The effect of different rates and forms of applied sulphur on nutrient composition of planted crops

A three-year field experiment was conducted from 2000 to 2002 in North-East Poland. Each year three sulphur fertilization rates in the form of sulphate (S-SO42-) and pure sulphur (S-SO) were applied: 40, 80 and 120 kg/ha. The most beneficial effect on the yields of cabbage, onion and barley was produced by the rates of 40 and 80 kg S/ha, while the dose of 120 kg S/ha (especially when applied as S-SO42-) reduced the yields of these crops. Increasing rates of sulphur used as a fertilizer caused increased concentration of sulphates in plants up to their luxury accumulation. Irrespective of the test crop species or form of sulphur applied, once the crops terminated their vegetative season, the plants fertilized with sulphur typically contained more total N than those fertilized only with NPK. The S-SO42- fertilization tended to raise the accumulation of N-NO3- in the crops, especially during the juvenile phase. The application of 120 kg S-SO42-/kg caused depressed amounts of potassium in cabbage, onion and in barley during the heading phase.