Cambodia usually enters the rainy season in mid to late April; however, this year, the drought has delayed its onset. During the monitoring period, late rice and floating rice in the Cambodia began to be harvested in January, while dry-season early rice and dry-season maize were harvested in February and March, respectively, with soybeans growing throughout the monitoring period. During this period, Cambodia experienced persistently higher temperatures and consistently lower precipitation since January. Compared to the past 15-year average, Cambodia's precipitation (RAIN) decreased significantly by about 88%, and the average temperature (TEMP) increased significantly by approximately 2.0°C. The radiation (RADPAR) increased by about 7%. The high temperatures and reduced precipitation exacerbated the drought during this dry season in Cambodia, resulting in a substantial decrease in potential biomass (BIOMASS) by about 39%. The drought also limited the planting area. CALF was only 72%. The VCIx was only 0.71, and the CPI was only 0.86, indicating that crop production in Cambodia during this dry season was generally far below average.

The negative impact of water scarcity on crops became evident from mid-February onwards, and since then, the growth of crops in Cambodia has consistently been below average. Furthermore, the NDVI of crops did not begin to rise as usual in April, indicating that the ongoing drought has delayed the planting of the rainy-season crops, such as floating rice and rainy-season early rice. Clustering results of NDVI departure indicate that almost all arable land experienced negative NDVI departures after mid-February. Approximately 83.2% of arable land (in red, orange, and blue color) had negative NDVI departures, indicating that crop growth on these lands was below average throughout the monitoring period. About 16.8% of arable land (in light green and dark green color) remained positive in January and February but rapidly declined to below 0 thereafter, indicating that crop growth on these lands was still relatively good during the early monitoring period. These arable lands are mainly located in the western part of Tonle Sap Lake and downstream areas of the Mekong River.

Regional analysis

Based on cropping systems, climatic zones, and topographic conditions, four sub-national regions are described below: The Tonle Sap Lake area (agro-ecological zone 117), a seasonally inundated freshwater lake which is influenced by the inflow and outflow from the Mekong River, the Mekong valley between Tonle Sap and Vietnam border (agro-ecological zone 118), Northern Plain and Northeast (agro-ecological zone 119), and the Southwest Hilly region along the Gulf of Thailand coast (agro-ecological zone 120).

In the Tonle Sap region, precipitation (RAIN) was significantly lower by about 82%, with an average temperature (TEMP) significantly higher by approximately 2.1°C. The radiation (RADPAR) increased by 6%, and the potential biomass (BIOMASS) decreased by 36%. Thanks to irrigation from the Tonle Sap Lake, crops in this region were not affected by precipitation deficiency until mid-February. However, after mid-February, crop condition remained below average. Meanwhile, it seems that the planting of rainy-season crops has been delayed in April. The CALF in this region is only 66%, with a VCIx of 0.74 and a CPI of 0.94. Overall, crop condition in this region were below average.

The Mekong Valley region is the most crucial crop-producing region in Cambodia. In this region, precipitation (RAIN) was significantly lower by about 95%, with average temperature (TEMP) increasing by approximately 2.2°C. The radiation (RADPAR) increased by about 6%, while the potential biomass (BIOMASS) decreased by about 46%. Crop condition in this region was slightly affected by drought before mid-February, with NDVI slightly below average. However, crop condition significantly declined below average after mid-February. Similarly, the planting of rainy-season crops in this region was also delayed due to drought. The VCIx was only 0.72, with a CPI of 0.82, and the CALF also decreased significantly by about 12%. Considering both agro-climatic and agronomical indicators, the overall crop production in this region was below average.

For the Northern Plain and Northeastern, there was a remarkable 91% decrease in precipitation (RAIN), a notable increase of 1.9°C in average temperature (TEMP), and an increase of 9% in radiation (RADPAR), resulting in a 36% decrease in potential biomass (BIOMASS). Due to the precipitation deficit, crop condition in this region were consistently below average, with the gap widening over time. Additionally, the CALF in this region decreased by about 8%. The VCIx was only 0.63, and the CPI was 0.67, indicating poor crop condition due to the precipitation deficit.

In the Southwest Hilly region, there was a significantly decrease of 79% in rainfall (RAIN), with average temperature (TEMP) increasing by approximately 1.4°C, and radiation (RADPAR) increasing by about 1%, resulting in a substantial decrease in potential biomass (BIOMASS) by about 39%. Due to the precipitation deficit, crop condition in this region were consistently below average, and the planting of rainy-season crops has also been delayed. The CALF has decreased by about 5%. The VCIx is only 0.67, and the CPI is 0.67, indicating worrying crop condition in this region.

Figure 3.26 Cambodia's crop condition, January - April 2024

(a) Phenology of major crops

(b) Crop condition development graph based on NDVI                  (c) Maximum VCI

(d) Spatial NDVI patterns compared to 5YA                                   (e) NDVI profile

(f) Time series temperature profile (left) and rainfall profile (right)

(g) Crop condition development graph based on NDVI (left) and time series rainfall profile (right) in Tonle Sap Lake region

(h) Crop condition development graph based on NDVI (left) and time series rainfall profile (right) in Mekong valley region

(i) Crop condition development graph based on NDVI (left) and time series rainfall profile (right) in Northern plain and northeast region

(j) Crop condition development graph based on NDVI (left) and time series rainfall profile (right) in Southwest hilly region

(k) CPI time series graph

Table 3.41 Cambodia's agro-climatic indicators by sub-national regions, current season's values, and departure from 15YA, January - April 2024

Table 3.42 Cambodia's agronomic indicators by sub-national regions, current season's values, and departure from 5YA, January – April 2024