. Potassium is a primary macro nutrients and it becomes a limiting factor of plant growth in the upland acid soil. There have not been much studied about the best K extraction, K nutrient status, and the rate of K fertilizer application for upland rice in Hapludults. The objective of this research is to investigate the best extractant for K nutrient, evaluate K nutrient status and the best rate of K fertilizer for each K nutrient status for upland Hapludults with very low K content. The study was conducted in the village of Braja Harjosari, Sub district of Braja Selebah, East Lampung (05o 10 '57.43 "S and 105o 46' 33.27" E), in dry season of 2015 until the rainy season of 2015/2016. In the first season, a series of artificial K nutrient status from low to high was made by adding K fertilizer with doses of 0 X, ¼ X, ½ X, ¾ X, and 1 X, where X is the amount of K fertilizer intended to achieve the levels of 0.6 cmol(+)kg-1 K in the soil. In the second season, a fertilization response trial on each K nutrient status, with doses of 0, 20, 40, 80, and 160 kg K ha-1 was established Plots dimension was 25 m x 6 m in the first season and 5 m x 6 m in the second season. Observations were made on soil chemical properties and dry grain weight. The K extraction tested were 1N NH4OAc pH 7, 1N NH4OAc pH 4.8, 25% HCl, Truog, Mehlich 1, Bray 1, Bray 2, Colwell, Morgan Venema. The results showed that the best nutrient K extraction of Hapludults soil was the Colwell. The low, medium and high K nutrient status was <21.5, 21.5 – 26.5 and > 26.5 mg kg-1, and the dosage of K fertilizer for upland rice in each nutrient status K was 125, 110, and 80 kg KCl ha-1.