Alternative sources of potassium for maize cultivation

Abstract

Brazil is the largest importer of potassium (K) fertilizers in the world, importing about 95% of all the potassium consumed by its agriculture. Thus, new sources and technologies to increase K availability have been studied. This study aimed to evaluate the agronomic viability of the use of calcined glauconite and phonolite blended and granulated with two organic materials on maize growth in pots, using two soils of contrasting texture in a controlled environment. Were evaluated eight sources of potassium: phonolite; phonolite + poultry manure; phonolite + cattle manure; calcined glauconite; calcined glauconite + poultry manure; calcined glauconite + cattle manure; negative control (no K); and positive control (K - KCl), and two soils of contrasting texture. The experiment was carried out for 38 d. The following parameters were analyzed: plant height, stem diameter, shoot dry mass, leaf number, leaf contents of nitrogen (N), K and phosphorus (P), and the SPAD chlorophyll meter. In the sandy soil, the source consisting of phonolite + chicken manure was similar to KCl application regarding plant height, stem diameter and shoot dry mass. As for the clayey soil, when both rocks were blended with the organic wastes, they were similar to KCl for shoot dry mass. The use of pure granulated rocks, calcined glauconite and phonolite without blending with the organic residues is not efficient to provide available K to maize plants.

Exchangeable potassium reserve in a Brazilian savanna Oxisol after nine years under different cotton production systems

“…Consumption of K fertilizers in Brazil reached 6.77 million tons of K 2 O in 2018, while worldwide use corresponded to 38.85 million tons of K 2 O (FAO, 2020). National mineral reserves are limited and currently about 95 % of the K fertilizer is imported (Boldrin et al, 2019), which justifies efforts in developing technical approaches to increase the K use efficiency in the Brazilian agriculture.…”

Broadcast application of ground silicate rocks as potassium sources for grain crops

“…Therefore, to meet the high demand of Brazilian agriculture for K fertilizers, alternative sources of the nutrient are required (Kulaif & Góes, 2016;Sipert et al, 2020), with a consequent reduction in costs and in the country's dependence on external markets (Martins et al, 2008(Martins et al, , 2015Mancuso et al, 2014;Dias et al, 2018;Boldrin et al, 2019). Among the alternative sources is rock dusting, a natural fertilization method (Martins et al, 2015;Manning, 2018;Boldrin et al, 2019), which consists of the direct application of finely ground rock or rock dust that normally releases gradually nutrients (Martins et al, 2008;Basak et al, 2017).…”

“…Therefore, to meet the high demand of Brazilian agriculture for K fertilizers, alternative sources of the nutrient are required (Kulaif & Góes, 2016;Sipert et al, 2020), with a consequent reduction in costs and in the country's dependence on external markets (Martins et al, 2008(Martins et al, , 2015Mancuso et al, 2014;Dias et al, 2018;Boldrin et al, 2019). Among the alternative sources is rock dusting, a natural fertilization method (Martins et al, 2015;Manning, 2018;Boldrin et al, 2019), which consists of the direct application of finely ground rock or rock dust that normally releases gradually nutrients (Martins et al, 2008;Basak et al, 2017). In Brazil, alkaline K-silicate rocks, such as phonolite and others found in the alkaline massif of the municipality of Poços de Caldas, in the state of Minas Gerais (Kulaif & Góes, 2016), stand out due to their high contents of K and other plant nutrients such as silicon (Mancuso et al, 2014;Martins et al, 2015;Ciceri et al, 2017), as well as for their large reserves (Kulaif & Góes, 2016).…”

Silicate rocks as an alternative potassium fertilizer for upland rice and common bean crops

“…Moreover, these Cl-free sources may be interesting options for organic agriculture, where KCl is not allowed (Ciceri et al, 2017). However, the obtained results are still inconclusive (Mancuso et al, 2014;Duarte et al, 2015;Martins et al, 2015;Boldrin et al, 2019;Ciceri et al, 2019) and experiments under field conditions continue scarce.…”