This report covers the major growth and harvesting stages of the dry-season rice. The previous monitoring results showed that the expected yield of these crops will be slightly lower than average. This period of monitoring also covers the main growth stages of corn and soybeans. According to the monitoring by the CropWatch system, conditions for these crops are fair due to the impact of precipitation deficits.

During the monitoring period, Cambodia has experienced drier weather conditions. Compared to the same period in the last 15 years, cumulative precipitation (RAIN) in Cambodia was significantly lower by about 31%, while the radiation (RADPAR) was slightly higher by 3%, and average temperatures (TEMP) remained normal. The apparent lack of rainfall resulted in a below-average potential biomass (BIOMASS) of about 8%, indicating that the low rainfall had a negative impact on dry season crop growth, which is consistent with the description of the NDVI profiles. They show that starting from the end of February, NDVI was significantly lower than the average of the last five years. The spatial clustering results at the NDVI distance level show that about 20.5% of the cropland (light green) generally had slightly above-average NDVI, indicating normal crop growth conditions. These croplands are mainly located in the lower Mekong Valley. Approximately 75.3% of the cropland (red, blue, and dark green) had NDVI fall gradually below average starting in March, indicating unfavorable crop growth conditions. These croplands are widely distributed around Tonle Sap Lake and in the lower Mekong Valley. In contrast, 4.1% of cropland (orange) showed a rapid increase in NDVI to slightly below average in February, and these croplands are mainly located along the lower Mekong River.

Considering that the maximum vegetation condition index (VCIx) is only 0.78, and the CALF index remains average, conditions can be assessed as slightly below average.

Regional analysis

Based on 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 subzone 117), cumulative precipitation (RAIN) was significantly lower by 43%, average temperature (TEMP) remained near the 15YA, and radiation (RADPAR) increased by 3%, resulting in a 14% reduction in potential biomass (BIOMASS). The NDVI in this zone was slightly above average until March, fell below average in March and remained below average thereafter. In addition, the CALF index in the zone was slightly higher by about 3%, but the VCIx index was only 0.79, indicating fair conditions.

For the Mekong Valley region (agroecological subzone 118), cumulative precipitation (RAIN) was significantly lower by 16%, average temperatures (TEMP) were close to average, and radiation (RADPAR) was 2% higher. The low precipitation resulted in a slight decrease of  potential biomass (BIOMASS) by about 1%. Similar to the Tonle-sap region, NDVI in the zone fell below average in March and remained below average throughout the rest of the period. Considering that the CALF in the region fell by about 1%, and that the VCIx was only 0.79 and the CPI was 0.93, crop growth in the region was slightly below average.

For the Northern Plain and Northeast region (agroecological subzone 119), the zone had significantly lower cumulative precipitation (RAIN) by 40%, higher average temperatures (TEMP) by about 0.1°C and higher radiation (RADPAR) by about 4%, resulting in lower potential biomass (BIOMASS) by about 9%. Crop NDVI in the zone remained at average levels until mid-February, when it dropped to below-average levels and remained below-average subsequently. The CALF in the zone was reduced by about 5% and the VCIx was only 0.69 and the CPI was only 0.86, both of which are the lowest value of four regions. It means that crop growth in this zone was poor.

For the southwestern hilly region (agroecological subzone 120), the cumulative precipitation (RAIN) in this area was 28% below average, the average temperature (TEMP) was 0.5°C lower and the radiation (RADPAR) was 2% higher, resulting in a decrease of potential biomass (BIOMASS) by about 7%. The NDVI curve shows that NDVI in the region also fell below average after mid-February and has remained below average since then. At the same time, the CALF was about 2% higher, with an VCIx of 0.80 and a CPI of 0.90. Although crop conditions were slightly better than in the other sub-regions, they were still below normal.

Figure 3.26 Cambodia's crop condition, January - April 2023

(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 in Tonle Sap Lake region (left) and the Mekong Valley region (right)

(h) Crop condition development graph based on NDVI in North Plain and northeast region (left) and Southwestern hilly region (right)

Table 3.41 Cambodia's agro-climatic indicators by sub-national regions, current season's values, and departure from 15YA, January - April 2023

Table 3.42 Cambodia's agronomic indicators by sub-national regions, current season's values, and departure from 5YA, January – April 2023