1. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought The early season droughts occur during the beginning stages of rainy season. This type of drought is identified based on the 1.Optimum sowing periods for the different crops under rainfed conditions, 2.Amount of rainfall needed to complete the sowing in a given region, and 3.The initial amount of rainfall required for safe germination and establishment of the crop stand. Lesson 2: What are the features of drought ? Early season drought

2. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought The mid-season droughts occur some time during the middle of the rainy season. This type of drought is identified based on the 1.Adverse effect on the standing crop, 2.Amount of rainfall needed for the continuation of stage of the standing crop, and 3.The amount of rainfall required during the critical stages of the standing crop. Lesson 2: What are the features of drought ? Mid-season drought

3. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought The late season droughts occur some time during the concluding period of the rainy season. This type of drought is identified based on the 1.Amount of rainfall needed at the reproductive stage of the standing crop, and 2.The amount of rainfall required for ripening and maturity stages of the standing crop. Late season drought Lesson 2: What are the features of drought ?

4. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought When the annual rainfall is less than 75% of normal rainfall in 20% of the years examined, then the year is considered as drought year as per the Central Water Commission in India. Lesson 2: What are the features of drought ?

5. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought However, the criteria for determining the drought occurrence differs in different parts of the world. United States (1942): less than 2.5 mm of rainfall in 48 hours. Great Britain (1936): 15 consecutive days with daily precipitation totals of less than 25 mm. Libya (1964): annual rainfall less than 180 mm. Bali, Indonesia (1964): a period of six days without rain. Lesson 2: What are the features of drought ?

6. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought Further, drought is classified as: Moderate drought: Seasonal rainfall deficiency is between 26 to 50% of normal rainfall. Severe drought: Seasonal rainfall deficiency is more than 50% of the normal rainfall. Lesson 2: What are the features of drought ?

7. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought Drought is a recurrent feature of climate in any region or country. For example: Based on the data collected using the criteria for a drought year, it has been noticed that there were 44 drought years since 1800 in India. Lesson 2: What are the features of drought ?

8. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought Drought occurs more frequently in the arid and semi- arid regions, where the variation in annual rainfall is high. In the arid areas with mean annual rainfall generally less than 400 mm, drought is a very frequent phenomenon. In semi-arid regions, where the mean annual rainfall varies from 400 to 1000 mm, droughts occur in 40 to 60% of the years either due to deficit in seasonal rainfall or of prolonged dry spells between successful rainfall during the main cropping season. Lesson 2: What are the features of drought ?

9. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought The regions in a country can also be categorized as drought prone areas based on the frequency of drought occurrence in the region. For example, in India: Western parts of West Rajasthan and Kuch are chronically drought affected. Other areas under dry farming tract come under drought areas (40% of the years examined). The humid and per-humid regions such as Assam rarely face drought. In contrast the hot arid regions can have a frequency of drought once every 2.5 years. Lesson 2: What are the features of drought ?

10. Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought This concludes the Lesson 2 on the features of drought in this Module. If you would like to check your understanding about the features of drought, click “Exercise” button. In the final Lesson in this Module, the causes of drought are briefly described. Click “Lessons” button to select Lesson 3 Exercise Virtual Academy for the Semi Arid Tropics Course on Coping with Drought About Drought Lessons