Cambodia usually enters its rainy season in April, however, the drought caused by El Niño has delayed its onset this year. The floating rice and the wet-season early rice are usually planted in April and May, respectively. The medium rice, late rice, and wet-season maize are all sown in July, with soybean harvesting beginning in July as well. Compared to the average, the potential biomass (BIOMASS) significantly decreased by about 21%, mainly due to lower precipitation (RAIN, -38%) and reduced radiation (RADPAR, -5%). Furthermore, the average temperature (TEMP) during this period rose notably by about 2.0℃. The higher temperatures combined with persistently low precipitation exacerbated the drought in Cambodia, delaying the sowing of wet-season crops, including the floating rice and early rice. Moreover, the CALF slightly decreased by 3%. The VCIx was at only 0.78, and the CPI at just 0.87. Overall, crop condition was poor, but greatly improved to average by the end of this monitoring period.

Although the overall crop growth was initially abnormal, the recent recovery is promising. As the NDVI time series graph shows, crop NDVI reached its lowest point at the end of April but gradually recovered to average levels and even exceeded the highest level of the past five years by the end of the monitoring period. This indicates that the negative impact of moisture deficiency on crops gradually diminished as precipitation returned. Specifically, nearly all cropland experienced an apparent decrease in NDVI departure in April. Following this, approximately 46.5% of these lands (red and orange) showed a gradual recovery to above-average. These cropland areas are mainly located in the lower Mekong River and around the Tonle Sap Lake. About 37% of croplands (dark green and light green) observed an NDVI recovery to average levels, primarily in Kampong Speu, Takeo, and Kampong Chhnang. The remaining 16.5% of croplands (blue) experienced a continously decline (or increased negative departures), indicating concerning crop growth conditions. These areas are mainly distributed along the western and northern shores of the Tonle Sap Lake.

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 33% below average, with a significantly higher temperature (TEMP, +2.0℃), lower radiation (RADPAR, -5%), and lower potential biomass (BIOMASS, -22%). Thanks to the recovery of precipitation, the crop NDVI in this region began to improve after May, eventually exceeding the highest level of the past five years by the end of the monitoring period. The CALF in this region was slightly below average by 4%, with the VCIx at 0.73 and the CPI at 0.82. Although crop growth in this region was initially below average, the subsequent recovery is promising.

The Mekong Valley region is the most crucial crop-producing region in Cambodia. In this region, the precipitation (RAIN) was about 47% below average, with a significant higher temperature (TEMP, +2.2℃), lower radiation (RADPAR, -8%), and lower potential biomass (BIOMASS, -28%). Similar to the Tonle Sap Lake region, the crop NDVI also approached the highest levels of the past five years by the end of the monitoring period. The VCIx for this region was only 0.83, and the CPI was 0.92, with a slight decrease of about 2% in the CALF. Overall, the crop growth recovery in this region was promising as well.

For the Northern Plain and Northeastern, the precipitation decreased by approximately 40% and the average temperature rose significantly by about 2.1°C. The radiation was near average levels and potential biomass was 20% lower. Thanks to the recovery of precipitation, the crop NDVI in this region gradually returned to average levels. The CALF slightly decreased by about 1%, with the VCIx at only 0.81 and the CPI at 0.87. By the end of the monitoring period, crop growth in this region had generally recovered to normal levels.

In the Southwest Hilly region, the precipitation was about 18% below average, with a higher temperature (TEMP, +1.1℃), lower radiation (RADPAR, -10%), and lower potential biomass (BIOMASS, -18%). By the end of the monitoring period, precipitation in this region was noticeably higher than average, and corresponding crop NDVI was above the highest levels of the past five years. The CALF slightly decreased by about 1%, with the VCIx at 0.82 and the CPI at 0.86. Although crop growth was initially below average, it has recovered to above-average level.

Figure 3.26 Cambodia's crop condition, April - July 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

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

(k) Time series CPI profile

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

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