1. After successful completion of this Lesson, you have learned to answer: 1.Why sorghum yields are often low when grown under rainfed conditions? 2.How irrigation helps sorghum crop? 3.What is the advantage of pre-sowing irrigation in sorghum cultivation? 4.Which are the critical stages for water requirement in sorghum plant growth? Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices

2. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices After successful completion of this Lesson, you have learned to answer: 5.What symptoms help you to decide the irrigation requirement for sorghum crop? 6.List the irrigation schedule for a ratoon sorghum crop? 7.What contingency plan you will follow in the event of drought during the sorghum crop growth?

3. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Sorghum is mainly grown under rainfed situation. Only about 8% of sorghum area is irrigated. Sorghum crop is exposed to drought conditions very often during its growth and consequently the yields are lower than the potential yield. So, if the farmers want higher sorghum yields even during the rainy season, the answer is irrigation if water is available.

4. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices How irrigation helps sorghum crop? Allows efficient use of inputs Increases yield Improves quality of grain Improves reliability and reduces risk Increases profitability

5. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Adequate soil moisture at sowing assure uniform plant stand and contributes to early plant growth. Pre-plant irrigation can supply this moisture when early rains do not fill the root zone prior to planting. If the seedbed contains sufficient moisture for good germination and early plant growth but subsoil moisture is lacking, water may be supplied by irrigating the crop after emergence.

6. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Allowing seed to remain in dry soil for several days may result in poor germination and seedling vigour. So, irrigation prior to sowing is recommended if water is available. Whether irrigating before or after planting, apply no more water than required to fill the effective root zone. Encourage deep rooting by maintaining only moderate soil moisture levels during early vegetative growth.

7. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Moderate plant moisture stress during early vegetative growth normally does not significantly limit grain yield. However, adequate moisture must be available by the boot stage. Irrigation at the milk to soft dough stages also has consistently maintained high yield potential.

8. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Irrigation intervals and the amount of water to apply is determined by: rainfall soil's water-holding characteristics plant rooting depth and other climatic conditions like air temperature etc.

9. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices The visible signs for giving the irrigation to the crop or the moisture requirement of crop are: drooping and withering of leaves during morning period, leaves feel some what warm during noon instead of cool, and cracking of the soil surface of the field. Plan for irrigations to provide adequate soil moisture during the high water requirement periods.

10. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Irrigation for a ratoon crop Irrigate immediately after cutting the main crop. Irrigation should not be delayed for more than 24 hours after cutting. Irrigate on 3rd or 4th day after cutting. Subsequently irrigate once in 7-10 days. Stop irrigation on 70-80 days after ratooning.

11. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Drought Contingency Plan For Rainy Season Crop 1. Early onset of monsoon followed by a long gap: Repeated intercultivation operations for some moisture conservation like hoeing, weeding and mulching are suggested. Under severe moisture stress, reduce the plant population by 2/3 by thinning for judicious use of moisture.

12. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Drought Contingency Plan For rainy season 2. Delayed onset of monsoon: Normal recommendation can be followed. In case there is delay in monsoon by 2-3 week, short duration cultivars such as CSH 6 and CSH 14 can be preferred.

13. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Summary: Light Soils

14. Virtual Academy for the Semi Arid Tropics Lesson 2: Irrigation Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices Summary: Heavy Soils

15. With this, the Lesson 2 on irrigation in sorghum cultivation, and also this Module X concludes. If you would like to check your understanding about soil moisture and irrigation in sorghum cultivation, please click on the “Exercise” button in Module X contents. Next, Module XI provides information about harvesting and storing of sorghum. Select Module XI from Course contents Virtual Academy for the Semi Arid Tropics Module X: Soil Moisture Relationships and Irrigation Course on Sorghum Production Practices