Soil Micronutrient Availability Research Articles

Essentiality of Micronutrients in Soil: A Review

Micronutrients are very abundant in soil but plants normally absorb only a little amount of them, giving them the name "trace elements". Boron (B), Copper (Cu), Iron (Fe), Manganese (Mn), Zinc (Zn), Molybdenum (Mo), and Nickel (Ni) are the essential micronutrients that are required in smaller amounts but crucial for plant growth and development. Besides providing essentiality in fruits and seeds formation, they are helpful in performing various metabolic processes, nutritional management, reproductive growth, chlorophyll synthesis, and other key plant activities. Among all the essential micronutrients, two particular elements, zinc (Zn) and boron (B) are deficit in acidic soils and zinc (Zn) and iron (Fe)are insufficient in semi-arid soils, which have become a rising problem in a variety of cropping systems thereby, raising alarms for the future. Our understanding of difficulties relating to micronutrients might be improved by the production of detailed soil micronutrient maps that cover wide geographic regions, making relevant judgments about the delivery and distribution of fertilizers supplemented with micronutrients to areas that are deficient in these particular micronutrients. The outcomes of these delineation efforts would also be very helpful in developing site-specific suggestions to increase the micronutrient content of food crops. It's important to note that soil micronutrient availability directly affects plant growth.

Micronutrient availability in soil–plant system as influenced by 47 years long application of chemical fertilizers, organics and lime under maize–wheat cropping in an acid Alfisol

Micronutrient availability in soil–plant system as influenced by 47 years long application of chemical fertilizers, organics and lime under maize–wheat cropping in an acid Alfisol

Restoring soil nutrient stocks using local inputs, tillage and sorghum-green gram intercropping strategies for drylands in Eastern Kenya

Soil macronutrient and micronutrient availability is particularly critical in semi-arid agro-ecological zones that are characterized by poor soil fertility and low rainfall regimes. An experiment was initiated in Siakago, Embu County to investigate the effects of tied-ridges, conventional tillage and input applications on soil nutrient fertility using a randomized complete block design with a split-split plot arrangement for 4 seasons (2018–2021). The treatments comprised of two main plot tillage systems, three cropping systems allocated to the sub-plots and four soil input management treatments assigned to sub-sub plots. ANOVA was used to test the effects of different treatments including tillage, crop system and soil fertility management using Genstat software. The data was also subjected to Principal Component Analysis procedures using R ("FactoMineR" and "factoextra") to examine the inter-relationship patterns between different soil fertility parameters and to reduce the data into independent soil fertility components. There were significant main effects due to crop system (Soil Mn), tillage and crop system interaction (SOC and TSN) and soil fertility management (TOC, TSN, Ca, Zn). Soil inputs significantly influenced soil carbon concentrations (p = 0.002), with the lowest values observed in the control (0.2 %), followed by sole fertilizer (0.35 %), manure + fertilizer (0.41 %) and the fully decomposed manure treatment (0.61 %). The soil-extracted manganese values recorded significant effects due to crop system, while soil-extracted Zn values were significant due to soil fertility management. Multivariate analysis results revealed the structure of soil nutrient distribution. Tied ridging can improve soil micronutrient availability through reduced soil erosion, conservation of soil organic matter, which can improve soil micronutrient availability. Soil conservation practices such as tied-ridging integrated with organic input applications can enhance multiple nutrient availability for improved crop performance and human nutrition in dryland farming systems where farmers lack soil moisture, technologies and resources to enhance crop nutrient availability.

Effect of different agricultural practices on yield, profitability and soil properties under maize (Zea mays) – barley (Hordeum vulgare) cropping system

The present study was conducted to quantify the effects of natural, organic, and integrated farming methods on yield, profit, and soil properties of maize (Zea mays) + soybean (Glycine max) – barley (Hordium vulgare) + vegetable pea (Pisum sativum) cropping system. The mean data of two years recorded 54% and 62% higher maize yield and net profit with applied NPK+FYM. Such increase in yield and net profit of barley was 48% and 47%. Soil properties showed a significant improvement due to applied NPK+FYM over FP and observed an increase of 23%, 14%, 8%, 30% and 16% for soil OC, MBC, available N, P and K, respectively. The availability of micronutrients in soil was maximum under organic and SPNF practice than other treatments. The study also revealed that SPNF practice was statistically at par with FP but these were found inferior to rest of the practices suggesting that natural and organic farming need to be practice for a longer period for better yield, profit, and soil environment.

Assessment of Soil Quality Indicators of Soil from Different Departments of NAI, SHUATS, Prayagraj

An assessment of soil health parameter properties of soil from different departments of NAI, SHUATS, Prayagraj carried out during 2022-23. The prime objectives of this study were to carry out the soil health parameter properties of soil at different depths of various department research farm to determine the availability of macronutrients and micronutrients in soil of these soil sample provide the assessment 7 sampling locations were selected. Soil samples were collected with depth of 0-15, 15-30 and 30-45 cm respectively. The soil colour dry condition varied from Light yellowish brown, dark yellowish brown, Pale olive, pale brown, pale yellow, Light olive brown, Yellowish brown, Olive yellow, Dark brown and in wet condition varied from Olive brown, Olive, Dark brown, Dark yellowish brown, light olive brown, Olive yellow and Dark yellowish. The soil texture was dominantly sandy loam in every site. The bulk density ranged from 1.170 to 1.432 Mg m⁻3. The Particle density ranged from 2.22 to 2.50 Mg m⁻3. The pore space ranged from 42.50 to 51.24 %. The soil pH ranged from 7.37 to 7.78. The electrical conductivity ranged from 0.28 to 0.44 dS m-1. The soil organic carbon ranged from 0.16 to 0.42%. The available nitrogen ranged from 195.5 to 256.0 kg ha-1. The available phosphorous ranged from 14.43 to 23.95 kg ha-1. The available potassium ranged from 132.00 to 206.00 kg ha-1. The available calcium ranged from 0.97 to 1.88 cmol (p+) kg-1. The available magnesium ranged from 0.76 to 1.69 cmol (p+) kg-1. The available zinc ranged from 0.60 to 0.72 mg kg-1. There is an including awareness of the need to pay greater attention in the role of macronutrients enhancement in the soil for good soil health and proper nutrition of plant so as to attain optimum economic yield and soil is suitable for all major tropical and sub-tropical crops.

Assessment of Physico-chemical Properties of Soil from Different Departments of NAI, SHUATS, Prayagraj, U.P., India

An Assessment of Physico-chemical properties of soil from different departments of NAI, SHUATS, Prayagraj carried out 2022-23. The prime objectives of this study were to carry out the physico-chemical properties of soil at different depths of various department research farms to determine the availability of macronutrients and micronutrients in soil of these soil sample provide the assessment 6 sampling locations were selected. Soil samples were collected with depth of 0-15 and 15-30 cm respectively. The soil colour dry condition varied from light yellowish brown, pale olive, light olive brown, yellowish brown, olive yellow, dark brown and in wet condition varied from olive brown, dark brown, olive yellow and dark yellowish. The sand, silt and clay varied from 53 to 65 %, 19 to 27 % and 15 to 20 % respectively, soil texture was dominantly sandy loam in every site. The bulk density ranged from 1.20 to 1.34 Mg m⁻3. The practical density ranged from 2.68 to 2.94 Mg m⁻3. The pore space ranged from 43.25 to 49.50 %. The water holding capacity ranged from 41.75 to 48.25 %. The soil pH ranged from 7.37 to 7.71. The electrical conductivity ranged from 0.21 to 0.48 dS m-1. The soil organic carbon ranged from 0.32 to 0.45 %. The available nitrogen ranged from 235.17 to 261.12 kg ha-1. The available phosphorous ranged from 19.66 to 25.50 kg ha-1. The available potassium ranged from 152.00 to 214.00 kg ha-1. The available Sulphur ranged from 8.80 to 14.42 mg kg-1. The available zinc ranged from 0.58 to 0.93 mg kg-1. The available boron ranged from 0.58 to 1.10 mg kg-1. The available iron ranged from 5.92 to 8.70 mg kg-1. The available manganese ranged from 3.21 to 3.61 mg kg-1. The available copper ranged from 2.00 to 2.94 mg kg-1. There is an including awareness of the need to pay greater attention in the role of macronutrients enhancement in the soil for good soil health and proper nutrition of plant so as to attain optimum economic yield and soil is suitable for all major tropical and sub-tropical crops.

Contrasting patterns and drivers of soil micronutrient availability in paddy and maize fields of eastern China

Micronutrient deficiencies, known as ‘hidden hunger’, harm the growth and development of plants and people alike. However, less attention has been paid to soil micronutrients, the main source of micronutrients for plants and humans, than macronutrients (e.g. N and P availability). Understanding the geographic distribution of soil micronutrients across different agricultural fields is critical to support crop production and quality. Here we investigated the micronutrient composition (total and available copper, iron, manganese and zinc) of parallel 114 maize and rice fields in major crop production regions of eastern China. We found that available iron, copper and manganese were significantly higher in paddy soils than in maize soils, and total zinc was significantly higher in maize soils than in paddy soils. There was geospatial variation in the composition of micronutrients across latitudinal gradients and crop types. Soil organic matter and pH drove geographic variation of available micronutrient concentrations and ratio of total to available micronutrient, which were specific to micronutrient and crop type. Available Fe was decoupled with environment and total metal in paddy fields. Our study sheds light on the distribution patterns and environmental drivers of soil micronutrients in eastern China, and provides theoretical guidance for agricultural practice and fertilization management.

The function of the Medicagotruncatula ZIP transporter MtZIP14 is linked to arbuscular mycorrhizal fungal colonization.

Soil micronutrient availability, including zinc (Zn), is a limiting factor for crop yield. Arbuscular mycorrhizal (AM) fungi can improve host plant growth and nutrition through the mycorrhizal pathway of nutrient uptake. Although the physiology of Zn uptake through the mycorrhizal pathway is well established, the identity of the related molecular components are unknown. Here, RNA-seq analysis was used to identify genes differentially-regulated by AM colonization and soil Zn concentration in roots of Medicago truncatula. The putative Zn transporter gene MtZIP14 was markedly up-regulated in M.truncatula roots when colonized by Rhizophagus irregularis. MtZIP14 restored yeast growth under low Zn availability. Loss-of-function mutant plants (mtzip14) had reduced shoot biomass compared to the wild-type when colonized by AM fungi and grown under low and sufficient soil Zn concentration; at high soil Zn concentration, there were no genotypic differences in shoot biomass. The vesicular and arbuscular colonization of roots was lower in the mtzip14 plants regardless of soil Zn concentration. We propose that MtZIP14 is linked to AM colonization in M. truncatula plants, with the possibility that MtZIP14 function with AM colonization is linked to plant Zn nutrition.

Influence of Salinity on Micronutrient Availability in Soil and Plant in Cowpea-Groundnut Cropping System

An experiment on cowpea-groundnut rotation was conducted to study the effect of saline irrigation water on the availability of micronutrient cations (Fe, Zn, Cu and Mn) in soil and in plants with the effect of a gradual imposition of irrigation salinity (ECiw). Three saline treatments (S1: 2.0 dS m-1, S2: 4.0 dS m-1, S3: 6.0 dS m-1 with a control S0) were maintained in long-term field trials. In summer (cowpea) the soil ECe was raised to 6.01 dS m-1 while in kharif (groundnut) the ECe was 2.21 with S3. A noticeable increase in soil pH (from S0 to S3) was also observed in cowpea (0.48 unit) and groundnut (0.97 unit) seasons. The four available micronutrients in soil did not show any significant trend in both seasons. The concentration of both shoot Fe and Zn increased from control (S0) to highest salinity (S3) to the tune of 19% and 74% respectively in groundnut. The accumulation of root Fe and Zn in groundnut declined to the tune of 53% and 40% respectively with the increasing salinity from S0 to S3. For cowpea, only Zn content showed a decreasing trend among the other micronutrients. Genotypic variation of groundnut did not affect the accumulation of micronutrients as observed by testing eight groundnut genotypes in the present study. A significant drop in yield was noticed for both crops due to saline irrigation, and the groundnut yield varied between 1.6 t ha-1 (in S0) to 0.14 t ha-1 (in S3). This study marks a relevance where very less information is available on micronutrient availability in plant tissues and soil under changing salinity, especially for groundnut, which is considered an important oilseed crop from the national perspective.

Effects of 12-Year Nitrogen Addition and Mowing on Plant-Soil Micronutrients in a Typical Steppe.

Changes in soil micronutrient availability may have adverse consequences on grassland productivity, yet it's still largely unclear how concurrent human practices, such as fertilization and mowing, affect micronutrient cycling in the plant-soil systems. Here, we measured six essential micronutrient (Fe, Mn, Cu, Zn, Co and Mo) contents in both plant pool (separated as aboveground plant parts, litter, and belowground roots) at the community level and soil pool (0-10 cm depth) after 12-year consecutive nitrogen (N) addition (0, 2, 10, and 50 g N m-2 year-1) and mowing in a typical steppe of the Mongolian Plateau. The results show that (i) medium-N (10 g m-2 year-1) and high-N (50 g m-2 year-1) addition rates significantly increased contents of soil-available Fe (+310.0%, averaging across the two N addition rates), Mn (+149.2%), Co (+123.6%) and Mo (+73.9%) irrespective of mowing treatment, whereas these addition treatments usually decreased contents of soil total Fe (-8.9%), Mn (-21.6%), Cu (-15.9%), Zn (-19.5%), Co (-16.4%) and Mo (-34.7%). (ii) Contents of Fe in aboveground plant parts, litter, and roots significantly decreased, whereas plant Mn increased with N addition. Contents of above ground plant Cu, Zn, Co, and Mo significantly decreased at high-N addition rate, whereas contents of micronutrients in roots and litters, except for Fe, generally increased with N addition. Moreover, the total amount of micronutrients in the plant pool (contents × biomass) significantly increased at the medium-N addition rate but decreased at the high-N addition rate. All N addition rates significantly enlarged the pool of litter micronutrients, and roots could hold more micronutrients under N addition, especially combined with mowing treatment. Importantly, although mowing could regulate the effects of N addition on variables (i) and (ii), the effects were weaker overall than those of N addition. (iii) Changes in root micronutrients, except for Mn, could explain corresponding changes in plant micronutrients (R2: 0.19-0.56, all p < 0.01), and significant linear correlations were also observed between soil-available Fe and Fe in plant and roots. Aboveground plant Mn was significantly correlated with soil-available Mn, while Co and Mo in roots were also significantly correlated with soil-available Co and Mo. These results indicate that soil micronutrient supply capacity may decrease due to a decrease in total micronutrient contents after long-term N addition and mowing. They also suggest that different magnitude responses of soil micronutrients in plants (i.e., litters, roots) and soil should be considered when comprehensively examining nutrient cycling in grassland ecosystems.

Influence of micronuitrients on cadmium toxicity

There is growing evidence that micronutrient intake can lead to the development of poisoning and carcinogenesis caused by various chemicals. The article considers the question of the influence of the status of micronutrients on the toxicity of cadmium. After analyzing the literature data from both Russian and foreign databases (Scopus, Web of Science, RSCI), it was found that this topic on the effect of trace elements on the toxicity of heavy metals is relevant for scientists of various profiles.Cadmium interacts with the metabolism of four metals necessary for a balanced diet: Zn, Fe, Ca, and Cu. As can be seen from the analysis of literature sources, one of the important aspects of cadmium metabolism is its interaction with the sulfhydryl protein metallothionein.Like heavy metals, micronutrient availability in soil is affected by a number of factors. First, the availability of trace elements is directly or indirectly determined by the physicochemical and biological properties of the soil, such as pH, redox potential, soil organic matter content, complexing ligands, and underground biotic interactions. Based on the literature data, and analyzing the data obtained, it can be concluded that this issue remains relevant to this day. There have been few studies specifically designed to investigate the effect of micronutrient status on toxicity from non-essential metal exposure.Thus, many factors other than diet can greatly influence the metabolism of toxicants in the body, and require further research.

Effect of Slag Based Gypsum on Nutrient Uptake and Yield of Rice (Oryza sativa L.) in an Alkaline Soil

A pot culture study was undertaken to study the effect of slag based gypsum as a source of nutrient to the rice crop in an alkaline soil. The treatments included recommended dose of fertilizer (RDF) as control, 450, 600, 750 and 900 kg ha-1 of slag based gypsum (SBG) along with RDF. The treatments were replicated thrice and complete randomized design (CRD) was followed for statistical analysis. The results revealed that application of 750 kg SBG ha-1 recorded significantly higher rice grain (8.85 g pot-1) and straw (9.00 g pot-1) yield when compared with other treatments. Further, application of 750 kg SBG ha-1 recorded higher nitrogen (N) (137.68 mg pot-1), phosphorus (P) (48.37 mg pot-1) and potassium (K) (45.38 mg pot-1) uptake by rice grain and also a significantly higher exchangeable calcium (Ca) (12.19 c mol (p+) kg-1) and magnesium (Mg) (12.93 c mol (p+) kg-1) in post-harvest soil. Whereas, application of 900 kg SBG ha-1 recorded higher N (75.64 mg pot-1), P (17.95 mg pot-1) and K (49.78 mg pot-1) uptake by rice straw and also higher pH (8.95), electrical conductivity (EC) (1.28 dS m-1), available N (160.53 kg ha-1) and available sulphur (S) (182.50 kg ha-1) in post-harvest soil. Moreover, application of 900 kg SBG ha-1 was also reported to give higher micronutrient uptake and availability in post-harvest soil of our studies.

Bioavailability of Micronutrient Cations in Rice as Influenced by Inorganic Nitrogen Dynamics in Soil under Typic Haplustepts

ABSTRACT Crop establishment methods play a vital role in the predominance of nutrient forms. Nitrogen dynamics in the soil can alter micronutrient availability and uptake. Four treatments each replicated thrice, comprising of three methods of rice establishment viz., puddled transplanted rice (PTR), unpuddled transplanted (UPTR), and direct seeded rice (DSR) in different combinations of rotation with conventionally tilled lentil (CTL) and zero till lentil (ZTL) were compared for their effect on inorganic nitrogen in the soil and its consequent effect on the micronutrient availability in soil and their uptake by rice grain. As per the results obtained from the study, the different establishment techniques with associated treatments after 7 years of continuous cultivation did not have any significant effect on general soil properties like pH, electrical conductivity (EC), organic carbon (OC), and cation exchange capacity (CEC). Treatments had a significant effect on soil nitrogen content and uptake and on soil micronutrient status and their uptake by rice as estimated after harvest of the rice crop. UPTR-ZTL crop rotation with crop residue management and biopriming with Azotobacter was found to be the most efficient management practice and performed better than the conventional crop establishment techniques like PTR and CTL systems. Nitrogen content in soil and plant N uptake showed positive correlations with micronutrient uptake by the rice grain. Significant positive correlations were obtained with the uptake of Fe, Mn, and Zn. Nitrogen dynamics (irrespective of crop establishment methods) in soil especially ammoniacal N, had a positive effect on the cationic micronutrient uptake by the crop, but results were not conclusive enough to suggest the role of N forms on uptake and translocation of micronutrient cations.

Iron fortification of food crops through nanofertilisation

Micronutrient deficiencies are a significant cause of malnutrition worldwide, particularly in developing countries, affecting nearly 1.8 billion people worldwide. Agriculture is the primary source of nutrients for humans, but the increasing population and reducing arable lands areas are putting the agricultural sector under pressure, particularly in developing and less developed countries, and calls for intensive farming to increase crop yield to overcome food and nutrients deficiency challenges. Iron is an essential microelement that plays a vital role in plant and human growth, and metabolism, but its deficiency is widely reported and affects nearly one-third of the world population. To combat micronutrient deficiency, crops must have improved nutritional qualities or be biofortified. Several biofortification programs with conventional breeding, biotechnological and agronomic approaches have been implemented with limited success in providing essential nutrients, especially in developing and under-developed countries. The use of nanofertilisers as agronomic biofortification method to increase yields and nutrients, micronutrient availability in soil and uptake in plant parts, and minimising the reliance on harmful chemical fertilisers is essential. Using nanoparticles as nanofertilisers is a promising approach for improving the sustainability of current agricultural practices and for the biofortification of food crop production with essential micronutrients, thus enhanced nutritional quality. This review evaluates the current use of iron nanofertilisers for biofortification in several food crops addressing critical knowledge gaps and challenges that must be addressed to optimise the sustainable application.

Evaluation of soil micronutrients under different spacing of Eucalyptus-based agroforestry system

A study was carried out during 2016–17 at Research Farm of the Department of Forestry, CCS Haryana AgriculturalUniversity, Hisar, Haryana to assess the effect of Eucalyptus planting geometry (17 m × 1 m × 1 m, 6 m × 1.5 m, 3 m× 3 m and devoid of trees, i.e. control) on soil micronutrients (zinc, iron, manganese, and copper) at the soil depths of 0–15, 15–30, 30-60 and 60–90 cm. The results showed that the different planting spacing of Eucalyptus, soil depths, and their interactions on micronutrients were significantly different and these were decreased with increasing the soil depth. The DTPA extractable micronutrient Zn, Fe, Mn, and Cu were in the range 0.8-1.3, 5.1-6.7, 6.8-8.1, and 2.6-3.1 mg/kg respectively. The soil micronutrient content decreased under a wider spacing agroforestry system but the maximum reduction was found under control treatment when compared with closer spacing (3 m × 3 m). The increase in micronutrient availability in soil due to the influence of Eucalyptus tereticornis was more in the surface (0-15 cm) than in subsurface soil (15-30, 30-60, and 60-90 cm) layers.

Aridity and geochemical drivers of soil micronutrient and contaminant availability in European drylands

AbstractDryland soils provide different societal and environmental services, such as food supply and biodiversity support. In Europe, most of the dryland areas are devoted to agriculture. In the next decades, both European and worldwide drylands are expected to suffer with increased intensity due to the expected climate change‐derived rise in aridity. Many studies have focussed on aridity‐induced changes in major nutrients in drylands, but little is known of the impact of environmental and biogeochemical factors on micronutrients with critical roles in life, and as inorganic contaminants with ecotoxicological implications. We analysed and explored drivers of total and available concentrations of micronutrients (Co, Cu, Fe, Mo, Mn, Ni and Zn) and contaminants (As, Cd and Pb) in 148 soil samples collected from European drylands covering a wide range of aridity and of other geochemical parameters. The availability of micronutrients increased with their total content, decreased with pH and was enhanced by organic C content. Aridity decreased the availability of Fe, a key element in human diet. Our findings also highlight the scarcity of this micronutrient in European drylands, as well as of some other important micronutrients like Zn and Mo in agricultural soils. Total content was the main driver of the availability of Cd and Pb, and organic matter exerted synergistic effects on contaminant release. Our data show the need for precise management practices to be incentivised by agricultural and environmental policies in order to ensure micronutrient supply and avoid contamination, thus maintaining adequate levels of agricultural productivity and simultaneously preserving dryland ecosystems.Highlights Drylands are important for food production in Europe and sensitive to climate change. The occurrence of metals in European Union dry soils and the drivers influencing them were studied. Some micronutrients (Fe, Mo and Zn) were scarce while contaminants were abundant. SOC, pH and clays were the main drivers of element availability; aridity reduced Fe. Agricultural practises are needed to ensure nutrient supply and prevent contamination.

Influence of Acidified Biochar on CO2–C Efflux and Micronutrient Availability in an Alkaline Sandy Soil

Biochar, an alkaline carbonaceous substance resulting from the thermal pyrolysis of biomass, reportedly enhances the micronutrient availability in acidic soils with little or no effect on alkaline soils. In this study, biochars were produced from poultry manure (PM) at 350 °C and 550 °C (BC350 and BC550 respectively). The acidified biochars (ABC350 and ABC550, respectively) were incorporated into an alkaline sandy soil, and their effects on the soil micronutrients (Cu, Fe, Mn and Zn) availability, and CO2–C efflux were investigated in a 30-day incubation study. The treatments (PM, BC350, BC550, ABC350, and ABC550) were administered in triplicate to 100 g soil at 0%, 1%, and 3% (w/w). Relative to the poultry manure treatment, acidification drastically reduced the pH of BC350 and BC550 by 3.13 and 4.28 units, respectively, and increased the micronutrient availability of the studied soil. Furthermore, the biochars (both non-acidified and acidified) reduced the CO2 emission compared to that of the poultry manure treatment. After 1% treatment with BC550 and ABC550, the CO2 emissions from the soil were 89.6% and 91.4% lower, respectively, than in the 1% poultry manure treatment. In summary, acidified biochar improved the micronutrient availability in alkaline soil, and when produced at higher temperature, can mitigate the CO2 emissions of soil carbon sequestration.

Effect of tillage and weed management practices on micronutrient availability in post-harvest soil under maize-wheat cropping system

Tillage practices play a major role in nutrient dynamics under different cropping systems. The objective of this study was to examine the influence of different tillage practices and weed management on micronutrient availability in soil. The treatments included three tillage in main plot and four weed management practices in sub plot were arranged in a spilt plot design with three replications.Measurements made at the end of 4 years, showed that in the 0-15 cm soil depth, effect of different tillage and weed management practices on soil properties was significant. The values of soil pH and EC declined under ZT. The mean value of SOC (8.9 g kg-1) was reported higher under ZT. Higher value of Zn and Fe was reported under ZT (3.63 mg kg-1, 15.49 mg kg-1) followed by CT (2.87 mg kg-1, 13.65 mg kg-1) and FIRBS (2.47 mg kg-1,13.47 mg kg-1) respectively. In case of Cu, the higher value (1.32 mg kg-1) was reported under ZT followed by FIRBS (1.30 mg kg-1) and CT (1.22 mg kg-1). Trend was reverse in case of Mn and content was significantly higher (9.4 mg kg-1) under CT followed by ZT (9.02 mg kg-1) and FIRBS (8.70 mg kg-1). The results suggested that ZT can play a vital role in sustaining micronutrient availability due to decreased soil pH and the greater amount of organic matter compared to other tillage methods.

Effects of Fertigation with Untreated and Treated Leachates from Municipal Solid Waste on the Microelement Status and Biometric Parameters of Viola × wittrockiana

Landfill leachate can release pollutants into the environment. Nevertheless, it can be treated using a phytodepuration system via constructed wetlands to reduce contaminants. Moreover, this leachate can also increase the availability of macro and micronutrients in soil and water. In this trial, the reuse of untreated and treated wastewater from municipal solid waste (MSW) for fertigation was assessed. Plantlets of Viola × wittrockiana (pansy) were grown in a greenhouse and five fertigation treatments were applied: W9.0 (pure wastewater, EC 9.0 dS m−1), W4.5 (diluted wastewater, EC 4.5 dS m−1), DW4.5 (depurated wastewater, EC 4.5 dS m−1), PW4.5 (phytodepurated wastewater, EC 4.5 dS m−1), and T (tap water, control, EC 1.5 dS m−1). The treatment with untreated wastewater had a negative effect on plant dry weight, leaf size, specific leaf area, water content, and the number of closed and open flowers, due to the high concentration of SO42− in the fertigation water. It also reduced the content of Cu, Mn, Fe, and Zn with respect to the control, because of the dry biomass diminution. Conversely, fertigation with phytodepurated wastewater enhanced root and shoot dry weight, water content, and the number of closed and open flowers. Cu and Mn contents in flowers surpassed the content detected in plants fertigated with untreated leachates. These findings demonstrate that phytodepurated wastewater obtained from MSW can be employed for the fertigation of this species.

Adaptability of Soil pH through Innovative Microbial Approach

Soil pH is a critical characteristic that regulates the abundance of essential nutrients in the soil system. Low soil pH reduces the supply of secondary macronutrients, whereas higher pH restricts soil micronutrient availability. In addition, soil nutrient sources such as organic and inorganic fertilizers by plants require an adequate pH for optimum plant growth and productivity. The soil pH is regarded as the “master of soil indices", which has a role to play in controlling biogeochemical cycles that influence plant growth. It also has an enormous influence on microbial biodiversity in the soil. Various approaches have been used to alter the soil pH, demonstrating that it is not easy to adjust soil pH. Therefore, a suitable but practical approach is required to control or change the pH of the rhizosphere. Microbial breeding technique such as genome replication may be an appropriate option to alter the pH of the rhizosphere. Genetically engineered microbes may have the exceptional ability to release sufficient acidic or basic compounds that could increase or decrease the pH levels in the rhizosphere. In recent years, this view has helped answer some common evolutionary concerns regarding how bacteria and their host species have evolved from their early ancestors. Greater exploitation of microbes in this respect would be necessary for sustainable crop production and helping to resolve issues related to soil-plant interactions for nutrients. To breed the microbes selectively for optimal nutritional interaction with plants, the genetic components of different traits must first be explored.