Sri Lanka cultivates maize and rice as its two main crops and two growing periods are rotated in one year for every kind of crop. The main season (Maha) covers October to March while the rest belongs to the second season, Yala. The reporting period covers the late Yala growth and harvest of rice and maize, and early sowing season of Maha rice and maize. According to theCropWatch monitoring results, crop condition was below average during August to early October, and departed far from average in late August.

Compared to average, rainfall increased 20%, while temperature and radiation were slightly below (0.5℃ and 2%, respectively). The fraction of cropped arable land (CALF) remained comparable with the five-year average.

As already shown during the  last two monitoring period, excess precipitation may have a negative influence on the sowing of Maha crops but not, however, on crop production; BIOMSS increased 7% compared to the five-year average. The crop condition development graph based on NDVI displayed an unfavorable situation. Crop condition dropped below average since August and recovered to average in late October. The poor performance of NDVI profile may be related to continued cloud over the country.

Spatial heterogeneity was significant throughout the country according to NDVI profile clusters and map. Cropland was average in July except for some patches in the Mid-Northern province and the coast of Northern province and Eastern province. In addition, close to average crop condition fluctuated around in early September and late October. The maximum VCI (VCIx) map shows a situation that is similar to the previous monitoring period, with low values over the northern region and east coast, and high values occurring throughout the country. The average VCIx value for Sri Lanka is rather high at 0.90.

Regional analysis

Based on the cropping system, climatic zones, and topographic conditions, three sub-national, agro-ecological regions can be distinguished for Sri Lanka. They are the Dry zone, the Wet zone, and the Intermediate zone respectively.

The Dry zone shows the most favorable agroclimatic and crop conditions for the country. Crop condition was similar to nationwide  patterns. RAIN was well over average (RAIN 34%) while temperature and radiation were low (TEMP -0.8℃, RADPAR -6%). The CALF was 96% and the VCIx value was 0.95.

The Wet zone, which covers the cropland of the north-eastern region, showed the least favorable values among the three sub-national regions according to the VCIx map and NDVI profile. The crop condition was below average except for early September; it reached the minimum level in late August. Less precipitation compared with other two sub-national regions may substantially impact the growth of Yala maize and rice. The CALF showed that cropland was fullly utilized. The VCIx value was 0.94.

The Intermediate zone is located between the Dry zone and the Wet zone, and its crop condition was intermediate between that of its neighbours. Agroclimatic indicators were close to national values. The rainfall increased by 20% while temperature decreased by 0.3℃. The CALF was the same as in the Wet zone. According to the NDVI development graphs, this region suffered below average crop condition like the Dry zone. The VCIx value was 0.86 and slightly lower than other two sub-national regions.

CropWatch puts the productions of maize and rice during 2018 slightly above those of 2017.

Figure 3.21. Sri Lanka cropcondition, July - October 2018

(a) Phenology of major crops

(b) Crop condition development graphbased on NDVI

(c) Maximum VCI

(d) Spatial NDVI patterns compared to5YA

(e) NDVI profiles

(f) Crop condition development graphbased on NDVI(Dry zone (left) and Wet zone (right))

(g) Crop condition development graphbased on NDVI (Intermediate zone)

Table 3.50. Sri Lanka agroclimatic indicators by sub-national regions, current season's values and departure from 15YA, July - October 2018

Table 3.51. Sri Lanka agronomic indicators by sub-national regions, current season's values and departure from 5YA, July - October 2018

Table 3.52. CropWatch-estimated maize and rice production for Sri Lanka in 2018 (thousand tons)