Soil Magnesium Research Articles

Effects of Different Nitrogen Fertilizer Rates on Soil Magnesium Leaching in Tea Garden

Effects of Different Nitrogen Fertilizer Rates on Soil Magnesium Leaching in Tea Garden

Soil Acidification Can Be Improved under Different Long-Term Fertilization Regimes in a Sweetpotato-Wheat Rotation System.

Soil acidification is a significant form of agricultural soil degradation, which is accelerated by irrational fertilizer application. Sweetpotato and wheat rotation has emerged as an important rotation system and an effective strategy to optimize nutrient cycling and enhance soil fertility in hilly areas, which is also a good option to improve soil acidification and raise soil quality. Studying the effects of different fertilization regimes on soil acidification provides crucial data for managing it effectively. An eight-year field experiment explored seven fertilizer treatments: without fertilization (CK), phosphorus (P) and potassium (K) fertilization (PK), nitrogen (N) and K fertilization (NK), NP fertilization (NP), NP with K chloride fertilization (NPK1), NP with K sulfate fertilization (NPK2), and NPK combined with organic fertilization (NPKM). This study focused on the soil acidity, buffering capacity, and related indicators. After eight years of continuous fertilization in the sweetpotato-wheat rotation, all the treatments accelerated the soil acidification. Notably, N fertilization reduced the soil pH by 1.30-1.84, whereas N-deficient soil showed minimal change. Organic fertilizer addition resulted in the slowest pH reduction among the N treatments. Both N-deficient (PK) and organic fertilizer addition (NPKM) significantly increased the soil cation exchange capacity (CEC) by 8.83% and 6.55%, respectively, compared to CK. Similar trends were observed for the soil-buffering capacity (pHBC). NPK2 increased the soil K+ content more effectively than NPK1. NPKM reduced the sodium and magnesium content compared to CK, with the highest magnesium content among the treatments at 1.60 cmol·kg-1. Regression tree analysis identified the N input and soil magnesium and calcium content as the primary factors influencing the pHBC changes. Structural equation modeling showed that the soil pH is mainly influenced by the soil ammonium N content and pHBC, with coefficients of -0.28 and 0.29, respectively. Changes in the soil pH in the sweetpotato-wheat rotation were primarily associated with the pHBC and N input, where the CEC content emerged as the main factor, modulated by magnesium and calcium. Long-term organic fertilization enhances the soil pHBC and CEC, slowing the magnesium reduction and mitigating soil acidification in agricultural settings.

Magnesium in Soils of Agricultural Landscapes of Western Siberia

Background: Western Siberia has great potential for crop and livestock production; it is limited by degradation of soil fertility due to depletion of biophilic elements, including Mg. Intensification of agricultural production requires monitoring and optimization of magnesium nutrition of field crops. This study aimed at investigating changes in content of magnesium forms Gleyic Chernozems and Luvic Greyzemic Phaeozem in the Western Siberia during their long-term agricultural use. Methods: Soil samples were taken from the fields of long-term experiments in 1978, 1988 and 2019. Three cores were taken from a soil layer 0-20, 20-40 cm thick and combined into composite samples. Composite samples were kept in the archives of the institute. Chemical analysis of composite soil samples was carried out in 2020. Chemical analyzes of soil and plants were carried out by conventional methods. Magnesium forms were extracted: easily exchangeable with 0.0025 M CaCl2 solution, exchangeable with 1 M CH3COONH4, non-exchangeable with 1 M HNO3 and determined on an atomic absorption spectrometer. Result: Systematic use of the ammonia form of nitrogen fertilizers (60-120 kg a.m./ha per year) led to a decrease in mobile forms of magnesium in the most root-inhabited soil layer. The removal of magnesium by potatoes was small (8-10 kg/ha, 80 % falls on the tops). Consequently, a significant decrease in the reserves of magnesium available to plants in soils is associated not so much with the alienation of the element with yield, but with leaching processes due to the displacement of magnesium from the soil-absorbing complex by ammonium ions introduced with fertilizers and also, probably, potassium.

Effect of Different Liquid Organic Manures on the Nutrient Release Pattern in Radish Grown Soil

The study of nutrient release patterns from various organic manures is critical for ensuring enough nutrient availability to crop plants at the right time and in the right quantity. To assess the nutrient release pattern from several organic manures, including farm yard manure, panchagavya and jeevamrutha, a field experiment was conducted at organic farming block of Zonal Agricultural Research Station, V. C. Farm, Mandya during late Kharif 2020. The experiment consists of 9 treatments including different rates of recommended dose of nitrogen was applied through FYM and one- and two-times application of panchagavya and jeevamrutha in different combinations. The experiment was laid out in a Randomized Block Design with three replications. The release pattern of available nitrogen, phosphorus, potassium, calcium, magnesium, sulphur and micronutrients in soil applied with various organic manures at various days (15, 30, 45 DAS and at harvest). The study revealed that application of various organic manures showed substantial increase in primary (N, P and K) and secondary nutrient (S) release and there were no significant variations found in Ca, Mg, Fe, Mn, Cu and Zn release pattern. Based on the release rate of nutrients, it was found that there was consistent and stable release of N, P, K and S from 75% RDN through FYM + two time application of Panchagavya followed by 75% RDN through FYM + two time application of Jeevamrutha, compared to other treatments.

Effect of pH, Carbonate and Clay Content on Magnesium Measurement Methods on Hungarian Soils

More exact information on soil nutrient management is crucial due to environmental protection, nature conservation, decreasing sources for mining, general precaution, etc. Soil magnesium (Mg) analytical methods of potassium chloride (KCl), Mehlich 3 (M3), water (WA) and cobalt hexamine (CoHex) extractions are compared with an elemental analysis and X-ray fluorescence (XRF) analysis. The ratio of the available to the total Mg content was calculated and compared on the whole dataset. The results showed that the linear regressions between all the pairs of Mg content measurement methods were significant. The linear relationship between the KCl and CoHex methods has the highest determination coefficient (R2 = 0.96), followed by WA–M3 (R2 = 0.68), M3–CoHex (R2 = 0.66) and M3–KCl (R2 = 0.60). The M3 solution demonstrated a greater capacity for extracting Mg from the soil. The second part is the analysis of the influence of CaCO3, pH, soil texture and clay content on the measurable magnesium content of soils. It was established that the extraction methods, the soil and the classification method of the soil properties affect the evaluation. These results may help through the nutrient replenishment and the melioration of soils. These results can help the examination of mineral nutrients, especially the Mg uptake.

Short-term effect of no-tillage management on the chemical attributes and bacterial diversity in soils in an organic production system

No-tillage (NT) has been adopted in organic agriculture as an alternative to conventional tillage (CT) for improving soil conservation. Cover crops (CC) play a vital role in this process by providing straw and releasing nutrients into the soil. Therefore, in this study, we aimed to evaluate the effects of NT and CT management on the chemical properties and bacterial diversity of soil following the cultivation of diverse CC in an organic system. The experiment was conducted using a randomized block design with subdivided plots, wherein the plots represented CT and NT, and the subplots represented the diverse CC tested, including pearl millet, sunn hemp, jack bean, seed mixes 1 and 2 (containing 100 % and 50 % of the recommended seeding rates for each crop), and spontaneous plants. The evaluations were conducted one year after the experiment was conducted. The results demonstrated that NT promoted increases in soil magnesium, phosphorus, and organic carbon contents, including increased bacterial richness. Moreover, NT resulted in a higher abundance of Bacteroidetes, GAL15, and Myxococcota. Conversely, CT favored a greater relative abundance of Actinobacteria, in addition to the members of Bacteroidetes. Regarding the influence of CC, no significant differences were observed in the diversity and structure of the bacterial communities, except for subgroup 17, which was more abundant in spontaneously grown plants. NT proved to be more effective than CT in improving soil chemical properties and bacterial diversity, implying its potential to contribute to sustainable agricultural systems.

Transcription-related metabolic regulation in grafted lemon seedlings under magnesium deficiency stress

Magnesium is one of the essential nutrients for plant growth, and plays a pivotal role in plant development and metabolism. Soil magnesium deficiency is evident in citrus production, which ultimately leads to failure of normal plant growth and development, as well as decreased productivity. Citrus is mainly propagated by grafting, so it is necessary to fully understand the different regulatory mechanisms of rootstock and scion response to magnesium deficiency. Here, we characterized the differences in morphological alterations, physiological metabolism and differential gene expression between trifoliate orange rootstocks and lemon scions under normal and magnesium-deficient conditions, revealing the different responses of rootstocks and scions to magnesium deficiency. The transcriptomic data showed that differentially expressed genes were enriched in 14 and 4 metabolic pathways in leaves and roots, respectively, after magnesium deficiency treatment. And the magnesium transport-related genes MHX and MRS2 may respond to magnesium deficiency stress. In addition, magnesium deficiency may affect plant growth by affecting POD, SOD, and CAT enzyme activity, as well as altering the levels of hormones such as IAA, ABA, GA3, JA, and SA, and the expression of related responsive genes. In conclusion, our research suggests that the leaves of lemon grafted onto trifoliate orange were more significantly affected than the roots under magnesium-deficient conditions, further indicating that the metabolic imbalance of scion lemon leaves was more severe.

The Use of Magnesium Fertilizer Can Improve the Nutrient Uptake, Yield, and Quality of Rice in Liaoning Province

In this study, the effects of the soil application and foliar spraying with magnesium fertilizers on rice yield and quality in Liaoning Province were investigated. Field experiments were conducted at Kaiyuan, Xinmin, and Dawa in 2022 and 2023. Magnesium fertilizers were used in the soil as magnesium sulfate monohydrate and silicon–magnesium fertilizer and on leaves was magnesium sulfate heptahydrate. The results showed that the application of 12 kg magnesium hm−2 in the soil at the Kaiyuan site can significantly increase rice yield by 14.8% compared with sites without magnesium fertilizer. The use of silicon–magnesium fertilizer showed a more obvious yield increase of 22.2%. The application of 3 kg magnesium hm−2 or 6 kg magnesium hm−2 on the leaf surface increased the rice yield at Kaiyuan by 19.4% and 21.6% and at Xinmin by 17.8% and 5.4%, respectively. The yield increase was more significant under the optimal fertilization treatment compared with the conventional fertilization treatment. The application of magnesium fertilizer increased the magnesium, nitrogen, and phosphorus contents in rice shoots and the potassium and crude protein contents in rice grains. The effect of foliar spraying with magnesium fertilizers was more obvious than soil application. Therefore, the magnesium fertilizer used on the leaf surface plays an important role in improving rice yield and quality in rice-growing areas with relatively rich soil magnesium content. Magnesium fertilizer can compensate for the yield decrease caused by the reduced use of nitrogen and phosphorus fertilizers by promoting nitrogen and phosphorus absorption in rice. Conclusively, the application of magnesium fertilizer is a promising measure to improve rice production in Liaoning province under a reduced nitrogen and phosphate fertilizer background.

Evolving dynamics of insect frass fertilizer for sustainable nematode management and potato production.

Potato production faces major challenges from inadequate soil fertility, and nematode infestation, yet synthetic fertilizers and nematicides are costly and harmful to the environment. This study explored the potential of chitin-fortified black soldier fly-composted organic fertilizer (BSFCOF) as a multipurpose organic fertilizer amendment for enhancing potato yield and suppressing potato cyst nematodes (PCN). The BSFCOF was applied at a rate equivalent to 150 kg N ha-1 and fortified with chitin from black soldier fly pupal exuviae at inclusion rates equivalent to 0.5, 1, 2, 3, 4 and 5% chitin. Data were collected on potato growth characteristics, PCN population densities, and soil chemical properties for two growing cycles. Results showed that chitin fortified BSFCOF significantly improved potato growth parameters, chlorophyll concentration, marketable tuber yield and number of marketable tubers. The marketable tuber yield achieved using chitin-fortified BSFCOF was 70 - 362%, and 69 - 238% higher than the values achieved using unfertilized soil during the first and second growing cycles, respectively. Soil amendment with chitin-fortified BSFCOF significantly reduced the number of cysts per 200 g soil-1, number of eggs and J2 per cyst-1, eggs g-1 soil and reproduction rate by 32 - 87%, 9 - 92%, 31- 98% and 31 - 98%, respectively. The PCN suppression increased with chitin inclusion rates. There were significantly higher values for soil pH, ammonium nitrogen, nitrate nitrogen, available phosphorus, calcium, magnesium, potassium, and cation exchange capacity in soil amended with BSFCOF compared to unamended soil. This study demonstrates that BSFCOF fortified with 5% chitin is an effective soil enhancer with multiple benefits, including improved soil fertility, potato performance, and effective management of potato cyst nematodes.

Erratum to: Comparison of soil‐test extractants for potassium, calcium, magnesium, sulfur, and micronutrients in Idaho soils

Erratum to: Comparison of soil‐test extractants for potassium, calcium, magnesium, sulfur, and micronutrients in Idaho soils

Improving soil fertility through dual inoculation with arbuscular mycorrhizal fungi and Rhizobium on a eutric cambisol cultivated with forage legumes in a semi-arid region

The Sub-Saharan region of southern Africa is characterized by high temperatures, low rainfall, and poor land-use management practices such as continuous cropping without replenishment of soil nutrients. The combination of these factors has resulted in nutrient depletion and land degradation. The current study aimed at investigating the effect of arbuscular mycorrhizal fungi (AMF) and Rhizobium bacteria inoculation on soil chemical properties in field-grown forage legumes, namely, Mucuna pruriens (mucuna), Lablab purpureus (lablab) and Vigna unguiculata (cowpea), in the semi-arid region of the Eastern Cape Province (South Africa). Forage legumes were inoculated with the AMF species Paraglomus occulum and the Rhizobia bacteria species Bradyrhizobium strain and grown for 120 days. Soil samples were collected in the following sequence: prior to planting, before flowering and after harvesting the forage legumes in each of the two seasons (2017/2018 and 2018/2019) and soil chemical properties were determined using standard procedures. The results showed that the addition of dual inoculation over time greatly improved soil chemical properties when compared to the control treatment. This was advocated by the significant (P ≤ 0.05) increase in soil pH, soil organic carbon, soil organic matter, total nitrogen, phosphorus, calcium, potassium, magnesium, sodium, sulfur and iron in soils. The concentration of cation exchange capacity was significantly (P ≤ 0.05) higher in cowpea treated with Rhizobium as compared to other treatment combinations. The control treatment of mucuna forage greatly improved the concentrations of manganese, boron, copper, molybdenum, and zinc over other treatment combinations only before the flowering stage. However, the concentrations of micronutrients were significantly higher on the treatment combination of lablab and single inoculation of AMF after harvesting. Generally, dual inoculation with AMF and Rhizobia enhanced soil properties when compared to a single inoculation or untreated control.

Distribution of Exchangeable Magnesium in Lowland Rice-Cultivated Soils of Sri Lanka as Affected by the Differences in Climate, Soil, and Water Source

Magnesium (Mg) is an essential macronutrient for plants. Even though Sri Lankans consume rice as the staple food, the Mg status in Sri Lankan paddy soils as affected by its climate, soils, and water sources used are not well understood. This study was conducted to (i) determine the distribution of exchangeable Mg (ex-Mg) concentration, and (ii) examine the interactive effects of agro-climatic zones (ACZs), soil order, and water source in determining the ex-Mg concentra-tion in lowland paddy fields of Sri Lanka. A total of 9,038 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. The ex-Mg concentration was determined after extracting in 0.01 M CaCl2 and detected using inductively coupled plasma-mass spectrometry. The range of ex-Mg was within 0.01-1,610 mg kg-1, with a mean of 210.4 mg kg-1. From the tested soil samples, 66% were Mg-deficient (<240 mg kg-1), 32% were Mg-optimal (240-730 mg kg-1) and 2% were Mg-excessive (>730 mg kg-1). Among the ACZ, the Dry zone Low country had the highest ex-Mg concentration (p<0.05). Among the soil orders tested, Vertisols had the highest and Histosols had the lowest ex-Mg concentration (p<0.05). Irrigated rice fields had higher ex-Mg than the rainfed systems (p<0.05). Soil ex-Mg concentration was positively correlated with soil pH (p<0.05) and crop productivity (p<0.05). As most rice-growing soils of Sri Lanka are Mg-deficient, it is important to implement strategies specific to ACZs, soil orders, and water sources to improve the soil-Mg status.

Which Soil Properties Determine Tree Nutrient Supply in Extreme Technosol Conditions?

In recent years, there has been an increased interest in the selection of tree species for their adaptation to difficult habitat conditions in post-mining areas. As global climate change can cause changes in the circulation of elements, it is vital to understand how soil and habitat conditions affect the mineral nutritional status of trees.The study compared the nitrogen (N) and phosphorus (P) content in the leaves of various tree species on different substrates created by mining activities. The research was carried out in stands growing on reclaimed post-mining soils composed of various parent materials, including sands, clays, and ashes. The factors influencing the N and P supply to trees in the designated parent material were investigated. The soil’s physicochemical properties were determined, and biochemical analyses were conducted. The tests performed showed that there were no differences in the N and P content in the leaves of scots pine (Pinus sylvestris), black locust (Robinia pseudoacacia), black alder (Alnus glutinosa), and common birch (Larix decidua) growing on different substrates. The results confirmed a significant relationship between the mineral nutritional status of trees and the chemical (N, Mg2+, and K+) and biological (AcdPhoSP) properties of soils. The N supply was related to the contents of nitrogen total (Ntot) and exchangeable magnesium (Mg2+) in soils and to the specific activity of acid phosphatase (AcdPhoSP). The level of phosphorus (P) supply to the studied tree species growing on technogenic soils was shown to be a factor related to the activity of acid phosphatase (AcdPhoSP).

Post Manure Application Time and Rate on Soil Nutrient Changes and Seed Proximate Contents of Egusi Melon (Colocynthis citrullus L.)

ABSTRACT The efficiency of manure application is a function of quantity and time of application. Two field trials were conducted to determine the effects of time and quantity of manure application on soil nutrient dynamics and proximate contents in Abeokuta, Nigeria, by cultivating egusi melon with 0, 5, 10, and 15 t.ha−1 poultry manure (PM) applied at 2 and 4 weeks before planting (WBP). Melon was planted at 2 and 4 weeks after manure application (WAMA). The year of cultivation affected post cropping soil nutrient contents. Soil organic matter was not reduced with 10 t.ha−1 application. It also maintained soil nitrogen content and increased exchangeable potassium. Soil calcium and magnesium content increased with cropping. In 2017, planting with 5 t.ha−1 PM applied at 2 WBP gave the highest exchangeable acidity content, but from 10 t.ha−1 PM applied at 4 WBP, in 2018. Soil calcium and magnesium contents were higher with 2 years cropping. It was highest with either 10 t.ha−1 PM at 2 WBP or 5 t.ha−1 PM at 4 WBP. Soil magnesium content was highest with 10 t.ha−1 PM at 2 WBP. Cropping increased soil sand and clay particles but reduced silt particles. Seed crude protein was reduced with 2 years cropping. It was highest from 15 t.ha−1 PM applied at 2 WBP in 2017. Seed fat and carbohydrate contents were increased with 2 years cropping. For soil calcium and magnesium contents, 10 t.ha−1 PM applied at 2 WBP poultry manure is optimum.

Magnesium Supplementation Concerning Soil Chemical Properties and Cowpea Yield in Ultisol of Kerala, India

Ultisol of Kerala faces high magnesium deficiency due to poor retention of magnesium to soil exchange surfaces under high rainfall conditions. Hence magnesium nutrition management is an important aspect of fertility improvement in these soils. We conducted a pot culture study to determine the influence of varying magnesium levels on soil chemical properties and yield of cowpea in Ultisols of Kerala. We used a completely randomized design. The study was carried out in the Radiotracer Laboratory, College of Agriculture, Vellanikkara, Kerala Agricultural University, in January-April 2019. Magnesium carbonate at levels 5 to 80 mg.kg-1 was provided along with recommended doses of fertilizers for cowpea maintained in pots. Rhizosphere samples were analyzed during flowering and at harvest of the crop following standard procedures. Yield and yield attributes are recorded at the time of harvest. Graded doses of magnesium introduced significant (P< 0.05) variations in the soil available nutrients and yield of cowpea. Soil pH and available magnesium in rhizosphere soil during flowering and post-harvest increased with the increasing levels of magnesium carbonate, and using 80 mg kg-1 of magnesium recorded the highest pH, available phosphorus, potassium, and magnesium. In contrast, the gradation of magnesium could not produce significant variation in yield. The highest yield was recorded in treatment supplied with 10 mg kg-1 of magnesium and was on par with those of higher levels of magnesium supplement. Graded doses of magnesium introduced variation in available nutrients but a better yield response in cowpea was obtained from magnesium at 10 mg.kg-1.

Magnesium in Saline Gypsum-Bearing Soils of Russia

Statistical analysis of 3802 samples of saline soils from different regions of Russia made it possible to substantiate preliminary conclusions about a higher proportion of magnesium in soils containing gypsum in comparison with gypsum-free saline soils. Gypsum is not a toxic salt and its presence does not cause an increase in salinity. Salinization is mainly related to sodium and magnesium salts, with the sodium percentage often exceeding the magnesium percentage. It is statistically substantiated that in the studied saline soils without gypsum, sodium often dominates among cations in the soil water extract (1 : 5) at any degree of salinity, The appearance of gypsum in the soil profile is accompanied by a significant increase in the proportion of magnesium. In slightly or moderately saline horizons with more than 1% of gypsum, the proportion of magnesium in the water extract (1 : 5) often exceeds 50% of the sum of sodium and magnesium according to the median, arithmetic mean, upper quartile, and maximum values. Even in strongly and very strongly saline soil horizons containing gypsum, the proportion of magnesium is significant with the median of 43 and 31%, respectively, which is 5.8–6.7 times higher than the proportion of magnesium in gypsum-free horizons of the same degree of salinity.

Magnesium in Saline Gypsum-Containing Soils of Russia

Statistical analysis of 3802 samples of saline soils from different regions of Russia made possible to substantiate observations of a higher proportion of magnesium in soils containing gypsum compared to saline soils without gypsum. Gypsum is not a toxic salt and its presence does not lead to an increase in salinity. The increase of the salinity degree is mainly associated with sodium and magnesium salts, with the proportion of sodium more often than the proportion of magnesium. The article statistically substantiates that in the studied saline soils that do not contain gypsum, among the cations in the water extract (1 : 5), sodium most often dominates at any degree of salinity. The appearance of gypsum in the soil profile is accompanied by a significant increase in the proportion of magnesium. With a low and medium degree of salinity in horizons containing more than 1% gypsum, according to the median, as well as the arithmetic mean, upper quartile and maximum, the proportion of magnesium from the sum of sodium and magnesium in the water extract (1 : 5) is often more than 50%. Even at a strong and very strong degree of salinity, the proportion of magnesium in gypsum-containing horizons is significant and amounts to 43 and 31%, respectively, on the median, which is 5.8–6.7 times higher than the proportion of magnesium in gypsum-free horizons of the same degree of salinity.

Unravelling the Release Kinetics of Exchangeable Magnesium in Acid Soil of Nilgiris

Magnesium deficiency is a pervasive and recurrent factor that significantly restricts crop production, primarily attributable to the low levels of exchangeable magnesium (ex-Mg) present in acidic soil conditions. This deficiency exerts a pronounced negative influence on the sustainability and progress of agricultural development. Hence the current study aspired at modeling the kinetics of Exchangeable Magnesium release from 3 fertilizer sources i.e., Epsom salt (MgSO4·7H2O), Magnesite (MgCO3) and Dolomite [CaMg(CO3)2] in the acidic soil of the Nilgiris district in Tamil Nadu, India. Four mathematical models were verified—Power function, parabolic diffusion, Simple-Elovich, and first-order to explain cumulative Mg2+ release. Power function was noticed to be an outstanding empirical equation finely fitted to the experimental data. The intensity, as well as the modality of the release pattern, was predicted by the numerical parameters. The power function as well as Parabolic Diffusion portrayed the Mg2+ release kinetics best as verified by the maximum correlation coefficients (r2). The parabolic diffusion model also designated the data as suitable, signifying diffusion-controlled exchange. From the derived dissolution rates, it was conceivable to agree Epsom salt (MgSO4·7H2O) from which the release was faster than the other two magnesium sources. In conclusion, these outcomes provided an insight into the temporal dynamics of magnesium availability in acidic soil, highlighting the importance of understanding its release kinetics for sustainable agriculture development. The findings contribute to the broader knowledge of magnesium management strategies, aiding in the development of targeted interventions to alleviate magnesium deficiency and optimize crop productivity in acidic soil environments.

Effect of iron nanoparticles and conventional sources of Fe on growth, physiology and nutrient accumulation in wheat plants grown on normal and salt-affected soils

Salt stress is becoming a serious problem for the global environment and agricultural sector. Different sources of iron (Fe) can provide an eco-friendly solution to remediate salt-affected soils. The Fe nanoparticles (FeNPs) and conventional sources of Fe (iron-ethylene diamine tetra acetic acid; Fe-EDTA; and iron sulfate; FeSO4) were used to evaluate their effects on wheat crop grown in normal and salt-affected soils. Application of FeNPs (25 mg/kg) on normal soil increased the dry weights of wheat roots, shoots, and grains by 46%, 59%, and 77%, respectively. In salt-affected soil, FeNPs increased the dry weights of wheat roots, shoots, and grains by 65%, 78%, and 61%, respectively. The application of FeSO4 and Fe-EDTA increased the growth parameters of wheat in both normal and salt-affected soils compared to the respective controls. The photosynthetic parameters, including chlorophyll a (50%), chlorophyll b (67%), carotenoids (62%), and total chlorophyll contents (50%), were increased with the application of FeNPs under salt stress. The FeNPs increased plant-essential nutrients like iron, zinc, calcium, magnesium, and potassium in both normal and salt-affected soils. The experiment revealed that the application of Fe plays a significant role in enhancing the growth of wheat on alkaline normal and salt-affected soils. Maximum growth response was recorded with FeNPs than other Fe sources. The future must be focused on long term field experiments to economize the application of FeNPs on a large scale for commercialization.

Investigation of Solid–Liquid Phase Equilibria of Mg2+, NH4+//Cl–, SO42–H2O at T = 303.15 K and P = 88.35 kPa

Nitrogen and magnesium compound fertilizer is an important and efficient fertilizer in the fertilizer industry. It can solve the problem of lack of sulfur, magnesium, and nitrogen in soil. MgCl2 can react with (NH4)2SO4 to produce Mg–N compound fertilizer. Therefore, the solid–liquid equilibrium data and physical properties (density and viscosity) of the quaternary system Mg2+, NH4+//Cl–, SO42––H2O and its ternary subsystems Mg2+, NH4+//Cl––H2O and Mg2+//Cl–, SO42––H2O at T = 303.15 K ± 0.05 K and P = 88.35 kPa were studied by an isothermal stripping equilibrium method. According to the experimental data, the phase diagram and physical property composition diagram of each system were drawn. The ternary subsystem Mg2+, NH4+//Cl––H2O contains two invariant points and three crystallization regions. The ternary system Mg2+//Cl–, SO42––H2O contains four invariant points and five crystallization regions. The quaternary system Mg2+, NH4+//Cl–, SO42––H2O contains seven invariant points and nine crystallization regions. MgCl2·NH4Cl·6H2O and MgSO4·(NH4)2SO4·6H2O exist in the quaternary system, and the quality of crops can be significantly improved by using the latter kind of complex salt. Therefore, this project is of great significance for the production of N–Mg compound fertilizers from magnesium resources in salt lake or other underground brines.