Mineral Soil Conditioner Research Articles

Biogas Plant Operation: Digestate as the Valuable Product

Fertilization is an essential element in plant cultivation. Supplying the right amounts of nutrients allows plants to grow and develop. Due to the rising price of mineral fertilizers, other fertilizers and soil conditioners are growing in importance. One of these is the digestate produced in agricultural biogas plants. Due to its properties, the digestate can be used directly as a fertilizer. In this case, the effects of application can both change the soil environment and directly affect plant growth. Physical, biological, and thermal transformations can also produce products based on the digestate or its fractions, which can be successfully used for fertilizer purposes. Among other things, this paper discusses the production and use of composts, biocarbon, and/or fertilizer granules from the solid fraction of the digestate. Numerous scientific studies, including the authors’ own research in this article, indicate that digestate can be successfully used as fertilizer, both without processing and with selected methods of treatment. However, further research is needed—especially on the diversity of raw materials used for biogas production and their effects on the composition and performance of the digestate. In addition, research should continue on the processing of digestate into specific products, depending on the needs of soils and plants.

Bromide Transport through Soil Columns in the Presence of Pumice

Solute transport parameters, similar to soil physical and chemical properties, can be affected by the presence of organic and mineral soil conditioners. In this study, the effect of different levels (0, 3, and 6 weight percent) of the inexpensive and easily accessible pumice conditioner on the parameters of bromide transport in sandy loam soil columns (diameter and height of 10 cm) was investigated. The transport parameters were estimated based on the breakthrough curves (BTCs) by the inverse modelling of the convection-dispersion equation (CDE) and the mobile-immobile model (MIM) using the CXTFIT software. The BTCs showed that bromide transport in the sandy loam soil columns, regardless of the presence of pumice, was mainly equilibrium, and the CDE was more efficient than the MIM, which is based on non-Fickian and non-equilibrium transport. The peak of the BTCs (maximum relative concentration) was lower in the treatments containing pumice and belonged to more pore volume than the controlled treatment did. This indicates a lack of preferential flow and thus, a reduction in the amount of bromide consumed in the treatments containing pumice. The increase of pumice content did not have a significant effect on the parameters of mobile water fraction (β) and mass transfer coefficient (ω) in the MIM, confirming the equilibrium transport of bromide. A 3% increase in the pumice content in the soil caused an increase and a decrease of 47% in dispersivity (λ) and Peclet number (Pe), respectively. In general, it can be concluded that the use of pumice in field conditions can prevent water loss and nutrients and reduce groundwater contamination by reducing the preferential paths.

Mineral soil conditioner requirement and ability to adjust soil acidity

Mineral soil conditioners (MSCs) are used to regulate soil acidity and improve soil quality; they are often made in sintering potassium feldspar, limestone, or dolomite, and are alkaline materials rich in silicon, calcium, potassium, and magnesium. The key point of how to apply them into farmlands is their ability to adjust soil acidity and the MSCs requirement (MSCR). In this study, inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and X-ray diffraction (XRD) were firstly used to determine the elemental and phase compositions of the MSCs in order to establish its equivalent relationship for the depletion of soil activity (H+) and its conversion relationship with CaCO3. Secondly, the soil culture method and the improved Shoemaker Mclean Peatt–Double Buffer (SMP–DB) method were compared using a group of 14 typical acid soils in MSCR. It is investigated that the MSCs contained four alkali/alkaline earth–metal elements: Ca, Mg, K, and Na in the bound aluminosilicate form (Ca2MgAlSi2O7, Ca3(SiO3)3, KAlSiO4, and KAlSi2O6); and the depletion of 2.31 mol of H+ required 100 g of MSCs and the amount of Si–Ca–K–Mg MSC needed to deplete the same quantity of H+ was only 0.87 times that of CaCO3. Based on the calculations by using the SMP-DB method and the soil culture method, the MSCR for treating the 14 typical acid soils were in the range of 0.56–8.27 t hm−2 and 0–10.8 t hm−2, respectively. Data from both methods were highly correlated with each other and there was a good linear correlation between them, and the equation: {{MSC}_{R}}^{{prime}}=30.29d-0.77 could be used to calculate the MSCs requirement. The recommended MSCR was approximately 4–8, 2–6, and 1–3 t hm−2 when soil pH < 4.50, 4.50 < pH < 5.50, and pH > 5.50, respectively. The experimental and computational methods established in this study could serve as the scientific basis and theoretical guidance for the production and agricultural use of MSCs.

Remediation of Cadmium Contaminated Paddy Fields Using Soil Conditioners

Four soil conditioners, SAMMNS, CCT01, Mineral, and Tebeigai were selected for this study. The effects of the four conditioners on soil pH, bulk density, organic matter, available nutrients, texture, microaggregates, Cd available in soil, and Cd content in brown rice were investigated using field-controlled cadmium tests conducted in cadmium-contaminated paddy fields in Pingxiang. The results showed that compared to the control, soil conditioners could increase pH, bulk density, and cation exchange capacity in soil. SAMMNS and CCT01 soil conditioners increased the amount of silt and clay, but that of sand decreased, whereas the Mineral and Tebeigai soil conditioners decreased silt and clay, and sand increased. In addition to the CCT01 soil conditioner, the application of soil conditioners increased large-scale agglomerates and reduced small-scale microaggregates. The effects of soil conditioners on soil physical and chemical properties promoted the conversion of Cd from contaminated soil from high activity to low activity, which reduced available Cd content in soil (5.21%-34.78%) and Cd content in brown rice (51.39%-68.06%). Correlation analysis showed that Cd content in brown rice was significantly positively correlated with available Cd and available phosphorus in soil, whereas it was negatively correlated with pH and bulk density in soil. Considering the effects of soil and brown rice on cadmium reduction and physicochemical properties, Tebeigai soil conditioner exhibited the best repair effects, followed by SENMES and Mineral soil conditioner.

Mechanism analysis of soil amelioration and phosphorus recovery by using a mineral soil conditioner in southern China

This study aims to identify the processes and mechanisms affecting physicochemical properties of soil following application of mineral soil conditioner and to investigate the behavior of PO4 sorption among 1:1 and 2:1 clay minerals and Fe/Al oxides in a ferralsol. Three replicates of five treatments, i.e., (1) a control without any application of inorganic P (CK), (2) inorganic P fertilization (CKP), and (3) combinations of inorganic P fertilization with mineral soil conditioner applied at 750 (M1), 975 (M2), and 1200 (M3) kg ha−1, were used to explore the influence of phosphate (PO4) sorption capacity and dynamic changes in clay mineralogy in the ferralsol, as examined using geochemical modeling (Factsage 6.1) and physical measurements (zeta potential, XPS, FTIR, and XRD analysis). We have found that the new formation of illite (a 2:1 phyllosilicate) was generated from the kaolinite (a 1:1 phyllosilicate) in the ferralsol after mineral soil conditioner (MSC) application. The iron in the ferralsol as well as the K+, Mg2+, and Si4+ in the MSC, played important roles in the clay mineral transformation. Meanwhile, the observed trends of phosphorus sorption competition suggested that the PO4 sorption capacity of the 2:1 clay minerals may be close to or even higher than that of the 1:1 clay minerals and Al oxides. The effects of Fe oxides on PO4 sorption could be ignored when Al oxides were present in the ferralsol. In comparison to the control and P-fertilized treatments, the PO4-binding capacity of the clay minerals in the MSC treatments could exceed that of the Al oxides because of the new formation of 2:1 clay minerals (illite). We demonstrate that the combination of zeta potential, XRD, FTIR, and XPS analysis is a promising strategy for distinguishing relationships between clay minerals and Al oxides in terms of phosphorus sorption. The MSC application was highly effective for soil amelioration and phosphorus sorption.

Improvement of nitrogen utilization and soil properties by addition of a mineral soil conditioner: mechanism and performance.

A mineral soil conditioner (MSC) composed of activated potash feldspar, gypsum, and calcium carbonate and containing an amount of available mineral nutrients, is shown to be effective for plant growth and acidic soil amelioration. In this study, a field test was conducted over four rice seasons by examining treatment with control check (CK), MSC, biological active carbon, and lime to investigate the nitrogen-use efficiency and mechanism of soil characteristic variations due to the desilicification and allitization of soil as well as the unrestrained use of nitrogen (N) fertilizer in recent years. Influences of MSC on the xylem sap intensity and mean rice yields were evaluated, and the soil type was also analyzed using the FactSage 6.1 Reaction, phase diagram, and Equilib modules. The results of the field trial showed that MSC application increased the xylem sap intensity and nitrogen export intensity by 37.33-39.85% and 31.40-51.20%, respectively. A significant increase (5.63-15.48%) in mean grain yields was achieved with MSC application over that with biological active carbon and lime application. The effects of MSC had a tendency to increase with time in the field experiment results, and grain yields increased after the initial application. The new formation of clay minerals exhibits a significant influence on [Formula: see text] fixation, especially for 2:1 phyllosilicates with illite, owing to the interlayers of the clay minerals. Our preliminary results showed that kaolinite, the main 1:1 phyllosilicate clay mineral in ferralsol, transformed to illite at room temperature as a consequence of the presence of H4SiO4 and available K+ supplied by MSC. This indicated that improving the soil quality combined with reducing N losses from soils is an efficient way to control non-point source pollution from agriculture without the risk of decreased in grain yield.

A Study of some Sandy Soil Characteristics Treated with Combinations of Bentonite and Vinasse which Reflected on Productivity of Pea Crop

This study examined the different rates of both bentonite and vinasse as mineral and organic soil conditioners, in combinations, to improve soil chemical properties which should be reflected on pea (Pisum sativum. L,Variety Master B) productivity during the two winter seasons of 2014 and 2015, on sandy soil under drip irrigation system. The experiment was implemented in Ismailia Agricultural Research Station (latitude, 30o 35' 41.901 N and longitude, 32o 16' 45.834 E). The objective of the work is to study the effect of the treatments for bentonite applied were rates of 2, 4 and 6 ton fed.-1 but vinasse with five rates treatments at 0, 0.25, 0.5, 0.75 and 1.0 ton fed-1,respectively. The obtained results revealed that pH values decreased as affected by applied all treatments compared to control treatment, especially with the gradual concentration increase of vinasse. Conversely, both EC and organic matter values increased with increased rates of vinasse and bentonite, in combination. Furthermore, data indicated that values of soil availability nitrogen, phosphors and potassium rise with high rates of bentonite and vinasse as combination compared to control treatment. Moreover, evaluation of pea yield (pods, seeds, straw), as affected by treatments, revealed an increase in yield components. Similar trend was found with total content of macronutrients in pea crop (straw and seeds) in both two studied seasons. Finally, the combination of bentonite and vinasse, working together as mineral and organic soil conditioners respectively, improved the chemical properties of sandy soil, which reflected on the developed pea plant.

Effect of Tillage System and Soil Conditioner Application on Soybean (Glycine Max (L.) Merrill.) and Its Crop Management Economic Indicators

Abstract Experiments with soybean on heavy soils of East Slovak Lowlands were established in the years 2010–2012. The effect of mineral fertilisers and soil conditioner application on soybean’s yield using three tillage systems (minimum tillage (MT), conventional tillage (CT) and no tillage (NT)) was studied. Production costs and economic efficiency of crop management practices were evaluated. The influence of production year on soybean crop was significant in the order of 2011, 2010 and 2012. Statistical evaluation confirmed that the effects of CT and MT systems were more significant compared with NT system. No significant differences were found between the variants of the mineral fertiliser and conditioner application. Differences in the total cost of soybean cultivation, as measured between years, were not significant. Fertilisation variants with application of HUMAC agro and NPK generated the highest costs. On the other hand, the lowest costs were achieved at fertilisation variants with application of NPK alone. Comparing tillage variants, the CT system had the highest costs each year. Significant savings were achieved on MT and NT variants. During the experimental period, a profit was reached on all variants. Applying NPK alone, the highest profit was achieved in 2010 and 2012 using MT system and in 2011 with CT tillage. The variant b2 with PRP sol in the years 2010 and 2011 was the most profitable using NT system and in 2012 using MT. Variant with HUMAC agro was the most profitable in each year using MT. The lowest income threshold for zero profitability was calculated in 2012. Using CT farming techniques at NPK fertilisation variant b1 in 2012, the income threshold was 1.85 t/ha, at variant b2 PRP sol it was 2.10 t/ha and at variant b3 HUMAC agro it was 2.42 t/ha. At MT and NT systems, the income threshold values for zero profitability were lower.