Drainage runoff and migration of mineral elements in organic and conventional cropping systems

In the present investigation, organic and intensive cropping systems were compared on small autonomous drainage plots in limed Luvisoils and Cambisoils as well as non-acid Cambisoils during the period 1995 - 1998. In the intensive cropping system with balanced nutrient application, the yield of all crops was 38 - 77% higher than in the organic cropping system. Cropping intensity had no influence on mineral concentration in drainage water, which depended on geochemical soil media. The concentrations of Cl- and NO3- in drainage water were, respectively, 8 - 22 and 24 - 80% higher than in the organic system. But at low N application, improvement of fertilisation efficiency increased crop yield and decreased nitrate leaching at the same time. The leached amount of solutes depended mainly upon drainage runoff, which was 6 - 57% lower in the intensive cropping system than in the organic one, and much less upon its concentration. From this study, organic agriculture has no essential advantage compared with intensive agriculture, considering the amount of leached elements and compounds, and secondarily, crop productivity.