Source: http://vasat.icrisat.org/crops/pearl_millet/pm_production/html/m6_2.3/index.html

Usually it is considered that most of the Indian soils are rich in potassium. Make sure that the soil will meet the potassium needs of the pearl millet crop in your field through soil testing. If the soil test reveals that the available potassium is less than 150 kg of K2O/ha, then there is a need to apply potassium in that field.

Potassium uptake is greater in the early part of pearl millet 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.Potassium fertilizers are placed along with nitrogen and phosphorus either in the seed furrows or side dressed before sowing. Potassium, if needed, is top dressed along with nitrogen application. The fertilizers are applied near the rows of the pearl millet 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.