Potential of basalt powder as a soil remineralizer in collard greens production systemsABSTRACT
This study aimed to evaluate different rates of basalt powder as a complementary source of mineral fertilization and its relationship with the nutritional status and agronomic traits of collard greens (Brassica oleracea var. acephala). The experiment was conducted in a completely randomized design, assessing six rates of basalt powder: T1 = 0; T2 = 2.0; T3 = 4.0; T4 = 6.0; T5 = 8.0; and T6 = 10.0 t/ha, with four replications. Three harvests of leaves were performed at approximately 30-day intervals, and the plant material was analyzed for nutritional status at harvest time, number of leaves per plant (NP), vertical length (VL), and horizontal length (HL), as well as fresh mass (FM) and dry mass (DM) of collard greens leaves. The application of basalt powder as a complementary source of mineral fertilization in collard greens cultivation promoted increases in VL and HL, with FM and DM of the leaves reaching maximum values of 33.11 and 23.40 cm, and 776.22 and 120.97 g/plant, respectively, up to the maximum applied rate of 6 t/ha. N, K, Ca, S, and Cu leaf contents increased, while that of P, Mg, Mn, Zn, B, and Mo levels decreased as basalt powder rates increased. Similarly, the accumulation of P, Mg, Mn, Zn, B, and Cu in the plant decreased with increasing basalt powder application. The use of basalt powder as a soil remineralizer to supplement mineral fertilization is feasible up to a dose of 6 t/ha.
Keywords:
Brassica oleracea var. acephala; rockdust; sustainable agriculture; vegetables; management system; Cerrado biome
RESUMO
O objetivo deste estudo foi avaliar diferentes doses de pó de basalto como fonte complementar da adubação mineral e sua relação com o estado nutricional e atributos agronômicos da couve-manteiga. O estudo foi conduzido no delineamento inteiramente casualizado, sendo avaliadas seis doses de pó de basalto: T1 = 0; T2 = 2,0; T3 = 4,0; T4 = 6,0; T5 = 8,0 e T6 = 10,0 t/ha, com quatro repetições. Foram realizadas três colheitas de folhas em intervalos aproximados de 30 dias e nesse material vegetal avaliou-se o estado nutricional da planta no momento da colheita, o número de folhas por planta (NP), o comprimento vertical (CV) e horizontal (CH), a massa fresca (MF) e massa seca (MS) das folhas da couve-manteiga. Observou-se que o uso do pó de basalto como fonte complementar da adubação mineral no cultivo da couve-manteiga proporcionou aumento do CV e CH, com MF e MS das folhas atingindo o valor máximo de 33,11 e 23,40 cm, com 776,22 e 120,97 g/planta, respectivamente, até a dose máxima aplicada de 6 t/ha. Os teores foliares de N, K, Ca, S e Cu aumentaram, enquanto os de P, Mg, Mn, Zn, B e Mo diminuiram à medida que as doses de pó de basalto aumentaram. O acúmulo de P, Mg, Mn, Zn, B, Cu na planta diminuiu à medida que as doses de pó de basalto aumentaram. O uso do pó de basalto como remineralizador do solo em complemento à adubação mineral é viável até a dose de 6 t/ha.
Palavras-chave:
Brassica oleracea var. acephala; rochagem; agricultura sustentável; hortaliças; sistema de manejo; Cerrado
Brassicas are short to medium-cycle crops that require high amounts of mineral fertilizers to meet their nutritional demands within relatively short periods (Ferreira Júnior et al., 2023). For these nutrients to be absorbed by plants, fertilizers must be highly soluble. However, in vegetable production, fertilization is often supplemented with cattle and poultry manure and organic composts (Vieira et al., 2020).
New technologies are being developed and used in vegetable cultivation to meet this demand for nutrients, among which organomineral fertilizers and soil remineralizers have gained prominence (Silva et al., 2020). These products are characterized by their slow solubilization, providing a steady and gradual release of nutrients throughout the crop cycle (Santos et al., 2022; Vieira et al., 2023).
The regulation of organomineral fertilizers in Brazil is mainly established by Law no. 6984 of December 10, 1980 and its amendments, together with Normative Instruction no. 61 of July 08, 2020 which defines that fertilizers must have 8% carbon content, 30% maximum moisture, 80 mmolc/kg cation exchange capacity, 10% primary macronutrients and 6% micronutrients (MAPA, 2020).
For remineralizers, Law 12.890 of October 12, 2013, regulated by Normative Instruction No. 05 of October 12, 2016, established that these materials of mineral origin must have undergone only reduction and classification of particle size by mechanical processes and that they may alter fertility indices, promote improvement of the physical-chemical properties or biological activity of the soil (MAPA, 2016). These laws and their regulations established minimum guarantees for organomineral and remineralizing products, which allowed for their production, registration, and commercialization for agriculture (Theodoro et al., 2021).
Basalt powder is one of the soils remineralizers that contains significant concentrations of calcium (Ca) and magnesium (Mg), as well as lower levels of potassium (K). These elements contribute to soil acidity correction and increase the soil cation exchange capacity (Hanisch et al., 2024). In addition, basalt powder supplies micronutrients and silicon (Si) (Santos et al., 2022), which, when applied to vegetable crops, has stood out as a technology with potential economic, environmental, and agronomic benefits across various cropping systems, especially when used in conjunction with highly soluble mineral fertilizers (N-P-K) (Lajús et al., 2021). Its slow nutrient release reduces leaching losses and promotes sustained nutrient uptake throughout the plant life cycle (Brito et al., 2019).
The release of nutrients retained in rock powder depends on the type of rock and the contact surface of the particle, because the smaller its size, the faster the nutrients will be available. However, further studies are still needed to better characterize the efficiency of these products as a supplement to mineral fertilization (Franco Júnior et al., 2024). When reduced to the powder form, basalt rock can provide reasonable amounts of nutrients to the soil, as well as provide negative colloids that allow the adsorption of Ca, Mg, K, and other nutrients, preventing them from being leached by water (Swoboda et al., 2022; Hanisch et al., 2024).
Studies have shown that rock dust slowly releases large amounts of nutrients to plants, which can increase the cation exchange capacity of low-fertility soils and soil pH. These effects are more intense in basic volcanic rocks, such as basalt (Van Straaten, 2006). Ground basalt improves the chemical properties of dystrophic Yellow Latosol by increasing the levels of Ca, Mg, Zn, Fe, and Cu, and by contributing to the neutralization of potential soil acidity (Melo et al., 2012).
In vegetables, practices involving the use of basalt powder are recent, showing the need for further evaluation, especially studies related to the concentrations used and crop production, given the positive potential of the product (Marchi et al., 2020; Lajús et al., 2021; Hanisch et al., 2024), however, the study results published in the literature are scarce. In this context, this study aimed to evaluate the use of different rates of basalt powder as a complementary source of mineral fertilization and to assess its relationship with the nutritional status and agronomic traits of collard greens.
MATERIAL AND METHODS
The study was conducted at the experimental area of the Fundação de Excelência Rural de Uberlândia (FERUB), located at the Fazenda Buriti, BR 050, km 63, in the municipality of Uberlândia, Minas Gerais State, Brazil (19°05′16″S, 48°21′11″W, altitude of 804 m), from July to November, 2022.
The soil at the experimental site was classified as an Oxisol (Santos et al., 2018) with clayey texture. At a depth of up to 20 cm, particle size analysis revealed 460, 128, and 412 g/kg of sand, silt, and clay, respectively. The chemical properties were pH (H₂O): 5.75; 3 mg/dm3 of P (Mehlich); 89.25 mg/dm3of K; 2.89 cmolc/dm3of Ca; 0.79 cmolc/dm3of Mg; 2.83 cmolc/dm3of H + Al; effective cation exchange capacity of 3.91 cmolc/dm3; potential cation exchange capacity of 6.31 cmolc/dm3; and base saturation (V%) of 63%. The micronutrient contents were 0.34, 4.30, 25.00, 9.60, and 1.52 mg/dm3 of B, Cu, Fe, Mn, and Zn, respectively.
The climate of the region is classified as Aw, tropical savanna with hot temperature regime, according to the updated Köppen classification (Beck et al., 2018). It is characterized by rainy summers and dry, cool winters, with an average annual temperature of 22.3°C and a total annual rainfall of 1,342 mm (INMET, 2024). However, during the study period from July to November 2022, the accumulated rainfall was 303.4 mm, and the average temperature was 23.38°C (Figure 1).
Monthly rainfall (mm) and temperature (°C) from July to November 2022 in Uberlândia, Minas Gerais State, Brazil. Source: INMET (2024).
The study was conducted in the field using a randomized block experimental design, with six treatments: T1 = 0.0; T2 = 2.0; T3 = 4.0; T4 = 6.0; T5 = 8.0; and T6 = 10.0 t/ha of basalt powder, all with four replications.
The basalt powder used in the study had the following chemical characteristics during soil application (Table 1).
Physicochemical characterization of the basalt powder applied to the Oxisol with a clayey texture. Uberlândia, UFU, 2022.
According to Normative Instruction (NI) No. 5, dated December 10, 2016 (MAPA, 2016), the remineralizer meets the requirements for the classification of basalt powder for agricultural use. The product falls under Class "E" as it is composed exclusively of raw materials of mineral or synthetic origin and also complies with Article 4 in terms of guarantees related to the sum of bases (CaO, MgO, K₂O), which must be equal to or greater than 9% by weight. The K₂O content must be equal to or greater than 1% by weight, and the measured pH was 9.3.
Regarding heavy metals, Normative Instruction No. 5 establishes a maximum allowable Arsenic (As) content of 15 mg/kg. The levels of Cadmium (Cd) and Lead (Pb) in the basalt powder were 80% and 94% lower, respectively, than the limits set by the regulation, while the mercury (Hg) content was below 0.1 mg/kg.
On February 7, 2022, liming was performed in the experimental area following a pre-established schedule by the technical team of the Municipal Government of Uberlândia, MG, Brazil. A rate of 1.0 t/ha of dolomitic limestone was applied based on the soil chemical analysis and following the recommendation for collard greens cultivation (Ribeiro et al., 1999).
Before transplanting the seedlings to the field on July 12, 2022, standard basal mineral fertilization was applied by broadcasting. All plots received the same planting fertilization, following the recommendation for collard greens by Ribeiro et al. (1999), at a rate of 111 g/m2 of the 8-28-16 fertilizer formulation. This corresponds to 88.8 kg/ha of N, 310.8 kg/ha of P₂O₅, and 177.6 kg/ha of K₂O. Additionally, 1,000 g/m2 of the organic compost Forte C (1.5% N, 2.5% P₂O₅, 0.8% K₂O, 1.0% Mg, 1.0% S, and 4.0% Ca) was incorporated into the soil across all treatments.
Topdressing fertilizations were broadcast after each harvest using the 20-05-20 formulation at a rate of 20 g/m2 per raised bed in treatments T1 through T6.
Limestone was applied by broadcasting at a 1.0 t/ha rate. Subsequently, raised beds were manually prepared, each measuring 1.0 meters in width and 6.0 meters in length per planting row. The corrective material was then incorporated into the soil to an average depth of 10 cm.
The irrigation system was a micro-sprinkler type, with water supplied daily in the early morning and late afternoon, considering weather conditions and crop needs, to maintain the soil at field capacity.
The collard greens seedlings (Brassica oleracea var. acephala L.). hybrid “Hi Crop” were acquired from the Hortiflora seedling nursery in Uberlândia, MG, Brazil. When the seedlings had developed three fully expanded leaves, on July 13, 2022, they were transplanted to the field at a spacing of 0.50 m between rows and 0.60 m between plants, with ten plants per row, totaling 20 plants per plot, considering the six central plants as a useful portion.
On September 12, 2022, excess collard greens leaves were removed, and the organic insecticide Pironim, combined with detergent and oil, was applied at 500 mL/100 L of water to prevent/control pests from attacking the crop. On September 14, 2022, the insecticide Decis was applied at 30 mL per 100 L of water. Decis is a contact and ingestion insecticide from the pyrethroid chemical group, with deltamethrin as its active ingredient. It was applied alternately between harvest and evaluation due to the incidence of cabbage aphids (Brevicoryne brassicae). Weed control in the raised beds was conducted through weekly manual weeding.
The agronomic characteristics of marketable collard greens leaves were assessed at three time points: starting 30 days after transplanting (DAT) on August 23, 2022; 62 DAT on October 24, 2022; and 86 DAT on November 17, 2022. Regular harvests of marketable leaves measuring between 20 and 30 cm in length were carried out every 10 days, to obtain a cumulative total every 30 days, throughout the approximately 100-day crop cycle.
At each harvest, the following parameters were measured: number of leaves/plant (NP); vertical length (VL) of the leaves, measured from the base of the petiole to the leaf apex; horizontal length (HL) of the leaves, corresponding to their widest point, measured with a measuring tape; fresh mass (FM); and dry mass (DM) of the leaves, using a precision scale accurate to two decimal places.
Samples were collected from the third or fourth leaf of the plant, from the apex of the plant to the roots, fully developed, before each harvest, in all experimental plots, to analyze the nutritional status of the plant (Trani et al., 2015). These samples were first washed in running water, followed by a detergent solution (3 mL/L), deionized water, a 0.1 M HCl solution, and distilled water. The samples were placed in a forced-air circulation oven at 65°C until constant weight was reached for dry mass (g) determination.
Once dried, the plant material was ground and sent to the foliar analysis laboratory for the determination of silicon content (%) following the method described by Korndörfer et al. (2004), as well as macro and micronutrient concentrations using the methodology developed by Teixeira et al. (2017).
Soil samples were collected in the 0-20 cm layer in each plot of the experimental area across all treatments immediately after the third leaf harvest (November 3, 2022), when the plants had reached approximately 100 DAT. These samples were analyzed for pH in water, as well as macro (N, P, K, Ca, Mg, and S) and micronutrient (Cu, Mn, Zn, B, and Mo) contents, according to the methodology described by Teixeira et al. (2017). The silicon (Si) percentage in the soil was also evaluated using extraction with 0.01 mol/L of CaCl₂ and 0.5 mol/L of CH₃COOH solutions, as proposed by Korndörfer et al. (2004).
The data were subjected to tests for residual normality and homogeneity of variances using the Shapiro-Wilk and Bartlett tests, respectively. Subsequently, analysis of variance (ANOVA) was performed, and when significant, means were compared using the Tukey test (α = 0.05) with the aid of the R Core Team software (2024).
RESULTS AND DISCUSSION
No significant differences were observed among the treatments evaluated when analyzing the number of leaves per plant (NP), which varied between 11 and 13 leaves. However, for the vertical length (VL) and horizontal length (HL) of collard greens leaves, the highest values were recorded with the application of 4 t/ha (33.00 and 23.23 cm) and 6 t/ha (33.87 and 23.97 cm) of basalt powder. These values were statistically similar and significantly higher than those observed in the other treatments (0, 2, 8, and 10 t/ha) (Figure 2).
Regarding fresh mass (FM) and dry mass (DM), the treatment with 6 t/ha of basalt powder stood out, showing the best results (p < 0.05), with yields of 810.92 and 118.17 g/plant, respectively. These values were significantly higher than those obtained with the 4 t/ha treatment, which produced 751.40 and 102.97 g/plant, superior to the remaining treatments. It is also worth noting that the treatments with the lowest (0 and 2 t/ha) and highest (8 and 10 t/ha) rates showed statistically similar values for all agronomic traits evaluated (NP, VL, HL, FM, and DM).
Number of leaves per plant (NP), vertical length (VL) and horizontal length (HL) (A), fresh mass (FM) and dry mass (DM) (B) of collard green leaves from three harvests under basalt powder rates. Uberlândia, UFU, 2022.
The application of basalt powder as a complement to basal fertilization at a rate of 6 t/ha influenced all agronomic parameters evaluated (VL, HL, FM, and DM), except for NP (Figure 2)
In a similar study, when evaluating four doses of basalt powder (0, 5, 10, and 20 t/ha) with and without soluble fertilization in two soil types in the production of cabbage and lettuce, it was observed that there was an increase in DM production of crops when grown in Neosol up to a dose of 10 t/ha, whereas this did not occur in Cambisol. In both soils, 115 days after incorporation of the doses, basalt powder was effective in altering soil attributes, with this effect being more pronounced in Neosol, with a quadratic increase in pH and P, K, Ca, and base saturation (V%) contents as the applied doses increased (Hanisch et al., 2024).
When using different substrates associated with the application of rock powder in seedling production and Chinese cabbage development in the field, the results showed that the addition of rock powder is a determining factor in seedling performance. The best results were obtained in substrates formulated with 7 and 9% basalt powder (Tessaro et al., 2013).
The values obtained for NP (from 10.92 to 12.69), MF (from 689.40 to 810.92 g/plant), and leaf DM (from 92.60 to 118.17 g/plant) are lower for NP and higher for DM when compared to 19.80 and 27.30 g/plant obtained by Mascari et al. (2022), and lower than 17.01 g of NP and higher than 79.32 and 181.94 g of DM and FM, respectively, obtained by Benício et al. (2011). This indicates that there are variations in the results, depending on the conditions and fertilizers used in the study.
Applying regression analysis to the basalt powder rates resulted in a polynomial fit curve, which allowed the determination of the maximum values for vertical length (VL) and horizontal length (HL) of 33.11 and 23.40 cm, respectively. These maxima were reached at 5.4 and 5.2 t/ha basalt powder rates, with correlation coefficients (R²) of 67% and 70%, respectively. Beyond these rates, the values declined (Figure 3A).
Regarding vertical length (VL), the average of the three harvests presented average values ranging from 30.78 to 33.87 cm, which are similar to those found in cabbage leaves grown with different doses of goat manure, where the highest CV (height) obtained was 32.08 cm (Carvalho et al., 2021). The maximum CV obtained was 33.11 cm (Figure 3A), which occurred at a dose of 5.4 t/ha of basalt powder, which was higher than the value of 32.08 cm cited by the author. The ideal size for commercialization of the leaf is when it has a CV of 30.00 cm (Trani et al., 2015), values observed in this study.
Regression analysis and polynomial fit curves for vertical length (VL) and horizontal length (HL) (A), fresh mass (FM), and dry mass (DM) of collard green leaves (B) under basalt powder rates. Uberlândia, UFU, 2022.
A polynomial fit curve was obtained through regression analysis of the basalt powder rates, allowing the determination of maximum values for fresh mass (FM) and dry mass (DM) of 776.22 and 120.97 g/plant, respectively. These maxima were reached at 5.69 and 5.97 t/ha basalt powder rates, with R² values of 71% and 82%, respectively. Beyond these rates, the values declined (Figure 3B).
In a study evaluating alternative substrate conditioners (carbonized rice husks, coconut husk fiber, pure organic compost, chopped ouricurí palm stumps, decomposed sumaúma stems, and commercial substrate) on seedling quality and productivity of butter lettuce, it was observed that FM values ranged from 362.5 to 656.7 g/plant and dry mass (DM) values between 64 and 79 g/plant. These values are all lower than those observed in the present study, where the use of basalt powder as a complementary fertilization source resulted in significantly higher values for these parameters at application rates of 4 and 6 t/ha (Silva et al., 2016).
The average foliar nutrient content in collard green leaves over the three harvests showed that for nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg), the values were statistically equal where doses of 4 and 6 t/ha were applied, while for phosphorus (P), the same occurred for doses of zero (4.05 g/kg), 2.0 t/ha (3.80 g/kg) and 4 t/ha (3.90 g/kg), and for sulfur (S) at doses of 6.0 (13.40 g/kg), 8.0 (13.12 g/kg), and 10.0 t/ha (13.17 g/kg) (Table 2).
These foliar macronutrient contents can be justified by the nutrient content found in the soil used in the study, which, added to the values of K (11.0 g/kg), CaO (90.0 g/kg), and MgO (57.0 g/kg) present in basalt powder (Table 1), contributed to having nutrients available in adequate amounts for absorption by the plant.
Taking as reference the sufficiency range for macronutrients in collard greens proposed by Trani et al. (2015), 30 to 55 g/kg for N, 3 to 7 g/kg for P, 20 to 40 g/kg for K, 15 to 25 g/kg for Ca, and 3 to 7 g/kg for Mg it can be stated that, at the time of harvest, the plants were within the nutritional sufficiency range for all macronutrients. Nutritional analysis at harvest revealed values ranging from 30.90 to 36.00 g/kg for N, 3.25 to 4.05 g/kg for P, 31.55 to 36.77 g/kg for K, 18.00 to 20.37 g/kg for Ca, 3.37 to 4.47 g/kg for Mg, and 12.12 to 13.40 g/kg for S (Table 2). Thus, it can be affirmed that both mineral fertilization and basalt powder contributed to achieving this adequate nutritional status.
With regard to the accumulation of macronutrients in the leaves, it was observed that only for P and Mg were there differences (α = 0.05) between the doses evaluated, with the highest accumulation for P occurring at doses of zero, 2.0, and 4.0 t/ha (100.97, 98.51, and 91.40 kg/ha) and for Mg at doses of zero and 2.0 t/ha (112.69 and 112.35 kg/ha) of basalt powder applied, respectively, while for the other nutrients (N, K, Ca, and S) there were no significant differences between them. These variations in the accumulated nutrient values are justified by the different quantified dry matter contents of the plant.
Analyzing nutrient content through regression analysis of the basalt powder application rates, polynomial fit curves were observed for N, K, and Ca (Figure 4A). The maximum foliar contents of 35.03, 35.66, and 19.73 g/kg were reached at basalt powder rates of 6.12, 5.25, and 6.52 t/ha, with R² values of 70%, 80%, and 54%, respectively. Beyond these rates, the nutrient levels declined. The curves exhibited a linear fit for P, Mg, and S (Figure 4B), with R² values of 67%, 96%, and 52%, respectively. While increasing basalt powder rates increased foliar sulfur content, foliar phosphorus, and magnesium levels decreased.
High doses of basalt powder can cause a decrease in the leaf content of some nutrients in some plants at harvest, mainly due to nutritional imbalance and the antagonistic effect between nutrients in the soil, in addition to possible changes in soil pH, because, in general, basalt is rich in various minerals, including Ca, Mg, and K, and excessive application of one of these cations can inhibit the absorption of others by the plant (Toscani & Campos, 2017). Even so, the maximum foliar contents of macronutrients N, K, and Ca at harvest were within the sufficiency ranges proposed by Trani et al. (2015).
Regarding nutrient accumulation in the plant, regression curves showed a polynomial fit for phosphorus (P) and magnesium (Mg) (Figure 4C). It was observed that increasing basalt powder rates led to a decrease in the accumulation of these nutrients, reaching minimum values of 79.97 and 85.78 g/kg at application rates of 7.21 and 8.53 t/ha, respectively, with R² values of 90% and 91%. Beyond these rates, the accumulation values increased again (Figure 4C).
Divergent results for P and similar results for Mg were observed by Toscani & Campos (2017) in their study, in which they found that the application of basaltic rock powder generally increased the pH and available P in the soil, in addition to decreasing aluminum (Al) saturation. However, the same did not occur with Mg, which did not show statistically higher values. For P, the authors justified that natural phosphate dissolves more readily under low pH conditions, while for Mg they argued that there may be some antagonistic effect between nutrients when there is a nutritional imbalance in the soil, citing that excessive Ca can induce Mg and some micronutrient deficiencies, as this imbalance affects the transport and availability of nutrients essential for healthy plant development.
No clear trend was observed in foliar micronutrient content (Cu, Mn, Zn, B, Mo, Si) across basalt powder rates, suggesting no defined optimum for collard greens under the conditions studied. However, it was evident that the lowest levels of all evaluated micronutrients were found at the highest application rate of 10 t/ha (Table 3).
Regarding micronutrient accumulation in the leaves, significant differences among treatments were observed only for Mn, Zn, B, and Mo. The highest accumulations were recorded at the 2 t/ha basalt powder rate, with values of 2331.07; 945.18; 462.42; and 27.71 g/ha, respectively. In contrast, the lowest accumulations of these nutrients were observed at the 6 t/ha rate, with values of 1240.21; 675.70; 313.04; and 7.77 g/ha, respectively. No significant differences were found in the accumulation of Cu or Si across the evaluated rates (Table 3).
Foliar content of macronutrients N, K, and Ca (A); P, Mg, and S (B); and accumulation of P and Mg (C) in collard greens plants across three harvests grown in soil with basalt powder rates. Uberlândia, UFU, 2022.
The brassicas are generally characterized by a high capacity to absorb nutrients from the soil, with macronutrient uptake typically following the order: K > N > Ca > S > Mg > P, and micronutrient uptake following: Zn >Mn> B > Cu > Mo (May et al., 2007). Among these, K, Ca, and Mg were present in the highest concentrations in the basalt powder applied (Table 1), whereas Zn and Mn exhibited the highest foliar contents and accumulation in the leaves (Table 3).
Evaluating the potential of basalt powder as a soil remineralizer in lettuce and cabbage production systems, it was observed that there was no significant increase in foliar contents of P, K, Mn, and Fe with the sole application of basalt powder, not even at the highest rates unlike the results observed in the present study (Hanisch et al., 2024).
Analyzing the foliar content of micronutrients, polynomial regression curves were observed for Mn, Zn, B (Figure 5A), and Cu (Figure 5B). The nutrient levels decreased until reaching minimum values of 31.71, 31.74, 13.65 and 0.37 mg/kg at basalt powder application rates of 7.10, 8.04, 7.06 and 7.61 t/ha, respectively, with R² values of 50%, 51%, 73%, and 90%. Beyond these rates, the values declined. In contrast, Mo content increased up to a maximum of 3.99 mg/kg at a rate of 5.92 t/ha (R² = 67%), after which it also declined (Figure 5B).
The sufficiency ranges for micronutrient collard greens as follows: 30 to 100 mg/kg for B, 5 to 20 mg/kg for Cu, 60 to 300 mg/kg for Fe, 40 to 250 mg/kg for Mn, 0.4 to 0.8 mg/kg for Mo, and 30 to 150 mg/kg for Zn (Trani et al., 2015; Luengo et al., 2018).
At harvest, the micronutrient levels observed in this study ranged from 13.85 to 17.75 mg/kg for B, 3.35 to 4.05 mg/kg for Cu, 54.87 to 100.10 mg/kg for Mn, 0.32 to 1.05 mg/kg for Mo, and 29.90 to 36.27 mg/kg for Zn. These results indicate that the plants were below the sufficiency range for B and Mo, as shown by the regression curves, which demonstrated that increasing basalt powder rates led to a decrease in Mo and B contents in the plant (Figures 5A and 5B).
The use of basalt powder in high doses has an alkalizing effect on the soil, as it acts to correct its acidity due to the reaction of the Ca and Mg oxides present in the material's composition, releasing hydroxyls (OH) and reducing acidity by increasing the pH. This decreases the availability of B in the soil, as it favors its binding to colloids, reducing its concentration in the soil solution and, consequently, its availability to plants (Lemiska et al., 2014), which was also observed in this study. On the other hand, the increase in pH increases the availability of Mo in the soil, a condition not observed in this study. Even so, the levels observed in the plant were within the range of sufficiency described for the crop (Trani et al., 2015).
Regarding nutrient accumulation in the plant, the regression curves for the micronutrients Mn, Zn, B (Figure 5C), and Cu (Figure 5D) showed a polynomial fit. It was observed that the accumulation decreased until reaching minimum values of 1564.74, 739.64, 314.84 and 8.60 g/ha at basalt powder rates of 6.75, 6.77, 6.66 and 7.41 t/ha, respectively, with R² values of 51%, 62%, 76%, and 96%. Beyond these minimum points, the accumulation values began to increase again.
Foliar content of micronutrients Mn, Zn, and B (A); Cu and Mo (B); and accumulation of Mn, Zn, and B (C) and Cu (D) in collard greens plants across three harvests grown in soil with basalt powder rates. Uberlândia, UFU, 2022.
Increasing soil pH decreases the concentration of many essential micronutrients, making them less available to plants, except Mo. This occurrs because, in more alkaline soils (with high pH), micronutrients such as Fe, B and Zn become less available to plants, a condition observed in this study (Lemiska et al., 2014; Trani et al., 2015; Toscani & Campos, 2017).
Regarding the average foliar contents of micronutrients Cu, Mn, Zn, B, Mo, and Si across the three collard greens harvests, the 10 t/ha basalt powder rate resulted in the poorest outcomes for all evaluated nutrients. No consistent pattern in plant performance was observed for the other application rates.
The average foliar contents and nutrient accumulation in the plant for both macro- and micronutrients across the three collard greens harvests (Table 2) fall within the sufficiency ranges proposed by Ayaz et al. (2006), as reported in their study that determined the nutrient content of collard greens.
The results observed in this study demonstrated that the remineralizer used (basalt powder) when applied as a complement to fertilization in collard greens cultivation, improved the soil’s chemical quality for certain macronutrients (N, K, Ca, and S) (Figure 3) and for the micronutrient Cu (Figure 4). The findings of this research are consistent with those reported by Beerling et al. (2020) and Theodoro et al. (2021), who confirmed the hypotheses tested in their studies. These authors showed that using remineralizers derived from basaltic rocks, whether combined with organic sources or not, effectively supplied macro- and micronutrients to the soil. Furthermore, they demonstrated that rock powders have a longer-lasting residual effect than soluble fertilizers, although this was not evaluated in the present study.
Evaluating doses of up to 8 t/ha of a basalt powder similar to that used in this study in two soils, linear increases were observed in the levels of P, K, Ca, Mg, and V% in the soil, with the highest doses showing a more than 15-fold increase in the concentration of these nutrients in the soil compared to the control (Conceição et al., 2022).
In the study evaluating basaltic rocks for rejuvenating weathered soils, changes in soil fertility profiles were observed one year after the experiments were established. They reported significant differences in the mean content of seven macro- and micronutrients (P, K, Mg, Mo, B, Mn, and Cu) among the 13 key parameters evaluated (P, K, Ca, Mg, S, CEC, organic matter, pH, B, Zn, Fe, Mn, and Cu) in areas where the remineralizer (basalt powder) was applied (Theodoro et al., 2021). Similar results were observed in the present study with collard greens.
Based on the conditions under which this study was conducted, it can be stated that the use of basalt powder as a complementary source of mineral fertilization in the cultivation of butter lettuce resulted in an increase in vertical length (VL), horizontal length (HL), fresh mass (FM), and dry mass (DM) of the leaves, reaching maximum values of 33.11 cm, 23.40 cm, 776.22 g/plant, and 120.97 g/plant, respectively, up to the maximum applied rate of 6 t/ha.
Foliar contents of N, K, Ca, S, and Cu increased, whereas those of P, Mg, Mn, Zn, B, and Mo decreased as basalt powder rates increased. Similarly, the accumulation of P, Mg, Mn, Zn, B, and Cu in the plant declined with increasing basalt powder application rates.
The use of basalt powder as a soil remineralizer to supplement mineral fertilization is feasible up to a dose of 6 t/ha.
ACKNOWLEDGMENTS
The authors would like to thank the Federal University of Uberlândia and the Fundação de Excelência Rural de Uberlândia for providing the necessary infrastructure. We are also grateful to the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) and the National Council for Scientific and Technological Development (CNPq) for the scholarships granted to the students and the Municipal Government of Uberlândia for the partial funding of the project.
REFERENCES
-
AYAZ, FA; GLEW, RH; MILLSON, M; HUANG, HS; CHUANG, LT; SANZ, C; HAYĐRLĐOGLU-AYAZ, S. 2006. Nutrient contents of kale (Brassica oleraceae L. var. acephala DC.). Food Chemistry6: 572-579. DOI: 10.1016/j.foodchem.2005.03.011.
» https://doi.org/10.1016/j.foodchem.2005.03.011 -
BECK, HE; ZIMMERMANN, NE; MCVICAR, TR; VERGOPOLAN, N; BERG, A; WOOD, EF. 2018. Present and future Köppen-Geiger climate classification maps at 1-km resolution. Scientific Data1: 1-12. DOI: 10.1038/s41597-020-00616-w.
» https://doi.org/10.1038/s41597-020-00616-w -
BEERLING, DJ; KANTZAS, EP; LOMAS, MR; WADE, P; EUFRÁSIO, RM; RENFORTH, P; SARKAR, B; ANDREWS, MG; JAMES, RH; PEARCE, CR; MERCURE, JF; POLLITT, H; HOLDEN, PB; EDWARDS, NR; KHANNA, M; KOH, L; QUEGAN, S; PIDGEON, NF; JANSSENS, IA; BANWART, SA. 2020. Potential for large-scale CO2 removal via enhanced rock eathering with croplands. Nature583: 242-248. DOI: 10.1038/S41586-020-2448-9.
» https://doi.org/10.1038/S41586-020-2448-9 - BENÍCIO, LPF; SILVA, LL; LIMA, SO. 2011. Produção de mudas de couve sob efeito de diferentes concentrações de biofertilizante. Revista ACTA Tecnológica - Revista Científica6: 1 - 6.
- BRITO, RS; BATISTA, JF; MOREIRA, JGV; MORAES, KNO; SILVA, SO. 2019. Rochagem na agricultura: importância e vantagens para adubação suplementar. South American Journal of Basic Education, Technical and Technological 6: 1-10.
-
CARVALHO, RS; DIDOLANVI, OD; FRANÇA, KS; RODRIGUES, RMP; OLIVEIRA, RL; REIS, LO. 2021. Efeito de diferentes doses de adubação orgânica no desenvolvimento da couve-manteiga no vale do submédio São Francisco. Agroecologia: métodos e Técnicas para uma Agricultura Sustentável1: 165-171. DOI: 10.37885/210203312.
» https://doi.org/10.37885/210203312 -
CONCEIÇÃO, LT; SILVA, GN; HOLSBA-CK, HMS; OLIVEIRA, CF; MARCANTE, NC; MARTINS, ES; SANTOS, FLS; SANTOS, EF. 2022. Potential of basalt dust to improve soil fertility and crop nutrition. Journal of Agriculture and Food Research10: 100443. https://doi.org/10.1016/j.jafr.2022.100443.
» https://doi.org/10.1016/j.jafr.2022.100443 -
FERREIRA JUNIOR, JJ; TORRES, JLR; CHARLO, HCO; ORIOLI JÚNIOR, V; LOSS, A; BARRETO, AC. 2023. No-till broccoli production using different cover crop residues and nitrogen doses. Horticultura Brasileira41: e2479. DOI: 10.1590/s0102-0536-2023-e2479.
» https://doi.org/10.1590/s0102-0536-2023-e2479 -
FRANCO JÚNIOR, KS; DIAS, MS; FERREIRA, L; PEREIRA, AC; ALMEIDA, SR; SILVA, AA; CAIXETA, EA. 2024. Potencial do Fosbio® para aumentar os níveis de fósforo e boro em um sistema de produção. Pesquisa, Sociedade e Desenvolvimento13: e5213144741. DOI: 10.33448/rsd-v13i1.44741.
» https://doi.org/10.33448/rsd-v13i1.44741 -
HANISCH, AL; CANTÚ, RR; JUSTEN, JGK; GONÇALVES, GLS. 2024. Potencial do pó de basalto como remineralizador de solo em sistemas de produção de hortaliças.Agropecuária Catarinense 37: 25-30. DOI: 10.52945/rac.v37i1.1788.
» https://doi.org/10.52945/rac.v37i1.1788 -
INMET. Instituto Nacional de Meteorologia do Brasil. Normas Climatológicas do Brasil (2020-2024). Brasília, DF. 2024. Available at https://portal.inmet.gov.br/ Accessed on march 15, 2024.
» https://portal.inmet.gov.br/ - KORNDÖRFER, GH. 2004. Análise de silício: solo, planta e fertilizante Uberlândia: Instituto de Ciências Agrárias, Universidade Federal de Uberlândia. 37p.
-
LAJÚS, CR; LUZ, GL; SILVA, CG; DALCANTON, F; BARICHELLO, R; SAUER, AV. 2021. Aspectos qualitativos e quantitativos de variedades de alface submetidas a concentrações de pó de rocha em cultivo orgânico. Brazilian Journal of Development7: 49498-49512. DOI: 10.34117/bjdv.v7i5.29933.
» https://doi.org/10.34117/bjdv.v7i5.29933 -
LEMISKA, A; PAULETTI, V; LUQUEL, FL; ZAWADNEAK, MAC. 2014. Produção e qualidade da fruta do morangueiro sob influência da aplicação de boro. Ciência Rural 44: 622-628. DOI: 10.1590/S0103-84782014000400008.
» https://doi.org/10.1590/S0103-84782014000400008 -
LUENGO, RFA; BUTRUILLE, NMS; MELO, RAC; SILVA, J; MALDONADE, IR; COSTA JÚNIOR, AD. 2018. Determinação de minerais no solo e análise de folhas de couve produzida em Brasília. Brazilian Journal of Food Technology 21: e2017141. DOI: 10.1590/1981-6723.14117.
» https://doi.org/10.1590/1981-6723.14117 - MAPA. Ministério da Agricultura e Pecuária - MAPA. 2016. Instrução Normativa Nº 5 de 10/03/2016. Brasília: MAPA.
- MAPA - Ministério da Agricultura, Pecuária e Abastecimento. 2020. Instrução Normativa n°. 61 de 08/07/2020, Brasília: Diário Oficial da União, edição 134, seção 1, p.5, 15 jul. 2020.
-
MARCHI, G; GUELFI-SILVA, DR; MALAQUIAS, JV; GUILHERME, LRG; SPEHAR, CR; MARTINS, ES. 2020. Solubility and availability of micronutrients extracted from silicate agrominerals. Pesquisa Agropecuária Brasileira v.55, e00807. DOI: 10.1590/s1678-3921.pab2020.v55.00807
» https://doi.org/10.1590/s1678-3921.pab2020.v55.00807 -
MASCARI, B; SANTOS, TMB; SILVA, CP; CORREA, JS. 2022. Desenvolvimento de couve manteiga (Brassica oleracea L.) sob diferentes doses de biofertilizante cultivada em wick system. Revista de Ciência Agroambiental 20: 1-9. DOI: 10.30681/rcaa.v20i2.4943.
» https://doi.org/10.30681/rcaa.v20i2.4943 - MAY, A; TIVELLI, SW; VARGAS, PF; SAMRA, AG; SACCONI, LV; PINHEIRO, MQ. 2007. A cultura da couve-flor Campinas: Instituto Agronômico de Campinas (Série Tecnologia APTA; Boletim técnico IAC, 200).
-
MELO, VF; UCHÔA, SCP; DIAS, FO; BARBOSA, GF. 2012. Doses de basalto moído nas propriedades químicas de um Latossolo Amarelo distrófico da savana de Roraima. Acta Amazônica 42: 471-476. DOI:10.1590/S0044-59672012000400004.
» https://doi.org/10.1590/S0044-59672012000400004 -
R CORE TEAM2024. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/ Available at Accessed on september 28, 2023.
» https://www.R-project.org/ - RIBEIRO, AC; GUIMARÃES, PTG; ALVAREZ, VVH. 1999. Recomendações para o uso de corretivos e fertilizantes em Minas Gerais Viçosa: UFV, 359p.
- SANTOS, HG; JACOMINE, PKT; ANJOS, LHC; OLIVEIRA, VA; LUMBRERAS, JF; COELHO, MR; ALMEIDA, JA; CUNHA, TJF; OLIVEIRA, JB. 2018. Sistema brasileiro de classificação de solos 5ª. ed. rev. e ampl. Brasília: Embrapa, 356p.
- SANTOS, RB; ALMEIDA, JCR; LABINAS, AM; REZENDE JUNIOR, DA; ENARI, EH. 2022. Viabilidade do uso de remineralizadores do solo para a recuperação de pastagem degradada no Estado do Tocantins. Revista Tecnológica Ciências Ambientais 6: 1-15.
-
SILVA, NM; SIMÕES, AC; ALVES, GKEB; FERREIRA, RLF; ARAÚJO NETO, SE. 2016. Condicionadores alternativos de substrato na qualidade da muda e produtividade de couve-manteiga. Revista Verde de Agroecologia e Desenvolvimento Sustentável 11: 149-154. DOI: 10.18378/rvads.v11i5.3963.
» https://doi.org/10.18378/rvads.v11i5.3963 -
SILVA, LG; CAMARGO, R; LANA, RMQ; DELVAUX, JC; FAGAN, EB; MACHADO, VJ. 2020. Biochemical changes and development of soybean with use of pelletized organominerals fertilizer based of sewage sludge and filter cake. Acta Scientiarum Agronomy 42: 1-9. 10.4025/actasciagron.v42i1.44249.
» https://doi.org/10.4025/actasciagron.v42i1.44249 -
SWOBODA, P; DÖRING, TF; HAMER, M. 2022. Remineralizing soils? The agricultural use of silicate rock powders: A review. Science of the Total Environment 807: 150976. DOI: 10.1016/j.scitotenv.2021.15 0976.
» https://doi.org/10.1016/j.scitotenv.2021.15 0976 - TEIXEIRA, PC; DONAGEMMA, GK; FONTANA, A; TEIXEIRA, WG. 2017. Manual de Métodos de Análise de Solos 3.ed. revista e ampliada. Rio de Janeiro: Embrapa, 573p.
-
TESSARO, D; MATTER, JM; KUCZMAN, O; FURTADO, LF; COSTA, LAM; COSTA, MSSM. 2013. Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa. Ciência Rural43: 831-837. DOI: 10.1590/S0103-84782013005000036.
» https://doi.org/10.1590/S0103-84782013005000036 -
THEODORO, SH; SANDER, A; BURBANO, DFM; ALMEIDA, GR. 2021. Rochas basálticas para rejuvenescer solos intemperizados. Revista Liberato22: 45-58. DOI: 10.31514/rliberato.2021v22n37.
» https://doi.org/10.31514/rliberato.2021v22n37 - TOSCANI, RGS; CAMPOS, JEG. 2017. Uso de pó de basalto e rocha fosfatada como remineralizadores em solos intensamente intemperizados. Geociências 36: 259-274.
- TRANI, PE; TIVELLI, SW; BLAT, SF; PRELA-PANTANO, A; TEIXEIRA, EP; ARAÚJO, HS; FELTRA, JC; PASSOS, FA; FIGUEIREDO, GJB; NOVO, MCS. Couve de folha: do plantio à pós-colheita Campinas: Instituto Agronômico de Campinas, 2015. 42p.
-
VAN STRAATEN, P. 2006. Farming with rocks and minerals: challenges and opportunities. Anais da Academia Brasileira de Ciências 78: 731-747. DOI: 10.1590/S0001-37652006000400009
» https://doi.org/10.1590/S0001-37652006000400009 -
VIEIRA, DMS; CAMARGO, R; TORRES, JLR; SILVA, AA; LANA, RMQ; CARVALHO, FJ. 2020. Growing vegetables in succession in diferent soils and doses of phosphorus in an organomineral fertilizer, Revista Brasileira de Engenharia Agrícola e Ambiental 24: 806-813.DOI: 10.1590/1807-1929/agriambi.v24n12p806-813.
» https://doi.org/10.1590/1807-1929/agriambi.v24n12p806-813 -
VIEIRA, DMS; TORRES, JLR; CAMARGO, R; SILVA, AA; LANA, RMQ; CHARLO, HCO; LEMES, EM; CARVALHO, ER. 2023. Residual effects of phosphorus and micronutrients in vegetable growing areas under different organomineral fertilizer doses. Horticuturae 9: 1-16. DOI: 10.3390/horticulturae9070761.
» https://doi.org/10.3390/horticulturae9070761
The data will be made available upon request to the corresponding author.
