Organic fertilization of potato | Fumure organique de la pomme de terre
2003
Reust, W. | Neyroud, J.-A. (Station federale de recherches en production vegetale de Changins (RAC), Nyon (Switzerland))
Farm manure has been compared to mineral fertilization alone on two potato cultivars, Matilda and Désirée. The test was carried out on a shallow, rather loamy medium soil of our experimental farm in La Frétaz, Bullet (VD) and lasted from 1996 to 2001. The main treatments were combined with 4 levels of N fertilizer. The potato followed a period of 3 years of sawn meadow in the crop rotation. The aim of the trial was to evaluate the efficiency of farm manure and to measure the evolution of the soil mineral nitrogen level. Manure applications of about 33 t/ha nearly covered the P, K and Mg crop requirements. Fertilisation with manure resulted into a 10% yield increase when combined with low or zero N application to Matilda cultivar. Higher rates of N fertilizer, up to 120 kg/ha, increased the tuber yields by about 25%, but decreased the starch content. Manure application had a positive effect on the starch content, that was more visible on Matilda than on Désirée cultivar, as well as on the percentage of marketable tubers. The soil mineral nitrogen content showed a similar behaviour during the yearshigher contents were however measured at the beginning of the growing season in the manure treatments. A sharp decrease of the contents could be related to the intensive nutrient absorption period of June/July. After the September harvest, nitrogen was mineralised again in all the treatments. Due to the following bare soil, a part of the accumulated nitrogen was lost during the winter.
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