Soil Potassium Research Articles

The Effect of Soil Nutrition and Foliar Fertilizers on the Soil Potassium Regime and Potassium Status of Apple Trees in a Rainfed Orchard

The Effect of Soil Nutrition and Foliar Fertilizers on the Soil Potassium Regime and Potassium Status of Apple Trees in a Rainfed Orchard

Deciphering Differences in Microbial Community Diversity between Clubroot-Diseased and Healthy Soils.

Clubroot (Plasmodiophora brassicae) is an important soilborne disease that causes severe damage to cruciferous crops in China. This study aims to compare the differences in chemical properties and microbiomes between healthy and clubroot-diseased soils. To reveal the difference, we measured soil chemical properties and microbial communities by sequencing 18S and 16S rRNA amplicons. The available potassium in the diseased soils was higher than in the healthy soils. The fungal diversity in the healthy soils was significantly higher than in the diseased soils. Ascomycota and Proteobacteria were the most dominant fungal phylum and bacteria phylum in all soil samples, respectively. Plant-beneficial microorganisms, such as Chaetomium and Sphingomonas, were more abundant in the healthy soils than in the diseased soils. Co-occurrence network analysis found that the healthy soil networks were more complex and stable than the diseased soils. The link number, network density, and clustering coefficient of the healthy soil networks were higher than those of the diseased soil networks. Our results indicate that the microbial community diversity and network structure of the clubroot-diseased soils were different from those of the healthy soils. This study is of great significance in exploring the biological control strategies of clubroot disease.

Effect of Inorganic Fertilizer, Farmyard Manure and Biofertilizer on Physical and Chemical Properties of Soil and System Yield of Maize – Wheat Rotation in Mollisol

A field experiment was conducted during the Kharif and Rabi seasons of 2020-21 and 2021-22 at the Norman E. Borlaug Crop Research Centre, G.B.P.U.A & T., Pantnagar. Randomized block design was followed with 11 treatments and 3 replications. The main objective was to assess the influence of fertilizer and farmyard manure application, with or without Azotobacter and zinc, on crop yield and soil properties in a maize-wheat crop rotation. The data demonstrated that application of 100% RDF + FYM 5 t ha-1, resulted in a significantly higher system yield of 12,137 kg ha-1. Intercropping of cowpea with maize along with the application of FYM 10 t ha-1 showed the lowest bulk density in both surface (1.38 Mg m-3) and sub-surface (1.49 Mg m-3) soil and also it led to a reduction in the soil pH and EC. Additionally, hydraulic conductivity was higher in organic treatments, specifically in T6. However, the application of 100% RDF + FYM 5 t ha-1 resulted in the maximum retention of organic carbon (1.06% and 0.71%) as well as higher content of available nitrogen (185.11 and 175.95 kg ha-1), phosphorus (36.17 and 31.65 kg ha-1) and potassium (147.90 and 120.68kg ha-1) in surface and subsurface soil, respectively. The study suggests that the application of 100% RDF + FYM 5 t ha-1 contributes to improved soil fertility and sustainable crop yields.

Improving apple orchard health: The role of arbuscular mycorrhizal fungi in alleviating replant disease and strengthening soil microbial communities

The occurrence of apple replant disease (ARD) is inevitable during the renewal and transformation of aging orchards. This disease seriously threatens the healthy and sustainable development of the apple industry. Arbuscular mycorrhizal fungi (AMF) have shown great potential in promoting plant growth, resisting soil-pathogen infection and improving soil quality. However, there is relatively little information available about the application of AMF in the prevention and control of ARD. In this study, we conducted a pot and field experiment were conducted with inoculation of AMF (Paraglomus sp. SW1) on apple rootstock (Malus hupehensis Rehd. in the pot experiment and M9T337 in the field experiment) to explore the biocontrol effect of AMF on ARD by comparing the changes in fungal and AMF communities after AMF inoculation on apples under replanting conditions. AMF-inoculated apple was used as the treatment, while non-inoculated apple was used as the control. The results showed that AMF-inoculated plants not only promoted the growth of M. hupehensis Rehd., but also stimulated the branch elongation growth of young apple trees, compared to the control. After inoculation with AMF, the community structure of soil fungi and arbuscular mycorrhizal fungi changed significantly, with an increase in the abundance of fungi and AMF in soil, and a significant reduction in the abundance of Fusarium spp., especially Fusarium moniliforme, Fusarium solani, and Fusarium proliferatum. Additionally, the soil enzyme activity increased significantly. Furthermore, the levels of ammonium nitrogen (NH4+), nitrate nitrogen (NO3−), available phosphorus (AP), available potassium (AK), organic matter (SOM), and pH in the rhizosphere soil were significantly related to the changes in the community structure of fungi and AMF. The AP, NH4+ and NO3− was found to drive the fungal communities, while NH4+ and NO3− drove the AM fungal communities in replanting soil. In conclusion, apple-arbuscular mycorrhizal symbionts can effectively alleviate ARD by promoting plant growth and optimizing the structure of soil microbial communities. Future research, should test other gardening plants following AMF inoculation to prepare for a wider application in controlling replant disease.

Evaluasi Status Hara N, P, K Berdasarkan Toposekuen pada Tanah Lahan Cengkeh di Desa Puulemo Kecamatan Lembo Kabupaten Konawe Utara

This research was carried out on a clove plantation in Puulemo Village, Lembo District, North Konawe Regency from June to July 2022. The purpose of this study was: to determine the nutrient status of different toposequences on community clove plantation in Puulemo Village, Lembo District, North Konawe Regency. The method used in the field is a survey method based on toposequence. Soil samples were taken by purposive sampling at three points, namely the top, middle and bottom of the slope with a depth of 0-30 cm and 30-60 cm. The samples were brought to the laboratory for analysis of the content of pH, Organic-C, nitrogen nutrients, phosphorus, soil potassium and soil CEC. The results showed that the assessment of some soil chemical properties in clove soil based on toposequences in Puulemo Village, Lembo District, North Konawe Regency, it can be stated that the total-N content in layers 0-30 cm and 30-60 cm were classified as moderate, available-K and available-P were classified as very low, pH values were classified as acidic, organic-C content was classified as very low and CEC content was classified as moderate at the top and bottom. in the middle and bottom at the 0-30 cm layer is classified as moderate while at the 30-60 cm layer it is classified as low.Keywords: Clove plant soil, nutrient status, toposekuen

Effects of coffee pericarp and litter mulsching on soil microbiomes diversity and functions in a tropical coffee plantation, South China.

In recent decades, ecological cyclic cultivation models have attracted increasing attention, primarily because the decomposition of crop residues and litter enhances soil organic matter content, thereby altering the soil microenvironment and regulating the diversity and functions of soil microbial communities. However, the effects of different coffee waste mulching on the diversity of soil microbial communities and their functions are still unclear. Therefore, this study set up four kinds of covering treatments: uncovered coffee waste (C), covered coffee litter (L), covered coffee pericarp (P), and both covered coffee litter and pericarp (PL). The results showed that compared to the control, coffee pericarp mulching significantly increased the soil available potassium (SAK) content by 18.45% and alkali hydrolyzed N (SAN) content by 17.29%. Furthermore, coffee pericarp mulching significantly increased bacterial richness and diversity by 7.75 and 2.79%, respectively, while litter mulching had little effect on bacterial abundance and diversity was smaller. The pericarp mulching significantly increased the abundance of Proteus by 22.35% and the abundance of Chlamydomonas by 80.04%, but significantly decreased the abundance of Cyanobacteria by 68.38%, while the coffee litter mulching significantly increased the abundance of Chlamydomonas by 48.28%, but significantly decreased the abundance of Cyanobacteria by 73.98%. The increase in soil SAK promoted bacterial Anoxygenic_photoautotrophy, Nitrogen_respiration, Nitrate_respiration, Nitrite_respiration, and Denitrification functions. The above results indicate that the increase in available soil potassium and alkali hydrolyzed N content under coffee pericarp cover is the main reason for promoting the diversity and richness of bacterial community and promoting the changes in bacterial community structure and function. The use of coffee pericarps in coffee plantations for ecological recycling helps to improve the diversity of the soil microbial community and maintain the relative stability of the microbial community structure and function, promoting soil health conservation and the sustainable development of related industries.

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

Impact of Jeevamrut formulations and biofertilizers on soil microbial and chemical attributes during potato cultivation

Application of jeevamrut, fortified with neem cake or vermitea, in combination with consortia of plant growth-promoting microorganisms such as Azotobacter, Vesicular Arbuscular Mycorrhiza (VAM) or Phosphate Solubilizing Bacteria (PSB) would attenuate the negative effects of synthetic fertilizers over microbial and physicochemical properties of soil. The present study was carried out during 2021–2022 and 2022-23 with two factors, namely Factor-J (Jeevamrut) of 4 levels and Factor-B (Biofertilizers) of 5 levels. Four levels of factor-J include three jeevamrut formulations with one control while five levels of factor-B include four biofertilizer combinations with one control. Observations of various soil-based parameters confirm a significant reduction in soil pH and electrical conductivity of soil after harvesting potato crops (variety Kufri Bahar) under different treatments in comparison to controls and the initial value. Further, the organic carbon, available nitrogen, phosphorus, and potassium of soil were reported to be enhanced after the application of jeevamrut fortified with vermitea or neem cake. The efficacy of fortified jeevamrut can be further improved by adding a consortia of biofertilizers consisting of PSB and Azotobactor or VAM fungi. These treatments have also a significant effect on enhancing soil microbial activities.

Evaluation of multi-nutrient extractants for determination of available phosphorus, potassium and micronutrient cations in red soils of Alfisols

Evaluation of multi-nutrient extractants for determination of available phosphorus, potassium and micronutrient cations in red soils of Alfisols

Quantity-intensity characteristics of potassium in coastal alluvial soils of Udupi district, under paddy land use cover

Quantity-intensity characteristics of potassium in coastal alluvial soils of Udupi district, under paddy land use cover

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.

Nutrient supplementation-induced metabolic profile changes and early appearance of free N-glycans in nutrient deficient tomato plants revealed by mass spectrometry.

Inorganic fertilizers are routinely used in large scale crop production for the supplementation of nitrogen, phosphorus, and potassium in nutrient poor soil. To explore metabolic changes in tomato plants grown on humic sand under different nutritional conditions, matrix-assisted laser desorption ionization (MALDI) mass spectrometry was utilized for the analysis of xylem sap. Variations in the abundances of metabolites and oligosaccharides, including free N-glycans (FNGs), were determined. Statistical analysis of the sample-related peaks revealed significant differences in the abundance ratios of multiple metabolites, including oligosaccharides, between the control plants, grown with no fertilizers, and plants raised under "ideal" and "nitrogen deficient" nutritional conditions, i.e., under the three treatment types. Among the 36 spectral features tentatively identified as oligosaccharides, the potential molecular structures for 18 species were predicted based on their accurate masses and isotope distribution patterns. To find the spectral features that account for most of the differences between the spectra corresponding to the three different treatments, multivariate statistical analysis was carried out by orthogonal partial least squares-discriminant analysis (OPLS-DA). They included both FNGs and non-FNG compounds that can be considered as early indicators of nutrient deficiency. Our results reveal that the potential nutrient deficiency indicators can be expanded to other metabolites beyond FNGs. The m/z values for 20 spectral features with the highest variable influence on projection (VIP) scores were ranked in the order of their influence on the statistical model.

Effects of Various Potassium Fertilizer Dosages on Agronomic and Economic Assessment of Sweet Potato Fields

To explore the effects of various potassium fertilizer dosages on sweet potatoes, field experiments were conducted in 2018 and 2019 using a randomized block design. In the experiment, the control (completely blank, no fertilizer), KS0 (potassium blank, no potassium fertilizer), KS100 (100 kg K2O ha−1), KS200 (200 K2O ha−1), and KS300 (300 K2O ha−1) treatments were set up. The application of potassium fertilizer increased the potassium content of sweet potato plants, thereby increasing the chlorophyll content, net photosynthetic rate, and the fluorescence chlorophyll parameters. It also increased the amylose content in tuber roots to increase the total starch content and yield of sweet potatoes. Specifically, the KS200 treatment significantly improved the soil potassium content, potassium absorption, potassium agronomic efficiency, and potassium recovery efficiency. Compared with the other treatments, the yield and net profit of the KS200 treatment increased by 0.89–27.05% and 2.34–30%, respectively, on average, over two years. Based on factors such as sweet potato yield and starch content, the recommended amount of potassium fertilizer was 200 kg ha−1, which has significant economic benefits and theoretical value.

Spatial distribution of soil organic carbon and macronutrients in the deep soil across a chronosequence of tea agroforestry

Due to the rapid growth of the tea industry, the tea plantation area has steadily increased worldwide. In some regions, croplands and natural forests have been converted into tea plantations causing habitat fragmentation, reducing landscape connectivity and loss of biodiversity. On the other hand, ancient tea forests, rustic tea and tea agroforestry have been shown to support higher native biodiversity. However, there is a dearth of information on the potential of tea agroforestry systems (TAFS) to store soil organic carbon (SOC) and nutrients in deeper soil layers. For the first time, here we provide estimates of concentrations and stocks of SOC and available nitrogen (N), phosphorus (P) and potassium (K) in deep soils in a chronosequence of tea agroforestry and adjacent natural forest stands. The concentrations of SOC, available N, P and K steadily decreased with soil depth across all the chronosequence of TAFS and natural forest stands. The SOC stocks in the 0–500 cm soil depth varied from 174.5 Mg C/ha in 20 years old TAFS to 213.2 Mg C/ha in 60 years old TAFS and 311 Mg C/ha in natural forest stands. Based on the empirical data, we propose the following predictive models for estimation of deep SOC concentrations (Y): Y=0.55+14.67e-0.013D in TAFS and Y=1.04+31.53e-0.014D in natural forests. The highest available N stocks were found in 60 years old TAFS (181.7 kg ha−1) while the available P and K stocks were highest in the forest soils (22.42 kg ha−1 and 56.86 kg ha−1). As in SOC, clay content and the SOC: clay ratios declined with soil depth in all the land uses studied. The SOC: clay ratios indicated a good soil structure in the study sites. It is concluded that TAFS store 39–46 % the SOC stocks and over 50 % of the available N, P and K stocks in the 100–500 cm soil depths. The predictive models developed here could be used for estimating deep soil SOC stocks after validation with independent datasets.

Effects of alpine meadows with different degradation gradients on the stability of the soil micro-foodweb in the Tibetan Plateau

Resource-transfer connections among bacteria, fungi, and microbivorous nematodes play an integral role in the decomposition pathways of soil micro-foodweb. Exploring the response of soil bacteria, fungi, and nematodes to grassland degradation is crucial for predicting the direction and trajectory of degradation. However, the knowledge about soil bacteria-fungi-nematode interactions in ecosystem function and nutrient cycling must be highlighted properly, especially in the Qinghai-Tibet Plateau. Therefore, this study focuses on four alpine meadows at different degenerate gradients (non-degraded grassland, slightly degraded grassland, moderately degraded grassland, and severely degraded grassland) on the Qinghai-Tibet Plateau. The investigation of soil bacteria-fungi-nematode interactions uses high-throughput sequencing and correlation network analysis. The results demonstrate significant variations in the composition of soil nematode genera, and bacterial and fungal phyla, across different degradation stages. Moreover, the diversity of nematodes, bacteria and fungi declined as grassland degradation worsened. Principal component analysis (PCA) revealed that alpine meadows with varying degradation gradients significantly influenced the community structure of bacteria, fungi, and nematodes. Mantel analysis indicated that soil water content (P < 0.05), total phosphorus (P < 0.05), and total nitrogen (P < 0.05) were the primary soil properties affecting the soil bacterial community. Similarly, available soil potassium (P < 0.05), microbial biomass carbon (P < 0.05), and microbial biomass nitrogen (P < 0.05) were the main soil factors influencing the soil fungal community. In contrast, the correlation between individual soil characteristics and soil nematodes did not reach a significant level, suggesting that a blend of physical and chemical properties regulates the soil nematode community. As grassland degradation intensified, the number of links in the interaction network of bacteria, fungi, and nematodes increased. Particularly, the networks between fungi and nematodes expanded, and the key species within each network varied with the different stages of grassland degradation. Concurrently, soil micro-foodweb decomposition pathways shifted. In the ND treatment, bacteria and fungi jointly dominated the degradation channels of the soil micro-food web, while the LD and MD treatments mainly dominated the degradation channels of fungi. On the other hand, SD treatment was dominated by bacterial degradation channels. This research adds to our theoretical understanding of meadow soil micro-foodwebs and the sustainable use of alpine grasslands in the Qinghai-Tibet Plateau.

Leaf and root traits are partially coordinated but they show contrasting multi-trait-based community trait dispersion patterns in a subtropical forest

Abstract The ecology of plant species relies on the synchronous functioning of leaves and roots, but few studies have simultaneously examined the community trait dispersion (CTD) patterns of both organs. We measured 16 analogous leaf and root traits on 44 co-occurring woody species in a subtropical forest in southern China, aiming to examine whether leaf and root traits were coordinated, organized into parallel trait axes, exhibited similar CTD, and displayed consistent responses in CTD and community-weighted means of (CWM) traits over environmental gradients. While the first axes of leaf and root trait variation similarly exhibited a fast–slow continuum, leaf traits covered a secondary “carbon economics” axis, contrasting to root traits depicting a collaboration axis reflecting species’ mycorrhizal dependency. Analogous leaf and root chemical traits were generally coordinated but less so for morphological traits. At the community level, changes in the CWM of the first axes were generally consistent among organs with more conservative traits found as increasing elevation but not for the second axis. While root traits became thinner and more conservative as soil phosphorus concentration decreased, leaf traits rarely varied. When different trait axes were combined, leaf traits were overdispersed but tended to converge with increased elevation and soil potassium and phosphorus levels, whereas root traits were clustered but tended to diverge along the same gradients. Our study highlights fine filtering of different suites of traits above- and belowground, which in turn might reduce overall niche overlap among species and promote coexistence with diverse functional designs.

Effect of Various Bamboo Species on Soil Properties in Pani Kholsi Micro-Watershed, Nepal

The biological characteristics and growth habits of bamboo enormously contribute to improving physical and chemical properties of soil. This study focuses on understanding the influence of four bamboo species on soil properties: Bambusa tulda, Bambusa balcooa, Dendrocalamus strictus and Bambusa nutans subsp. cupulata. For this, 15 soil samples were collected from open space (degraded land site) and bamboo species plantation areas in Pani kholsi micro-watershed and analysed in laboratory to determine soil pH, organic carbon content, available Nitrogen, Phosphorus and Potassium in soil. The soil pH decreases under all bamboo species compared rather than in open space. Lowest soil pH was recorded in the surface soil of B. balcooa and D. strictus. The organic matter content was the highest in surface soils under B. tulda (1.68%) and the lowest in the soil of open space (0.08%). Similarly, availability of Nitrogen (0.14%) and Phosphorus (4.27 kg/ha) was the highest in surface layer soil under B. tulda but the lowest (0.1% and 0.71 kg/ha respectively) in open space. And, the surface soil under B. tulda had much higher potassium content (68.4 kg/ha) than the soil in open space (8.88 kg/ha). Overall, the soil chemical properties under B. tulda were found to be better than under other species.

The Effect of the Vertical Distribution of Nutrients for some Soils in Babylon Governorate

An experiment was conducted at one of Babylon’s farms in Mahaweel, which spanned the coordinates (45o 6′ 40" - 44o 20′ 5") east and (32o 49′ 20" - 32o 25′ 20") north. Al-Mahaweel District is a part of Babylon Governorate in central Iraq. Fifteen pedons were tracked using a GPS device inside the lab. Soil horizon, pedon, and interstitial samples were collected at four depths (0-30, 30-60, 60-90, and 90-120 cm) to investigate the soil’s layered structure. The samples were subsequently subjected to statistical and laboratory analysis. The statistical study revealed that the soil’s nitrogen content was significantly influenced by the horizon and pedon uncles’ bilateral interaction, with the maximum value (53.60 mg kg-1) being found in the AP15 binary overlap treatment. Values of 52.18 and 51.82 mg kg-1 soil were recorded for the AP15 and AP14 two-interference treatments, respectively. The highest value of phosphorus was in the treatment of the binary overlap between horizons and pedons represented by the AP9 treatment, with a value of 43.41 mg kg-1 soil, which did not differ significantly from the binary overlap treatment C2, P7, C2P6, which each had a value of 40.17, 40.33 mg kg-1 soil, while the lowest value of phosphorus was in the treatment of the binary overlap between horizons and pedons represented by the AP9 treatment The lowest result for soil potassium was 159.82 mg kg-1 soil, which was found in the binary interaction treatment C3P15. Iron availability was also increased by the binary interference between horizons and pedons, with the highest value being 13.95 mg kg-1 for the treatment of binary interference AP1, with no significant difference between this value and the values for the two-interference treatments, AP3 and AP2, which were 13.45 and 13.00 mg kg-1, respectively. Iron availability was lowest when horizons and pedons interacted, a phenomenon that was reversed. Copper availability, measured in milligrams per kilogram of soil, was shown to increase significantly where pedologically significant overlap between horizons and pedons was present. The highest value was found in the non-significantly different binary overlap treatment AP3, with values of 6.93, 6.75, and 6.55; the lowest value was found in the two non-significantly different binary overlap treatments C3P15 and C3P14, at 1.02 and 1.00, respectively.

Soil Potassium Fractionations, Release and Fixation in a Cadmium Contaminated Soil Treated with Plant Residue and Biochar

Soil Potassium Fractionations, Release and Fixation in a Cadmium Contaminated Soil Treated with Plant Residue and Biochar

Effect of Long-Term Application of Inorganic Fertilizers, Organic Manure, and Lime on Different Forms of Potassium in Soil under Maize-Wheat Cropping System

The field study was undertaken with the major emphasis on potassium fractionation and its contribution in acid alfisol soils as affected by adoption of continuous cropping, fertilization, and manuring under maize-wheat cropping system in same field over 62 years of crop cycles. The experiment consisted of fourteen treatments, replicated thrice times in a randomized block design, out of which nine treatments were selected for the present study. The selected treatments were as follows - control, T2-100% N, T3- FYM, T4-100% NP, T5-100% NPK, T6- 1/2(N+FYM) + P(A-X/2) + K(B-Y/2) (INM), T7-100% NPK + Lime where the lime application in LR once in 4 years, T8-Lime+ FYM+ P(A-X) + K(B-Y), T9-Lime+N. Surface soil (0-15cm) and subsurface soil (16-30 cm) samples were collected after the harvest of wheat in 2017-18 to observe the initial Physico-chemical properties. Different fractions of potassium, viz., water-soluble K, exchangeable K, available K, 1NHNO3K, non-exchangeable K, Lattice K, and Total K were analyzed for the study. There was a significant difference among the different treatments with respect to potassium fractions in 0-15 cm, and 16-30 cm layers. Moreover, K fractions were significantly decreased with increasing depth of soil. Results showed that the percentage contribution of different forms of K with regard to the total K in surface soil and subsurface soil followed as: Lattice K (68.75-78.11%) &gt; Non – Exchangeable K (19.15-25.49%) &gt; Exchangeable K (1.65-2.45%) &gt;Water soluble K (0.18-0.62%). Application of N and P without K caused depletion of soil, water-soluble K, available K, exchangeable K, non-exchangeable K, and lattice K because of continuous omission of potassium content during the all crop growing stages or the simultaneous leaching nature of residual potassium under same field of the experiment. Therefore, the present investigation stresses the vital importance of the inclusion of organic manure and lime in the fertilizer schedule to maintain soil K dynamics over the long run under the maize-wheat cropping system.