Sulphur Balance in Agroecosystem

This field study shows how different crops and soil treatments with different nitrogen fertilization levels affect sulphur balance. Sulphur deposition, leaching through soil and water seepage, availability and uptake by crops, effects on crop yield and losses were investigated. The research was conducted on a field trial from 1996 to 2014 in temperate continental climate on Stagnosols. The soil was treated 10 times with mineral nitrogen fertilizers in an ascending doses from 0 to 300 kg N ha-1 and additional two 250 kg N ha-1 treatments, one with phosphogypsum and one with zeolite tuff and CaCO3. Drainpipes and lysimeters were installed to collect water samples and measure the effects of N doses, amendments and precipitation on sulphur losses. Average annual sulphur losses were from 4.9 to 68.7 kg ha1 through drainage water, and from 1.5 to 24.9 kg ha-1 through lysimeter water. Depending on a crop, year and yield, average crop losses ranged from minimal 2.8 kg ha-1 in winter wheat up to 17.6 kg ha-1 in oilseed rape. Average total S content in soil varied from 882 to 1764 kg ha-1. Overall agroecosystem S balance between input and output, calculated for all crops and all treatments was positive only in the treatment with phosphogypsum for winter wheat, corn and oilseed rape. Water shortage in 2011 caused positive S balance for soybean in other treatments too, not only in the treatment where phosphogypsum was applied.