SKW Trostberg AG

A review with 6 references The fertilizer calcium cyanamide allows for higher cabbage yields even on soils heavily infested with clubroot.It reduces the viability of resting spores of Plasmodiophora brassicae in the soil.High soil humidity is necessary to release, dissolve and distribute hydrogen cyanamide, the fungicidal metabolite of calcium cyanamide, in the soil.This increases the percentage of resting spores which contact with cyanamide.Best results are obtained when calcium cyanamide is mixed into the soil and slight irrigation or rainfall follows thoroughly.Efficacy is improved with increasing application rates.Depending on the crop demand for nitrogen, an application rate should be chosen which is as high as possible.Cyanamide is quickly decomposed in soil; therefore, it gives mainly control of primary infections.As protection against clubroot is most important during the first growth stages, the waiting period between application and planting or sowing should be as short as possible, normally this means one to two weeks depending on dose rate and prevailing soil temperatureTo achieve a reduction of soil infestation by Plasmodiophora brassicae, crop rotation has to be combined with recurrent applications of calcium cyanamide.

A new technique for lowering the reagent consumption to ∼0.5 kg/ton is developed, high Au and Ag yields are achieved, and passivation of feed is avoided.Formamidine disulfide  [3256-06-2] oxidation product is selectively reduced to thiourea  [62-56-6] during leaching, and the oxidized part of the initial thiourea is maintained to ∼50%.This prevents the generation of passivating S, and enables high redox potentials >400 mV for rapid metal dissolution at low thiourea concentrationPulp process with activated C or resins as adsorbents can be applied.Stripping of precious metals is achieved with hot thiourea or acid solutions