Rese­arch and deve­lo­p­ment pro­ject: Deve­lo­p­ment of peat-free gro­wing media with a balan­ced nut­ri­ent sup­ply and regu­la­ted water balance on the basis of bio­ge­nic resi­dues and regio­nal, natu­ral clays — sui­ta­ble pro­ces­sing methods and use of the con­trol func­tions of the clay aggre­gate (KuReTo)

Plan­ned period: 2020 to 2024

For peat sub­sti­tu­tes, bio­ge­nic resi­dues from other pro­ces­ses are often sui­ta­ble for fur­ther value crea­tion. Howe­ver, their che­mi­cal and phy­si­cal pro­per­ties do not rea­dily per­mit their use in gro­wing media. In order to solve these qua­lity pro­blems, ques­ti­ons arise on the one hand about their pre­pa­ra­tion with sui­ta­ble stra­te­gies for pre-tre­at­ment and mixing, and on the other hand about sui­ta­ble aggre­ga­tes that can solve these pro­blems. Clays have estab­lished them­sel­ves as an addi­tive to peat-based sub­stra­tes. They achieve a balan­ced nut­ri­ent sup­ply, impro­ved rewettabi­lity and an ade­quate sup­ply of trace ele­ments. Con­tai­ned mine­rals such as iron sul­phide or vol­ca­nic glas­ses can lower the pH to an opti­mum range for plants. They also require a con­ti­nuous sup­ply of plant-available Si. 

The pro­ject aims to put the pre­pa­ra­tion of various peat sub­sti­tu­tes, the sel­ec­tion of clays and their mix­tures on a broa­der, sci­en­ti­fi­cally and hor­ti­cul­tu­rally sound basis. In coope­ra­tion with one part­ner each from the recy­cling indus­try, the spe­cial clay indus­try and soil sci­ence rese­arch, sui­ta­ble pro­ces­ses are to be deve­lo­ped for the opti­mal pre­pa­ra­tion of peat sub­sti­tu­tes for later use in the sub­strate, inclu­ding sto­rage, crus­hing, dry­ing and mixing tech­no­logy. Mine­ra­lo­gi­cal, che­mi­cal and phy­si­cal para­me­ters for the sel­ec­tion and pro­ces­sing of clay as an addi­tive are to be deve­lo­ped. High-qua­lity hor­ti­cul­tu­ral sub­stra­tes are to be pro­du­ced from the available bio­ge­nic resi­dues such as com­post, fer­men­ta­tion resi­dues, cham­post and horse manure through tar­ge­ted pro­ces­sing and a coor­di­na­ted clay addi­tive. Our aim is to pro­duce peat-free sub­stra­tes from peat sub­sti­tu­tes that meet the qua­lity stan­dards of the RAL Qua­lity Asso­cia­tion for Sub­stra­tes and are the first sub­stra­tes to be awarded EU Eco­la­bel certification.