Soil Leaching Research Articles

Evaluating the impact of a cemetery on groundwater by multivariate analysis.

Water analyses in conjunction with hydrological and geotechnical investigations were carried out to assess the potential for groundwater contamination from the decomposition of buried human bodies. Water samples were collected from 2007 to 2018 in three monitoring wells built within the cemetery area. Water quality was evaluated based on the determination of 25 analytical parameters (20 physical-chemical and 5 microbiological). Laboratory data reported by the local sewage water company for water collected in household cisterns located outside the cemetery area were also evaluated. Multivariate analysis showed a similar pattern between iron content, turbidity, and rainfall data collected at the rainfall station closest to the study area. This behavior is a direct consequence of soil leaching (oxisol). The physical characterization of the soil of the unsaturated area above the aquifer indicates that the absorption of body waste by the soil is favored, preventing surface contaminants from reaching the aquifer. This work also found that the water samples collected outside the cemetery area do not comply with the Brazilian limits for drinking water. In conclusion, water samples collected from monitoring wells located within the cemetery area have little to none impact on both subsurface and underground contamination.

Effect of sterile rice spikelets derived biochar amendment on nutrient leaching and availability in paddy soil under continuous standing water

ABSTRACT Undisturbed soil columns were used to study the effect of sterile rice spikelets-derived biochar (SRSB) on NH4 +-N, available P, and available K leaching and nutrients availability in a paddy soil under continuous standing water (CSW) condition. The experiment was conducted for two crop cycles and comprised of three treatments: recommended dose of sole chemical fertilizers (CF), CF+SRSB (2 t ha−1), and control. In both crop cycles, incorporation of SRSB reduced the leachate NH4 +-N and available K concentrations, while increased the available P concentration compared to sole CF. The SRSB amendment reduced the cumulative losses of NH4 +-N by 35–38% and available K by 23–25% than CF only. However, there was no significant variation in cumulative available P loss between SRSB and CF only. The reduced leaching loss of NH4 +-N and available K could be attributed to the better nutrient adsorption capacity of SRSB. After completion of two crop cycles, the soil pH, soil organic carbon, soil total N, available P, and available K increased with SRSB amended soils than sole CF. This study showed positive effects of SRSB on retaining nutrients and increasing their availability in the soil which could benefit efficient fertilizer management in paddy soil under CSW.

Sustainable and reagent-free cathodic precipitation for high-efficiency removal of heavy metals from soil leachate

Heavy metal pollution of soils has become a serious environmental problem. Soil washing with degradable reagents is an effective remediation technique of heavy metal pollution, and the generated leachate must be appropriately treated before discharge. However, the existing methods usually have the problems of large consumption of regents, high cost, and secondary pollution. This study proposed a reagent-free electrochemical precipitation method to remove mixed heavy metal ions extracted from soils by citrate using inert electrodes (IrO2–Ta2O5/Ti anode and graphite cathode). The results showed that the low potential of cathode led to the electrodeposition of Cd; the local alkaline environment provided by electro-mediated water reduction caused the hydrolytic precipitation of Zn and Pb; and the precipitation of Fe washed out from Fe-rich soil resulted in the coprecipitation of As on cathode surface. These combined cathodic precipitation processes decreased the concentrations of toxic heavy metals by over 99.4% after 12 h of electrolysis at 26 mA cm−2. The electrodes exhibited high stability after multiple successive cycles of reuse. The concentrations of As, Zn, Pb and Cd in the leachate decreased to below the limits of industrial wastewater discharge in each cycle, and those in soils could be reduced by 53.8%, 58.8%, 25.5%, and 70.2% at the initial concentrations of 1549, 1016, 310 and 50 mg kg−1, respectively. The heavy metal removal rate increased with increasing current density in the range of 0–52 mA cm−2. This work provides an efficient and sustainable method for the remediation of site soils polluted by mixed heavy metals.

ДЕЙСТВИЕ ОРГАНОМИНЕРАЛЬНОГО МЕЛИОРАНТА ПРИ ПРОМЫВКАХ НА ОЗДОРОВЛЕНИЕ СОЛОНЦЕВАТЫХ ПОЧВ АЗЕРБАЙДЖАНА

Purpose: to study the impact of ameliorant and leaching on the properties of saline and alkaline soils in laboratory conditions. Materials and methods. Research work was carried out on the basis of currently known methods, widely used in the territory of the republic. The experimental experiment was carried out in four variants: 1) soil leaching with plain water; 2) soil leaching using 5 t/ha ameliorant; 3) soil leaching with application of 10 t/ha ameliorant; 4) soil leaching with application of 15 t/ha ameliorant. In all cases, the soil was washed with a norm of 15 thousand cubic m/ha. Experimental soil leaching under laboratory conditions was carried out in 5-fold repetition in special vessels in the following sequence. The air-dry soil was ground and sifted through a sieve with a hole diameter of 1 mm, the calculated amount of ameliorants was added to the soil and thoroughly mixed. The reclaimed soil was filled in special vessels with perforated bottom. By lightly tapping on the vessel, soil compaction was achieved up to 1.4 g/cubic cm, which was determined by the weight of the soil. A constant water layer of 5 cm was maintained above the soil in the vessel during the leaching period. Results. When conducting a laboratory experiment, it was revealed that when washing with ordinary water at a rate of 15 thousand cubic m/ha without ameliorant, the salt content decreased by 42 % in relative terms (from 2.188 to 1.265 %), alkalinity decreased by 7 % (from 12.24 to 11.34 % in terms of exchangeable sodium). The best option is leaching with a ameliorant + 15 t/ha, in which the total salt content decreased by 76 % (from 2.188 to 0.530 %), and solonetzization – by 73 % (from 12.24 to 3.35 %). Conclusions. The ameliorant is convenient to apply and creates conditions for desalinization and alkalinity reduction.

Nitrate losses from Midwest US agroecosystems: Impacts of varied management and precipitation

Nitrate (NO₃⁻) losses from agricultural fields to groundwater and surface waterways are a major concern that could be further exacerbated by a changing climate. Although individual field-scale studies provide critical information, investigation on the interactive effect of various management practices across different soil types experiencing wide variations in precipitation is necessary to extend our understanding of what approaches may mitigate NO₃⁻ losses to the environment. Synthesizing and analyzing large data sets from multiple studies provides an opportunity to investigate the interactive impact of multiple management practices, soil texture, and rainfall. We assembled peer-reviewed field studies from the Midwest United States and analyzed their associated field data to (1) quantify the range of NO₃⁻ leaching associated with different agroecosystems and (2) determine the individual and interactive effect of management practices (tillage and amount of nitrogen [N] fertilizer added), cropping systems (crop type and rotation), and precipitation across multiple soil types on NO₃⁻ leaching. Our results showed that fertilized potatoes (<i>Solanum tuberosum</i> L.) had the highest NO₃⁻ leaching rate among all systems studied (59.3 ± 8.4 kg N ha⁻¹ y⁻¹) while unfertilized perennial systems exhibited the lowest NO₃⁻ leaching (6.1 ± 0.9 kg N ha⁻¹ y⁻¹). Our results suggested that corn (<i>Zea mays</i> L.)–soybean (<i>Glycine max</i> [L.] Merr.) rotations can reduce NO₃⁻ leaching compared to continuous corn by 25% in clay soils and also reduce the impact of high rainfall on NO₃⁻ leaching compared to continuous corn management. Nitrate leaching in sandy soils exhibited a greater sensitivity and amplified response to increasing N fertilizer amount and annual precipitation compared to other soil types. Compared to conventional tillage, no-tillage soil management significantly reduced NO₃⁻ leaching in sandy and silty loam soils. While some management practices can curb NO₃⁻ leaching losses, more drastic land management change from row crops to perennial systems offered the most benefit. We conclude that a changing climate will make it more challenging for farmers to increase N use efficiency and reduce NO₃⁻ leaching, especially on coarse textured soils.

Biochar: An Eco-friendly Approach for the Alleviation of Nitrate Leaching and Augmentation of Soil Health

Our study investigated the efficacy of barberry biochar in reducing nitrate leaching in arid and semi-arid area. The experiment was conducted in factorial design investigating the effect of two biochar particle sizes (less than 1mm and more than 2.8 mm) and three biochar amounts (1%, 2%, and 3% by mass ratio) on nitrate leaching in soil. Our findings revealed significant reductions in nitrate leaching upon the application of barberry biochar. The experimental treatments had a significant effect on nitrate concentration in leached water in both sampling stages. Although the initial sampling indicated non-significant variances between particle size, clear statistical differences emerged in the second sampling. The smaller biochar particle sizes (less than 1 mm) recorded greater reductions by 76.3% in nitrate leaching compared to larger ones (exceeding 2.8 mm) that resulted in 66.2% reduction. Our results indicated that a 1% weight of biochar produced the lowest leaching rate, with reductions of 79.7% in the first sampling and 82.6% in the second sampling. Finer biochar particle sizes (&lt; 1mm) were the most effective at reducing nitrate leaching, which achieved to an 80.9% reduction. Overall, barberry biochar shows potential in mitigating nitrate pollution, enhancing soil quality, and promoting agricultural sustainability. It is important to consider the optimal biochar application rate and particle size to maximize its effectiveness in reducing nitrate leaching while minimizing any potential negative impacts on crop yield. Further research is required to optimize biochar application rates, particle sizes, and long-term effects in diverse agricultural systems. Implementing biochar as a soil amendment holds promise in improving soil health, water quality, and overall sustainability.

Morphological characteristics of top soiling in the reclamation areas of post-coal mining at Kutai Kartanegara and Kutai Timur Regencies

This study aimed to obtain information about the impact of different morphological characteristics and genesis at some reclamation sites after coal-mining activities. Two coal sites were chosen as study areas, i.e. the Separi site, which is located in Kutai Kartanegara regency and the Bengalon site, located in Kutai Timur Regency. A descriptive research method was used to identify the morphological characteristics of reclamation sites at different times (chronosequence). The results showed that in-situ weathering, indicated by soil leaching caused by rainwater infiltration, led to the formation of the Ah horizon more than two years after the reclamation activity. The process of material removal and disposal (cutting, filling, transporting and levelling) from coal mining operations tends to accelerate the decomposition of parent soil material and promote the formation of pre-cambic horizons. The soils used (horizon A, B, and C) for the topsoil of the reclamation site were initially Typic Hapludults and Typic Dystropepts, although Typic Tropaquents and sandy parent materials were also used. Due to the impermeable layers of overburdening where water channels in the soil profile and deeper layers have not yet formed as human-made soil and landscape (artificial) cause rainwater to fail to infiltrate deeper layers so that with less heavy rain, the groundwater level will rise to the surface and the land will become waterlogged/flooded.

Technologies to reduce water waste during land leaching and cultivation of industrial crops

More than half of Uzbekistan's irrigated land is saline to some degree. The drying up of the Aral Sea has intensified this process. For many years, chronic salt storms in the northern part of the country have sprayed large quantities of salt onto agricultural land, leading to increased salinization. These processes cause the water required to flush saline soils year after year. The problem is exacerbated by water shortages worldwide, including in Central Asia. This requires the leaching of saline soils and a multiplication of the water used in crop cultivation. Therefore, alternative use of water resources in our country is one of the most important issues for agriculture. The introduction of salt leaching and cultivation in farms based on outdated technologies and the low efficiency of new technologies (bio-solvent washing, etc.) in the production of new salt leaching and cultivation remain a negative obstacle for the economic development of farms and the country as a whole. The analysis shows that in our country, billions of cubic meters of water are used to flush saline soils and cultivate agricultural crops. Still, only 60% of this water reaches the fields where crops are grown, while the rest of it disappears into the irrigation systems and irrigation processes (canals, ditches, and branch lines). When providing water resources for soil salinization and cultivation using trapezoidal canals, part of the water flowing through them dissolves and filters the mineral and organic fertilizers in the soil due to air pressure and gravity; as a result, up to 30% of water is lost (wasted). In this paper, the water resources for soil washing and crop cultivation are replaced by a parabolic excavator with a trapezoidal boom, designed to save up to 30% of water resources.

Application of one-point calibration LIBS for quantification of analytes in samples with distinct matrix characteristics: a case study with Hg

Combining calibration-free LIBS with the one-point calibration method can mitigate matrix effects and compensate for variations in system optimization, enabling accurate Hg quantification in soil and landfill leachate samples.

The benefit of the Arabidopsis halleri ssp. gemmifera root exudate in cadmium extraction from the cadmium contaminated soil

&lt;p align="left"&gt;This study focuses on how to solve cadmium (Cd) contamination in soil because this contaminant decreases soil quality. Soil remediation using the hyperaccumulator plants is an optional process to solve soil contamination. &lt;em&gt;Arabidopsis halleri&lt;/em&gt; ssp. &lt;em&gt;gemmifera &lt;/em&gt;(hereinafter referred to as &lt;em&gt;A. halleri&lt;/em&gt;), is one of the candidate plants expected to be used for phytoremediation of Cd contaminated soil. The &lt;em&gt;A. halleri &lt;/em&gt;promote solubilization of Cd in the soil directly or indirectly using its secreted root exudate. However, the effect of the metabolites profile of this plant to Cd uptake from contaminated soil is still unclear. The purpose of this study is to examine the contribution of root exudates of &lt;em&gt;A. halleri &lt;/em&gt;to extract Cd in the soil. Cd-contaminated soil used in this study was a farmland soil containing 5.8 mg kg&lt;sup&gt;-1&lt;/sup&gt; of Cd and 648 mg kg&lt;sup&gt;-1&lt;/sup&gt; of Zn taken from Tome City, Miyagi Prefecture, Japan. Soil leaching tests were conducted using the solution containing the root exudates from &lt;em&gt;A. halleri &lt;/em&gt;plant.&lt;em&gt; &lt;/em&gt;The accelerating effect of root exudates of &lt;em&gt;A. halleri &lt;/em&gt;on solubilization of Cd is fundamental information to construct the benefit of phytoremediation.&lt;/p&gt;

The Efficiency of Mineral and Water-Soluble Complex Fertilizers in Potato Fields

Application of fertilizers is among the prior agriculture measures to achieve sustainable potato yield in conditions of leached soils of Lori region, poor in essential plant nutrients. The field experiments established that to obtain maximum potato yield in addition to the introduction of the main mineral fertilizer (NPK) it is necessary to apply complex water-soluble fertilizer (CWF) via foliar feeding thrice during the vegetation period with 10-12 days of interval. In this case the yield amount was 286 c/ha, 40.0 % of which was large and 35.0 % were medium size. The tuber’s chemical composition was also improved. In the case of using N120P120K120 the yield amount was 261.0 c/ha, out of which 30.2 % were large and 40.5 % were medium size, while in the control variant 207.5 c/ha yield was received, out of which only 15.1 % were large and 35.9 % – medium in size.

Biochar-blended manure modified by polyacrylamide to reduce soil colloidal phosphorus leaching loss.

Combined application of biochar and organic fertilizer improves soil structure and crop yield but may lead to increased loss of phosphorus (P). To reduce the P loss risk in this case, rice straw biochar (BC) and sheep manure (SM) were modified using polyacrylamide (PAM). The effects of using organic amendments (BC, SM, and PAM-modified organic mixtures) and no amendments (CK) on soil total and colloidal P leaching loss from paddy soils were evaluated through soil column leaching experiments. The soil leachate volume was increased by 8.91% with BC treatment and reduced by 15.3% with SM treatment. The total P leaching loss (973.9μgkg-1) from the BC-treated soil was higher than that from other treatments (541.4-963.5μgkg-1). However, there was much more colloidal P loss (480.0μgkg-1) from SM treatment. The optimal conditions for the preparation of BC and SM modified using polyacrylamide (PSB) for reducing P leaching loss were SM/BC = 4:1, 1% PAM, and 100°C. Molybdate-unreactive P accounts for 58.61-86.89% of the colloidal P in the soil leachate with organic amendments. PSB reduced colloidal P loss (particularly in 10-220nm range) by ~ 50% compared with BC and SM treatments. The colloidal P concentration in the leaching solutions was significantly correlated with TOC and susceptible to Fe and Al concentrations. Using PAM-modified mixture instead of manure and biochar as a soil amendment can effectively control P leaching from fields.

Approaches to the development of environmental standards for the content of petroleum hydrocarbons and Pb, Cr, Cu, Ni in soils of Greatest Caucasus

&lt;p&gt;The development of tourism and leisure infrastructure results in a continuous increase of anthropogenic impact on soils of wet and dry subtropics of the Greatest Caucasus. It is very important for the region to preserve the sustainable functions of soils and ecosystems, maintain a comfortable life and recreation environment create environmentally friendly agricultural products. It is conducted studies to determine the limits of resistance of soils in wet and dry sub-tropics to priority pollutants, especially petroleum hydrocarbons and heavy metals (Pb, Cr, Cu, Ni). It was found that the soils of wet and dry subtropics for resistance by Pb, Cr, Cu, and Ni are located as follows: south-ern chernozem &amp;gt; typical sod-carbonate soil ≥ brown typical soil ≥ brown carbonate soil = brown leached soil ≥ leached sod-carbonate soil = yellow soil &amp;gt;acid brown forest soil ≥ acid brown forest podzolized soil. In terms of the degree of resistance to oil pollution, studied soils create certain series: brown carbonate ≥ brown typical = sod-carbonate leached ≥ sod-carbonate typical &amp;gt; southern chernozem ≥ yellow soil ≥ brown leached soil &amp;gt; acid brown forest soil = acid brown forest podzolized soil. Heavy metals by ecotoxicity to the soils of wet and dry subtropics from the following series: Cr&amp;gt; Cu ≥ Ni = Pb. Based on the degradation of ecological functions of soils, we offer regional standards of the maximum permissible content of Pb, Cr, Cu, and Ni for the main soils of wet and dry subtropics.&lt;/p&gt;

Growth and productivity of energy plantations of poplars in the Right-Bank Forest Steppe conditions

Purpose. To determine the features of the growth of an energy plantation of poplar variety ‘Robusta’ on leached chernozems in the conditions of the Central Forest Steppe of Ukraine. Methods. Field, laboratory, statistical. Results. One-year lignified cuttings 25 cm long and 0.8–1.0 cm in diameter were used as planting material. The designed layout of planting places: 2.0x0.8 m (more density version) and 2.0x0.9 m (more sparse version). After the first year of cultivation, the studied plots had the same height (1.6 m). During the second growing season, their growth in height was 2.0±0.05 m in the more sparse version, and 2.1±0.05 m in the thicker version. After the first year, the diameter at a height of 1.3 m was greater in the thicker version (0.5 cm versus 0.3 cm), but already in the next year, the trees of the more sparse stand became 2 mm thicker, and this difference persisted in the third year, when the average diameter of the trees of the denser version was 5.8 cm, and of the sparser — 6.2 cm. As a result of the higher diameter of trees of the more sparse version, they had a higher weight of the average tree, but due to the smaller number of trees, their productivity was lower. So, after three years of growing a poplar plantation created by cuttings, one hectare can yield 11.66–14.58 tons of dry biomass, or 207.5–259.5 GJ of energy. A sharp increase in morphometric indicators during the third year of cultivation indicates the feasibility of using a longer period of cultivation of such plantations to obtain the maximum amount of biomass. Conclusions. The study of a three-year energy plantation of the ‘Robusta’ variety, created by one-year lignified cuttings on the leached soils of the Right Bank Forest Steppe, with the placement of planting sites 2.0 x 0.8 m and 2.0 x 0.8 m, showed that after three years of growing a poplar plantation, one hectare can get 11.66–14.58 tons of dry biomass, or 207.5–259.5 GJ of energy. A significant increase in growth indicators and biomass productivity of poplar plantations during the third year of cultivation indicates the feasibility of using a 4–6-year period of cultivation of such plantations to obtain the maximum amount of biomass.

Clay stabilization and recovery of soil functions of a degraded solodic planosol through incorporation of agrominerals: A case study in southern Brazil

This paper describes the performance of addition rates of basaltic breccia and agricultural gypsum on clay stabilization and nutrients release of a solodic Planosol from a degraded borrow area located in Southern Brazil. A leaching experiment was carried out in PVC cylinders filled with 1.5 kg of soil (C horizon), in which two chemical amendments were added in three different proportions: a) basaltic breccia in 7, 14 and 21 Mg ha−1 doses; b) agricultural gypsum in 7, 14 and 21 Mg ha−1 doses; and c) a standard soil, without chemical correction. Distilled water (300 mL) were added every 7 days for 20 weeks and the pH, electrical conductivity, calcium, magnesium, sodium and potassium contents and the water-dispersible clay were analyzed in the collected leachates. Gypsum was more efficient than basaltic breccia to promote clay flocculation, even at the lower rate (7 Mg ha−1). The application of basaltic breccia up to 21 Mg ha−1 reduced the amount of nutrients released directly to the soil solution, reducing soil leaching. The application of basaltic breccia at the dosage of 7 Mg ha−1 was able to reduce more than 65% of the water-dispersive clay from the degraded solodic Planosol.

Bio-Organic Fertilizer Combined with Different Amendments Improves Nutrient Enhancement and Salt Leaching in Saline Soil: A Soil Column Experiment

Salt-affected soils frequently experience leaching and desalination issues, which severely restrict plant growth and water uptake. Hence, in this experiment, four treatments including CG (no amendments addition); OF (organic fertilizer addition); OH (organic fertilizer and Hekang amendment addition); and OB (organic fertilizer and fulvic acid addition) were designed to examine the effect of organic amendment on soil chemical properties, water and salt transport, and soil desalination laws of coastal saline soil. The results showed that the addition of organic amendments significantly reduced soil pH (8.47–8.52) and salt content (2.06–2.34 g kg−1), while increasing soil organic matter content, available phosphorus, and available potassium. OH treatment has a higher available phosphorus content than other treatments. OH and OB treatments elevated the soil desalination ratio (32.95% and 32.12%, respectively) by raising the leaching volume and leaching rate. Organic amendments significantly promoted Na+ (4.5–32%) and SO42− (12–27%) leaching compared to CG. Organic treatments, particularly OB treatment, not only increased the content of soil organic matter and available nutrients but also promoted salt ion leaching, improved soil permeability and increased soil desalination and water leaching rates. Our results may provide a theoretical basis for revealing the desalination law of coastal saline soil.

Desalination of saline fields by soil leaching in the Karkhehnur Watershed, Iran

Abstract Since large parts of agricultural fields are saline or subjected to salinity stress, practical and efficient methods may be used for recycling fields, worldwide. The effects of the type and amount of soil leaching on the quality of saline fields, in different parts of the world have yet to be investigated. The objectives were to investigate: (1) the optimum depth of water required to decrease soil salinity of saline fields to the levels, suitable for crop production in the Karkhehnur Watershed, Khuzestan province, Iran, and (2) the most suitable method of soil surface leaching. Four different regions were selected for the experiment, and a wide range of soil-related parameters as well as water properties was determined. Soil leaching was conducted by surface continuous irrigation (three regions), and surface alternative irrigation (one region). The depths of soil leaching were equal to 0–25, 25–50, 50–75, 75–100, 100–125, and 125–150 cm. The class of salinity was changed to S2 (EC = 24 dS/m) from an initial class of S4 (EC = 87 dS/m) using a water depth of 25–125 cm in different experimental regions. If soil is highly saline, continuous irrigation may be a more effective method, however, under less stressful conditions, alternative irrigation can also be recommendable.

Evaluation of Predrying Steps, Cadmium, and Pesticide Residues on Dried Powders from Romaine Lettuce Outer and Heart Leaves

Romaine lettuce (Lactuca sativa var. longifolia) outer leaves are discarded in fields during harvest and present a prime upcycling opportunity. Although Romaine lettuce is abundant in healthy nutrients, it may contain trace amounts of heavy metals, mainly cadmium (Cd), and pesticides that could lead to acute poisoning. Physical attributes, total soluble phenolics, antioxidant capacity, Cd, and pesticides in powders with different predrying treatments for hearts and outer leaves of two varieties of Romaine lettuce from farms with different Cd content in soils were quantified. Lettuce powders from the Valencia variety had a higher greenish color and true density than the Duquesne variety. Heart leaves from Valencia variety presented higher total soluble phenolics. However, outer leaves from Valencia and Duquesne varieties presented similar levels of total soluble phenolics. Valencia outer and heart leaves presented higher antioxidant capacity. Infrared dry blanching resulted in lower color parameters, total soluble phenolics, and antioxidant capacity, evidencing thermal degradation during this predrying step. Cd concentrations were 10 times higher in the soil where Duquesne Romaine lettuce variety was grown. Accordingly, Duquesne had significantly higher levels of Cd in outer or heart leaves. Outer leaves had higher levels of Cd compared to heart leaves. No differences in pesticides were found in lettuce from both harvesting fields. It is possible to obtain edible powders from Romaine lettuce outer leaves from low-Cd soils and controlled pesticide management, and it may be an alternative way to reduce nitrogen leaching in agricultural soils.

Biochar and NPK fertilizer co-applied with plant growth promoting bacteria (PGPB) enhanced maize grain yield and nutrient use efficiency of inorganic fertilizer

A field experiment was carried out for two consecutive years to assess the yield response of maize and the use efficiency of nitrogen, phosphorus and potassium following the application of biochar and mixed culture of Bacillus spp and Pseudomonas spp to Inorganic NPK fertilizer. Seven treatments comprising: control, inorganic NPK fertilizer at half rate (HR), inorganic NPK fertilizer at full rate (FR), inorganic NPK fertilizer (HR)+biochar (1500 kg ha -1 ), inorganic NPK fertilizer (FR) + biochar (1500 kg ha -1 ), inorganic NPK fertilizer (FR)+biochar (1500 kg ha -1 )+P + B, inorganic NPK fertilizer (HR)+biochar (1500 kg ha -1 )+P + B were laid in a randomized complete block design. Bulk density reduced only in fields amended with the treatments that included biochar. Also, soil pH increased in all plots that were co-amended with inorganic NPK and biochar. Soil organic carbon, cation exchange capacity, dehydrogenase activity and metabolic quotient significantly increased in the amended plots compared with the control. However, inorganic NPK fertilizer + biochar with mixed bacteria cultures, enhanced organic C, dehydrogenase activity and metabolic quotient compared with NPK alone or NPK + biochar. Nitrogen, phosphorus and potassium uptake and the use efficiency and yield of maize, were superior in treatments that included mixed bacteria cultures compared to the addition of NPK alone or NPK + biochar. Our study showed that the inclusion of mixed culture of bacteria in combination with biochar is a promising strategy to increase grain yield, enhance the use efficiency and reduce the rates of inorganic NPK fertilizer application recommended for cultivating maize in the coastal savannah agroecological zone of Ghana. • Arable soils in sub-Saharan Africa are characterised by aluminium toxicity and nutrient deficiency hence causing yield decline of maize. • Chemical fertilizers, although successful in supplying macro- and micro-nutrients, their use efficiency is reduced due to nitrogen leaching and phosphorus precipitation in tropical acid soils. • The co-application of biochar and microbial resources proved superior in improving the use efficiency of inorganic NPK fertilizer and maize yield compared with either inorganic NPK fertilizer alone or inorganic fertilizer + biochar.

Cultivo de alface sob diferentes doses de organomineral como fonte de fósforo e micronutrientes

ABSTRACT The use of organomineral fertilizers (OF) in the cultivation of vegetables has been considered a promising technology to provide nutrients gradually. The OFs can reduce the phosphorous (P) soil adsorption and leaching of nitrogen and potassium with the supply of some micronutrients. This study aimed to evaluate doses of OF as a source of P and micronutrients (boron and zinc) for curly lettuce cultivation. Five OF doses were evaluated: T1 = 0% (no P2O5 fertilization); T2 = 50% (75 mg/dm3 of P2O5); T3 = 100% (150 mg/dm3 of P2O5); T4 = 150% (225 mg/dm3 of P2O5); T5 = 200% (300 mg/dm3 of P2O5) of the lettuce recommended fertilization; T6 = 100% mineral fertilizer (MF) (150 mg/dm3 of P2O5). The fresh (FM) and dry mass (DM) of the lettuce shoot (aerial part), the soil nutrient level, and the plant nutritional status at harvest were evaluated. We observed that (i) the doses of 225 and 300 mg/dm3 of P2O5 via OF provided the same availability of P in the soil as the dose of 150 mg/dm3 of P2O5 of MF; (ii) the doses of 225 and 300 mg/dm3 of P2O5 of OF provided higher levels of soil boron and zinc compared to other treatments and (iii) the MF fertilization was more efficient than that of OF in the production of curly lettuce in a protected environment.