Effects of form, fineness and placement of lime with and without soil tillage on barley and canola growth and development

摘要

No-tillage systems and slow movement of surface-applied limestone can lead to stratification of soil acidity. Incorporation of lime by tilling soil is not preferred by producers following conservation agriculture practices. There is limited research on ways to facilitate lime movement without soil disturbance. This study aimed to determine the effects of form, fineness and calcium carbonate equivalent (CCE) of calcitic lime on its movement in soil with or without different soil disturbance actions and consequent effects on productivity of barley (Hordeum vulgare L.) and canola (Brassica napus L.). A field trial was established in the Western Cape province, South Africa. Ten treatments included a control, lime with different forms and fineness, and tillage practices. Due to the slow movement and reactivity of lime in soil, it was unlikely that growth responses from barley or canola would be detected within the first two years following liming. A once-off strategic tillage action promoted crop growth. This was attributed to deeper redistribution of lime in the soil (15-30 cm depth), among secondary agronomic responses to tillage. Strategic once-off tillage may address the stratification of both soil acidity and nutrients, such as calcium (Ca) and magnesium (Mg), and could be considered as an option to incorporate into management of no-tillage production systems.