A preliminary study of eight farmers from Champakulam village panchayat, which is part of the Kuttanad wetland ecosystem, presents some unexpected findings. Kuttanad wetland ecosystem is a globally important agricultural heritage system in south-central Kerala.

For farmers who cultivated the “Uma” rice variety as a punja (October–November to March) crop, the yields in 2018-19 season were between 8003 and 8892 kg per hectare, a year-on-year increase in yield levels that ranged between 44 and 75 per cent. In 2017-18, rice yields ranged between 4940 and 6175 kg per hectare. While the exact numbers may vary, farmers and experts from the rice research system told us that the increase occurred across all agro-ecological sub-regions in Kuttanad. Most farmers in Kuttanad cultivate Uma; it is also the most commonly cultivated variety in the State.

News about the bumper crop were reported by various media agencies(see, for instance, here and here).

What are the reasons for this bumper yield? Farmers, Government officials, and research scientists identify four main reasons for higher yields:

1. high siltation during the floods;
2. the destruction of the first crop, which increased the amount of organic matter in the soil and brought down the prevalence of weeds;
3. the date of the post-flood sowing was advanced across the region; and
4. the floods brought with them an infusion of fresh water.

Two other contributing factors were also reported. First, Government officials tested the soil after the floods and recommended that farmers apply specific micronutrients, such as magnesium sulphate and boron, to the soil (this was also in response to an increased demand from farmers for individual plot-level soil tests). Secondly, seed material in this season was of a higher quality than in the preceding year. Further inquiries have to be made to evaluate the role of these factors in increased yields.

Kuttanad, spread across Alappuzha, Kottayam, and Pathanamthitta districts in Kerala, is a major centre for rice production in the State, accounting for nearly one-fifth of the State’s total rice production. It is divided into six agro-ecological sub-regions and rice is grown in all regions, on the sides of canals and on land reclaimed from water bodies. Rice production is mainly undertaken in two seasons: the first crop sown in May–June and harvested in September, and the second crop sown in October–November and harvested by March. Most areas are single-cropped and the best land is double cropped; the latter was the site of the yield increase.

As mentioned, high silt deposits are considered to be the most important reason for high yields. Silt deposits varied from about 5 cm in Champakulam, which falls under the Lower Kuttanad agro-ecological region, to 10 cm in the Upper Kuttanad agro-ecological region. Silt brought much-needed nutrients to the soil. Farmers who had used the same amount or less fertilizer in 2018-19 than in 2017-18 also harvested more grain in 2018-19 than before.

Kuttanad region was flooded three times in 2018: in June, when about 10 per cent of sown area was affected, in July, when about 90 per cent of sown area was affected, and in August, the most devastating flood of all, when the entire region was submerged. These floods destroyed the first crop, which was sown in May–June. The flood created a natural “stale seed bed,” a technique otherwise employed artificially by farmers. A stale seed bed is prepared by letting weeds grow and then inundating fields to destroy weeds. The plant residue of the first crop acted as organic manure for the punja crop, contributing to higher yields.

The overall agro-climatic conditions after the floods were also favourable to the rice crop. Since the first crop was destroyed in August, land preparation for the punja crop began in September, earlier than usual. Sowing occurred during a period of low rainfall and low temperatures in the growing period, which resulted in a lower-than-usual incidence of pests and diseases. The incidence of commonly found pests and plant diseases like brown plant hopper and sheath blight was significantly lower in 2018-19 than in 2017-18. Further, the floods washed away stagnant water, a phenomenon that is a feature of the specific geography of Kuttanad. The influx of fresh water helped farmers gain access to clean water for irrigation and the application of plant protection chemicals. At the same time, soil tests also showed a marked reduction in acidity. From a usual pH factor of 3.5–5, the pH factor in the 2018-19 crop season across different regions of Kuttanad ranged between 5.5 and 6. This helped rice plants better absorb nutrients from fertilizers.

While the floods brought higher crop yields we must not forget that farmers realised a higher crop yield after losing their first crop entirely. Farmers also lost assets in the floods and inundation.

While the yield increase of 2019 could turn out to be a one-off event, the increased yields are nevertheless indicative of the potential yields that can be achieved in Kuttanad. In their quest to improve rice yields in Kerala, the State Government and the rice research system may have lessons to learn from this unusual phenomenon.