Context: Silicon (Si) is a beneficial element which can improve plant tolerance to abiotic and biotic stresses, while also improving nutrient uptake. Aim: The aim was to determine the extent of Si depletion and the crops most responsible by developing a partial Si balance for Australian cropland. Methods: A literature review was performed to assess Si content in Australian cropland soils and, based on records from the Australian Bureau of Agricultural and Resource Economics and Science, annual Si removal from the soils due to uptake by the main crops was estimated. Australian results were compared to global Si removal estimates for the 15 most harvested crops recorded by the FAO. Key results: The estimate of Si removal rate for cropland in Australia in 2020, from 66.6 million tonnes (Mt) annual production on 31 million ha, was 3.8 Mt, equivalent to 122.6 kg ha−1. Based on two scenarios (I – annual replenishment of plant-available Si in soils; II – same as Scenario I plus significant Si leaching from soils), there are negative Si balances in Australian agriculture. The seven top Si accumulator crops account for 77% of Si removal in Australian croplands. Conclusion: The negative Si balance in Australian croplands is lower than for other parts of the world (−35 to −87 vs −83 to −137 kg ha−1 year−1) but these values may be underestimates, pending determination of Si leaching rates in Australian croplands. Implications: The implications of soil Si depletion warrant further examination considering the numerous stresses encountered by the crops grown in Australia.
Details
Title
Silicon depletion in Australian cropping soils: implications for crop tolerance to stresses
Authors/Creators
Babak Motesharezadeh - University of Tehran
Richard Bell - Murdoch University, Centre for Sustainable Farming Systems