Preparation of Potash for Injection. A stock solution of potassium chloride (KCl) was prepared by dissolving solid, granular potash (special standard grade product from Agrium® Inc.) into potable water at a rate of about 0.3 kg L-1. Following mixing, removal of solids, and filtration, the resulting clear stock solution had a final concentration of about 120,000 mg L-1 potassium (K+) and 108,800 mg L-1 chloride (Cl-) Pipeline Injection Study. Five irrigation pipelines within three irrigation districts were used to test the injection of dissolved KCl into pipelines to achieve a target concentration of 100 mg L-1 K+. Three pipelines (Pipelines A, B, C) in the EID, one pipeline (Pipeline D) in the Taber Irrigation District (TID), and one pipeline (Pipeline E) in the St. Xxxx River Irrigation District (SMRID) were used in the study. The pipelines ranged in size from 207 to 3194 m3. The number of irrigation systems supplied by the pipelines ranged from 1 to 18 systems. The KCl stock solution was injected using an injection wand inserted through vertical air-vent pipes at the pipeline inlets. When the pivots were turned on to start flow through the pipeline, a dosing pump was used to inject the KCl stock solution. When the last pivot was turned off, the injection was stopped and the pipeline inlet closed. The KCl-treated water was held in the pipelines for about 24 to 48 h. After the hold period, the pivots were turned on and the pipeline inlet open and the KCl-treated water was purged from the pipelines and applied to the fields. Water samples were collected at the pivots to determine the final concentration of K+ in the water. Surface soil samples (0–2.5 cm and 0–15 cm layers) were collected in ten locations before and after the KCl-treated water was applied to the fields. Samples were analyzed for extractable K+, extractable Cl-, and electrical conductivity (EC). Alfalfa sampled were collected at Site 3, Pipeline B in two transects: one transect where KCl-treated water was not applied and the other transect where KCl-treated water was applied. The plant samples were analyzed for chemical content.
Preparation of Potash for Injection. Lessons learned from the laboratory investigations carried out prior to the start of the project were applied to develop a method for large-scale dissolution of granular potash (special standard grade product from Agrium® Inc.). A stock solution of potassium chloride (KCl) was prepared by dissolving solid, granular potash into potable water at a rate of about 0.3 kg L-1. The stock solution was prepared in batches by mixing in a mixing tank (1100 L) using a trash pump for 1.5 h until all the potash was dissolved. As the potash dissolved, residual flocculants and residue floated to the solution surface, and these residues were removed by skimming the solution surface by hand throughout the mixing step and during the settling period. After mixing, the solution was allowed to settle for 2 wk to allow other, insoluble residual particulates to settle to the bottom and sides of the tank. Following the settling period, the solution was pumped from the mixing tank to a storage tank (6826 L), leaving behind the settled residues. The resulting stock solution was reasonable clear and colourless. However, a circulating filtration system was developed for the storage tank to further clarify the stock solution. The concentration of the final stock solution was about 120,000 mg L-1 K+ and 108,800 mg L-1 chloride (Cl-).
