Conversion of dissolved phosphorus in runoff by ferric sulfate to a form less available to algae: Field performance and cost assessment

Abstract

Conversion of dissolved P by ferric sulfate into a particulate form sparingly available to algae was studied in 15 ditches in Finland using stand-alone dispensers for ferric sulfate administration. Ferric sulfate typically converted 60–70 % of dissolved P into iron-associated form, a process which required 250–650 kg per kg dissolved P. Mean cost was 160 EUR per kg P converted (range 20–400 EUR kg−1). The costs were lowest at sites characterized by high dissolved P concentrations and small catchment area. At best, the treatment was efficient and cost-effective, but to limit the costs and the risks, ferric sulfate dispensers should only be installed in small critical source areas.

Effects of Crop Rotation on Spring Wheat Yield and Pest Occurrence in Different Tillage Systems: A Multi-Year Experiment in Finnish Growing Conditions

“…The positive effect of crop rotation on crop nutrient uptake (Venkatesh et al, 2017) was also verified in our study: spring wheat had better N and P uptake in CR2 and CR4 than in CR1 with both tillage conditions, the effect being even higher in notillage conditions as also reported by Malhi and Lemke (2007). Higher nutrient balance increases the risk of nutrient leaching (Uusitalo et al, 2015;Turtola et al, 2017) which can be prevented with proper crop rotation (Kayser et al, 2010), tillage method (Wang et al, 2015) and successful crop protection (Delin et al, 2008;Kauppi et al, 2021).…”

Impact of Pests on Cereal Grain and Nutrient Yield in Boreal Growing Conditions

“…As shown in Turtola et al [37] study, higher N-balance (nitrogen applied as in fertilize/manurenitrogen harvested in grain (yield)) increase the risk of nitrogen leaching. Similarly, in Uusitalo et al [53] study, values of phosphorus in soil tests change over time affected by the reduction of P-balance and the reduction of soil P level decreases the risk of phosphorus leaching. As pests disturb crop growth causing significant yield losses and increasing the positive nutrient balance, this probably also increases the risk of nutrient leaching.…”

“…Even though pests and their effect to crop yield has been an object of interest in agricultural studies for decades, the effect of pests on nutrient yield harvested in grain yield is seldom reported. There is, however, an urgent need to reduce nutrient leaching from field to surface water [30,[51][52][53]. Crop nutrient uptake efficiency related to nutrients applied as fertilizer is one indicator for the risk of nutrient leaching especially outside growing season [33,42,54].…”

Phosphorus speciation in agricultural catchment soils and in fresh and dried sediments of five constructed wetlands

“…Two of the sites (Kakskerta and Nautela) had chemically assisted P precipitation, with aluminium chloride solution (trade name Kempac 18) at Kakskerta and granular ferric sulphate (Fe2(SO4)3, trade name Ferix-3) at Nautela being added into the water entering the CWs. This chemical treatment has been performed for 9 years at Kakskerta (since 2003), with the exception of occasional interruptions, and for 1.5 years at Nautela (since 2011; see Uusitalo et al, 2015).…”