Horton Plains | Potato Cultivation Era

Today, Houghton Plains is one of Sri Lanka's most important highland ecosystems. Its grasslands and forests form the headwaters of some of the island's most important rivers. But less than a century ago, parts of these plains were being used for something very different, potatoes. In the early 1960s, Ceylon was pursuing a policy of increasing domestic food production and reducing its dependence on imported food. It was against this background that the government began cultivating seed potatoes at Houghton Plains. In 1960, Sirimavo Bandaranayake became Prime Minister of Ceylon. Her government placed considerable emphasis on state involvement in the economy and on increasing domestic food production. At Houghton Plains, the Department of Agriculture established a potato seed station. But why Houghton Plains? Records of parliamentary debates from 1958 reveal a statement by then Minister of Agriculture, Philip Gunawadena, who claimed that a foreign expert had advised the government to open a seed potato station at Houghton Plains. It was believed that the high elevation of Houghton Plains, situated over 6,000 feet above sea level, would protect the crop from diseases like bacterial wilt. By November 1962, the potato station at Houghton Plains was an established government facility. The Ceylon Government Gazette records a tender for the construction of three large open sheds at the potato station. Another government notice, in October 1963, the Department of Agriculture was purchasing a power sprayer specifically for the potato seed station at Houghton Plains. As shown in this photo, taken by Nihal Fernando at Houghton Plains, sections of the natural grassland had to be cleared to grow potatoes. The ground was leveled and terraced, transforming the rolling contours of the plains into agricultural fields. Scientific accounts estimate that around 120 hectares of grassland were used for seed potato cultivation. Some of those terraces can still be seen today. And the evidence suggests that the cultivation continued well beyond its initial establishment. A botanical specimen collected in 1968 records its location as cultivated ground on the Ohio Road, specifically describing a potato farm past the old farm. Scientific literature describes potato cultivation extending into the 1970s. And then there was the water. Houghton Plains is not simply a grassland, it is a watershed. Rain falling here feeds streams that flow out towards the surrounding valleys and ultimately become part of much larger river systems. In 1974, zoologist H. H. Koster published a detailed study of the streams of Houghton Plains. He reported that the cultivation of seed potatoes and the subsequent use of fertilizers had caused extensive silting of the stream system. When the grassland was cleared and the soil disturbed, rain could carry loose sediment from the cultivated fields into nearby streams. And the potatoes required something else, fertilizer. When excess nutrients accumulate in a stream, they can stimulate excessive growth of algae and other aquatic plants. This process, known as eutrophication, can transform clear, nutrient-poor water into a system increasingly dominated by algae and organic matter. As this excess organic matter decomposes, microorganisms consume dissolved oxygen in the water, potentially creating oxygen-poor conditions that can harm or even kill aquatic life. And this had consequences for one of the most unusual inhabitants of these streams, trout. Trout were not native to Houghton Plains. They had been introduced to Sri Lanka around 1899 and by Koster's time, the introduced trout, now generally known as rainbow trout, was the only fish recorded from these streams. Records of trout stocking and fishing at Houghton Plains showed that fewer trout were being caught relative to the numbers being released. According to Koster, from 1949 to 1959, 2,083 trout were caught. But from 1961 to 1971, only 903 trout were caught. 1961 was the year potato cultivation was initiated at Houghton Plains. Koster suggested that eutrophication could have contributed to the decline of trout. He also raised the possibility that pollutants associated with seed potato cultivation were affecting the fish. While Koster described these as possible causes, he didn't establish that potato cultivation alone was responsible for the decline. Furthermore, by 1963, bacterial wilt had affected the potato crops. This was a major blow, since experts believed that such diseases were absent at higher elevations. Although the tracts affected by bacterial wilt were abandoned in 1963, a 1977 study detected the pathogen in the soil. Even after the land was reclaimed by natural plant species, the pathogen survived for 14 years. Another study revealed that chemicals used during potato cultivation, like biocides, caused small mammals to avoid open grasslands, regardless of ample food availability. The story did not end when the potato fields were abandoned. The disturbance had changed the landscape. In areas where the natural wet patana grassland had been cleared, exotic grasses subsequently became established. Today, some former potato growing areas are dominated by carpet-forming exotic penicetum grasses, rather than the native tussock grassland. And these new grasses found an unlikely ally, the samba deer. A study of samba food habits at Horton Plains found that the deer were primarily grazers, with grasses making up a large proportion of their diet. The researchers concluded that the deer had become considerably dependent on these exotic grasses, like penicetum. In areas dominated by penicetum, between 10 and 39 percent of the plant material identified in their droppings consisted of these exotic grasses. So, a crop introduced to produce food for people had ultimately helped create a new food source for one of Horton Plains' most iconic animals. The potato fields were created with a simple objective, to produce more food. At the time, clearing part of a remote mountain grassland may have seemed like a reasonable price to pay. But Horton Plains was not an isolated piece of land. It was a watershed. Its soils, grasslands, and streams were part of a single interconnected system. When the grassland was cleared, the consequences traveled beyond the fields. By the 1970s, the potato experiment eventually ended. The fields disappeared. Their legacy remained.