Effects of Chloride Fertilization on Wheat (Triticum aestivum L.) Productivity in the Sandy Pampas Region, Argentina

The soils from the sandy Pampas region (Argentina) are coarse‐textured Mollisols with high to very high extractable K levels. However, in several KCl fertilization field trials, wheat ( Triticum aestivum L.) grain yield and alfalfa ( Medicago sativa L.) dry matter production increments have been reported. Our objective was to determine the contribution of Cl − fertilization on dryland spring wheat productivity. The study was performed during the 2001 and the 2002 growing seasons on 10 experimental sites establishing 14 treatments in completely randomized blocks with four replications: Cl − fertilization rates (0, 23, 46, and 69 kg ha −1 ), Cl − fertilizer sources (KCl and NH 4 Cl), and crop disease control (with and without fungicide applications during stem elongation). Chloride fertilization increased grain yields in 50% of the sites independently of the fertilizer source and the fungicide treatments. Averaged over the 10 locations, the grain yield response to Cl − fertilization was of 253 kg ha −1 , and it was mostly explained by a greater number of grains per square meter. Soil Cl − levels >13.2 mg kg −1 (0.0 to 0.2 m) were adequate for maximum grain yields. Foliar fungicide application also improved wheat grain production, enlarging the single weight of the grains. In the absence of water, N, P, and S deficiencies, the fertilization with 23 to 46 kg ha −1 of Cl − –containing fertilizers after the emergence of wheat crops is a recommended practice for achieving high‐yielding crops in the sandy Pampas region of Argentina.