Boron and Zinc Deficiency in Nepalese Soils: Small-Scale Variations and the Influence of Farming System Dependent Factors
Total Page：16
File Type：pdf, Size：1020Kb
Boron and zinc deficiency in Nepalese soils: Small-scale variations and the influence of farming system dependent factors. A case study from Sedi Bagar, Kaski District, Nepal. By Kristian Eide Jensen A masters`s thesis in Environmental Geography Spring 2007 Department of Geography University of Bergen, Norway II Acknowledgements The process of writing a master’s thesis contains bottomless valleys as well as high mountain peaks of mental wellbeing. Still, I look back at the last year’s studies as an entirely positive experience. Much of the credit should be given to the fantastic social community at the Institute of Geography, University of Bergen. Here, the fellow feeling is stronger than most places I know. I am also very grateful to my supervisor, Peter Andersen, who has been supportive and constructive in his feedbacks on this thesis. Peter Andersen is the person that introduced me to the wonderful country of Nepal and the interesting study of farming systems and micronutrients in soils. The gathering of data could not have done without Roshani Rai. I found her guidance, knowledge and good humour priceless when I was wandering around in a totally unknown country. Dr. Desh Subba at LI-BIRD was also a valuable help during my time in Pokhara. I have worked hard to produce some good results in this thesis, but in the moment of conclusion, it stands clear for me that the path to the findings is more important than the findings themselves. Bergen, April 2007 Kristian Eide Jensen II I IV Contents Abbreviations VII List of figures VIII List of tables VIII 1. INTRODUCTION. ............................................................................................................ 1 1.1. RESEARCH QUESTION ...................................................................................................................... 2 1.2. HYPOTHESES ...................................................................................................................................... 2 1.2.1. Deficiency issues. ........................................................................................................................... 4 1.2.2. Farming System Intensity............................................................................................................. 5 1.2.3. Fertilizer use .................................................................................................................................. 6 1.2.4. Fertilizer Recommendations ........................................................................................................ 7 1.2.5. Spatial patterns.............................................................................................................................. 7 1.3. ORGANIZATION OF THE THESIS.................................................................................................... 8 2. STUDY AREA DESCRIPTION....................................................................................... 9 2.1. NEPAL.................................................................................................................................................... 9 2.2. SEDI BAGAR....................................................................................................................................... 10 2.3. PHYSICAL CHARACTERISTICS...................................................................................................... 11 2.4. SOSIO-CULTURAL CHARACTERISTICS....................................................................................... 12 2.5. INFRASTRUCTURE........................................................................................................................... 13 3. THEORETICAL FRAMEWORK................................................................................. 15 3.1. DEDUCTION AND INDUCTION ...................................................................................................... 15 3.2. REVIEW OF ZINC AND BORON ISSUES IN NEPALESE SOILS................................................ 17 3.2.1. The law of the minimum............................................................................................................. 19 3.2.2. Effects of zinc and boron deficiency in crops............................................................................ 20 3.2.3. Natural agents affecting zinc and boron levels of the Nepalese soils. ..................................... 22 3.3. PLANTS AND FARMING SYSTEM.............................................................................................. 27 3.3.1. The nutrient budget. ................................................................................................................... 29 3.3.2. Nutrient output............................................................................................................................ 29 3.3.3 Nutrient input - Organic Fertilizers .......................................................................................... 30 3.3.4. Nutrient input - Chemical Fertilizers ........................................................................................ 32 3.3.5. Annual rotation cycles. ............................................................................................................... 36 3.3.6. High Value Cash Crops. ............................................................................................................. 37 3.4. HUMAN NUTRIENT DEFICIENCIES............................................................................................. 39 3.5. THE ECONOMIC BEHAVIOUR OF SEMI-SUBSISTENCE PEASANTS .................................... 40 3.6. KNOWLEDGE ..................................................................................................................................... 41 3.6.1. Extension service ......................................................................................................................... 41 3.6.2. Blanket recommendations. ......................................................................................................... 43 V 4. METHODOLOGY .......................................................................................................... 45 4.1. WORKING IN AN UNFAMILIAR CULTURE.................................................................................. 45 4.1.1. Status............................................................................................................................................ 45 4.1.2. Operating in an unknown area .................................................................................................. 46 4.1.3. Case study .................................................................................................................................... 47 4.2. DATA COLLECTION.......................................................................................................................... 48 4.2.1. Quantitative and qualitative data. ............................................................................................. 50 4.2.2. Validity and reliability................................................................................................................ 51 4.2.3. Sampling pattern......................................................................................................................... 52 4.2.4. Soil sampling methods. ............................................................................................................... 55 4.2.5. Interview guide............................................................................................................................ 55 5. DATA PRESENTATION AND ANALYSIS ................................................................ 57 5.1. EXPLORATORY DATA ANALYSIS .................................................................................................. 57 5.2. EXTENT OF BORON AND ZINC DEFICIENCY IN SEDI BAGAR................................................... 62 5.3. SPATIAL DATA ANALYSIS............................................................................................................... 63 5.3.1. A map overview of the zinc and boron data.............................................................................. 63 5.3.2. Spatial autocorrelation. .............................................................................................................. 66 5.3.3. Spatial interpolation.................................................................................................................... 71 5.3.4. Geology and soil cover. ............................................................................................................... 74 5.3.5. Streams and rivers ...................................................................................................................... 76 5.4. FARMING SYSTEM ANALYSIS ....................................................................................................... 79 5.4.1. Rotation cycles............................................................................................................................. 79 5.4.2. Fertilizing practices..................................................................................................................... 82 5.5. CORRELATION ANALYSIS AND STATISTICAL RELATIONSHIPS .......................................... 86 5.5.1. Land categories............................................................................................................................ 87 5.5.2. Number of rotations...................................................................................................................