Crop Rotation and Soil Pathogens — Trends in Germany

Abstract

The need to cut costs has led to a simplification of crop rotation in several fields of plant cultivation. The results of Thormann, who has grown wheat continuously on parts of his farmland for 10 years, are discussed. Also, the preliminary results of our own experiments with increasing proportions of wheat and barley suggest that more wheat and barley may be cultivated in crop rotation than is allowed according to the conventional limits determined by the increase of foot rot diseases and cereal root eelworm. Even in successive crops of maize the problem of soil‐borne pathogens can be tackled: the spread of blister smut is stopped by the control of the frit fly and by selection of tolerant varieties; root and stem rots of maize are overcome by the selection of appropriate varieties, too. On the contrary, the potato root eelworm is a serious pest in all sites of intensive potato production. Only an integrated control including the use of resistant varieties and the application of nematicides gives success. Much research work has to be done mainly to get more information on the biotical defence mechanisms of the soil.

Produkcyjne, ekonomiczne i środowiskowe aspekty uproszczenia struktury zasiewów

“…Ze wzglêdu na ograniczon¹ objê- toae artyku³u ten w¹tek pominiêto w analizie, jednak¿e nale¿y podkreliae, ¿e to zagadnienie jest przedmiotem licznych badañ i opracowañ naukowych. Wskazuje siê miêdzy innymi na zachwianie równowagi pomiêdzy ró¿nymi organizmami, prowadz¹ce do nasilenia wystêpowania patogenów, zmniejszenie ¿yznoci gleby i zjawisko kompensacji chwastów [Ku 1996] czy te¿ wzrost zagro¿enia chorób rolin wywo³anych przez patogeny glebowe [Obst, Diercks 2008]. Znacz¹cy problem, szczególnie w uprawach rolin w monokulturze, stanowi wzrost zanieczyszczenia wód pozosta³ociami pestycydów i wymywanych sk³adników pokarmowych, g³ównie azotu.…”

Cultural Measures, Crop Protection and Economics in Cereal Monocultures in Bavaria1

“…These considerations prevailed when the research projects were established in Bavaria (DIERCKS, 1972, BACHTHALER, 1974, BACHTHALER et ul., 1973, OBsT and DIERCKS, 1972, NEUMANN, 1974, PFISTER, 1973. Data pertaining to these publications will be studied, but final conclusions cannot yet be drawn since the experimentation which included cereal monoculture (winter wheat, spring barley) started only in 1968.…”