This monitoring period covers the harvest of main (wet season) rice, the planting of dry season rice, the growing and harvesting of medium, late and floating rice and the early stage of dry season maize and soybean in Cambodia. Compared to average, the CropWatch agro-climatic indicators describe a relative dry season with a 37% drop in rainfall. Air temperature (TEMP +0.3°C) and radiation (PADPAR +12%) were both higher than average. Environmental indicators mentioned above caused a 8% decrease in the potential biomass production (BIOMSS -8%). However, the maximum VCI value for the country is at 0.92, which means favorable crop conditions. The fraction of cropped arable land (CALF +2%) was slightly above the average of previous five years.

Water deficits harmed the crops  and resulted in well below average crop condtions, especially after November 2019. This is clearly shown in the NDVI profile. According to the Spatial distribution of NDVI profiles, a small area (5.4% of cropland), mainly in Kandal and along the MeKong river, had an above-average NDVI before December. It subsequently dropped to average gradually in January. About 3.9% of the crop land, which mainly lies in the southeast of Banteay Meanchey, suffered a NDVI deficit in the early part of the season, but had recovered since December. About 81.2% of crop land shared the same trend of NDVI departure: it was close to the average before November and decreased gradually during reporting period. 

High value of Maximum VCI index (VCIx >0.8) in most parts of the country indicate a limited negative impact of drought from December to January on crop growth. Generally, seasonal rainfall deficiency did not impact the overall crop development, and the wet-season rice production of Cambodia can be expected to be favorable.

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, the Southwestern Hilly region along the Gulg of Thailand coast.

In the Tonle Sap lake area, NDVI was below average during reporting period. Compared to average, sunshine and temperature were relatively high (RADPAR +12%, TEMP +0.2°C) and fraction of arable land (CALF +1%) was above average as well. However, the rainfall (RAIN -34%) and the biomass production potential (BIOMASS -12%) were below average. The maximum VCI value for the region is at 0.89. 

The Mekong valley between Tonle-sap and Vietnam border, the main rice growing area in Cambodia, was affected by low precipitation (RAIN, -44%) with above average RADPAR (+9%) and below average temperature (TEMP, -0.4°C). CALF was above the 5-year average (CALF, +2%) and the biomass potential was below average by 10%. The NDVI for the region was above average from October to December 2019 and below average after December, according to the NDVI profile. The maximum VCI for the region was 0.96. The overall crop outputs are expected to be good.

The Northern plain and northeast recorded a drop of rainfall below average by 47%. The temperature was slightly below average (TEMP, -0.1°C) and radiation significantly exceeded average (RADPAR, +12%). CALF was a little higher compared to the 5-year average (CALF, +1%).  Crop condition was below average for the region, where the biomass potential was 13% below average while the maximum VCI reached 0.92.  Altogether, this region had a below-average NDVI during reporting period.

The Southwest Hilly region had favorable VCIx (0.92) accompanied by increased BIOMSS (+4%) resulting from the increase in radiation (RADPAR +12%) and above average temperature (TEMP +0.4°C), while the NDVI for the region was below average in the whole reporting period. The precipitation was below average (RAIN -29%). 

Cambodia’s crop condition, October 2019-January 2020

(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

Cambodia agroclimatic indicators by sub-national regions,current season's values and departure from 15YA, October, 2019-January 2020

Cambodia, agronomic indicators by sub-national regions, current season's values and departure from 5YA, October, 2019-January 2020