Extensive Investigation Into Field Based Responses to a Silica Fertiliser

Silicon (Si) is a beneficial plant nutrient and yield responses to its application have been frequently demonstrated in Si-accumulator crops such as rice and sugarcane. Increased yields are the result of simultaneous increases in plant tolerance to a wide range of stresses, yet the actual stress experienced by crops in the field is poorly quantified and understood today. The purpose of this paper is to provide results from extensive, replicated field trials in diverse regions, across different crops and seasons with the same Si fertiliser and to demonstrate the value of this fertiliser as a source of silicon. In the replicated field trial program, amorphous silica was applied to all the crops and the Si availability of the soils is quantified using a CaCl 2 extractant. The applied silica results in yield increases of up to 35 %. There is a variability in yield responses that cannot be explained by initial Si soil availability, rates of application, varietal or soil differences and must be attributed, at least in part, to stress experienced by the plant in different seasons or environmental conditions. Aspects that require future research include a better quantification of the availability of Si in the soil and a greater understanding of the effects of stresses experienced by crops in the field. This research would allow improved recommendations of Si fertiliser applications in standard crop practices.