It’s safe to say that climate conditions in Ladakh, a cold desert, are not exactly suited for growing warm-weather crops like tomato, capsicum, muskmelon and watermelon. Characterised by a rugged topography at an average altitude of over 3,000 metres (approximately 10,000 feet) above sea level, the region endures long and harsh winters and receives a little over 100 mm of annual rainfall.
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The cropping season lasts just four months, and remains cut-off for the rest of the year due to heavy snowfall. For locals, fresh fruits and vegetables are available only during the summer. Most fresh produce is imported, and self-sufficiency becomes a real concern.
Importing goods into Ladakh necessitates transport on diesel-run trucks across the Himalayas with passes as high as 5,300 metres, covering distances of 480 km from Manali, and 420 km from Srinagar. This means greater air pollution.
Addressing these concerns, a research team from the Defence Institute of High Altitude Research (DIHAR), under Dr Tsering Stobdan, found unique ways of helping small and marginal farmers in Ladakh double their crop productivity.
Moreover, these ways are helping them save water, without the use of chemical fertilisers or pesticides, to grow cash crops like watermelons.
Their remarkable work also includes the identification of a native variety of apricots as the sweetest in the world and the commercialisation of Seabuckthorn-based products. For these achievements, Dr Stobdan’s team won the Fakhruddin Ali Ahmed Award for Outstanding Research in Tribal Farming Systems by the Indian Council of Agricultural Research (ICAR) this year. The DIHAR is an arm of the Defence Research Development Organisation (DRDO).
The Better India spoke to Dr Stobdan about his work and its relevance to Ladakh.
Doubling crop productivity
With scarce water and small landholdings, crop productivity in the region is low. However, using black polythene mulching has proven to be highly beneficial.
How does it work?
Dr Stobdan answers, “We lay out a black plastic sheet just above the ground, make a 5 cm hole, and plant the sapling. Plastic mulching increases the soil temperature by 5-6° Celsius. With higher soil temperature, the crop can grow faster. Since we’re covering the ground with a black plastic sheet, it doesn’t allow the water to evaporate. It cuts the requirement for water by almost 60 per cent. Based on feedback from 100 farmers, the average yield of tomatoes has doubled to 80 metric tonnes per hectare, annually. For capsicum, it has tripled to 9.2 metric tonnes.”
Other advantages of this practice include increasing the number of intervening days before a farmer has to irrigate their land. Traditionally, farmers irrigate after every seven days for tomatoes, but thanks to plastic mulching, they can do this after 11-12 days.
Finally, farmers are also saving 75 per cent of the time they would have otherwise spent on weeding. Plastic mulching prevents sunlight from falling on unwanted seeds that grow into weeds. Thus, only those seeds that need to grow, germinate.
Besides tomato and capsicum, black plastic mulching is effective for other warm-weather crops like brinjal, chilli, pumpkin, and cucumber. The process is organic, without the use of chemical fertilisers, pesticides or herbicides. As a result, the yield is more than double the national average of 24 metric tonnes per hectare.
“This isn’t a new or novel technique. But its application and the spurt in yield has not been seen anywhere in the world. All our trials are around 11,500 feet above sea level, but we have much higher yields than in the plains. Also, these tomatoes can be grown at altitudes of up to 15,000 feet,” says another researcher on the team.
Using a low-input system, researchers at DIHAR have also found a way to grow warm-weather cash crops like watermelons and muskmelons. They began work in 2012, although trials on fields only started in 2016, with ten farmers from Phey village, 12 km from Leh town. The technical know-how behind growing watermelon in Ladakh was finally transferred to the State Agriculture Department in October 2017.
Dr Stobdan says, “These farmers have excellent annual yields of 30-40 metric tonnes per hectare. The national average is about 25 metric tonnes per hectare. Last year, farmers in Ladakh earned Rs 10-12 lakh per hectare, which is 4-5 times the return as compared to traditional crops like wheat and barley.”
He adds that 300 farmers are growing watermelons in the open field this year. “We can grow the crop during the off-season in August and September, a time when the rest of the country doesn’t get it!”
Interestingly, the watermelons grown in Ladakh are fully organic and very sweet. This additional sweetness, according to Dr Stobdan, can be attributed to the higher altitude.
Although they haven’t done trials to determine the effect of geographical elevation on higher sugar and acid content on the crop grown in the region, the same can’t be said of apricots.
“We have demonstrated that as the altitude increases, the apricot fruit becomes sweeter. Identified locally as Raktsey Karpo (apricots with white seed coats), this unique genetic resource is available only in Ladakh. We identified it as the world’s sweetest apricot (based on sugar and acid content). Normally, apricots have brown seed coats,” informs Dr Stobdan.
Once again, none of this would have been possible without the black polythene mulching technique. The crop is sown mid-May and harvested in August (at 10,000 feet) and the first week of September (at 11,500 feet).
Nonetheless, there remain concerns about alternatives to plastic that can survive the harsh weather in Ladakh.
“A major concern for large-scale adoption of plastic mulch for crop productivity enhancement in the trans-Himalayan region could be the resultant pollution hazards caused by residual plastic film. However, the adverse effect, in part, could be compensated by reducing vehicular pollution during long-distance transportation of fresh tomatoes from nearby towns… Future research is needed on the effect of low-cost biodegradable mulching materials on crop growth and yield,” says this January 2018 paper published in the Defence Life Science Journal.
Passive solar greenhouses
In 1964, the first greenhouse was introduced to Ladakh. This allowed the locals to grow a few crops, particularly leafy vegetables like spinach during the harsh winter, when temperatures drop to -20° Celsius.
However, with temperatures dropping to -7° inside these conventional greenhouses with walls made of mud brick from three sides and the fourth covered by a polythene sheet, even leafy vegetables find it hard to thrive. Also, these greenhouses would last only 5-10 years with the walls collapsing because of humidity.
DIHAR developed these passive solar greenhouses with walls made of stone and cement on three sides, which can store and absorb more heat. More importantly, the fourth side of the greenhouse is covered with a polycarbonate sheet, which has a better insulation capacity than the average polythene.
Work on this project began 5-6 years ago, but on-field trials began in the winter of 2017.
“In our greenhouses, the temperature inside does not reach sub-zero levels, but it is around 3° Celsius in the peak of winter from December-January. Tomato is a temperature-sensitive warm season crop. If temperatures hit zero or lower, then the crop dies the very same day. If we can grow them under these conditions, we can also grow other warm-weather crops. In the past two years, we have demonstrated that tomatoes can be grown even in December and January,” says Dr Stobdan.
Farmers can also grow crops like capsicum and cauliflower in these conditions!
“If the greenhouse is small but uses the same materials, it won’t be as effective. We have determined that the size of the greenhouse has to be at least 60×27 feet. The bigger the greenhouse, the greater its ability to absorb and store more heat. Meanwhile, the height we are recommending is 9 feet,” he adds.
Farmers go for transplanting in September, and from December, they can harvest crops until March. From a single plant, a farmer can get 2.5-3 kg tomatoes!
It’s the only kind of greenhouse in Ladakh which can grow these crops under these conditions without additional heating or covering. If you use a conventional heating system or certain curtains, it complicates matters and raises costs for the average farmer.
“We want it to be farmer-friendly. The emphasis is on simplicity so that any farmer can use it,” says a fellow researcher, who worked with Dr Stobdan on the project.
It is innovations like these that ATL Tinkering Innovation Marathon aims to develop by giving young innovators a platform to take their ideas to products and help solve issues in different fields from agriculture and infrastructure, to environmental conservation and waste management.
Know more about the ATL Tinkering Innovation Marathon here.
(Edited by Shruti Singhal)
Images Courtesy: Dr Tsering Stobdan