Effectiveness of fused magnesium potassium phosphate for marandu grass

Abstract

SUMMARYThe current high price of KCl and great dependence on importation to satisfy the Brazilian demand indicate the need for studies that evaluate the efficiency of other K sources, particularly those based on domestic raw material. For this purpose, a greenhouse experiment was conducted with samples of a sandy clay loam Typic Haplustox, in a completely randomized 4 x 3 x 2 factorial design: four K rates (0, 60, 120, and 180 mg kg -1 ), three sources (potassium chloride (KCl), fused magnesium potassium phosphate (FMPP) and a mixture of 70 % FMPP + 30 % KCl) and two particle sizes (100 and 60 mesh), with three replications. Potassium fertilization resulted in significant increases in shoot dry matter production and in K concentrations, both in soil and plants. The K source and particle size had no significant effect on the evaluated characteristics. Potassium critical levels in the soil and the shoots were 1.53 mmol c dm -3 and 19.1 g kg -1 , respectively.

Efficiency of phonolite as a potassium source for Paiaguás palisadegrass

“…As observed here, other authors have reported the beneficial effect of potassium fertilization on dry weight production in U. brizantha (Orioli Júnior & Coutinho 2009, Megda & Monteiro 2010, Morais et al 2016) and that KCl is a fertilizer more efficient than phonolite (Bianchini & Marques 2019, Boldrin et al 2019. Given the low efficiency of phonolite, adding 30 % of KCl to the blend to provide the K needed for initial plant growth was insufficient to produce the same amount of dry weight obtained with the application of the water-soluble source (KCl) alone.…”

“…It has been suggested that materials insoluble in water that release K slowly, such as phonolite (Martins et al 2015), could be mixed with potassium chloride, a highly water-soluble potassium source, to meet initial crop needs for this nutrient (Orioli Júnior & Coutinho 2009). As such, the hypothesis of this study is that ground phonolite may be used as a K source for forage grasses.…”

Verdete de cedro do abaeté como fonte de potássio: caracterização, tratamento térmico e reação com CaO

“…Os fertilizantes termopotássicos caracterizam-se por insolubilidade em água e solubilidade em ácido cítrico e em solução de citrato de amônio. Esses fertilizantes possuem caráter alcalino [13,14].…”

Siltito glauconítico calcinado e não calcinado como fertilizantes para Urochloa brizantha cv. Marandú

“…Os minerais potássicos presentes no siltito glauconítico apresentam baixa solubilidade em água, o que torna necessário o beneficiamento da rocha para a liberação do potássio (ORIOLI JUNIOR;COUTINHO, 2009;SILVA et al, 2012a). Os ensaios de liberação de K2O em solução ácida dessa rocha mostraram que somente uma parcela desse nutriente encontra-se na forma solúvel (SILVA et al, 2012a).…”