Triple Rice Cropping Research Articles

Multi-Scale Drivers of Land-Use Changes at Farm Level I: Conceptual Framework and Application in the Highly Flooded Zone of the Vietnamese Mekong Delta

There is an implementation gap between government plans and land-use changes at the local level in the Vietnamese Mekong Delta. This stands in the way of the sustainable development of the delta, especially in the face of environmental degradation, climate change, and water-use conflicts. To narrow the gap between plans and practice, the government needs a better understanding of what drives land-use decisions at the farm level. Our research developed and applied a multi-scale framework to identify the principal drivers of land-use changes at the farm level in the Vietnamese Mekong Delta over the past 40 years. We conducted semi-structured interviews with 31 farmers in the highly flooded zone, then used transcript analysis to quantify the influence of the drivers mentioned by farmers. We found drastic shifts in land uses, predominantly towards rice intensification. Among the 43 change drivers the farmers mentioned, those operating at the regional scale were particularly influential, including the activities of local authorities, neighborhood effects, and the development of water management infrastructure. Market factors have become more prominent in the last two decades, motivating farmers to shift from double to triple rice or to gradually diversify into vegetables. However, agricultural diversification remains limited by the agro-hydrological context, which favors triple rice cropping, as well as household scale factors such as natural and physical assets of the farm, household capital, and labor capacity. The local community also played a key role in land-use change, though with a double-edged effect, both delaying implementation of central government policy and forcing farmers to follow the majority’s decision.

Fluctuations in rice yields and productivity in the comprehensive flood control dike area of the upstream VietNam Mekong Delta: A case study of An Giang province

Full dyke system has greatly benefited farmers in cultivating triple rice cropping during flooding seasons in the Mekong Delta. Although tripple rice cropping brings benefits, its full dyke system has changed flooding situation in the Mekong Delta and stopped sediments to enrich the rice fields. Long-term intensive rice cultivation leads to soil degradation, which is one of the causes of reduced rice yields and productivity. The study aims to evaluate the changes in triple rice yield and productivity under the effect of a flood control dyke system in An Giang province. Spatial data on flooding and land use derived from MODIS satellite imagery was analyzed and compared with data of flood extension from Radar satellite product, while land use data from MODIS was verified with cultivation rice data from Statistical Yearbooks issued by An Giang province from 2000 - 2020. The result of this study shows that the flooded area decreased by 65.92%, creating conditions for farmers to expand the triple rice cropping area by 46,61%. However, the area of triple rice cropping in the phase of 2011 - 2020 has reduced 13,90%. As a result, the production decreased by 9,82% in the proportion of rice in the whole year and a 0,83 ton/ha decreased in comparison with the period when the dyke system was still under construction (2000-2011). In addition, triple rice cropping was practised in the protected flood control dyke systems in the upstream districts has higher average yields than those in the downstream districts (5.60 tons/ha compared to 5.40 tons/ha). The research shows a positive correlation between the increase in the area of flood control dyke system and the yield and production of triple rice cropping. The research results provide insights for researchers and policymakers in the region to adapt appropriate plans to minimize flood risks and ensure livelihood stability for farmers in the flood control dyke system in the upstream area, e.g. An Giang province, of the Mekong delta.

Increased rice yield and reduced greenhouse gas emissions through alternate wetting and drying in a triple-cropped rice field in the Mekong Delta

For sustainable food production in the Mekong Delta, greenhouse gas (GHG) emissions from rice cropping activities need to be reduced without sacrificing rice productivity. Each year, a substantial amount of straw is incorporated into paddy soils through triple rice cropping, which is characterized by a short cropping period and nearly year-round flooding, such that a large amount of methane is emitted. Exposing these soils to oxidative conditions by altering the cropping-period water regime might have the potential to reduce GHG emissions with increased rice yield. To test this potential, a split-plot experiment was conducted in a typical triple-cropped alluvial farmer's paddy in a central delta area over five years and 15 consecutive cropping seasons.The emissions observed from the continuously inundated paddies were 1.1–2.7 times greater than the reported emission factors for Vietnamese continuously inundated paddies. A significantly higher emission peak was detected at the beginning of the rice cropping and flooding fallow periods in continuously flooded (CF) paddies than in alternate wetting and drying (AWD) paddies, although the differences in field water level and soil moisture among the paddies were negligible. AWD reduced annual methane emissions (−51 %) and increased rice yield (+9 %), presumably through enhanced translocation of carbohydrates from leaves to panicles. The amount of GHGs emitted from straw use also decreased (11 %) under AWD management because the straw production rate was significantly lowered (9 %) by enhanced nutrient translocation. These results indicate that GHG emission reduction potentials in the Mekong Delta have been underestimated by previous studies, corroborate the necessity of additional long-term observations of triple rice cropping systems and demonstrate the need for a robust methodology for monitoring the permanence of AWD effects after policies promoting its widespread dissemination take effect.

Alternate wetting and drying enhanced the yield of a triple-cropping rice paddy of the Mekong Delta

ABSTRACT In the Mekong Delta, triple rice cropping is widely spread. The rice cultivation is characterized by a short cropping period and nearly year-round flooding. Putting the soil under an oxidative condition through changing the water regimes during cropping periods might have a potential to increase the rice yield. To test this potential, an experiment was conducted at a typical triple-cropping farmer’s alluvial paddy in a central area of the delta for five years, 15 consecutive cropping seasons. We adopted an intermittent irrigation technique known as alternate wetting and drying (AWD). Under AWD, we irrigated to a depth of 5 cm above the soil surface only when the field water level dropped to 15 cm below the soil surface, with some exceptions. As a control, we prepared a treatment under which the paddy was continuously flooded (CF) except 2 weeks before expected harvest. We also prepared three straw treatments: all raw straw return, all straw-ash return, and no straw return to the paddy. For other field management, we adopted locally conventional methods. Results show that the straw treatment effects on the rice yield were not significant. For water treatments, the soil redox potential under AWD remained higher, in most cases, than that under CF; and the rough rice yield, harvest index, and percentage of ripened grains under AWD respectively became 8.9%, 4.4%, and 3.5% higher (p < 0.01) than those under CF, with lower N contents in rice grains and 43% less irrigation water use. The increase in rice yield by AWD was found with an increase in harvest index and a decrease in aboveground biomass and nitrogen content, indicating that it was due to the promotion of nutrient translocation in rice by AWD. The effect of AWD was enhanced particularly in the winter–spring cropping season, during which the nighttime temperature was the lowest. This piece of evidence that the rice yield of the delta can be increased simply by introducing AWD has the potential to encourage farmers to take voluntary actions that will also lead to a reduction in methane emission from rice paddies.

Methane emissions in triple rice cropping: patterns and a method for reduction

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies because total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after the annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that avoiding rice straw incorporating into soil and decomposing rice straw in paddy surface-water reduces methane emissions.

Methane emissions in triple rice cropping: patterns and a method for reduction.

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

Methane emissions in triple rice cropping: patterns and a method for reduction.

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

Methane emissions in triple rice cropping: patterns and a method for reduction

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

Methane emissions in triple rice cropping: patterns and a method for reduction

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

Methane emissions in triple rice cropping: patterns and a method for reduction.

The Mekong Delta paddies are known as hotspots of methane emission, but these emissions are not well studied. We analyzed methane emission patterns based on monitoring data from typical triple rice cropping paddies collected over 5 years. We found that the total emissions in a crop season doubled in the second crop, tripled in the third crop, and reset after the annual natural flood of the Mekong River. The emission peaks occurred around 0 to 3 weeks after starting irrigation, then gradually decreased. This suggests that methane was generated by the soil organic matter, because the small rice plants provide little carbon for methanogenesis. In general, the main source of emitted methane is rice-derived carbon by current-season photosynthates and the emission peaks at the rice heading stage. However, the contribution of the rice-derived carbon is negligible in the hotspot paddies while total emission is high. The increase in emission levels from the first to the third crop can be explained by the accumulation of rice residue from the preceding crops, especially rice straw incorporated into the soil. The reset of emission levels after annual flood means that the rice straw is decomposed without methanogenesis in water with dissolved oxygen. Thus, the annual emission pattern shows that decomposing rice straw in paddy surface-water is an effective method to reduce methane emissions.

Economic Feasibility of Diversified Farming System in the Flood-Prone Mekong Delta: Simulation for Dike Area in An Giang Province, Vietnam

A simulation of crop choice was performed to examine the feasibility of introducing diversified farming systems, coexisting with seasonal floods, as an alternative to triple rice cropping system in the flood-prone Mekong Delta in Vietnam. A combination of 1.78 to 1.88 ha of double rice cropping and 0.12 to 0.22 ha of upland cropping can achieve an equivalent income or profit from 2 ha of triple rice cropping. Farmers evaluated the full-dike system positively in terms of both economic aspects and living conditions. Some farmers recognized that full flood control might have worsened the natural environment and reduced soil fertility resulting in declining rice yields. To establish a smart flood control system as an adaptation strategy against expected climate change, the following measures must be undertaken: (1) sensitize farmers to the increasing climatic risk in the near future and long-term adverse effects of intensive triple rice cropping; (2) offer alternative environmentally sound and economically profitable farming systems; and (3) develop institutional design for well-coordinated gate and pumping operations both at dike units and in canal network systems.

Đánh giá tính tổn thương đối với đất nông nghiệp trong điều kiện biến đổi khí hậu cho các tỉnh ven biển Đông Đồng bằng sông Cửu Long

The study aimed to evaluate the factors and agricultural zones suffered by climate change in 8 land use type including triple rice cropping, double rice cropping, intensive shrimp, rice-shrimp rotation, rice-cash crop rotation, fruit orchard, sugar cane, and intensive cash crop. The data was collected via 192 farmer and expert interviews. The data was analyzed and assessed by multi-critical evaluation and geographic information system. The results showed that saline and flood were the most influencial factors to triple rice cropping, double rice cropping, intensive shrimp, rice-shrimp rotation, rice-cash crop rotation, fruit orchard, sugar cane, and intensive cash crop. The flooding factor was the most influencial factor to the sugar cane and fruit orchard. This study determined 5 vulnerability levels to agricultural production systems including very low, low, medium, high, and very high. The vulnerability areas at medium, high and very high levels tended to increase while the vulnerability areas at very low and low levels showed a decreasing trend in 2016, 2030, and 2050.

Tác động của mặn và ngập theo kịch bản biến đổi khí hậu đến tiềm năng thích nghi đất đai vùng ven biển Đồng bằng sông Cửu Long

Agriculture is an important sector in the Vietnamese Mekong Delta (VMD), a major agricultural zone in Vietnam. Besides, the VMD has been identified as being particularly susceptible to the impacts of climatic variability. Land use systems in the coastal zones of the VMD have changed to improve local farmers’ income and to adapt to changes of socio-economic settings and natural conditions, especially in the climate change context. The data on natural conditions, current land use types, land use planning and scenarios of climate change (sea level rise and salinization) in VMD were collected. In this study, physical land suitability evaluation was implemented for 10 major land use types in the coastal provinces of the VMD (including: triple rice cropping, double rice cropping, single rice cropping, rice - cash crop rotation, rice – shrimp rotation, intensive shrimp, shrimp/mangrove, intensive sugarcane, intensive cash crop and fruit orchard) by using the land evaluation approach (FAO, 1976) in different scenarios. The results showed that there were 09 land suitability units of 10 major land use types in both the present and future climate change scenarios (2030 and 2050), and identified the dispute areas between of freshwater and salinity water affected to land use change in Kien Giang, Ca Mau, Bac Lieu, Soc Trang, Tra Vinh and Ben Tre. This study provided a good reference in orientation of agricultural land use planning and support adaptation and mitigation strategies for climate change in the future.

Increasing profitability and water use efficiency of triple rice crop production in the Mekong Delta, Vietnam

SUMMARYRice production in the Mekong Delta, Vietnam is threatened by future water scarcity caused by changing rainfall patterns and increasing irrigation costs. To improve resilience of the triple rice farming system to future climate-related stresses, profitability needs to be increased through water use efficiency, fertilizer management and planting methods.During four cropping seasons in 2011–13, alternate wetting and drying (AWD) irrigation was applied in the triple rice production area within An Giang Province, Vietnam. An issue with the application of AWD is the prevalence of acid sulphate soils in the Mekong Delta. Three types of irrigation management were tested; continuously flooded (CF) where the water in the paddy was maintained at 5 cm; AWD where the water level was allowed to fall to 15 cm below the ground surface, at which point the field was irrigated until the water level was at 1 cm above the ground surface (designated −15 cm); AWD where the water level was allowed to fall to 30 cm below the ground surface before irrigation until the water level was at 1 cm above the ground surface (designated −30 cm). Two further experiments were also undertaken which examined the planting method (transplant v. direct sowing) and phosphorus rate on rice yield. There was no effect on yield caused by P fertilizer rate and irrigation management in any year, and there was no significant effect on soil pH or salinity caused by irrigation management. Overall net profitability was greatest for the AWD treatments because of the reduction in pumping and labour costs in the dry season. Transplanted rice improved yields, but the labour cost reduced overall profitability. The study shows that AWD (−15 cm) can be safely applied in acid sulphate soil areas within the triple rice areas of An Giang Mekong Delta and saved at least 0·27 of total irrigated water quantity used during three of the six cropping seasons. The increased profitability of the AWD rice production system will help to improve the resilience of triple rice cropping systems to future water scarcity.

Greenhouse gas emissions from rice straw burning and straw-mushroom cultivation in a triple rice cropping system in the Mekong Delta

The Mekong Delta produces 21 Mt of rough rice (Oryza sativa L.) and an estimated 24 Mt of straw (dry weight) annually. Approximately one fourth of the straw is burned on the field, which is a common practice in intensive rice cultivation systems in this region because there is limited time to prepare the field for the next crop. The spread of intensive rice production in the Delta may increase the total biomass of burning crop residues, significantly impacting greenhouse gas (GHG) emissions in Vietnam. In this study, GHG emissions from the major uses of straw (burning and mushroom beds) were monitored in a triple rice cropping system located in the central Mekong Delta. Between September 2011 and November 2012, both wind tunnel and closed chamber methods were used to measure the emissions of major GHGs from straw-burning and straw-mushroom cultivation systems, respectively. The global warming potential (GWP) was then determined. Methane (CH4) and non-methane volatile organic carbon emissions (NMVOC) increased with lower modified combustion efficiency [MCE: emissions ratio of Carbon composing carbon dioxide (CO2-C) and carbon monooxide (CO-C) (CO2-C/(CO-C + CO2-C))]. Furthermore, higher moisture straw stacks generated lower nitrous oxide (N2O) emissions. Small straw stacks (5 or 10 kg dry straw) with higher moisture content emitted more carbon monoxide (CO), CH4 and NMVOC. These results suggest that factors that increase the straw moisture content, such as rainfall, can cause smoldering combustion in small straw stacks or when straw is scattered on the ground, thereby inhibiting N2O emissions but enhancing CO, CH4 and NMVOC. The measured N2O emissions contributed negligible amounts to the GWP compared with measured CO and CH4, which are relatively intense GHG emissions; this was likely a result of the slow and inefficient burning that was observed from the smaller straw stacks with higher moisture content. In this study, rice straw burning threatened to generate more GHGs than straw-mushroom (Volvariella volvacea (Bul. ex Fr.) Singer) cultivation under the studied agroecosystems.

Mapping the irrigated rice cropping patterns of the Mekong delta, Vietnam, through hyper-temporal SPOT NDVI image analysis

Successful identification and mapping of different cropping patterns under cloudy conditions of a specific crop through remote sensing provides important baseline information for planning and monitoring. In Vietnam, this information is either missing or unavailable; several ongoing projects studying options with radar to avoid earth observation problems caused by the prevailing cloudy conditions have to date produced only partial successes. In this research, optical hyper-temporal Satellite Pour l'Observation de la Terre (SPOT) VEGETATION (SPOT VGT) data (1998–2008) were used to describe and map variability in irrigated rice cropping patterns of the Mekong delta. Divergence statistics were used to evaluate signature separabilities of normalized difference vegetation index (NDVI) classes generated from the iterative self-organizing data analysis technique algorithm (ISODATA) classification of 10-day SPOT NDVI image series. Based on this evaluation, a map with 77 classes was selected. Out of these 77 mapped classes, 26 classes with prior knowledge that they represent rice were selected to design the sampling scheme for fieldwork and for crop calendar characterization. Using the collected information of 112 farmers’ fields belonging to the 26 selected classes, the map produced provides highly accurate information on rice cropping patterns (94% overall accuracy, 0.93 Kappa coefficient). We found that the spatial distributions of the triple and the double rice cropping systems are highly related to the flooding regime from the Hau and Tien rivers. Areas that are highly vulnerable to flooding in the upper part and those that are saline in the north-western part of the delta mostly have a double rice cropping system, whilst areas in the central and the south-eastern parts mostly have a triple rice cropping system. In turn, the duration of flooding is highly correlated with the decision by farmers to cultivate shorter or longer duration rice varieties. The overall spatial variability mostly coincides with administrative units, indicating that crop pattern choices and water control measures are locally synchronized. Water supply risks, soil acidity and salinity constraints and the anticipated highly fluctuating rice market prices all strongly influence specific farmers’ choices of rice varieties. These choices vary considerably annually, and therefore grown rice varieties are difficult to map. Our study demonstrates the high potential of optical hyper-temporal images, taken on a daily basis, to differentiate and map a high variety of irrigated rice cropping patterns and crop calendars at a high level of accuracy in spite of cloudy conditions.

Analysis of rapid expansion of inland aquaculture and triple rice-cropping areas in a coastal area of the Vietnamese Mekong Delta using MODIS time-series imagery

We applied a remote-sensing method using MODIS time-series imagery to detect the expansion of intensive farming systems (shrimp farming and triple rice cropping) in the Soc Trang and Bac Lieu provinces of the Vietnamese Mekong Delta (VMD). Field surveys for interpreting the estimates derived from the remote-sensing analyses were conducted in June and September 2007. From 2000 to 2006, there has been rapid expansion of inland aquaculture, especially shrimp farming, in the western part of the Bac Lieu province and the coastal regions of both the Bac Lieu and Soc Trang provinces. The triple rice-cropped area expanded concentrically from specific small locations in the Bac Lieu province from 2001 to 2006. The triple rice-cropped areas in Soc Trang province also expanded concentrically from 2001 to 2003, but some of these new triple rice-cropped areas returned to double rice cropping after 2004. Interviews with farmers and ancillary hydrological monitoring data suggested that changes in the water environment and transmission of information about new farming systems are closely connected with the annual expansion of triple rice-cropped areas in both provinces. The availability of salt-free irrigation water in the dry season may have led some pioneering farmers to attempt full-scale dry-season cropping. Furthermore, successful dry-season harvests and recent increases in the price of rice might have encouraged neighboring farmers to follow suit. Based on MODIS time-series imagery with field interviews at land-use change hotspots, the spatial structure of coastal farming systems and their recent changes were revealed from a macroscopic view point.

Detection of Yearly Change in Farming Systems in the Vietnamese Mekong Delta from MODIS Time-Series Imagery

This paper briefly introduces an integrated remote-sensing methodology based on MODIS time-series imagery for detecting spatiotemporal changes in Vietnamese Mekong Delta (VMD) farming systems. The integrated methodology consists of six parts, and uses a wavelet-based filter to smooth MODIS-derived time-series indexes (EVI, LSWI, and DVEL) from 2000 to 2008. Through a proposed decision tree using the smoothed indexes, we classified several farming systems, viz., triple rice cropping, two types of double rice cropping, shrimp-rice farming (rotational cropping), and inland aquaculture (monoculture). The MODIS-derived estimate of the total rice-planted area, shrimp-rice farming area, and inland aquaculture area agreed well with statistical data at the province level (R2 ≥ 0.96). However, in some provinces, the estimate has a large margin of error, probably because of the mixed-pixel effect due to the moderate spatial resolution of MODIS (250 m). According to the estimated spatial pattern of the farming systems in the whole VMD, inland aquaculture and shrimp-rice farming areas are distributed mostly in the coastal provinces. The areas of the farming systems steadily expanded until 2007, and double rice cropping systems in both upper and coastal regions were replaced by triple rice cropping because of infrastructure improvements. The proportion of the triple rice cropping area peaked in 2005 and then declined steadily over the next 2 years. We discuss the advantage of the proposed methodology for detecting the spatiotemporal changes of land use patterns, especially of farming systems in a regional area.