This monitoring period covers the entire period from the sowing to harvesting of summer rice in the Central part. In May, winter-spring rice in the north and summer-autumn rice in the  Mekong Delta and the south-east had reached maturity. In July, the production of spring-winter rice started in the Mekong Delta and South-east region. The planting of rainy season rice in the north started as well. CropWatch agro-climatic indicators show average precipitation (1137 mm, +1%) and TEMP (25.1°C, +0.2°C), but with higher RADPAR (+7%), the BIOMSS (+8%) showed a marked increase compared to the 15YA. Both, VCIx (0.94) and CALF (96%) were high. Based on the NDVI development graph, the crop conditions were below the 5YA and the average of the same period last year, especially at the beginning of this monitoring period. The precipitation during this monitoring period showed an average level compared with the 15YA, while the temperature fluctuated near the 15YA. According to distribution of the VCIx, crop conditions in the North were favorable, while in the South Central Coast they showed an area with low values. As to the spatial distribution of NDVI profiles, crop conditions in about 40.1% were above average mainly in the central of Nghe An Province, Ninh Thuan Province and the South Central Coast region. About 18.3% were below average at the beginning of this monitoring period, mainly distributed in the Northeast of the country. Overall, crop conditions were favorable. 

Regional analysis

Based on cropping systems, climatic zones, and topographic conditions, several agro-ecological zones (AEZ) can be distinguished for Vietnam: Central Highlands, Mekong River Delta, North Central Coast, North East, North West, Red River Delta, South Central Coast, and South East.

In the Central Highlands, RAIN was below average (1080 mm, -9%) and TEMP was near average (23.8°C). While RADPAR increased significantly (1234 MJ/m2, +8%), BIOMSS was also higher by 9%. CALF was 99% and VCIx was 0.91. The crop condition development graph based on NDVI indicated that the conditions had fallen from favorable levels to below the 5YA and last year's levels starting in May. Crop production is expected to be average at best. 

In the Mekong River Delta, RAIN (1059 mm, 0%) and TEMP (27.9°C, -0.1°C) were close to the 15YA. The favorable radiation (RADPAR +6%) caused  an increase of BIOMSS by 7%. CALF was also higher (86%, +3%) and VCIx was 0.93. According to the NDVI-based development graph, crop conditions were near the 5YA, except for early April and late July. Crop production is expected to be favorable.

In the North Central Coast, with average TEMP (25.1°C, +0.3°C), above average RAIN (1080 mm, +19%) and RADPAR (1300 MJ/m2, +9%) were observed, resulting in an above-average BIOMSS (+11%). VCIx was 0.95 and CALF was 98%. According to the NDVI‐based development graph, crop conditions were low in April but close to average from May to June, and finally surpassed the 5-year-maximum in July. Crop production in this area is expected to be above the average.

In the North East, TEMP (24.3°C, +0.5°C) and RAIN (1421 mm, 0%) were near the 15YA. RADPAR was above the 15YA (1211 MJ/m2, +5%), which resulted in an increased BIOMASS (779 gDM/m², +7%). CALF was 100% and VCIx was 0.97. Overall, the crop output  is expected to be favorable. 

In the North West, with significantly increased RAIN (1322 mm, +18%)  and RADPAR (1255 MJ/m², +6%) and normal TEMP (23.1°C, 0.2°C), BIOMSS increased by 8%. CALF was 100% and VCIx was 0.96. According to the NDVI‐based development graph, crop conditions improved and exceeded the 5-year-maximum before May and then decreased below the 5YA. Crop conditions in this region were close to or above the average.

The situations of agro-climatic indicators in the Red River Delta were the same as in the North West. Increased RAIN (1186 mm, +12%)  and RADPAR (1262 MJ/m², +6%) and average TEMP (27.2°C, 0.4°C) resulted in an increased BIOMSS (864 gDM/m², +8%). CALF was 96% and VCIx was 0.92. According to the crop condition development graph, the NDVI was below the 5YA during the whole monitoring period. Crop output is estimated to be below average.

In the South Central Coast, RAIN greatly decreased (606 mm, -36%), together with average TEMP (24.6°C, +0.3°C) and increased RADPAR (1318 MJ/m2, +10%) an increased BIOMSS (807 gDM/m², +6%) resulted. CALF was 96% and VCIx was 0.86.  According to the crop condition development graph, the NDVI was below the 5YA during the whole monitoring period. Crop conditions were slightly unfavorable.

The situations of agro-climatic indicators in the South East were the same as those in the South Central Coast. Average TEMP (26.5°C, +0%), slightly decreased RAIN (1113 mm, -5%) and increased RADPAR (1301 MJ/m2, +7%) resulted in an  increased BIOMSS (870 gDM/m², +7%). CALF was 95% and VCIx was 0.92. According to the crop condition development graph, the NDVI was close to the 5YA in April but decreased below the 5YA after May. Crop conditions in this region were slightly unfavorable.

Figure 3.44 Vietnam's crop condition, April-July 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 profiles

(f) Crop condition development graph based on NDVI Central Highlands Vietnam(left), and Mekong River Delta(right).

(g) Crop condition development graph based on NDVI North West Vietnam(left), and Red River Delta(right).

(h) Crop condition development graph based on NDVI South Central Coast Vietnam(left), and South East Vietnam(right).

(i) Crop condition development graph based on NDVI North Central Coast Vietnam(left), and North East Vietnam(right).

(j) Proportion of NDVI anomaly categories compared with 5YA

(k) Proportion of VHIm categories compared with 5YA

Table 3.79 Vietnam’s agronomic indicators by sub-national regions, current season's values and departure from 15YA,  April–July 2021

 Table 3.80 Vietnam’s agronomic indicators by sub-national regions, current season's values and departure from 5YA,  April–July 2021