Abstract

Understanding the physiology and time-course of above ground biomass (AGBM) and potassium (K) accumulation pattern in plants and removal from soil is essential to simultaneously increase crop yield and synchronize K demand and K supply, thereby predict crop yield. It is also an essential criterion for optimizing fertilizer practices, and may help to enhance soil and crop quality. A pot experiment was conducted using teff (Eragrostis tef Zucc. Trotter) to determine AGBM, K concentration and uptake at three growth stages. Two soil types (Vertisols and Nitisols) and four K levels were used. Soil samples (120) were collected at planting and three stages while plant samples (160) were collected at the three growth stages. Above ground biomass increased as growth stage advances regardless of K levels in both soil types. Maximum AGBM was observed at tillering stage and at 120 kg K ha-1 and was higher in Vertisols at all growth stages. The study concluded that sufficient supply of nutrients from soil/fertilizers at early growth stages is required for higher yields. The study suggested that determining the right rate for different soil and crops is required. Repeating the experiment at field condition to draw sound conclusions was also recommended.

Key words: Growth stages, potassium concentration, biomass, teff, Vertisols, Nitisols, Central Highlands.