This reporting period covers the main harvesting stage of the early rice (wet season), which starts in September and ends in January. The harvest of the wet season maize was completed at the end of October, followed by the sowing of the early rice (dry season), dry season maize and soybean. Moreover, the dry season maize and the soybean had entered the early growing stage in January 2021. The harvest of the medium rice, late rice and the floating rice had started in January, 2021.

Cambodia generally experienced a wetter and slightly cooler period as compared to the average weather conditions of the past 15 years. As the agro-climate indicators show, the rainfall (RAIN, +17%) for the country was above average. However, most of the precipitation occured in October, when the rainy season was coming to an end. The radiation (RADPAR, -8%)  and temperature (TEMP, -0.7°C) were lower than average. As a result, the biomass was also below average (BIOMASS, -17%). At the same time, the cropped arable land fraction (CALF 98%) was almost near the average and the maximum VCI value was at 0.86.

According to the NDVI profile for the country, the NDVI values were always lower than the average of the previous 5 years. It trended even lower than or close to last year's, when rice production was reduced due to lack of water.  The Mekong river was at record low water levels again this year, especially in January. The very low NDVI value in early October was presumably due to cloud cover in the satellite image. Considering the spatial patterns of NDVI profiles, for about 5.3% of crop land, mainly located in the northeast of the Battambang and the southwest of the Kampong Thom, the NDVI departure from the average was around -0.1 units at the beginning and dropped about 0.25 NDVI units in October and then stayed stable in November. After that, it increased gradually. For about 8.9% of crop land, mainly located in the middle of Banteay Meanchey, the NDVI departure was around -0.25 at the beginning. About 85.8% of crop land had a relatively stable NDVI, which was close to the average before mid-January and dropped in late January.  All in all, the prospective production of rice is below average and the growth conditions of the medium, late and floating rice, maize and the soybean are sub-optimal as well.

Regional analysis

Based on cropping systems, climatic zones and topographic conditions, four sub-national regions are described below: The Tonle Sap lake area where the seasonally inundated freshwater lake and especially temperature are influenced by the lake itself, the Mekong valley between Tonle Sap and Vietnam border, Northern plain and northeast, and the Southwestern Hilly region along the Gulf of Thailand coast.

In the Tonle Sap lake area, the NDVI was lower than average all the time, which indicates the crop condition for the region was poor. Rainfall was above average (RAIN +23%), while both the temperature (TEMP -0.7°C) and the radiation (RADPAR -10%) were below average. The corresponding biomass for the region was lower (BIOMSS -19%). At the same time, the cropped arable land fraction (CALF) was 99% and the maximum VCI value was at 0.87.

The Mekong valley between Tonle Sap and Vietnam border, the main rice growing area of Cambodia, recorded  above-average rainfall (RAIN +13%), slightly cooler temperature (TEMP -0.5°C) and below-average radiation (RADPAR -6%), which resulted in a below-average biomass (BIOMASS -12%). The regional NDVI was lower than average all the time as well, especially in early November. The cropped arable land fraction was 97% and the maximum VCI value was at 0.85.

In the Northern plain and northeast, the NDVI was slightly lower than average. The region had an above-average precipitation (RAIN +8%), accompanied by below-average temperature (TEMP -0.7°C) and below-average radiation (RADPAR -7%). As a result, the biomass for the region was lower than average (BIOMSS -18%). The cropped arable land fraction was 99% and the maximum VCI value was at 0.89.

The Southwest Hilly region experienced a large increase of rainfall (RAIN +34%), while both the temperature (TEMP -0.5°C) and the radiation (RADPAR -9%) were lower than average. The potential biomass for the region was below average (BIOMASS -15%). At the same time, the cropped arable land (CALF 99%) remained close to average and the maximum VCI value was at 0.85. However, the NDVI values were below average except for mid-November, when the NDVI for the region was almost near average.

Figure 3.26 Cambodia’s crop condition, October 2020- January 2021

(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) Crop condition development graph based on NDVI_Tonle-sap (left) and NDVI_Mekong valley (right)

(g) Crop condition development graph based on NDVI (Northern plain and northeast (left), Southwest Hilly region (right))

(h) Time series temperature profile          (i) Time series rainfall profile

Table 3.41 Cambodia's agro-climatic indicators by sub-national regions, current season's values and departure from 15YA, October 2020- January 2021

Table 3.42 Cambodia's agronomic indicators by sub-national regions, current season's values and departure from 5YA, October 2020- January 2021