YIELD DEVELOPMENT IN THE LONG-TERM EXPERI MENT CONTINUOUS RYE CROPPING HALLE AFTER THE CHANGES IN THE FERTILIZATION IN 1990

The long-term experiment continuous Rye Cropping being established 187 8 on a degraded chernozem (from sandy loess) includes among others a t reatment with application of mineral N only over 112 years in which du ring the last decades the grain yields ranged about 30% below that on the plots with farmyard manure (FYM) or complete mineral fertilization (NPK). The considerable depletion of available P and K in the respect ive soil was practically overcome in 1990 by a single application of 2 00 kg P ha(-1) and 400 kg K ha(-1) and thereafter the exclusive fertil ization with mineral N was substituted by a combined application of NP K and FYM. Already in the first year the previous yield decline in com parison to 'NPK' or 'FYM' had been overcome completely. An additional yield increase, however, could only be realized under conditions espec ially favourable for yield production, so in 1993 and 1995.