Identification of Shift in Sowing and Harvesting Dates of Rice Crop (L. Oryza sativa) through Remote Sensing Techniques: A Case Study of Larkana District

The present study aimed to determine the impact of climate variability on rice crops in terms of sowing and harvesting dates and crop period. The identification of sowing and harvesting dates were spotted by mask identification, variations in land surface temperature (LST) on a temporal scale in the respective months, and a field-level social inquiry. The study was conducted during a time period (1994–2017), in which geo-referenced crop samples, farmer’s perception survey data, Landsat satellite images, and climate data of district Larkana were used. The analysis of satellite imageries revealed that on 20 June 1994, the rice was transplanted on 14.7% of the area of the region while it was only 7.1% of the area in 2017. Similarly, the area under rice crop in the first week of July 1994 was 18.3% compared to 8.15% during the same period in 2017. However, in the first week of October 2017, the rice crop was standing on 46.8% of the area while it was on 34.6% of the area during the year 1994 on the same date. This LST variation depicts a delay in the sowing and harvesting of the rice crop. This changing pattern is further confirmed through mean LST. Mean LST (°C) has been increasing in the sowing period of rice crop from 31.9 °C in June 1994 to 35.8 °C in June 2017, and from 32.8 °C in July 1994 to 36.8 °C in July 2017. Furthermore, the LST decreased during the harvesting period of rice crop from 31 °C in October 1994 to 28.6 °C in October 2017. The present study quantifies a delay of 15–30 days in sowing and harvesting dates of the rice crop in the district due to climate variability.