Agricultural drought management in Northeast China and Inner Mongolia 中国東北部と内モンゴルにおける農業干ばつの管理 Li Rui 李 睿 The United Graduate School of Agricultural Sciences Tottori University, Japan 2015 Agricultural drought management in Northeast China and Inner Mongolia 中国東北部と内モンゴルにおける農業干ばつの管理 A thesis presented to The United Graduate School of Agricultural Sciences In partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Li Rui 李 睿 The United Graduate School of Agricultural Sciences Tottori University, Japan 2015 TABLE OF CONTENTS TABLE OF CONTENTS ........................................................................................................ I LIST OF FIGURES ............................................................................................................ IV LIST OF TABLES ............................................................................................................... VI SUMMARY ........................................................................................................................ VII 摘 要 ................................................................................................................................. XII ACKNOWLEGEMENTS ................................................................................................... XV ABBREVIATIONS ........................................................................................................... XVII Chapter 1 ............................................................................................................................. 1 General introduction ............................................................................................................ 1 1.1 The terminology related with agricultural drought .................................................. 1 1.1.1 Drought concepts ......................................................................................... 1 1.1.2 Drought types ............................................................................................... 1 1.1.3 Aridity, water shortage and drought ............................................................. 2 1.2 Drought in the world ............................................................................................... 3 1.3 Reviews of drought researches .............................................................................. 3 1.3.1 Climate background and drought ................................................................. 3 1.3.2 Basic characteristics of drought and drought indices .................................. 5 1.3.3 The prediction of drought impact on vegetation......................................... 10 1.3.4 Drought monitoring framework................................................................... 11 1.3.5 Modeling of water stress ............................................................................ 11 1.3.6 The impact of agricultural drought and drought mitigation assessment .... 18 1.4 The impact of drought on crop physiology ........................................................... 19 1.5 The objectives of the thesis .................................................................................. 20 1.6 The structure of the thesis .................................................................................... 22 Chapter 2 ........................................................................................................................... 23 Temporal-spatial precipitation variation in Northeast China and Inner Mongolia .............. 23 2.1 Background .......................................................................................................... 23 2.2 Study area ............................................................................................................ 23 2.3 Data and Method .................................................................................................. 24 2.3.1 Data ............................................................................................................ 24 2.3.2 Method ....................................................................................................... 26 2.4 Results .................................................................................................................. 26 2.4.1 Temporal pattern of precipitation from 1961-2010 ..................................... 27 2.4.2 Spatial pattern of seasonal precipitation variation ..................................... 29 2.4.3 Spatial pattern of annual precipitation trend .............................................. 29 2.5 Discussion ............................................................................................................ 30 2.6 Conclusion ............................................................................................................ 30 Chapter 3 ........................................................................................................................... 32 Index-based agricultural drought monitoring in Hailar County, Inner Mongolia ................ 32 3.1 Background .......................................................................................................... 32 3.2 Study area ............................................................................................................ 34 3.3 Conceptual model of the agricultural drought process ........................................ 36 I 3.4 Data and Method .................................................................................................. 36 3.4.1 Data ............................................................................................................ 36 3.4.2 Method ....................................................................................................... 38 3.5 Results .................................................................................................................. 39 3.5.1 Seasonal trends of drought indices ........................................................... 39 3.5.2 Relationships of drought indices with crop yield ........................................ 40 3.5.3 Temporal relationships between drought indices ....................................... 41 3.5.4 Drought assessment .................................................................................. 42 3.6 Discussion ............................................................................................................ 45 3.6.1 Recent trends of climate and agricultural drought in Hailar County .......... 45 3.6.2 Critical growth stages related with yield reduction ..................................... 46 3.6.3 Time lags between water deficit and NDVI ................................................ 47 3.6.4 Feasibility of SPI, CMI, and NDVI for monitoring agricultural drought ...... 48 3.7 Conclusion ............................................................................................................ 48 Chapter 4 ........................................................................................................................... 50 Agricultural drought severity assessment based on a crop model ................................... 50 4.1 Introduction ........................................................................................................... 50 4.2 Materials and methods ......................................................................................... 52 4.2.1 Description of study area ........................................................................... 52 4.2.2 Agricultural drought assessment framework .............................................. 54 4.2.3 Model calibration and validation ................................................................ 55 4.2.4 Drought index assessment and framework validation ............................... 56 4.2.5 Soil moisture simulation ............................................................................. 58 4.2.6 Data sources and collection ....................................................................... 58 4.3 Results and Discussion ........................................................................................ 60 4.3.1 Crop model performance ........................................................................... 60 4.3.2 Agricultural drought indices assessment ................................................... 62 4.3.3 Validation of assessment framework ......................................................... 67 4.3.4 The relationship between soil moisture simulation and CMI ..................... 69 4.4 Conclusions .......................................................................................................... 70 Chapter 5 ........................................................................................................................... 71 The comparison of agricultural practices to mitigate drought by the crop model ............. 71 5.1 Introduction ........................................................................................................... 71 5.2 Date and Methods ................................................................................................ 73 5.2.1 Study area .................................................................................................. 73 5.2.2 Materials ..................................................................................................... 74 5.2.3 Agricultural practices .................................................................................. 76 5.3 Results