Amorphous silica reduces N2O emissions from arable land at the field plot scale

Increasing greenhouse gas emissions pose a strong threat due to accelerating global warming. N ₂ O emissions are highly important in this regard as N ₂ O is a very powerful greenhouse gas. Agriculture is the main human-induced source for N ₂ O emissions contributing roughly 60% to total N ₂ O emissions. Soil amorphous silica (ASi) contents are reduced in arable soils due to yearly exports by crop harvest as most crops are silicon accumulator plants. Most recently it has been shown that ASi is increasing water and nutrient availability in soils. Both factors are known to directly and indirectly affect N ₂ O emissions from agroecosystems. In this study we conducted a field plot trial on arable soil depleted in ASi and fertilized this soil its pre-agricultural ASi level. Our data clearly shows that increasing soil ASi to a pre-agricultural level decreased seasonal N ₂ O emissions by ~ 30%. This reduction of N ₂ O emissions due to ASi might be of global relevance as agricultural practice has reduced the ASi content in agricultural soils. If future studies confirm the effect of ASi on N ₂ O emissions, the soil ASi depletion by agricultural practice in the last decades may have led to a substantial increases of N ₂ O emissions.