THE EVOLUTION OF RICE-GROWING AREAS                                 from 1952 to 2015          Flooded rice cultivation (1952, 1975, 1989, 2015) :       its relationship with plant formations, soils and floods

1 – INTRODUCTION………………………………………………………………………………………… 2 1.1 – Objectives………………………………………………………………………………..  2 1.2 – Sources…………………………………………………………………………………...  2 1.2.1 - The study by Mark Haywood (1952 & 1975)   1.2.2 - Map of agricultural land use. (PIRL 1989)   1.2.3. Data from Léo Zwarts (2015): 2 - METHODOLOGY AND DATA QUALITY ISSUES…………………………………………. ………… 5 2.1 - Data entry and processing………………………………………………………………  5 2.2 – The problem of data quality……………………………………………………………  7   2.2.1 - Definition of themes and media        2.2.2 - Data accuracy 3 - RICE CULTIVATION IN THE INNER DELTA……………………………………………………….  11        3.1 – The three coexisting rice farming systems in the Delta:……………………………..  12         3.1.1 - Irrigated rice cultivation         3.1.2- Rice cultivation in paddies         3.1.3- Rain/river fed rice cultivation or uncontrolled flooding 3.2 - Changes in the area under rain/river-fed rice cultivation from 1952 to 2015………  18 3.3 - Rice cultivation remains nomadic……………………………………………………...  21         3.3.1 - Cultivated land per municipality and per capita         3.3.2 – Rice-growing basins and hydrological basins         3.3.3. A very ancient form of agricultural nomadism that is still relevant today... 4 - RICE FARMERS' STRATEGIES: RICE FIELDS AND VEGETATION............................…………  39 4.1. - The choices made by rice farmers in the western Delta from 1952 to 2015................  40        4.1.1 - Rice farmers' choices in the western Delta in 1952        4.1.2 – The situation in the western Delta in 1975        4.1.3 – The situation in the western Delta in 1989        4.1.4 – The situation in the western Delta in 2015 4.2. - The choices made by rice farmers throughout the Delta in 1989 and 2015..........….  46         4.2.1 – The year 1989 in the Delta         4.2.2 – The year 2015 in the Delta 4.3. Conclusion: the choices of rice farmers.......................................................................…  48 5 - STRATEGIES AND CONSTRAINTS: THE ROLE OF FLOODING. ...............................…………   52 5.1 - Rice fields and water levels..........................................................................................…  55 5.2 - Rice fields and floods...................................................................................................…  56 6- CONCLUSION.................................................................................................................…………………  61 6.1 - 2010, a good year..........................................................................................................…   62 6.2 - 1972: a mediocre year...................................................................................................…  63 6.3 - 1989: a bad year............................................................................................................…  64 6.4 – What future for rain/river-fed rice cultivation?......................................................….  65