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Rock powders, named as remineralizers, have been studied due to the constant research for alternatives to supply nutrients, which present several different responses according to material. Thus, this study aims at determining which nutrients are released and extracted by crops with the application of the studied basalt, due to the obtained differences. So, in order to evaluate the effect of basalt powder, this study included four experiments in a 2 × 4 + 2 factorial arrangement: two soils (clay and sandy), four doses (Remineralizer: 0, 33, 66, and 99 Mg ha-1; limestone: 0, 1, 2, and 4 Mg ha-1) and 2 treatments fertilized with K2O and P2O5 at a 80 kg ha-1 dose, in soybean and corn, with four replications. The supplies have improved soil proprieties and provided gains in shoot dry matter mass of both crops, but cropped corn in sandy soil. Some obtained benefits were: increase in pH in all essays, increase in Ca2+ in soil due to the supplies application. There was also a small release of K by remineralizar, which was efficient to keep the levels of this nutrient in soil, despite its increased extraction. This interfered on reducing its levels as it was observed when limestone was applied. Finally, there were increases in P levels only in soils with REM application. [ABSTRACT FROM AUTHOR]

The use of rock dust in agriculture as a soil remineralizer can reduce costs with the use of fertilizers, being an excellent alternative for improving soil fertility, especially for agroecological agriculture. In this sense, the study aimed to carry out a systematic review of the literature on the use of rock dust as a soil remineralizer in order to optimize the performance of forage plants. For this, the literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. To identify the articles on the subject of "Application of rock stone in forage farming", searches were carried out in the SCIELO and EMBRAPA databases. After developing an established article search strategy, identification of inclusion and exclusion criteria, critical evaluation of the results, thirty articles were selected for study and refinement proposed in the work. As for the general characteristics, two publications dated from the year 2000 and another twelve articles were published in the last 5 years, and the others between 6 and 10 years or over 10 years. Most of the articles selected in the present study are written in English and 75% of them were from studies conducted in Brazil. It was observed that the literature is extensive regarding the use of rock dust in agriculture, however, when it comes to its application in the production and management of pasture intended for the production of forage to be harvested mainly by grazing, the articles are scarce. In the technical analysis of the articles, it was found that most of them present positive aspects of the application of rock dust in the cultivation of forage plants. More studies are needed to confirm this fact, since publication bias must be taken into account. [ABSTRACT FROM AUTHOR]

Remineralizers are comminuted rocks that are applied to soil, and their use as an agricultural amendment was regulated in Brazil in 2013. However, mechanisms of action of these materials must be better known to enable them to be best used in agricultural fields. Soil chemical attributes of an Oxisol were monitored after the application of a diabase remineralizer. The increase in exchangeable Na observed was associated with the dissolution of the border of the plagioclase crystals where this element is highly concentrated (albite). Therefore, it was inferred that the time since the application of the remineralizer (1 to 2 years depending on the treatment) was not sufficient to exhaust this crystal volume. Unfortunately, the presence of several sources of Ca-containing minerals in the remineralizer did not allow to infer if the calcic nuclei was dissolving. An increase in effective cation exchange capacity was observed without the concurrent increase in the pH of the soil. The two non-exclusive hypotheses proposed to explain this result were that an extra surface charge has originated on the surface of the newly precipitated oxidic phases and/or from the dissolution of the remineralizer grains. Rapid precipitation of amorphous solids (as measured by the increase in Alo and Feo) would also explain the lack of increase in exchangeable Fe and Al despite the large amount of Al2O3(11.90%) and Fe2O3 (14.45%) in the remineralizer. [ABSTRACT FROM AUTHOR]

Some strains of nitrogen fixing bacteria, besides fixing the N2, can produce phytohormones, control pathogens, act in solubilization of minerals containing phosphorus (P) and potassium (K), contributing to plant growth. However, the solubilization of minerals containing K has been little exploited. Therefore, the aim of this study was to evaluate potassium solubilization (K) of phonolite rock by strains of associative nitrogen fixing bacteria supplied with two different carbon sources. Twelve bacterial strains were cultured for seven days at 25°C in Aleksandrov medium supplemented with phonolite rock powder. The experiment was carried out in a completely randomized factorial design, 13 x 2 (12 bacterial strains and a control without inoculation) and two carbon sources (glucose and sucrose) with four repetitions. After the growth, the supernatant was separated by centrifugation and analyzed for the final pH value and the content of K. All diazotrophic bacteria strains contributed to increase the release of K when compared to the control treatment. The strain UNIFENAS 100-94 solubilized 130 mg L-1 K in the presence of the two carbon sources, indicating the potential use of these diazotrophic bacterial strains for K solubilization from minerals. [ABSTRACT FROM AUTHOR]

Knowledge of a rock's composition allows for inferences regarding several properties, ranging from its physical characteristics to its solubility. This study aimed to evaluate the use of different extractants to solubilize the K present in rocks as a potential source of nutrients and the effects of extractant contact time and temperature on rock solubilization. Samples of two rocks and a mineral concentrated from a granitic rock were treated with ammonium dihydrogen phosphate (NH4(H2PO4)), calcium dihydrogen phosphate (Ca(H2PO4)2), sodium hydroxide (NaOH) and water (control). Sample-extractant treatments were performed using a water bath shaker at temperatures of 25 and 50°C for periods of 3, 7, 10, 20, and 30 days. The amounts of K extracted from rocks using the extractants were in the following order: NH4H2PO4>Ca(HPO4)2>NaOH>water. The sequence of K release (ppm) based on the rocks studied was as follows: nepheline syenite>green banded argillite>concentrated biotite. Increasing the extractant contact time and temperature enhanced the solubilized K content. [ABSTRACT FROM AUTHOR]

Seed phytate and protein content in beans depending on the application of basalt powder. The content of phytate in the grains is correlated with the supply of phosphorus to the plant, but there is a lack of knowledge as to possible effect of slower availability of nutrients in the soil. The objectives of this study were to assess the effect of rock powder, alone or combined with cattle manure, on the productivity, levels of phosphorus, protein and phytate content in beans. The experiment was carried out in a randomized blocks design, with four replications. The treatments were control (limestone, granite and natural phosphate); conventional fertilization; powder basalt (2.5, 5.0, 10.0 and 20.0 ton. ha-1); cattle manure, and doses of powder basalt with cattle manure. In the treatment with conventional fertilizer, the total phosphorus content in grain was higher than the control, but the application of powder of basalt did not show a difference significant. Increase in the doses of basalt powder increased the phosphorus content, but phytate content remained constant. Basalt powder proved to be an alternative to maintain low levels of phosphorus in the form of phytate in the grains. [ABSTRACT FROM AUTHOR]