Auswirkungen einer Schwefeldüngung auf den Ertrag und die Nährstoffzusammensetzung eines Kleegrasbestandes

Summary

In a field experiment at the Experimental Farm for Organic Farming in Northern Germany, the effect of sulphur application in the form of MgSO4 to a red clover-grass mixture was measured in the year 2011. At the beginning of the vegetation period in the spring plots were fertilised with 30 and 60 kg S ha-1. The sulphur fertilisation resulted in significantly higher fresh weight and dry matter yields and otherwise in a lower dry matter content as compared to an unfertilised treatment. The content of crude protein and sulphur were significantly increased by sulphur application. The N/S-ratios in the fertilised plots showed values below the threshold of 15 for an adequate supply of sulphur. The N-withdrawals added up over the three cuts increased in the fertilised plots by over 55 %. S-withdrawals increased from 8 kg S ha-1 in the unfertilised plots by more than 10 kg S ha-1. In the comparison of the 30 and 60 kg S ha-1 fertilisation level there was no significant effect on yield level, but on N/S-ratio and N uptake. Therefore, a sulphur fertilisation level of 30 kg ha-1 can be considered sufficient.