The monitoring period covers the harvest of maize in September and the complete cycle of the main rice crop (from sowing to harvest). According to CropWatch agroclimatic indicators, Thailand experienced wet and warm weather compared to the 15YA. The rainfall (RAIN, +12%) and temperature (TEM, +0.1°C) from July to October was above average, while radiation was below average (-2%), resulting in a close-to-average biomass production potential (BIOMSS), only 1% below average. According to the NDVI development graph, crop conditions were above average until early September, but were below average after that mainly due to the cloud contamination in the satellite images. Increased rainfall provided plenty of water for the crops in this wet season. According to the NDVI departure clusters and the corresponding profiles, the crop conditions were above average except for the end of September on 44% of total arable land, mostly located in Central double and triple-cropped rice lowlands, Chaiyaphum, Nakhon Ratchasima, Phachinburi, Chachoengsao, Chonburi Nakhon Si Thammarat, Songkhla. This was confirmed by the VCIx map. The crop conditions on 21.5% of total cropland were below average throughout this monitoring period, mostly located in Western hill areas, Udon Thani and Kalasin. The crop conditions in the remaining regions were close to average in the beginning but deteriorated to below average after August. In general, favorable condition for crops was observed during the July to October period as indicated by high VCIx values at 0.97. Considering the average CALF, the crop conditions during this season are assessed as close to the average level.

Regional analysis

The regional analysis below focuses on some of the already mentioned agro-ecological zones of Thailand, which are mostly defined by the rice cultivation typology. Agro-ecological zones include Central double and triple-cropped rice lowlands (115), South-eastern horticulture area (116), Western and southern hill areas (117) and the Single-cropped rice north-eastern region (118).

The Central double and triple-cropped rice lowlands is the major rice production zone of Thailand. It had received plenty of rainfall during this period. Rainfall was above average (RAIN, +37%), accompanied by average temperature (TEM, 0.0°C), while radiation was below average (RADPAR, -2%). Although rainfall was significantly above average, radiation was the limiting factor during this rainy season. As a result, the low radiation resulted in a decrease of potential production (BIOMSS, -2%). The NDVI development graph shows that crop conditions started to drop below average in September, when the crops were approaching maturity.

The agro-climatic conditions in the South-eastern horticulture area were the same as in the Central region: Rainfall was above average (RAIN, +10%), accompanied with lower radiation (RADPAR, -2%). Temperature was above average by 0.1℃. This agro-climatic condition led to a slight decrease of potential production (BIOMSS, -3%). According to the NDVI development graph, the crop condition is close to the average of recent 5years. 

In the Single-cropped rice north-eastern region precipitation was above average by 7%, while temperature was above average by 0.1℃. These agro-climatic conditions accompanied with an average radiation led to a average potential production. As a result, crop conditions were above average before September but dropped to below average in September according to the NDVI development graph.

For each region, the VCIx ranging from 0.95 to 0.98 indicates that the peak season was comparable to the 5YA. Almost all cropland was cultivated during the monitoring period.

Figure 3.39 Thailand’s crop condition, April-July 2020

(a). Phenology of major crops

(b). Time series temperature profile. (c). Time series rainfall profile

(d) Crop condition development graph based on NDVI  (e) Maximum VCI

(f) Spatial NDVI patterns compared to 5YA   (g) NDVI profiles

(h) Crop condition development graph based on NDVI (Central double and   triple-cropped rice lowlands (left) and Western and southern hill  areas (right))

(h) Crop condition development graph based on NDVI (South-eastern horticulture   area (left) and Single-cropped rice   north-eastern region (right))

Table 3.15. Thailand's agroclimatic indicators by sub-national regions, current season's values and departure from 15YA, July- October 2020

Table 3.16. Thailand's agronomic indicators by sub-national regions, current season's values and departure, July- October 2020