Search

Made available in DSpace on 2022-04-28T19:49:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 The manufacture of asbestos materials has been banished worldwide due to their toxicity, but discarding the existing wastes remains a challenge. We investigated an alternative mechanochemical method to treat asbestos-cement materials by loading them with potassium and phosphorus from KH2PO4 during the milling process to obtain a product used as liming and soil conditioner. The results showed total asbestos fibrous elimination after 7 to 8 h of milling. The materials showed a slow-release fertilizer profile. The liming property is maintained when the asbestos-cement weight proportion used is equal to or higher than KH2PO4. A comparative soil experiment with limestone also indicates that lower doses of the K- and P-enriched detoxified asbestos cement were required to reach similar liming effects. Maize cultivation (greenhouse) was used to evaluate its performance showing higher biomass production for the sample loaded with potassium and phosphorous. Embrapa Instrumentation, 1452 XV de Novembro Street, SP Agricultural Research and Rural Extension Company of Santa Catarina, 6800 Highway, Antônio Heil, Santa Catarina São Paulo State University - UNESP Botucatu Av. Universitária, 3780 - Altos do Paraíso, SP São Paulo State University - UNESP Botucatu Av. Universitária, 3780 - Altos do Paraíso, SP

Made available in DSpace on 2021-06-25T10:15:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-14 Nissan North America Food security is one of the biggest challenges for the next few decades, especially with the accelerated population growth rates. Therefore, achieving a better nutrient use efficiency is crucial to enhance crop yields and productivity, which depend directly on how macronutrients are supplied. It is notably complex because fertilizers are often applied as granules instead of more soluble powdered forms. Here, we propose a new model for an all-in-one NPK fertilizer production, which allows quickly adjustable compositions in multi-nutrient granules. Thus, thermoplastic starch has been used as a biodegradable matrix binder mixed with the fertilizers in a continuous process by extrusion. Urea and KCl were considered as N and K sources, respectively. P sources with different solubilities (triple superphosphate (TSP) and Bayovar and Patos phosphate rocks) have been tested and compared. The greenhouse experiment revealed that the TSP composite promoted superior biomass production than the standard application, in addition to an overall better nutrient uptake. While Bayovar did not benefit from the all-in-one granule, Patos results were improved in this system, revealing a boost in its solubilization. Embrapa Instrumentation Agricultural Research and Rural Extension Company of Santa Catarina Federal University of Saõ Carlos Department of Chemistry UNESP Botucatu Av. Universitaria Embrapa Pecuaria Sudeste UNESP Botucatu Av. Universitaria