowledged. We hope that the present publication will be useful to the researchers, students, extension worker, fertilizer industry, planners and administrators concerned with balanced fertilization, more particularly with potassium. We also acknowledge our debt to those colleagues who put very sincere efforts in contributing different chapters. November 2001 (N.S. Pasricha) 7 Director, PRII Kinetics of Potassium Release and Fixation in Soils S.K. SANYAL AND K. MAJUMDAR* Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur-741252, West Bengal INTRODUCTION A large number of experimental studies have been conducted to probe the dynamic nature of equilibria between different forms of soil potassium (K), namely water-soluble K, exchangeable K, non-exchangeable K and the mineral or structural K. Most of these studies have employed a batch technique; allowing the system, namely soil K/solution K, to attain equilibrium at a constant temperature (and pressure). The ensuing distribution ratio (Goulding, 1983) has been related to the approximate thermodynamic equilibrium (K) constant. From the latter, as well as from a study of its temperature dependence, a number of 0 thermodynamic parameters (such as standard free energy change, AG ; enthalpy change, AH; and entropy change, AS) of K* exchange equilibria between soil solid and solution phases, have been computed. The negative sign of AG at a constant temperature and pressure of the ion-exchange reaction is taken to indicate the spontaneity of the given ion-exchange reaction,