1. After successful completion of 3 Units in this Lesson, you will be able to answer: 1.What is the role of nitrogen, phosphorus, and potassium in plant nutrition in general, and in sorghum crop in particular? 2.What is the recommended rate and method of nitrogen application to sorghum? 3.What is the recommended rate and method of phosphorus application to sorghum? 4.How do you decide whether to apply potassium or not? 5.What is the recommended rate and method of application of potassium to sorghum? Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition

2. The 3 Units in this Lesson are: Unit 1: Nitrogen Nutrition Unit 2: Phosphorus Nutrition Unit 3: Potassium Nutrition Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition

3. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition After successful completion of this Unit, you will be able to answer: 1.What is the role of potassium in plants? 2.How do you decide whether to apply potassium or not? 3.What is the recommended rate of potassium application to sorghum crop? 4.What is the method of potassium application to sorghum? 5.Under what conditions potassium is applied as top dressing? 6.Which potassic fertilizer is useful to sorghum crop and why?

4. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition Though potassium application is not regularly practiced, it plays equally important role as nitrogen and phosphorus in plants for their growth and development. Potassium is involved in the plants to: provide resistance to insect pests, diseases, and water stress; use the water economically; improve the quality of the crop produce.

5. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition Potassium is to a plant what breaks are to a car. Good brakes are a must for safe journey to reach the destination and so is potassium for good quality crop produce. Usually it is considered that most of the Indian soils are rich in potassium. Is this true in case of the soil in your field?

6. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition Make sure that the soil will meet the potassium needs of the sorghum crop in your field through soil testing. If the soil test reveals that the available potassium is less than 150 kg of K 2 O/ha, then there is a need to apply potassium in that field. Normally, about 30 to 50 kg K 2 O/ha will be adequate for sorghum sown in soils deficient in potassium.

7. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition Potassium uptake is greater in the early part of sorghum growth than that of nitrogen and phosphorus. So, potassium fertilizers are usually applied in one dose at the time of sowing. However, in light soils, to minimize the loss of potassium due to leaching under heavy rainfall conditions, apply potassium in two splits doses. In such cases, the top dressing is to be done 30 to 40 days of sowing.

8. Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition Unit 3: Potassium Nutrition Potassium fertilizers are placed along with nitrogen and phosphorus either in the seed furrows or side dressed before sowing. Potassium is top dressed along with nitrogen application, if any. The fertilizers are applied near the rows of the sorghum plants and incorporated either by intercultivation or by manual weeding. There should be sufficient moisture in the soil at the time of this top dressing of fertilizers.

9. With this, the Unit 3 on Potassium Nutrition, and this Lesson 2 on the Importance of Primary Nutrients concludes. The next Lesson is about the importance of other plant nutrients for sorghum. The last lesson is about application of manures and fertilizers in sorghum. Select Lesson 3 from Module V contents Virtual Academy for the Semi Arid Tropics Lesson 2. Importance of Primary Nutrients Course on Sorghum Production Practices Module V: Sorghum Plant Nutrition