The ongoing monitoring period coincides with the transition from the rainy season to the dry season in Cambodia. During this period, the harvesting of rainy season maize and medium rice are completed in November and December, respectively. The sowing of dry season early rice, dry season maize, and soybeans starts from November, while late rice and floating rice enter their harvesting period from January. According to the CropWatch system,   crop conditions were normal, despite the negative impact of the precipitation deficit starting in mid November.

During the monitoring period, Cambodia experienced more humid and warmer weather conditions. Compared to the average level of past 15 years, the rainfall (RAIN) in Cambodia was approximately 6% above average, the average temperature (TEMP) significantly increased by 1.0°C, and radiation (RADPAR) increased by about 11%. Although there was an increase in cumulative precipitation, the additional rainfall was mainly concentrated before the beginning of November. Thereafter, the precipitation remained below the average. The noticeable increase in average temperature in December further exacerbated crop water stress due to precipitation deficit. However, the impact of the precipitation deficit since the dry season has been limited, with the model-calculated potential biomass (BIOMASS) being only slightly lower, around 2% below the average. The national NDVI time series also indicates that since November, Cambodia's crop NDVI has consistently remained slightly below the average. The spatial distribution of NDVI departure clustering clearly describes three patterns of crop growth across the country: 1) for the majority of cropland (approximately 84.1%, represented by blue, light green, and red areas), crop NDVI decreased from slightly above or close to the average level to average or slightly below the average level, with the decline concentrated in November and December. 2) a small portion of cropland (about 9%, represented by dark green areas) showed an increase in crop NDVI from slightly below average to slightly above average, mainly distributed in the western areas of Tonle Sap Lake. 3) approximately 7% of cropland (orange areas) exhibited a recovery in crop NDVI from below average to slightly above average. The spatial distribution of VCIx also aligns with this observation, with most croplands exhibiting an VCIx higher than 0.8.

Cambodia's VCIx reaches as high as 0.94, with a CALF close to 98%, and a CPI of 1.07. Considering the agro-climatic and agronomic indicators in Cambodia, the assessment indicates that the overall crop condition in the country is normal.

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, there is a significant increase of 14% in rainfall (RAIN), a notable rise of approximately 1.0°C in average temperature (TEMP), and a substantial increase of 12% in radiation (RADPAR), leading to a 2% higher potential biomass (BIOMASS). Although the precipitation in this region has been below average since the beginningn of the dry season in November, the irrigation from Tonle Sap Lake has mitigated the adverse effects of the precipitation deficit. The CALF in this region is exceptionally high, reaching 99%, with a VCIx index of 0.94 and a CPI index of 1.09. The NDVI of crops in this region has also consistently remained at the average level since November, indicating that the overall crop condition in this region is normal.

The Mekong Valley region is the most crucial crop-producing region in Cambodia. In this region, there is a slight increase of 1% in rainfall (RAIN), a significant rise of 1.1°C in average temperature (TEMP), and a notable increase of 11% in radiation (RADPAR). However, there is a slight decrease of about 5% in potential biomass (BIOMASS). Since the dry season, the NDVI of crops in this region has consistently remained slightly below the average level. Nevertheless, the VCIx index is high, reaching 0.93, with a CPI index of 1.06. The CALF has also slightly increased by 1%. Considering both agro-climatic and agronomical indicators, the overall crop production in this region is normal.

For the Northern Plain and Northeast, there is a 4% increase in rainfall (RAIN), a significant rise of approximately 0.9°C in average temperature (TEMP), and a notable increase of about 12% in radiation (RADPAR). However, there is a slight decrease of 2% in potential biomass (BIOMASS). Due to the impact of the precipitation deficit, the NDVI of crops in this region has also been slightly below the average level since the start of the dry season. However, the CALF in this region is exceptionally high, reaching 99%, with a VCIx index of 0.92 and a CPI index of 1.04. This indicates that the impact of the precipitation deficit is limited, and the overall crop condition in this region is normal.

In the Southwest Hilly region, there is a significant increase of approximately 14% in rainfall, a higher average temperature (TEMP) of about 0.7°C, and an elevated radiation (RADPAR) of about 11%. However, there is a slight decrease of approximately 4% in potential biomass (BIOMASS). Due to the impact of the precipitation deficit, the planting of crops including soybeans and dry-season maize in this region appears to be slightly delayed, resulting in the NDVI of crops being below the average level since late December. The CALF in this region is close to 100%, with a VCIx index of 0.94 and a CPI index of 1.07. Overall, the crop condition in this region is considered normal.

Figure 3.27 Cambodia's crop conditon, October 2023 - January 2024

(a) Phenology Crop

(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 3.45 Cambodia's Agro-Climatic indicators by sub national regions, current season's values and departure from 15YA, October 2023 - January 2024

Table 3.46 Cambodia's Agronomic-indicators by sub national regions, current season's values’ and departure from 15YA, October 2023 - January 2024