Effect of soil tillage, crop rotation and nitrogen application rates on bread-baking quality of spring wheat (Triticum aestivum L.) in the Swartland wheat producing area of South Africa
Spring wheat (Triticum aestivum L.) is produced in the wheat producing areas of the Western Cape Province, Republic of South Africa, primarily for bread-baking purposes. Milling and baking characteristics are therefore of utmost importance. In a long-term tillage and crop rotation experiment in the Swartland, it was found that during the 2000 growing season, flour yield was increased by conventional tillage but hectolitre mass did not respond to tillage during the same season or on average for the period 1992-1998. Although grain protein content and ultimately loaf volume were also higher with conventional tillage when compared to no-tillage, the latter resulted in the highest grain protein yield owing to slightly higher grain yield obtained with no-tillage. The inclusion of a legume crop (lupin) and canola in rotation with wheat had little effect on either milling or baking characteristics, possibly owing to the fact that legumes were only planted once in a four-year cycle. Increased N-fertiliser rates (140 kg N ha-1) resulted in reduced hectolitre mass, but higher grain protein when compared to low N rates of 60 kg N ha-1. This study once more illustrated the complexity of the bread-baking process and the need for good management practices in order to obtain both high yield and good bread-baking quality under Mediterranean climatic conditions.