Research Findings: e-ifc No. 15, March 2008

Research work from Argentina: Wheat: yield response to chloride fertilization on different cultivars and its effect on foliar disease severity

J. Castellarín, H.M. Pedrol, L. Ortis, M.C. González, M. González, and O. Rosso

The effect of fertilization with sulphur, potassium and chloride on plant health is clearly seen. The picture is from the IPI-INTA project 1998-2004 on Long-Term Effects of Fertilization with K, S, and Chloride in the Pampa region. Arecifes, Buenos Aires, 2001. Photo by IPI.

An experiment was performed to study the yield response of wheat to KCl application and its effects on foliar disease severity in different varieties varying in phytosanitary behaviour. A field trial was conducted in Oliveros, Santa Fe province, evaluating grain yield and disease incidence on a factorial designed experiment with six wheat varieties, (Don Mario Onix, Baguette Premium 13, Baguette 11, ACA 304, Don Mario Cronox and INIA Sirirí), four levels of KCl (0, 30, 60 and 90 kg K₂O/ha), with and without fungicide treatment (Pyraclostrobin, 133 g/l + epoxiconazole, 50 g/l).

Fig. 1 and Table 1 show that all tested wheat varieties differentially benefited from fungicide application (Fig. 1), and also from increased levels of KCl (Table 1). Yield response to KCl was on average increased between 5 to 13 per cent. However, at best it could reach even a 20 per cent yield increase. Except for Baguette 11, all other varieties responded best to the highest level of K applied (90 kg K₂O/ha). On average, there was a significant yield response to KCl application, with best yield achieved with the high KCl rate (90 kg K₂O/ha; Fig. 2). Response to KCl in some cultivars did not relate to foliar disease as measured by percentage of severity. However, the infection and the incidence of disease was rather low. The yield increase due to KCl differed according to the cultivar. Response to fungicide application varied depending on fertilization treatment. Increasing KCl rate resulted in a decreased response to fungicide.

Fig 1. Yield response of different wheat varieties to fungicide application.

Fig 2. Average yield response of different wheat varieties to KCl application. Significance at Duncan at 5% represented by different letters.

Results suggest that fertilization with KCl, even at K levels in soil, as high as 1.3 meq/100 g soils, benefits yield of various wheat varieties and provides a promising alternative and complementary means of controlling foliar diseases in wheat.