Agroscope, Principi di concimazione delle colture agricole in Svizzera: PRIC 2017, p. 5/3 ([Internet, 2025-09-08](https://www.agroscope.admin.ch/agroscope/it/home/temi/produzione-vegetale/campicoltura/Pflanzenernaehrung/grud/chronik-duengungsgrundlagen/_jcr_content/par/columncontrols/items/0/column/externalcontent_1130603460.bitexternalcontent.exturl.pdf/aHR0cHM6Ly9pcmEuYWdyb3Njb3BlLmNoLzAvQWpheC9FaW56ZW/xwdWJsaWthdGlvbi9Eb3dubG9hZD9laW56ZWxwdWJsaWthdGlv/bklkPTU2MzU0.pdf))