Yield and Quality of Potato Tubers: Effects of Different Intensity and Kind of Manuring (Biodynamic or Organic)
Neuhoff, Daniel und Schulz, Dirk Gerhard und Köpke, Ulrich (1999)
Discussion and Conclusion
With analysis of variance, only two significant differences between organic and biodynamic manuring were detected. The significant increase of tuber yield in the biodynamic treatment agrees with other results of ours (slightly higher tuber yields in the biodynamic treatment) and those reported by Lücke and v. Boguslawski (1982). The higher tuber potassium content detected once in the organic treatment cannot be explained. Lower nitrate and higher dry matter contents in the biodynamic treatment were found only in the Darmstadt trials. In 9 cases the standard deviation was lower in the biodynamic treatment, whereas in the other cases it was either lower in the organic treatment (6 cases) or equal (8 cases). In the entire study the ratio was 31 (BD) to 30 (OR). Although present data show a small positive impact on yield and tuber quality, a clear advantage of using the biodynamic preparations cannot be established from these results. The effects of manuring on yield were stronger on the sandy soil (Darmstadt), with low soil nitrogen content and high mineralisation rate of manure. In the Wiesengut trial, with its higher soil nitrogen content (preceding crop: grass/clover mixture), manuring affected tuber yield only slightly. Plant uptake and content of potassium was largely improved by manuring, whereas negative effects (decreasing d.m. content, slightly increasing nitrate contents) were not very pronounced. Therefore the amount of manure applied should be based on optimal shoot growth and sufficient potassium supply, thus promoting tuber yield and quality.