Introduction

Nepal’s Department of Hydrology and Meteorology (DHM) considered normal arrival in eastern and departure dates of South Asian Monsoon in Nepal (SAM-N) to be June 10 and September 23 respectively[1]. With these dates, a SAM-N would last for 106 days. In 2021, the DHM has reivised the arrival and withdrawl dates of SAM-N. The new dates are June 13 and October 2 respectively, with the duration increased to 112 days. Climate change may further alter this dynamics in future with more variability in rainfall over the period. There may be more heavy rain events in short span of time localised across the country. These shifts will have far reaching conseqences on water supplied by monsoon rainfall, and on agriculture. Furthermore, future scenarios show that total precipitation in monsoon and post-monsoon seasons in Nepal over the short, medium and long-term are likely to increase[2]. Changes in behavior of SAM and rainfall will impact, paddy one of the main crops cultivated during the season.

Normal dates of onset and retreat of monsoon in Indian Subcontinent[3]

Observed dates of onset and retreat of monsoon in Nepal[4] Number of days from the 1st January of each year.

2021 October Rainfall

The heavy rainfall of October 2021 is an indication that changes are no longer in the future but are real and happening. In 2021, the monsoon was formally declared to have withdrawn on October 11, nine days after the new withdrawal date[5]. But six days later, on October 17, Nepal experienced heavy rainfall, which lasted till October 22. It seriously damaged the main season paddy, which was almost ready for harvesting. Compared to 2020, in 2021, the area under paddy had increased by 0.48%, but the total production had reduced by 9.52%, which was attributed to the unexpected heavy October rainfall[6]. These lived experiences show the imperatives of adapting paddy cultivation to the changes.

Providing weather warning is part of a larger adaptation package. Nepal’s DHM has an established weather-forecasting mechanism. A weather alert issued by DHM on October 15, 2021 stated that parts of the country will experience heavy rains from October 17. The alert also suggested that appropriate measures be taken to minimise damage. Indeed, heavy rainfall occurred, and the floods and inundation in its wake caused widespread damage across the various sectors of the economy. The hazards also damaged ready-to-be harvested paddy.

The following sections pesent three strategies for adaptation of paddy cultivation to suit changes in the behaviour of SAM-N. There are various facets of changes in monsoon: change in total rain, change in spatial distribution, change in temporal distribution, change in dates, etc. This paper particularly focuses on “change in dates”.

Adaptation Strategy 1: Adjusting rice cultivation practices to change in monsoon season dates

If SAM-N begins a week later in Nepal than the expected date, there may be potential shortage of water for paddy seedling and transplanting with consequences for production. On the other hand, if the withdrawal date is delayed by a week with untimely rainfall, such as that in October 2021, paddy at harvesting stage will be damaged. In the future, a potential increase in post-monsoon rainfall may seriously affect paddy at the harvesting stage. Theoretically, paddy cultivation practice should align with these shifts.

However, we need better understanding of the interactions between overall changes in monsoon and paddy cultivation. To that end, it is necessary to study specific localized impacts on the various activities related to paddy cultivation at the farm level: raising seedling, transplanting and providing supplemental irrigation at different stages. Irrigation is provided by canals and also by groundwater. Once growth has happened, the next actions are harvesting, storage and subsequent processing of paddy. The study should include understanding of community and household-level activities linked to paddy farming. Some of such activities are moving of livestock from household to farms, collecting, harvesting, processing and using natural resources, and application of water to other crops. Adaptation would also mean concomitant changes in social and cultural practices associated with paddy cultivation. Such practices passed on through generations will not change just like that.

It is also necessary to study the impacts of increase in temperature on summer paddy. The study on temperature–paddy performance during the changed period of SAM is vital to understand the effects of increased temperature on paddy’s grain-filling, ripening and harvesting stages. In Nepal, monsoon and post-monsoon maximum temperatures have increased by 0.058 and 0.056⁰C/year from 1971 to 2014 respectively[7]. Models analysis suggest that during SAM, by 2045, 2065 and 2100, the average temperatures are expected to rise by 0.8, 1.1 and 1.4⁰C respectively, and the post-monsoon average temperature by 1.3, 1.8 and 2.5⁰C during the same periodsⁱ. Simulatenously, the changing rainfall pattern should be assessed to study if the time of harvesting coincides with the period of least post-monsoon rainfall or avoid potentially high post-monsoon rainfall dates.

The assessment of both rainfall and temperature changes should be carried out in the country’s different agro-ecological zones across the altitudinal range. Improving understanding of these dynamics will help in making a decision, in partnership with the farming households, if paddy plantation and harvesting should be extended or delayed by certain days. Another important study is identifying the optimum planting dates for different paddy varieties in different agro-ecological zones. Research needs to look at these varieties in relation to their sowing, grain-filling and ripening stages to understand the impacts on productivity.

Activities pursued in strategy 1 can help in achieving the strategies 2 and 3, described below, and vice versa.

Adaptation Strategy 2: Making early warning effective

DHM forecasts rains and disseminates the information via various social platforms. The information is supplemented by a warning to those living along the flood-prone regions to stay alert and be careful with agricultural activities. However, in 2021, the information did not get serious attention from stakeholders and farmers. Some farmers were ready to harvest, some were harvesting, while others had left the crop in the field. Local agencies did not warn the farmers for protecting the crops.

With prior information, farmers could pursue different options such as holding back the harvesting of crops, collecting and piling up of harvested crops and protecting them from rain and runoff water. They could break field bunds and dig trenches to let the accumulated rainwater drain out. They could also provide physical support to the standing crops and not allow them to fall on the ground when hit by rains or wind. They could bind the harvested crops in bundles and keep them upright with support of wooden sticks.

The early warning system (EWS) requires further development to enhance its effectiveness. An effective EWS should provide information on hazards, exposure, potential impacts, and measures to be taken. Information should consist of type, location, time, and category and severity level of hazard. Lead time of warning should be increased from two days to at least one week. Information should include details on population and property likely to be exposed to the imminent hazard and to get damaged. The warning should be accompanied by advisories regarding measures to be taken by the communities and other responsible agenices before, during and immediately after the event to minimise the level of impact. A farmer may contact micro finance company for covering some of his/her risk of crop failure or shift the burden of risk to another party through insurance.

Adaptation Strategy 3: Developing response mechanisms

Developing and using technologies to protect the grain from getting damaged by rainfall or becoming wet after getting immersed in water is the third strategy. In 2021, farmers seemed without support: they did not get any advice for saving grains from being damaged when it became wet. Grains had germinated in the plants. The farmers, however, received neither advice nor support for preventing further germination and damage.

Draining out the accumulated runoff water from the field is another immediate action. Another action would be binding harvested plants in bundles and keeping them upright supported by wooden sticks. The third action would be providing physical support to the fallen plants and bringing them to upright position. In 2021, it seems, the line agencies were unaware or inconfident of such techniques. In future, farmers must be better prepared with stocks of sticks (wooden or metal) for use. Another method is reducing the duration of exposure of harvested grains to potential adverse weather conditions. This can be done by using an appropriate “combined harvesting and threshing machine” that transfers the grains from plants to bins. The machine must adopted to be used in hill terrains as well. At the same time, farmers should be provided with capacity building and skill development support so that they can deal with more severe but unpredictable rains in the future.

Conclusion

The changes in onset and withdrawal dates, rainfall intensity, duration, frequency, and spatial distribution will impact Nepal’s main season paddy production. The cultivation practices have to adapt to the changes. Adaptation is not only about adjusting to new sequences of ongoing and potential changes in SAM-N spawned by climate change but also social practices. Adaptation measures should use science-based knowledge to prepare farmers and local institutions to deal with the changes in SAM-N’s wider characters. Building the capacity of farmers and service providers with technology, finance and knowledge is key to successful adaptation efforts. It is equally important to glean lessons from past reaseach and practices, take them to the farmers in a language they understand, and promote mutual learning. Farmers on the ground are already facing the impacts and every efforts must be made to help them adapt.

Notes

[1] The onset and withdrawal of monsoon is based broadly on the criteria used by Indian Meteorological Department (IMD). According to Nepal’s DHM, in east Nepal Monsoon is declared to begin when south easterly winds reach up to 700 hPA, easterly winds upto 200 hPA to 500 hPA, cloudiness and continuous 3 days of rainfall.  Nepal needs to further develop criteria for onset and withdraw dates.

[2] MoFE, 2019. Climate change scenarios for Nepal for National Adaptation Plan (NAP). Ministry of Forests and Environment, Kathmandu

[3] Das,P.K 1968 The monsoons, Edward Arnold Ltd, London, 162 pp.

[4] Monsoon Onset and Withdrawal date information Government of Nepal Ministry of Energy, Water Resource and Irrigation.  Department of Hydrology and Meteorology Climate Division (Climate Analysis Section). Babarmahal, Kathmandu

[5] https://twitter.com/DHM_FloodEWS/status/1447793001602826241

[6] Press release regarding the production of rice. December 31, 2020, Ministry of Agriculture and Livestock Development, Nepal

[7] DHM, 2017. Observed Climate Trend Analysis in the Districts and Physiographic Regions of Nepal (1971-2014). Department of Hydrology and Meteorology, Kathmandu