Assessment of Length of Growing Period for Efficient Crop Planning in the Tarai and Mid Himalayan Regions of Uttarakhand, India

Abstract

The Tarai region, with 55-60% of its agricultural area under rainfed farming, and the mid-Himalayan region, with 80-90%, experience humid to Perhumid climatic conditions. However, erratic rainfall distribution in the Tarai and significant topographical variations in the mid-Himalayas contribute to yield losses. This study aims to determine the length of the growing period (LGP) and assess moisture suitability for various crops in both regions of Uttarakhand for the period 1981-2020 (Tarai) and 1985-2020 (mid-Himalayan). Three methodologies were employed to estimate the LGP: the NBSSLUP criteria (PPT, PET, 0.5PET), the RF/PET ratio, and the Moisture Adequacy Index (MAI) based on Thornthwaite’s water balance method on a weekly scale. The average LGP was determined to be approximately 227 days in the Tarai region and 313 days in the mid-Himalayan region with Humid-Perhumid type of climate in the both the regions. To mitigate water stress during the post-monsoon and summer seasons, appropriate irrigation strategies must be implemented in the Tarai region to ensure optimal crop yields. Conversely, in the mid-Himalayan region, rainfed crops can be cultivated year-round, supplemented by irrigation from natural springs during dry spells in October and May. The primary crops in these regions include rice, wheat, soybean, maize, pulses, vegetables, fruits, and minor millets.