|Title||Een onderzoek over de stroomruggronden van de Bommelerwaard met als proefgewas de aardappel|
|Source||University. Promotor(en): A.C. Schuffelen; N.H. Kuiper. - 's-Gravenhage : Staatsdrukkerij - 132|
|Publication type||Dissertation, internally prepared|
|Keyword(s)||solanum tuberosum - aardappelen - zware kleigronden - bodemkarteringen - kaarten - nederland - bommelerwaard - gelderland - potatoes - clay soils - soil surveys - maps - netherlands|
|Categories||Soil Fertility / Potatoes / Soil Science (General)|
|Abstract||In agricultural research many factors have to be studied simultaneously to clarify a problem. The usual field trial with interference is not usable for this purpose. It is difficult or expensive to investigate the influence of factors, which are difficult or impossible to change, such as watertable, structure and clay content.
The method proposed avoided normal field trials with interference and used single plots distributed over a wide area. Natural variation in factors was used without interference. A graphic method of regression analysis, multifactorial analysis (Du. polyfactor analyse), was used to distinguish the influences of all growth factors. A method of testing the reliability of the results was worked out.
A trial with potatoes demonstrated the method. About 88 % of the explainable yield variance could be explained by nine factors: date of planting, distance to farmstead, acidity, K content, K dressing, content of organic matter, clay content, watertable and depth of reduction. This makes it plausible that important factors have not been neglected. The correlation coefficient between calculated and actual yields was 0.86.