This monitorig period covers the rainy season. September marked the end of the early rice harvest. This period also covered the sowing and growth of medium and late rice. Maize sown in July is harvested through October. CropWatch indicators show that sufficient rainfall and sunshine in this period enhanced crop growth in Cambodia.

Cambodia experienced warmer and clearer weather during the monitoring. According to Cropwatch agricultural conditions, rainfall was close to average (RAIN), while temperatures and radiation were above average 0.6℃ (TEMP) and 8% (RADPAR). Potential biomass was 3% (BIOMASS) higher than the average. According to the NDVI development graph, crop conditions were close to average. The drops in mid-August and September may be due to the cloud cover in the satellite images. According to the NDVI cluster map, in 34.8% of the total cultivated area, crop conditions were always above average during the inspection period, located in the Tonle Sap and Mekong River valleys, including Siem Reap, Kampong Chhnang, Kampong Cham, Kampong Speu, Prey Veng. In 31.3% of the total cultivated area, crop conditions were below average (red and orange areas) for most of the inspection period, located southeast of the Mekong Valley; In the northwest, in 20.3% of the area (blue zone), crop conditions were below average at the beginning of the monitoring period, but there was a slight recovery after September to average. For the rest, crop conditions fluctuated around average but worsened below average after September. CALF was slightly above average by 1% and the VICx was 0.94. All in all, the crop condition were average.

Regional Analysis

The cropping systems, climatic zones, and topographic conditions, four sub-national regions are described below: The Tonle Sap Lake area, 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, Northern Plain and Northeast, and the Southwest Hilly region along the Gulf of Thailand coast.

For the Tonle Sap region (agroecological zone 117), rainfall was sufficient (RAIN +3%) and temperatures were slightly warmer (TEMP +0.7°C). Solar radiaton was above the 15YA (RADPAR +8%), resulting in a 3% (BIOMASS) increase in potential biomass. The NDVI was slightly below average except for September and mid-October when it was close to average. Crop conditions were average.

The Mekong Valley region (agro-ecological zone 118) is the most important agricultural production zone in Cambodia. Precipitation in this region was near average, accompanied by an increase in temperature of 0.7°C (TEMP), while there was decrease in radiation by about 8% (RADPAR), resulting in a 2% increase of BIOMASS. Crop NDVI was also well below average before mid-August and gradually recovered to above average after August. The CALF index shows a drop of around 2% (CALF) levels, with the VCIx index reaching as high as 0.94, indicating an overall healthy crop growth status.

For the Northern Plain and Northeastern region (agro-ecological zone 119), there was a 5% (RAIN) deficit in precipitation, coupled with an increase in temperature of about 0.6°C (TEMP) and an increase in radiation of about 9% (RADPAR). The potential biomass in this region was above average (BIOMASS, +3). Similar to the Tonle Sab region, crop NDVI was  normal and dropped in September due to cloud cover. The CALF index shows near the average levels, with the VCIx index reaching as high as 0.93, indicating an overall healthy crop growth status.

For the Southwestern Hilly region (agro-ecological region 120), rainfall was about 19% (RAIN) above average with a decreased temperature of about 0.4°C (TEMP). Separately, there was a slight decrease of radiation of 6% (RADPAR). The estimated potential biomass was slightly below average (BIOMASS -1%). NDVI crops in the region have recovered slightly from below average to normal levels. There was a sharp drop in late July due to cloud cover satellite images. The proportion of arable land in the area remained normal (CALF). The VCIx index reached as high as 0.95, indicating an overall healthy crop growth situation.

Figure 3.26 Cambodia's crop condition, July - October 2023

(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

Table 3.41 Cambodia's Agro-Climatic indicators by sub national regions, current season's values and departure from 15YA, July - October 2023

Table 3.42 Cambodia's Agronomic-indicators by sub national regions, current season's values’ and departure from 15YA, July - October 2023