Effect of Land Use Types on Selected Physical and Chemical Properties of Ultsiols in Umudike, Southeastern Nigeria.

Field experiments were carried out in 2018 and 2019 at the National Root Crops Research Institute Eastern Farm, Umudike, Southeastern Nigeria to examine the different forms of potassium and their contributions toward potassium uptake under ginger production using ginger variety (UG 1) as the test crop. There were seven treatments consisting of sole and combinations of NPK15:15:15, poultry manure and rice mill waste with a rate of 45kg N/ha regarded as 100%. They were arranged in RCBD with three replications. The available potassium in 2018 and 2019 were 0.080 and 0.100 cmol/kg. They were low in status. The variations in different forms of K status were due to the application of mineral and organic fertilizers. Among the five forms, water-soluble K and total K contributed predominantly to K uptake by ginger. The highest yield of 49.6 and 47.5 t/ha and K uptake of 128.5 and 127.5 kg/ha were obtained from 50% NPK and 50% rice mill waste at 5 MAP, and the highest yield of 49.6 and 51.0 t/ha and K uptake of 160.8 and 158.7 kg/ha were obtained from 50% NPK and 50% poultry manure at 8 MAP in 2018 and 2019, respectively. It can therefore be concluded that combination of NPK fertilizer with rice mill waste will give a better yield and K uptake of ginger if harvested earlier at 5 MAP while poultry manure with NPK15:15:15 is a promising amendment for i