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Press release - Tuesday, January 6, 2015

Improved soil fertility without extra phosphorus buildup when fertilising with compost

ILVO-KU Leuven doctoral thesis of Thijs Vanden Nest: ‘Long term use of different organic fertilizer types and impact on phosphorus leaching’
The organic fertilisers farmyard manure, composts and digestates have a different effect on the amount of phosphorus in the soil available for crops and on phosphorus leaching. Compost and barn manure add equal amounts of organic matter to the soil. But cattle manure increases not only the crop-available phosphorus but also the P leaching.

Compost, in contrast does not have that (undesired) effect of leaching. Compost thus appears to be the best organic fertiliser for soils that already have a too-high level of phosphorus. Barn manure appears to be a good choice for soils that need additional P. These results are based on field experiments at ILVO and Ghent University in Flanders and the INRA in France. Researcher Thijs Vanden Nest defended his doctoral research on this theme. Creating the right fertiliser strategy is a challenging search for balance when striving for simultaneous increase in fertility, soil quality, and minimum environmental impact. Various stable organic fertilisers such as barn manure, composts and digestates (the end product of biomass fermentation) are compared in this doctoral thesis as sources of organic material to successfully increase the level of organic matter in soils.


Thijs Vanden Nest, doctorandus,, +32 9 272 26 74
Greet Riebbels, communicatie ILVO,, +32 486 26 00 14
Bart Vandecasteele, Eenheid Plant ILVO,, +32 9 272 26 99
Greet Ruysschaert, Eenheid Plant ILVO,, +32 9 272 26 98

Promotors: Prof. Dr. ir. Roel Merckx; Dr. ir. Bart Vandecasteele; Dr. ir. Greet Ruysschaert
Partners: Prof. Dr. ir. Dirk Reheul (UGhent University), Dr. Sabine Houot (INRA France) en ir. Janjo de Haan (Wageningen UR The Netherlands).