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Rhubarb is a popular food in Europe due to the purgative action. Cultivation is the key way to ensure sustainable development and utilization of this herbal plant. In this paper, standardized cultivation of Rheum tanguticum (a kind of rhubarb) was explored through a three-year field experiment which investigated the effect of phosphorus (P) and potassium (K) fertilizer on growth indexes, sennoside content of R. tanguticum at different harvesting stages. Results showed that P and K fertilizer significantly increased root length, root diameter and root fresh weight, the maximum root fresh weight was 894.22 g/plant. Sennoside content of three-year-old R. tanguticum applied K fertilizer was over 5.87% at each harvesting stage in the third growth cycle and it increased along with growing year. Sennoside content has no obviously increment at the same harvesting stage, it also has no positive correlation with different harvesting stages and the wilting stage > green stage > growth stage in the same year. This study demonstrated that P and K fertilizer had accelerated effect on growth of R. tanguticum at the same harvesting stage, but had no obvious influence on the sennoside content. This will provide experimental data and guidance for the standardized cultivation of R. tanguticum. The effect of different fertilizer (P, K) doses, harvesting stages and growth years on growth indexes and sennosides contents of R. tanguticum was firstly explored. A modified HPLC detective method was developed to quantify the sennosides content of R. tanguticum. The effect of different fertilizer doses on growth indexes of R. tanguticum was firstly explored. Variation of sennoside content after applying fertilizers was firstly explored. The effect of harvesting stages on growth indexes and sennosides contents was firstly explored. [ABSTRACT FROM AUTHOR]

The experiment was conducted using Potato( Solanum tuberosum L.) at the eastern Radwaniyah at private field during fall season 2020/2021 and spring 2021 to study the effect of nitrogen levels to 350, 275, 200 kg N h-1 ( N1, N2, N3) and phosphorous to 100, 180, 360 kg P2O5 h-1 ( P1, P2, P3) and potassium to 100, 200, 300 kg K2O h-1 ( K1, K2, K3) to vegetative growth and yield of industrial potato, The seeds of the hybrid potato Sinora, Class A, were planted in the fall season on 15/9/2020 and Elite in the spring season on 31/1/2021. The experimental fertilizers were added in four batches and in proportions according to the stages of plant age, Factorial experiment with RCBD using three replications. The results showed that changing the levels of the elements used to N3, P3, K3 led to a significant increases in most traits of vegetative growth for both seasons, while the change of phosphorous and potassium levels to P2 and K3 had a significant effect on the quantitative and qualitative yield for both seasons. The N1P2K3 interaction gave the highest marketable tuber weight, marketable yield plant-1, total yield for the fall and spring seasons, and the highest percentage of dry matter in tubers in the fall season [ABSTRACT FROM AUTHOR]

This work presents the fabrication of potassium chloride encapsulated in starch–alginate matrix, crosslinked by calcium chloride to form hydrogel bead. Sixteen formulations (S1–S16) were designed in four levels sodium alginate (SA 0.5% w/v to 2.0% w/v) and potassium chloride (KCl 5% w/v to 20% w/v) with 10% w/v starch and 0.75 M calcium chloride. The analysis reviewed that a higher concentration of sodium alginate, coupled with a lower KCl concentration, results in enhanced encapsulation efficiency. Notably, hydrogel beads formulated with higher concentrations of SA exhibited a more uniform, spherical shape with compact surfaces. Higher SA concentration has lower the swelling of the beads and therefore reduces its potassium release in general. In another word, with higher SA concentration, the release rate was at a better control to the expected release timeframe. On the contrary, it was also observed that the sample's dissolution in water after 24 h increased with the rising SA content. A higher concentration of sodium alginate led to an increased biodegradation rate, with the biodegradation rate increasing by 25% as the SA concentration was raised from 0.5% to 2% over a period of 5 days. In conclusion, this study represents a preliminary exploration into the viability of encapsulating potassium within a starch/SA matrix, with the optimal ratio of starch, alginate, and potassium was found to be 10:2:5. The significance of this work lies in its potential applications within agricultural practices, particularly in drought‐prone regions, owing to its hydrogel properties. By precisely tailoring the starch, alginate, and potassium ratios, this study opens avenues for further advancements in sustainable nutrient delivery systems. [ABSTRACT FROM AUTHOR]

Lilium davidii var. unicolor (Lanzhou lily) is rich in nutrients, making it an important economic plant widely used in the fields of food and medicine. In this study, potted lily bulbs were treated with nutrient solutions containing K+ and nutrient solutions without K+ (CK and KT). The contents of nutrients in lily bulbs at different stages after treatment were compared. It was found that the application of potassium fertilizers increased the content of total phenols, flavonoids, and flavanols in lily bulbs and the antioxidant activity in the bulbs. Simultaneously, the study observed that potassium fertilizers could impact the accumulation of polysaccharides and saponins. Furthermore, employing non-targeted metabolomics, the secondary metabolites of mature Lanzhou lily bulbs were scrutinized both with and without potassium fertilization (KT and CK). A total of 607 metabolites were identified, including 573 in positive ion mode and 34 in negative ion mode. These metabolites were classified into 13 categories at the superclass level, with lipids and lipid molecules (37.93%), organic acids and their derivatives (16.52%), organic oxygen compounds (14.88%), and phenylpropanoids and polyketides (13.61%) being the most prominent. Differential metabolite enrichment analysis between the experimental and control groups showed that the differential metabolites were mainly concentrated in metabolic pathways related to amino acid biosynthesis, such as arginine and proline metabolism, beta-alanine metabolism, alanine, aspartate, and glutamate metabolism. Additionally, it was found that the application of potassium fertilizer increased the accumulation of amino acids in Lanzhou lily bulbs. Overall, this study provides a theoretical reference for the development of nutrients and efficient cultivation techniques for L. davidii var. unicolor bulbs. [ABSTRACT FROM AUTHOR]

The remediation of organic-contaminated soil using microwave heating is widely concerned because of its advantages of low-cost, high efficiency, and short processing time. In the present work, the bluecoke-based conditioner (KHCO3@BC) prepared by ultrasonic impregnation was employed to further improve the removal efficiency of naphthalene. The removal efficiency of naphthalene and the characteristics of remediated soil and by-products were investigated via experimental calculation, analysis of physical and chemical properties of soils, field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC–MS). Besides, the removal process of naphthalene in microwave remediation was presented. Results indicated that the maximal removal of naphthalene by using KHCO3@BC-assisted microwave remediation reached 96.46% with the highest temperature of 575 ℃, when 4 wt% of KHCO3@BC conditioner was added, microwave power was 700 W, and heating time was 25 min. The content of total K and available K in remediated soil rose to 2.03 and 0.51 g/kg, thus improving the inorganic fertilizer of remediated soil. The size of soil particles significantly decreased after microwave remediation, which optimized the mechanical component of remediated soil. The removal process of naphthalene in microwave remediation mainly contained the gas stripping and naphthalene vaporization. The prepared KHCO3@BC conditioner could realize the removal of contaminants, and increase K fertilizer for acid organic-contaminated soils in microwave remediation. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to examine the effect of co-application of phosphorus (P) and/or potassium (K) fertilizer to a soil layer on Mung bean (Vigna radiata R. Wilczek) grown in a Yellow Chromosol soil. We hypothesized that adding K to a P- enriched soil layer would increase recovery of K due to increased root proliferation. Layers enriched with P, K or a combination of P and K were placed at either 5 or 20 cm depth in 50 cm deep pots, and a uniform PK application treatment included for comparison. Mung bean was grown for 45 days and key growth and nutrient uptake attributes were assessed. Phosphorus application increased shoot and root dry matter yield and shoot yield was 40% higher in the shallow P treatment and 77% higher in the shallow PK than in the uniform PK treatment. Shallow co-application of P and K increased shoot P and K content compared with shallow P alone. Apparent P fertilizer recovery (%PAFR) followed the same pattern, and there was an 8 to 12-fold increase in %KAFR. There was no evidence of an increase in either the proportion or mass density of roots in the enriched soil layers in any treatment. P and K fertilizer use efficiency was maximized by co-application in an enriched soil layer. When multiple nutrient deficiencies occur co-application of nutrients in a soil layer accessible to roots maximizes fertilizer use efficiency. [ABSTRACT FROM AUTHOR]

To develop targeted yield-based integrated nutrient recommendation of sesame, soil test-based crop response field studies on major nutrients were undertaken during two consecutive seasons (2016 and 2017) in an Inceptisol. For this, quantitative estimations of basic parameters viz. nutrient requirement (NR), percentage contribution of nutrients from soil (CS); from fertilizer (CF); from farm yard manure (CFYM) were done. The essential informations obtained from soil and crop testing were used for development of fertilizer prescription equations for different nutrient management practices using organic (FYM) and inorganic chemical fertilizer alone or in combinations. The mean nutrient requirement for the production of 100 kg of sesame grain was 6.98, 1.61 and 3.92 kg of nitrogen (N), phosphorus (P) and potassium (K), respectively. The CS, CF and CFYM values were 21.84, 49.35 and 6.95 for N; 40.23, 26.25 and 4.57 for P; 12.80, 53.13 and 4.07 for K, respectively. Those parameters were used for preparation of ready reckoners of fertilizer prescription for range of soil test values of N, P and K to get targeted yield (±5 to ±10% of potential yield of variety) of 9 q/ha for sesame grain using FYM and inorganic chemical fertilizer alone or in combinations. Amount of N, P and K fertilizer could be reduced by a significant amount if fertilizers were applied on soil test basis in integration with FYM. [ABSTRACT FROM AUTHOR]

Conventional potassium chloride granules have inefficient applications in agricultural production due to particle irregularity and low fluidity. The application of controlled-release potassium chloride could increase the potassium-use efficiency and alleviate the shortage of potassium ore resources. In this study, a well-rounded potassium chloride fertilizer core was prepared, using the graft modification of polyurea to enhance the coating rate and release performance. The adhesive and tensile characteristics of the modified polyurea binder, as well as the granule properties of modified polyurea binder potassium chloride, were studied to determine the ideal lignin-grafted ratio. The effect of the modified polyurea binder with potassium chloride on the properties of coated fertilizer was investigated. The findings, shown by radar maps of the binder's properties, demonstrated that the ideal mass ratio of the modified lignin polyurea binder to urea is 1:2. The Fourier-transform infrared spectroscopy results demonstrated that the amino functional groups of lignin were enhanced, improving the product's interfacial compatibility with the polyurea matrix. Compared to humic acid (HA; 12%) and bentonite (Ben; 30%) treatments, the granule intensity of the 9.9%—1:2 treatment considerably increased by 139.10% and 38.86%, respectively, while the static angle of the granules reduced by 16.67% and 3.81%. The 28-day cumulative release rate of the modified polyurea (9.9%—2:1) with a 5% coating thickness was the lowest (28%), 42% lower than that of the lowest conventional treatment. In summary, the creation of a bio-lignin polyurea binder under the optimum conditions reduced the need for petrochemical-based materials, allowed the preparation of fertilizer with granules of increased fluidity, and enabled the successful coating of a high-salt potassium fertilizer, offering a novel technique for the high-value application of potash fertilizer coating. [ABSTRACT FROM AUTHOR]

Soybean is the main leguminous crop in Brazil, mostly grown in tropical soils with low potassium (K) availability. Therefore, the identification of new genotypes with efficient K uptake and utilization in environments with low exchangeable K content is an economically viable alternative to maximize crop yield in Brazil. A study was conducted to investigate the response of 25 modern high-yield soybean genotypes for K-use efficiency in a sandy tropical soil of the Brazilian Cerrado. Treatments were distributed in a completely randomized design in a 2 × 25 factorial scheme: two levels of K fertilization [20 mg K dm−3 (low level) or 200 mg K dm−3 (high level)] and 25 soybean genotypes with three replicates. Plant morphological traits, leaf K, and crop production components were measured. Based on grain production data, K-use efficiency (KUE) and response efficiency (RE) to K fertilization were calculated. Leaf area, shoot dry matter, pod number per plant, 1000-grain weight, and grain yield were the crop characteristics most limited by low soil K availability. The soybean genotypes "TMG7061 IPRO", "BMX Bônus IPRO", "RK6719 IPRO", and "RK8317 IPRO" were classified as efficient in the use of soil K and are the most suitable genotypes to be cultivated in agricultural soils with low K availability. The genotypes "98R35 IPRO", "HO Maracaí IPRO", "BMX Bônus IPRO", and "RK7518 IPRO" were classified as responsive to K fertilization and are the most recommended genotypes for cultivation in agricultural areas with the application of high K fertilizer rates. The genotype "BMX Bônus IPRO" simultaneously combines characteristics of K-use efficiency and response to K fertilization and hence can be grown in both K-deficient and optimal soils. [ABSTRACT FROM AUTHOR]

For improvement and rational use of rainfed lands, a study on the influence of different tillage methods proceeded on the soil-water physical relationship and soil agrochemical properties in Southeast Kazakhstan. In the arable soil layer (0-30 cm), the soil density during the studied crop's life from sowing to harvesting, enhanced to a medium compacted state with the traditional method of tillage (1.28-1.29 g/cm3), slightly higher with the minimum tillage (1.30-1.31 g/cm3), and the highest with zero tillage (1.32-1.33 g/cm3). Tillage with better crumbling, dissolution, and superior ingestion of plant vestiges in the cultivated soil layer contributed to a slight decrease in soil density, both with traditional and minimum tillage regimes. Given the least rainfall in summer, there was a decline in the productive moisture reserves in the soil with customary tillage (15.9-34.5 mm). However, the soil moisture enhanced gradually with reduced tillage, i.e., minimal tillage (20.7-36.7 mm) and zero tillage (29.8-54.8 mm). The nitrate nitrogen content in the soil also decreased from the initial state to the cultivated crops' harvest, and a significant decrease emerged with zero tillage. The prolonged rainless period, accompanied by a decline in relative air humidity, soil moisture, and temperature increases, affected plants' physiological processes and, eventually, the studied crops' yield. In the studied crops, on average, acquiring the highest yield of 1.76 t/ha was with minimal tillage. Based on two-way analysis of variance (ANOVA), the contributed share of the crops in the grain yield formation was according to crop season, ranging from 0.73% to 2.89%, and the soil cultivation methods' share was 83.3%-93.8%. The grain yield formation has a greater dependence on the tillage regimes, although that reliance might vary in association with weather conditions during the crop life. In rainfed conditions of Southeast Kazakhstan, zero tillage results in a significant reduction in nitrate nitrogen compared with conventional and minimum tillage. Therefore, with no tillage, more nitrogen fertilizer is necessary than usual plowing and the application of potash fertilizers, regardless of tillage methods. [ABSTRACT FROM AUTHOR]

Water deficiency, is one of the most important environmental stresses, resulting in serious yield reductions in wheat production. Enhanced wheat resistance to drought stress has been attributed to silicon (Si). Therefore, two field experiments were conducted in order to study the effects of two potassium silicate treatments, mineral or nano form, under water stress on the growth and yield performance of three wheat cultivars. Experimental design, was a split split-plot design, with three replications. Drought stress significantly reduced grains per spike, 1000-grain weight, grain yield, and biomass of all wheat cultivars. In contrast, foliar-applied silicon, significantly increased these parameters and reduced electrolyte leakage. The results suggested that water stress during vegetative and reproductive development is equally injurious to wheat, and adequate water supply throughout crop development is essential to harvest maximum biological potential. In conclusion, the foliar application of silicon was very effective in indorsing tolerance of wheat plants to drought conditions by maintaining cellular membrane integrity and relative water content and increasing grain yield, and biomass of all wheat cultivars. [ABSTRACT FROM AUTHOR]

Soil fertility problem is a major constraint to faba bean production in Wolaita Zone in Ethiopia. Hence, a field experiment was conducted in Kokate Marachare sub-district during 2019 and 2020 cropping seasons to determine the optimum N, P, and K fertilizers for enhanced uptake and use efficiency of faba bean. Three rates of N (0, 23, and 46 kg N ha-1), P (0, 46, and 92 kg P2O5 ha-1), and K fertilizer (0, 30, and 60 kg K2O ha-1) were tested using RCBD with three replications. Data on agronomic efficiency (AE), agrophysiological efficiency (APE), apparent recovery efficiency (ARE), and utilization efficiency of N, P, and K nutrients were analyzed. The results revealed N, P, and K uptake efficiency (UE) indices of faba bean were significantly influenced by the main effects of the rate of nitrogen, phosphorus, and potassium fertilizers. Thus, applying 23 kg N ha-1, 46 kg P2O5 ha-1, and 30 kg K2O ha-1 resulted higher N, P, and K AE, respectively (33.70 kg kg-1, 13.43 kg kg-1, and 27.32 kg kg-1); PE (76.87 kg kg-1, 104.51 kg kg-1, and 118.83 kg kg-1); APE (40.49 kg kg-1, 104.51 kg kg-1, and 68.07 kg kg-1); ARE (84.48%, 2.00%, and 40.30%); and UE (63.47 kg kg-1, 2.52 kg kg-1, and 56.08 kg kg-1). Therefore, 23 kg N ha-1, 46 kg P2O 5ha-1, and 30 kg K2O ha-1 are recommended for the higher N, P, and K uptake and use efficiency of faba bean. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to clarify the expression pattern and molecular regulation mechanism of genes related to sugar, lipid and protein metabolism in maize ear leaves under different fertilization in field conditions. [ Method] Maize cultivar 'Luyu 16' was used as the material and five treatments were set up: No fertilizer (CK), nitrogen fertilizer ( N), N + P fertilizer (NP), N + K fertilizer ( NK) and N + P + K fertilizer ( NPK). At grain filling stage, the upper part of ear leaves was harvested for transcriptome analysis using RNA-Seq techniques. The differentially expressed genes ( DEGs) under different fertilizer treatments were analyzed by Hisat2 software. [Result]GO(Gene ontology)analysis showed that DEGs related to sugar, lipid and protein metabolism were enriched in Biological process ( BP), Cell components( CC) and Molecular function( MF). Although the enriched items were the same, the number of DEGs varied under different combinations. KEGG ( Kyoto encyclopedia of genes and genomes) analysis exhibited that more DEGs were enriched in carbon metabolism, starch and sucrose metabolism, and amino acid synthesis pathways. The total number of DEGs with both I log2 FC I > 1 and P < 0. 05 involved in sugar, lipid and protein metabolism under different fertilizer treatments was 82, 29 and 84, respectively. Among them, the total number of DE Gs with I log2 FC I > 2 was 6, 24 and 17. The number of DE Gs showed the maximum in comparisons of NPvsCK and NPKvsCK but the minimum in NvsCK comparison. Further analysis of DEGs with I log2 FC I showed that these DEGs had significant differences in the expression level and expression patterns. [ Conclusion] The combined of nitrogen, potassium and phosphorus fertilizer significantly affected the transcription levels of genes related to sugar, lipid and protein amino acids metabolism in maize ear leaves. Some key genes participating in the three organic substances' metabolism were identified. The results provided molecular basis for improving the photosynthetic efficiency of maize leaves by rational fertilization in the future. [ABSTRACT FROM AUTHOR]

In order to achieve high yields and environmental friendliness simultaneously, the replacement of chemical fertilizers by manure has become a research hotspot in recent years. Roots absorb nitrogen, participate in its assimilation and contribute to the cereal's dry matter accumulation. A 5‐year filed experiment in the North China Plain was initiated to assess the response of root morphology and distribution of summer maize (Zea mays L.) to fertilizer application and contribution to crop yield. The treatments included CK (unfertilized control), NPK (inorganic nitrogen/phosphorus/potassium fertilizer) and NPKM (manure + 70% NPK). We determined the root biomass, root diameter, root length density (RLD) of three diameters (>0.8 mm, 1stRLD; 0.2–0.8 mm, 2ndRLD; <0.2 mm, 3rdRLD) and the soil chemical properties at 60 cm with 10 cm increments. At 40–60 cm, NPKM significantly decreased the root diameter than NPK. Fertilization showed no effect on total RLD, 1stRLD, 2ndRLD and 3rdRLD for a 60‐cm soil profile. At 40–50 cm, the NPKM increased the RLD compared to NPK, mainly by increasing the 2ndRLD and 3rdRLD. Under CK and NPK, root lengths of 0–20 cm made up 62% and 57% of the total root length, respectively. Under NPKM, root lengths of 40–60 cm made up 46% of the total root length. Our results indicate that maize yield was preserved after replacing 30% of N fertilizer with manure, presumably depending on the change of root vertical distribution pattern and increase of the fine root length in deeper soil. [ABSTRACT FROM AUTHOR]

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Background. Undoubtedly, the importance of food and food security as one of the present and future challenges is not invisible to anyone. Nowadays, the development of methods for monitoring the nutrient content in crop products is an essential issue for implementing reasonable and logical soil properties management. The modeling technique can evaluate the soil properties of fields and study the subject of crop yield through soil management. This study aims to predict fruit yield and macro-nutrient content in plant organs of Cucumis melo in response to soil elements using support vector regression (SVR). Methodology. In the spring of 2020, this study was done as a factorial test in a randomized complete block design with three replications. The first factor was the use of fertilizers in six levels: no fertilizer (control), cow manure (30 t ha-1) sheep manure (30 t ha-1), nanobiomic foliar application (2 l ha-1), silicone foliar application (3 l ha-1), and chemical fertilizer from urea, triple superphosphate, and potassium sulfate sources (200, 100, and 150 kg ha-1). In addition, four levels of vermicompost considering as the second factor: no vermicompost (control), 5, 10, and 15 t ha-1. Input data sets such as fruit yield and nitrogen, phosphorus, and potassium levels in the seeds, fruits, leaves, and roots are used to calibrate the probabilistic model of SP using SVR. Results. According to the results, when the data sets of the nitrogen, phosphorus, and potassium in the fruit uses as input, the accuracy of these models was higher than 80.0% (R² = 0.807 for predicting fruit nitrogen; R² = 0.999 for fruit phosphorus; R² = 0.968 for fruit potassium). Also, the results of the prediction models in response to soil elements showed that the soil nitrogen content ranged from 0.05 to 1.1%, soil phosphorus from 10 to 59 mg kg-1, and soil potassium from 180 to 320 mg kg-1, which offers a suitable macro-nutrient content in the soil. Likewise, the best fruit nitrogen content ranged from 1.27 to 4.33%, fruit phosphorus from 15.74 to 26.19%, fruit potassium from 15.19 to 19.67%, and fruit yield from 2.16 to 5.95 kg per plant obtained under NPK chemical fertilizers and using 15 t hawhich offers a suitable macro-nutrient content in the soil. Likewise, the best fruit nitrogen content ranged from 1.27 to 4.33%, fruit phosphorus from 15.74 to 26.19%, fruit potassium from 15.19 to 19.67%, and fruit yield from 2.16 to 5.95 kg per plant obtained under NPK chemical fertilizers and using 15 t ha-1 of vermicompost. Conclusions. Because the fruit values had the highest contribution in prediction than observed values, thus identified as the best plant organs in response to soil elements. Based on our findings, the importance of fruit phosphorus identifies as a determinant that strongly influenced melon prediction models. More significant values of soil elements do not affect increasing fruit yield and macro-nutrient content in plant organs, and excessive application may not be economical. Therefore, our studies provide an efficient approach with potentially high accuracy to estimate fruit yield and macronutrient in the fruits of Cucumis melo in response to soil elements and cause a saving in the amount of fertilizer during the growing season. [ABSTRACT FROM AUTHOR]

In Japan, additional potassium fertilization is used as a countermeasure for radiocesium-contaminated grasslands in the Tohoku and North Kanto regions. A 2-year pot experiment was conducted to assess the efficacy of using tall fescue (Festuca arundinacea Schreb.), a low-cesium-absorption grass species, to replace orchardgrass (Dactylis glomerata L.), the most common forage grass species in these regions, to reduce potassium fertilization and improve the forage mineral balance. The treatments were a combination of two grass species (tall fescue and orchardgrass) and two potassium application rates (0 [K0] and three times the conventional amount [K3]) with four replications. The grass species and potassium application rate had significant (p < .001) effects on plant cesium-137 concentrations. The results of the generalized linear mixed-model analysis indicated that when tall fescue replaced orchardgrass, cesium-137 in the forage grass was reduced to 34% and that the K3 treatment reduced cesium-137 to 46% relative to the K0 treatment. The difference in cesium-137 concentration between the two grass species increased as the soil exchangeable K2O content decreased. The equations for estimating the cesium-137 concentration (y [g/kg]) from the exchangeable K2O content (x [g/kg]) were obtained as y = 63.7e-2.095x for tall fescue and y = 185.5e-3.327x for orchardgrass. These equations indicate that tall fescue cultivation can reduce the risk of elevated radioactive Cs in the grass by reducing potassium fertilizer to approximately half that of orchardgrass. There were no differences in the response of plant potassium concentrations or the potassium/(calcium + magnesium) equivalent ratio to soil exchangeable K2O content among the grass species. However, the mineral balance of forage can be improved by reducing potassium fertilizer applications for cesium-137 remediation. Tall fescue has good potential to remediate contaminated grasslands as it reduces additional potassium fertilization and improves the mineral balance of forage. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at the Research Farm of the ICAR-Indian Institute of Soil Science, Bhopal (India) to study influence of different integrated nutrient management (INM) modules on soil potassium (K) fractions. The experiment comprised with twelve treatments laid out in randomized block design (RBD) with three replications under maize-chickpea cropping sequence. The treatments included general recommended dose (GRD), soil test crop response (STCR) dose; combinations of inorganic and organic inputs and only organic modules. The soil samples were collected at crop harvest and analyzed for various K fractions viz., water soluble-K, available-K, exchangeable-K, HNO3-K, lattice-K and total-K. The results indicated that potassium fractions were significantly (p = 0.05) affected by different treatments. Different INM modules significantly enhanced significantly K availability in soil. Among various INM modules studied, treatment 11 (application of 20 t ha-1 FYM in maize with 5 t ha-1 FYM every year in chickpea) proved most beneficial for improving the soil K fractions. Findings of this type are important for K fertilizer management during crop production in areas with low soil fertility. [ABSTRACT FROM AUTHOR]

Potassium-solubilizing bacteria are an important microbial group that play a critical role in releasing mineral potassium from potassium-containing minerals, e.g., potassium feldspar. Their application may reduce eutrophication caused by overused potassium fertilizers and facilitate plants to utilize environmental potassium. In this study, a high-efficiency potassium-solubilizing bacterium, named NK851, was isolated from the Astragalus sinicus rhizosphere soil. This bacterium can grow in the medium with potassium feldspar as the sole potassium source, releasing 157 mg/L and 222 mg/L potassium after 3 days and 5 days of incubation, respectively. 16S rDNA sequencing and cluster analysis showed that this strain belongs to Priestia megaterium. Genome sequencing further revealed that this strain has a genome length of 5,305,142 bp, encoding 5473 genes. Among them, abundant genes are related to potassium decomposition and utilization, e.g., the genes involved in adherence to mineral potassium, potassium release, and intracellular trafficking. Moreover, the strong potassium-releasing capacity of NK851 is not attributed to the acidic pH but is attributed to the extracellular potassium feldspar-binding proteins, such as the elongation factor TU and the enolase that contains potassium feldspar-binding cavities. This study provides new information for exploration of the bacterium-mediated potassium solubilization mechanisms. [ABSTRACT FROM AUTHOR]

Cotton is a major cash crop that is widely cultivated in tropical and subtropical regions around the globe. Cotton leaf curl virus disease is a major threat to lower the cotton yield in Pakistan. The present study aimed to predict the disease severity at different potassium (K) dosses based on abiotic environmental factors with respect to two sowing times. Three potassium (K) doses (90, 60, and 30 kg acre−1) were applied to observe the impact on disease severity. In control, no extra K was applied. Two sowings were done at 15 days intervals. Data was recorded using at seven days intervals after the appearance of the disease. A significant difference in disease severity was observed in K applied cotton plants and between the two sowing times. Maximum disease severity was noticed in control plants and was found maximum where 90 kg acre−1 K was applied. Maximum air temperature, minimum air temperature, rainfall, and windspeed exhibited a negative relationship with disease severity. A positive relationship was seen between disease severity and relative humidity irrespective to sowing times. In 1st sowing, maximum air temperature (35–38 °C), minimum air temperature (23–24 °C), relative humidity (65–75%), rainfall (1–2 mm), and windspeed (1.5–2.5 km/h) significantly contributed in disease progression. In second sowing, maximum air temperature (34–36 °C), minimum air temperature (19–21 °C), relative humidity (75–78%), rainfall (0.5–1.5 mm), and windspeed (1.5–2.5 km/h) favoured the disease development. [ABSTRACT FROM AUTHOR]

Partial substitution of synthetic nitrogen fertilizer with manure (organic substitution) is highly recommended to minimize environmental risks without compromising crop productivity in intensive agricultural systems. However, our understanding of the effect of organic substitution on soil organic carbon (OC) and total nitrogen (TN) in deep soil and its impact on crop productivity remains limited. Here we investigated OC and TN changes in soil profile down to 100 cm, crop yield, and sustainable yield index under synthetic nitrogen, phosphate, and potassium fertilizers (NPK), NPK plus straw (NPKS), and organic substitution (NPKM) treatments over two decades in four upland fields across different climate zones. Compared with the initial values, two decades of NPKM treatment significantly (p < 0.05) increased OC and TN stocks in either topsoil (by 25.6–103.8 and 15.8–89.8%) or deep soil (by 2.9–71.3 and 5.7–36.9%), respectively, across all sites. The increases in OC and TN stocks in 0–100 cm soil receiving NPKM were significantly higher than those receiving NPK at all sites and NPKS at three high-evaporation sites. Compared with NPKS and NPK treatments, crop yield and N uptake were significantly increased under NPKM treatment only at the Qiyang site. Furthermore, OC sequestration in the entire soil profile down to 100 cm and TN accumulation in topsoil exhibited significant positive correlations with crop N uptake, relative crop yield, and sustainable yield index. In conclusion, long-term partial substitution of synthetic N fertilizer with manure facilitates soil OC and TN sequestration in the entire 100 cm profile and thus maintains high crop productivity in upland areas. [ABSTRACT FROM AUTHOR]

Field experiments were conducted to investigate the effects of K application on the nitrogen and potassium utilization efficiency and yield of foxtail millet (Setaria italica L.). The experiment was performed with a completely randomized design with two millet cultivars (Jingu 21 and Zhangza 10) and five K2O rates (0, 60, 120, 180, and 240 kg/hm2) in 2020 and 2021. We found that K promoted K and N absorption; significantly increased dry matter (DM), N, and K accumulation in millet organs; caused dry matter accumulation to peak earlier; and increased the DM accumulation rate. In addition, K accumulation preceded that of DM or N. Relative to the crop cycle, most K (61.07%) accumulated at booting, whereas N accumulated mostly (33.86%) during grain filling. N absorption efficiency increased by 31.87%, and the apparent and agronomic utilization rate of K fertilizer remained high, increasing millet yield, which peaked at a K rate of 180 kg/hm2 for both cultivars, by 29.91% and 31.51% in Jingu 21 and Zhangza 10, respectively, relative to untreated controls. Stepwise regression and path analysis showed that the leaf and spike K accumulation, stem N accumulation, and stem DM were the main factors affecting yield, with DM having the greatest direct effect, followed by leaf K accumulation. The K concentration (0.77–3.04%) in Zhangza 10 was higher than that in Jingu 21 (0.69–2.91%) in untreated plants. Under the same K application rate, N and K accumulation and the harvest index were higher for Zhangza 10 than those for Jingu 21, and the nutrient utilization ability was greater for Zhangza 10. The results demonstrated that rational K fertilizer application can increase K concentration and accumulation in leaves, promote N metabolism and accumulation, increase N and K utilization efficiency, and improve DM accumulation and millet yield. [ABSTRACT FROM AUTHOR]

Soil test phosphorus (P) and potassium (K) and the associated soil test critical values (CSTVs) are widely used as the primary diagnostic tool to determine if a crop needs P and K fertilizer. However, identifying robust and predictive CSTVs requires a large number of field trials in representative soils and environments to assess crop fertilizer responses. From 1976 to 2021, a total of 457 P trials and 458 K trials were conducted in corn (Zea mays), soybean (Glycine max), and wheat (Triticum aestivum) across 40 counties in Ohio. The trials consisted of both multi‐rate, multi‐year trials and single‐year, single‐rate and large strip trials. Across all crops, grain yield responded to P and K fertilizer in 23.4% and 25.3% of trials, with average yield increases of 8.8% and 11.0%, respectively. Corn yield was more responsive to P and K fertilizer (∼30% of P and K trials) than soybean yield (14% of P trials, 20% of K trials). Several models were run to identify CSTVs, but models imparted systematic bias in CSTVs, and a superior model was not identified due to poor model fit and indiscernible criteria to guide model selection. Instead of a single CSTV, data were classified into five discrete categories based on relative yields and Mehlich‐3 soil test values. These classifications provided a useful and consistent framework for assessing the probability of crop response to P and K fertilizer. Ohio soils with Mehlich‐3 values greater than 20 mg P kg−1 and 130 mg K kg−1 have a low probability of responding to P or K fertilizer application. Core Ideas: 457 P and 458 K response trials in corn, soybean, and wheat were conducted across 40 Ohio counties over 45 years.Grain yield response to P and K fertilizer occurred in ∼25% of trials and increased grain yields by ∼10%.Robust critical soil test values (CSTVs) were not identified due to lack of model fit and divergent CSTVs.Classifications based on soil test values and relative yields better conveyed probabilities of crop response.Ohio soils > 20 mg kg−1 Mehlich‐3 P and > 130 mg kg−1 Mehlich‐3 K have a low probability of crop fertilizer response. [ABSTRACT FROM AUTHOR]

Cassava (Manihot esculenta Crentz) is one of the most important root crops in tropical regions of the world. However, little or no study was carried out to determine the optimum rates of nitrogen (N) and potassium (K) for better cassava root yield. N and K fertilizers are the major factors limiting the growth and yield of cassava. Thus, this experiment evaluated the effect of N and K fertilizer rates on the growth, and yield of cassava. Four levels of N (0, 46, 92, and 138 kg N ha−1) and three levels of K (0, 60, and 120 kg K ha−1) were arranged in factorial combination in a randomized complete block design (RCBD) with three replications. The results revealed that the main effects of N fertilizer influenced all the studied parameters, while the main effect of K affected number of tubers per plant and tuber diameter. Interaction effect of N and K influenced fresh tuber yield of cassava. The highest fresh tuber yield of cassava was achieved from 92 kg N ha−1, whereas the lowest fresh tuber yield of cassava was obtained from the control plant. The economic analysis showed that higher net benefit and marginal rate of return were obtained from the application of 92 kg N ha−1, reflecting that it could be an optimum N for cassava yield in the study area. [ABSTRACT FROM AUTHOR]

Soil potassium (K) content in the swell-shrink soils of Central India has been decreasing in recent decades due to higher inputs of N and P fertilizers concomitant with lower or no inputs of K fertilizers. Therefore, nutrient management to mitigate the negative K budget is urgently required. Therefore, we aimed to exploit the abundance of K in gliricidia (Gliricidia sepium) to substitute the fertilizer K requirement to improve soil quality and sustain cotton productivity. Results indicated a significant (p < 0.05) improvement in soil physical properties and organic carbon under treatment 100% NP + 10 kg K (inorganic) + 20 kg K (gliricidia) (T4). The same treatment had 18.2 and 11.4, 36.22 and 4.7, and 17.8 and 9% higher content of available N, P, and K compared to the control and 100% RDF, respectively. Available micronutrients and biological properties were significantly higher under treatment T4 and 100% NP + 15 kg K (inorganic) + 15 kg K (gliricidia) (T3). Hydraulic conductivity, organic carbon, and microbial biomass carbon were identified as key SQ indicators for the experimental soil. The treatments T3 and T4 had about 105 and 122% more seed cotton yield compared to the control and 17 and 27% more than 100% RDF treatment (T2). We conclude that gliricidia can be efficiently utilized in the nutrient management packages to partially substitute the fertilizer K requirement of rainfed cotton. This will further address the K depletion and nutrient imbalances and help to restore the soil K in shrink-swell soils of Central India. [ABSTRACT FROM AUTHOR]

Field trials were conducted over two years at ICAR–Indian Agricultural Research Institute, New Delhi, to examine the effect of different rate, time, source and method of potassium fertilization on the uptake of Fe, Cu, and Zn by basmati rice under aerobic rice system. The study found that, with the exception of K fertilizer source, application timing, method, and rate significantly affected the uptake and translocation of Fe, Cu, and Zn in rice, with all three nutrients showing higher concentrations in straw than in grain across all treatments. The grain nutrient concentration improved with K application rates up to 60 kg K2O/ha, beyond which the effect was insignificant. Split application of K fertilizer in two doses of 30 kg K2O/ha each resulted in 7.1%, 2.3%, and 1.7% (pooled data) increase in grain Zn, Fe, and Cu concentrations, respectively, compared to basal application of 60 kg K2O/ha. The foliar sprays of K (2.5%) during active tillering and panicle initiation, along with basal (45 kg K2O/ha), had a statistically equivalent effect to that of two split applications of K. The harvest index (ratio between the amounts of nutrient stored in the grain to the total nutrient uptake by the plant) for Zn (21–26%), Fe (10–13%), and Cu (17–21%) indicates that only one-fourth, one-tenth, and one-fifth of the absorbed nutrients are transported to the grain, respectively. Thus, best K fertilization in aerobic rice increases uptake of Zn, Fe, and Cu from soil, enhances remobilization from straw to grain thereby improves grain nutritional quality. [ABSTRACT FROM AUTHOR]

This article presents the results of a study of glauconite obtained from phosphate rock waste. The aim is to study the morphological, structural and chemical characteristics of glauconite and to determine the potential for secondary use of mining waste in the agricultural sector. The electromagnetic separation method was used to obtain glauconite concentrate. The optimum parameters for obtaining the maximum mineral content in the concentrate were determined. Studies have shown that glauconite is characterised by globular, granular grains of the highly mature variety. Glauconite almost invariably contains inclusions of pyrite and apatite, which significantly improve the characteristics of the fertiliser. Laboratory experiments have shown that glauconite waste and glauconite concentrate have a positive effect on plant growth and development. The high potassium content, the favourable globular shape of the grains, and the presence of apatite and pyrite inclusions indicate the potential use of glauconite from mining waste as a potash fertiliser. Application of glauconite fertiliser to the soil will provide an opportunity to improve its texture, providing better moisture and aeration. The use of glauconite fertiliser is particularly valuable on acidic soils where apatite can be dissolved, making phosphorus available to plants. This nutrient additionally favours plant growth, as well as reducing the risk of heavy metal accumulation in the soil. Thus, glauconite from the waste of the Egorievsk deposit represents a promising fertiliser for improving soil quality and increasing crop yields. [ABSTRACT FROM AUTHOR]

Sodium ions are commonly found in natural water sources, and their high concentrations can potentially lead to adverse effects on both the water sources and soil quality. In this study, we successfully synthesized potassium polyacrylate (KMAA) hydrogel through free radical polymerization and evaluated its capability to remove sodium ions from and supply potassium ions to aqueous solutions. To assess its performance, inductively coupled plasma emission spectroscopy (ICP) was employed to analyze the sodium ion removal capacity and potassium ion exchange capability of the KMAA hydrogel at various initial sodium ion concentrations and pH values. The results demonstrated that the KMAA hydrogel exhibited remarkable efficiency in removing sodium ions and providing potassium ions. At pH 7, the maximum adsorption capacity for sodium ions was measured at 70.7 mg·g−1. The Langmuir model, with a correlation coefficient of 0.98, was found to be more suitable for describing the adsorption process of sodium ions. Moreover, at pH 4, the maximum exchange capacity for potassium ions reached 243.7 mg·g−1. The Freundlich model, with a correlation coefficient of 0.99, was deemed more appropriate for characterizing the ion exchange behavior of potassium ions. In conclusion, the successfully synthesized KMAA hydrogel demonstrates superior performance in removing sodium ions and supplying potassium ions, providing valuable insights for addressing high sodium ion concentrations in water sources and facilitating potassium fertilizer supply. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

(Background) Raspberry (R. idaeus L.) is very popular with consumers around the world for its intense flavor, attractive appearance, and health benefits. In recent years, interest in healthy eating and natural products has increased, and raspberry fits perfectly into these trends, which translates into its greater importance on the consumer market. (Aim) The aim of this study was the commodity evaluation of raspberry fruits bearing fruit on 2-year-old shoots, cultivated under conditions of varied nitrogen fertilization against the background of constant phosphorus-potassium fertilization. (Methodology) The first-order factors were cultivars ('Laszka' and 'Glen Ample'), and the second-order factor was nitrogen fertilization (0, 50, 100, and 150 kg N ha−1), against the background of constant phosphorus-potassium fertilization (100 kg P2O5 and 120 kg K2O ha−1). The experiment was set up in a dependent split-plot design with three repetitions. (Results) The importance of raspberry on the consumer market was shaped by taste and quality of fruit, health benefits, naturalness and freshness, universality of use, availability, and nutritional trends. (Conclusions) The tested cultivars were characterized by similar production and quality capabilities. Fertilization of the tested cultivars with a dose of 135 kg N·ha−1 turned out to be justified in terms of yield. Increasing nitrogen doses resulted in a significant increase in fresh fruit yield and fruit weight. Different doses of nitrogen increased fruit resistance to mechanical damage, firmness, and quality indices. [ABSTRACT FROM AUTHOR]

This research aimed to study interannual and seasonal dynamics of different potassium compounds in orchard soil and the potassium status of sour cherry trees affected by the application of nitrogen and potash fertilizers. Afield experiment was started in 2017 at an orchard located in the forest-steppe zone of the Central Russian upland. Urea and potassium sulfate were applied to the soil once a year in early spring with rates from N30K40 to N120K160 kg/ha. The content of exchangeable and water-soluble potassium compounds was determined in soil samples five times throughout the growing season from May to September 2018–2020. The content of non-exchangeable potassium was determined twice, in 2017 and 2020. The interannual and seasonal dynamics of plant-available potash in unfertilized soil depended on the weather patterns and the uptake of potassium by trees. In the unfertilized plots, the first signs of potassium nutrition insufficiency appeared, such as low leaf and fruit potassium status and a decrease in the non-exchangeable potassium reserves in the20–40 cm soil layer. The annual fertilization led to the gradual accumulation of exchangeable potassium in the root zone. The accumulation was accelerated with increasing rates. When the exchangeable potassium level in the topsoil reached 200 mg/kg, the intensification of both the seasonal fluctuations in potash content and the potash leaching into the depths of the soil occurred in all treatments. In the conditions of our experiment, one-time treatments with superfluous potassium rates (over 80 kg/ha) did not provide an enlarged stock of plant-available potash in the soil but caused unreasonable losses of it due to leaching. An increase in fertilizer rates was not essential for normal metabolic processes and did not manifest itself as an increase in potassium content in leaves and fruits or as an increase in yield. [ABSTRACT FROM AUTHOR]

Kencur (Kaempferia galanga L.) widely cultivated in shaded dry land because it is one of the plants with a good level of tolerance to shade. The low sunlight intensity will have an impact on the low nutrient uptake because transpiration will be reduced, so the kencur plant needs more nutrients in the soil, particularly potassium. The study aim to investigate the influence of shade and potassium fertilizer in Kaempferia galanga plant. The experimental farm of Agro Techno Park, Faculty of Agriculture, University of Brawijaya, Jatikerto Village served as the site of this study from October 2021 to May 2022. Three replications of a split-split plot were used in this study. The two shade levels that make up the main plot are (N25) for 25% shade and (N50) for 50% shade. The subplots is potassium fertilizer doses with four levels, namely (K0) fertilizer 0 kg ha-1 K²O; (K120) Fertilizer 120 kg ha-1 K²O; (K180) Fertilizer 180 kg ha-1 K²O; and (K240) Fertilizer 240 kg ha-1 K²O. The sub-plots consist of 2 accessions (A1) Lumajang and (A2) Nganjuk. The parameters that are divided up include chemical content analysis, yield parameters, and shade observation. According to the findings, kencur plants produced their highest yields in 50% shade. Based on the highest EPMC value content, the treatment of 50% shade and application of potassium fertilizer at a dose of 240 kg ha-1 also demonstrated the best quality of kencur. The results also indicate that the Lumajang accession has lower yields than the Nganjuk accession. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The significance of potassium has been well documented as one of the major macronutrients for many crops, particularly wheat. Herbicide resistance in weeds and other environmental issues in the wheat crop has encouraged researchers to find alternative methods for weed management. Research Method: A field experiment was conducted during the winter season 2021-2022 at a private farm in North Samawah city, Iraq to examine the competitive ability of two European wheat cultivars against weeds as affected by potassium (K) levels. Treatments included two wheat cultivars (Milano and Pick-row), and three K fertiliser levels (0, 200 and 400 Kg K2O/ha). Findings: The results showed that Pick-row was a superior cultivar in terms of crop competitive ability with weeds compared with Milano. Pick-row was taller, produced the largest number of spikes, had the greatest grain yield, greatest crop biomass and least weed biomass about 61.5 cm, 70 spike/m2, 0.66 t/ha, 2.29 t/ha, and 52.5 g/m2 respectively. The increased K fertiliser level has a positive effect on crop production and weed biomass reduction, especially with Pick-row cultivar. Originality/Value: It is implicated that Pick-row can be useful as a competitive cultivar under Al-Muthanna Province environments. Potassium K fertiliser is better to be increased and split into a number of equal doses and applied at different growth stages of wheat to avoid critical competitive timing risks. [ABSTRACT FROM AUTHOR]

Scientific and reasonable application of potassium fertilizer is an important agronomic measure to achieve high yield and high quality of sweetpotato, and it is of great significance to determine the appropriate amount of potassium fertilizer in the field. For this we constructing a model of the critical K dilution curve (CKDC) of sweetpotato under different N levels to determine crop nutritional statuses. In this study, a 3-year field experiment was conducted in Zhejiang Province in China, using two nitrogen levels (N0: 0 kg ha-1 and N1: 120 kg ha-1) and five K fertilization rates (K0: 0, K1: 75, K2: 150, K3: 225, K4: 300 kg ha-1) for two sweetpotato cultivars of 'Shang 19' and 'Yan 25'. Plant dry matter first increased and then decreased and the K concentration increased continuously with an increase in K application rate. The required amount of K fertilizer to achieve maximum sweetpotato yield under high N conditions was greater than that under low nitrogen conditions. A new CKDC based on dry matter and K concentration was created to assess K nutrition in sweetpotato. At two N levels, CKDC was expressed by the negative power function equation, aboveground: Kc(N0)=5.30W-0.463, R² = 0.79, and Kc(N1)=4.23W-0.298, R² = 0.78, under-ground: Kc(N0)=1.38W-0.125, R² = 0.81, and Kc(N1)=1.32W-0.132, R² = 0.72; whole-plant: Kc(N0)=4.31W-0.421, R² = 0.80; Kc(N1)=3.89W-0.415, R² = 0.79. There is no significantly different for CKDC of whole-plant and underground between N0 and N1 levels, while there is significantly different for CKDC of aboveground between N0 and N1 levels. N fertilizer can strengthen the dilution effect of K concentration, and its effect on the aboveground is greater than that on the underground and whole-plant. Then, potassium nutrition indexes were constructed to identify K nutrition status and could be used as a reliable indicator for K nutrition diagnosis of sweetpotato. The results provide a theoretical basis to improve K fertilization management and sustainability of sweetpotato. [ABSTRACT FROM AUTHOR]

To investigate the effect of fertilization on Pb content in vegetables, pepper was planted in L1645 (the 5 influencing factors are fertilizers (N, P, K), organic fertilizers (sheep manure) and Pb2+; the 4 levels are blank, low, medium and high; a total of 16 treatments) pot orthogonal experiment. The effects of fertilizers on the growth and Pb content in various parts of pepper under Pb stress were analyzed. The results showed that: (1) The Pb content in pepper fruit ranged from 0.011 mg·kg−1 to 0.085 mg·kg−1, which did not exceed the limit value (0.1 mg·kg−1) in the National Standard for Food Safety-Limit of Contaminants in Food (GB2762-2017); (2) The effect order of fertilization on pepper fruit weight was P2O5 > sheep manure > N > K2O; The horizontal combination of factors that promoted the maximum fruit weight of pepper was N (0.15 g·kg−1), P2O5 (0.225 g·kg−1), K2O (0.15 g·kg−1) and sheep manure (9 g·kg−1); (3) The order of fertilizer effects on Pb content in pepper fruit was Pb2+ > K2O > N = sheep manure > P2O5; the factor level combination that resulted in the maximum Pb content in pepper fruits was N (0.15 g·kg−1), P2O5 (0 g·kg−1), K2O (0.45 g·kg−1), sheep manure (6 g·kg−1) and Pb2+ (350 mg·kg−1); (4) Based on the soil fertility characteristics of Urumqi, the recommended optimal fertilizer application rate was: high phosphorus fertilizer P2O5 (495 kg·hm−2), low-level potassium fertilizer K2O (330 kg·hm−2), medium-level nitrogen fertilizer N (660 kg·hm−2) (or low-level nitrogen fertilizer N (330 kg·hm−2) + high-level organic manure sheep manure (19,800 kg·hm−2), which can achieve high yield while ensuring that the Pb content in the fruits does not exceed the standard. Strengthening control of effective and reasonable fertilization methods in Urumqi agricultural land is helpful to reduce the Pb content in vegetables. [ABSTRACT FROM AUTHOR]

The impact of long-term application of nitrogen, phosphorus, and potassium fertilizers and their combinations (N, P, K, NP, NK, PK and NPK) on changes in the contents of total, easily exchangeable, exchangeable, and nonexchangeable potassium in a heavy loamy soddy-podzolic soil (Albic Abruptic Retisol (Loamic, Aric)) was studied. The research was carried out in a one-meter layer of soil in the long-term stationary experiment laid down in Perm region in 1978. Ammonium nitrate or urea, double or simple superphosphate, and potassium chloride were used in the experiment. The rates of fertilizers were 90 kg/ha. Long-term application of potassium chloride in pure form and in combination with superphosphate and nitrogen fertilizers (K90, (PK)90, (NK)90, (NPK)90) provided an increase in the total content of potassium in the plow layer by 1.1–1.2 times and in the contents of various potassium compounds by 1.1–2.8 times (relative to the control variant). A narrowing of the ratio of nonexchangeable potassium to exchangeable potassium was noted. The changes in the one-meter soil layer depended on the combination of fertilizers and the studied form of potassium compounds in the soil. The introduction of only nitrogen and phosphorus fertilizers (N90, P90, (NP)90) without compensation for potassium removal during five rotations of the eight-field crop rotation led to a decrease in the reserves of exchangeable and nonexchangeable potassium in the layer of 0–40 cm by 15–20%. The minimum level of exchangeable potassium in the upper 20-cm layer of the heavy loamy soddy-podzolic soil was 108–112 mg/kg. [ABSTRACT FROM AUTHOR]

The Yellow River Delta is an important grain production base in China, and it is a typical Yellow River irrigated area. Chemical fertilizer overuse has seriously affected grain production safety, and understanding the fertilizer application situation is useful for scientific agronomy management. In this study, we collected the data of the N, P, K fertilizers for crop cultivation in Donging City from 2011 to 2020, and we collected 185 investigating questionnaires to gather information on the fertilizer application rate for small farmers. The results showed that the amount of total fertilizer used has decreased from the year 2015, but the macro element fertilizer rate for crop cultivation exceeded the recommended dosage. The application of compound fertilizer increased during the investigated 10 years, and its proportion in 2020 was 1.65 times higher than in 2011. For obtaining an ideal grain yield, the N and P2O5 had relative reduction rates of 67.8% and 69.6% for wheat planting. Furthermore, the relative reduction rates of N, P2O5, and K2O were 25.9%, 69.6%, and 59.7%, respectively, for maize cultivation when compared to the recommended dosage. During wheat growth, the potassium fertilizer was needed to increase the dosage, although the K element content in the soil was high. Furthermore, the medium and trace elements are all important nutrients for improving crop yield and quality which need to be studied. More scientific measurements should be conducted to match chemical fertilizer reduction to constructing healthy and sustainable agriculture in the Yellow River irrigated area. [ABSTRACT FROM AUTHOR]

Foxtail millet is highly valued in China; however, its optimal fertilization parameters are unknown. This study investigated the effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizer combinations on foxtail millet agronomic traits, photosynthetic characteristics, yield, and quality to promote rational fertilizer application. Pot experiments were conducted using the "3414" fertilizer effect scheme and the representative crop variety was JG21, containing four NPK levels and 20 replicates per treatment, individually. The effects of N, P, and K levels on agronomic traits were analyzed during the jointing, heading, and filling stages. JG21 performed optimally under treatment with N160P90K150 (T6); the yield and fat content increased by 49.32% and 13% compared to the control. Correlation analysis revealed that N was significantly positively (negatively) correlated with the protein (amylose) content. P was significantly positively correlated with the fat and moisture content and K was correlated with the moisture, fat, and protein content, but was negatively with the amylose content. Overall, rational ratios of NPK fertilization improved foxtail millet yield and quality. Based on fuzzy comprehensive evaluation, the T6 treatment (N160P90K150) demonstrated the highest comprehensive effect among 13 NPK fertilizer combinations. Rational application of NPK in foxtail millet may improve agronomic performance by enhancing leaf photosynthetic efficiency and aboveground biomass accumulation. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate fertilization management based on fruit nutrient removal, soil nutrient-supplying capacity and tree nutritional status with standard nutrient values as a reference and the effects on fruit size and yield in Hass avocado trees. The soil chemical characteristics, foliar nutrient content interpreted with the Kenworthy balance index (KBI) method and fruit nutrient removal for a planned yield of 20 ton/ha were used to determine the fertilization management plan for the crop. The experimental area had soils with Andic characteristics and sandy loam texture, low cation exchange capacity and acidic pH. The farmer's standard fertilization plan was based on excessive fertilizer doses for N, P, K and Ca, and an imbalance of P, Ca and micronutrients was observed with the diagnosis of plant nutrient status. The fertilizer plan based on the KBI method had an effect on yield variables in the second crop year, with an increase in production of 20 kg/tree as well as an increase in the percentage of fruits with a size higher than 22 (165–196 g/fruit) according to the Codex Alimentarius standards. These findings indicate that the reincorporation of minerals extracted by the harvest into the soil and the plant nutrient status are useful tools to guide crop fertilization management when fine-tuned to local soil chemical conditions and crop requirements to minimize nutrient losses. [ABSTRACT FROM AUTHOR]

Job's tears (Coix lacryma-jobi L.) is an indeterminate food crop that requires more than onetime application of fertilizer. This study aims to determine the effect of additional doses of phosphorus and potassium at the beginning of the generative phase as side dressing fertilization on yield components, yield, and yield quality of the Job's tears plant. The research was conducted in dry season March - August 2021 at the Experimental Field of the Faculty of Agriculture, Universitas Padjadjaran at Jatinangor, Sumedang Regency around 750 m above sea level. The experimental design used randomized block design (RBD) consisting of nine treatments and three replications, namely P and K fertilizers, respectively at doses of: 0, 20, 30, 40, and 50 kg/ha through one or two frequencies of fertilization. Data analysis used analysis of variance and Scott-Knott test at 5% significance level. The results showed that the application of phosphorus and potassium fertilizers affected the number of panicles, seed weight, and harvest index, but no one effect on other yield components and yield quality. The yield component and the Job's tears yield were decreased compared to previous studies, which were carried out in sufficient water conditions. [ABSTRACT FROM AUTHOR]

Aims: Organic fertilizer addition plays a significant role for soil organic carbon (SOC) storage. The interaction between bacteria and clay minerals for the mechanism of SOC storage with organic fertilization was investigated in saline-alkaline paddy soil. Methods: A 9-year field experiment was arranged, which included: (a) CK, without fertilizer addition, (b) NPK, mineral N, P and K fertilizer addition, (c) NPKC1, and (d) NPKC2, mineral N, P and K fertilizer plus 450 and 900 kg C ha−1, respectively. Results: In comparison to only mineral fertilization, the content of humic acid-C and humin-C was significantly increased by 58.8%–70.6% and 46.9–53.1% with organic fertilizer addition, respectively. The 2:1 type clay minerals (vermiculite and illite) were also increased, which were positively correlated with SOC storage due to the formation of clay minerals-humus complexes. Meanwhile, the abundance of Geobacter and Anaeromyxobacter was increased with organic fertilization, which accelerated the transformation of clay minerals by promoting Fe reduction, and then increased SOC storage. While, compared with NPKC1 treatment, more Gammaproteobacteria and Anaerolineae, involved in the decomposition of SOC, were found in NPKC2 treatment. Relative to NPK treatment, SOC storage of NPKC1 and NPKC2 treatments increased by 23.3% and 29.8%, respectively, and there was no significant difference between the two treatments. Conclusions: Therefore, appropriate addition of organic fertilizer is a better fertilization practice to promote stability and storage of SOC, which provided an important contribution to elucidate the role of mineral-microbial interactions for storage of SOC in saline-alkaline paddy soil. [ABSTRACT FROM AUTHOR]

【Objective】 The aim was to explore the effects of potassium application rate on the growth and development, yield and quality of tobacco leaves and potassium utilization efficiency of new flue-cured tobacco variety 'chuanyan 200', so as to provide theoretical support for rational application of potassium fertilizer.【Method】 Taking 'chuanyan 200' as the test object, a field experiment was carried out with six potassium application rates of 0, 240, 285, 315, 345 and 390 kg/hm² (named K0, K240, K285, K315, K345 and K390, respectively). The characteristics of agronomic traits, yield, output value, internal chemical composition and potassium utilization efficiency of tobacco plants under different potassium application rates were analyzed. 【Result】 The application of potassium fertilizer could promote the growth and development of tobacco plants in the early stage (before the rosette stage), especially the growth of plant height, effective leaf number and pitch, but had little effect on the growth in the middle stage (from the rosette stage to the topping stage). Compared with K0 (CK), the yield, output value and average price of flue-cured tobacco increased by 19.02%-22.60%, 24.65%-47.28% and 3.26%-20.33% respectively after potassium application. K315 treatment showed the best performance in all indexes, and the proportion of superior tobacco in K315 treatment was the largest, which was 5.5 percentage points higher than that of K0 (CK). Compared with K0 (CK), potassium application could significantly increase the nicotine content in tobacco leaves by 37.29%-66.10%, and the application amount of potassium fertilizer in 315-345 kg/hm² was more conducive to the coordination of chemical components in tobacco leaves. Compared with K0 (CK), the appropriate application of potassium fertilizer could increase the biomass of each organ and the whole plant of tobacco plant. The biomass accumulation of stem was the highest in K315 treatment, which was 1 585.77 kg/hm². There was no significant difference in biomass accumulation of root, leaf and whole plant among different potassium treatments.The distribution characteristics of potassium in different organs of flue-cured tobacco were leaf>stem>root, and potassium was mainly distributed in leaves. The distribution ratio of potassium in leaves treated with K315 was as high as 50.89%. Compared with K0 (CK), potassium application significantly increased the accumulation of potassium in tobacco leaves by 54.27%-109.31%. The accumulation of potassium in stem, leaf and whole plant of K315 treatment was the largest, which was 25.73, 35.06 and 68.90 kg/hm², respectively. The apparent use efficiency, recovery rate and economic utilization efficiency of potassium fertilizer increased first and then decreased with the increase of potassium application rate, and K315 treatment showed the best performance. The apparent use efficiency, recovery rate and economic utilization efficiency of potassium fertilizer were 14.06%, 13.15% and 7.01%, respectively. However, the agronomic efficiency, partial factor productivity and physiological efficiency of potassium fertilizer decreased with the increase of potassium application rate, and the surplus amount of soil potassium also increased significantly with the increase of potassium application rate.【Conclusion】 Reasonable application of potassium fertilizer can increase the yield and output value of tobacco leaves, increase the proportion of high-quality tobacco leaves, coordinate the chemical composition of tobacco leaves, promote nutrient absorption, and improve the utilization efficiency of potassium fertilizer. Considering the quality, economic traits and potassium fertilizer utilization efficiency of tobacco leaves, the reasonable recommended amount of potassium fertilizer for 'chuanyan 200' in Guangyuan tobacco area is 315 kg/hm². [ABSTRACT FROM AUTHOR]

Background: Potassium (K) substitution by sodium (Na) in sugar beet nutrition has been investigated during the last two decades and promising results have been revealed. However, substitution is still not used in agriculture although it has been recommended that Na can replace K to a large degree, proposing an interesting fertilization strategy for such plants. This study investigates the feasibility of sugar beet production on saline–sodic soils considering Na as a substituent for K. Aims: The aim of this study is to develop a fertilizer strategy considering Na concentration in saline–sodic soils as a partial substituent to K fertilizer and to determine the level of substitution. Methods: Two saline–sodic soils (SAR15 and SAR19 representing sodium adsorption ratios 15 and 19 [mmol L–1]1/2, respectively) with low plant‐available K were selected to investigate the substitution of K fertilizer requirements with indigenous soil Na. A pot experiment was conducted with 20 kg soil per pot having four treatments, that is, KA: recommended K; KB: recommended K–K equivalent to 2.5% of soil Na; KC: recommended K–K equivalent to 5% of soil Na; and control without K fertilizer application were established mixing potassium sulfate (K2SO4) in the soil at the time of sugar beet sowing. The sugar beet plants were harvested 90 days after sowing. Results: The results revealed that total plant biomass was significantly improved in KB as compared to KA. This indicates that K requirement of sugar beet was substituted by Na, and KB provided optimum results on SAR15 as compared SAR19 considering all other K combinations. Conclusion: In sugar beet nutrition, K can be replaced by Na to a large degree on saline–sodic soils under K‐deficient conditions. Therefore, sugar beet production on marginal saline–sodic soil can be a win–win strategy boosting sugar beet production and reducing input cost. [ABSTRACT FROM AUTHOR]

[Objective] The study aimed to explore effects of applying commercial organic fertilizer with different organic materials on soil nutrient content and aggregate distribution, yield, quality and nitrogen ( N), phosphorus ( P) and potassium ( K) fertilizer utilization rate of flue-cured tobacco, and provide technical support for scientific fertilization of flue-cured tobacco in Qujing tobacco-growing area. [ Method] Using flue-cured tobacco variety Yunyan 100 as material, a field experiment was established in red soil in Qujing tobacco planting area, and five fertilization treatments were set up including Tl ( traditional chemical fertilizer, CK1), T2, T3 and T4 ( 70% traditional chemical fertilizer combined with commercial organic fertilizer A, B and C, respectively), TS ( without fertilizer, CK2). [Result] Compared with treatment Tl (CK1), treatments T2, T3 and T4 significantly improved soil pH by 0.14 -0. 31 units, and soil fertility was also improved. The contents of soil organic matter, available N, P and K were significantly increased by 6. 47% -42. 79%. Meanwhile, the conductivity of three organic fertilizers treatments was significantly decreased by 20. 03% -26. 73%. Compared with Tl ( CK1l), the contents of large-size aggregates ( >5 mm, 2 -5 mm) in treatments T2, T3 and T4 were significantly increased by 69. 28%, 172. 67% and 90. 89%, and contents of powder clay ( < 0. 25 mm) were decreased by 4. 61 %, 13. 73% and 7. 37%, respectively. Compared with Tl (CK1), T3 and T4 treatments significantly increased leaf coefficient by 15. 55% and 10. 60%, T2 and T3 treatments increased yield by 13. 19% and 9. 09%, and output values were significantly enhanced by 25. 49% and 20. 35%, respectively. Treatments T2, T3 and T4 increased total sugar, reducing sugar and potassium oxide in the middle leaf, and decreased total nitrogen and nicotine compared with Tl ( CK1 ), and chemical composition of tobacco leaves was more harmonious. Compared with Tl ( CK1), treatments T2, T3 and T4 significantly increased apparent and physiological nitrogen use efficiency by 13.48% -27. 46% and 5. 42% -17. 81 %, respectively. Treatments T2, T3 and T4 promoted P, K fertilizer absorption, and T3 showed the best effect. The apparent and physiological phosphorus efficiency of T3 increased significantly by 35. 44% and 36. 07%, while the apparent and physiological potassium efficiency increased significantly by 12. 16% and 13. 08%, respectively. [ Conclusion] Replacing 30% traditional chemical fertilizer combined with commercial organic fertilizer can improve soil pH and soil fertility, increase tobacco yield and quality, and improve nitrogen, phosphorus and potassium fertilizer utilization efficiency of flue-cured tobacco. [ABSTRACT FROM AUTHOR]

The remarkable yield performance of super hybrid rice has played a crucial role in ensuring global food security. However, there is a scarcity of studies investigating the contribution of radiation use efficiency (RUE) to hybrid rice yields under different nitrogen and potassium treatments. In this three-year field experiment, we aimed to evaluate the impact of two hybrid rice varieties (Y-liangyou 900: YLY900 and Quanyouhuazhan: QYHZ) under varying nitrogen regimes (N90: 90 kg N ha−1, N120: 120 kg N ha−1, N180: 180 kg N ha−1) and potassium regimes (K120: 120 kg K2O ha−1, K160: 160 kg K2O ha−1, K210: 210 kg K2O ha−1) on grain yield and its physiological determinants, including RUE, intercepted photosynthetically active radiation (IPAR), aboveground biomass production, and harvest index (HI). Our results revealed that both rice varieties exhibited significantly higher yields when coupled with nitrogen and potassium fertilization. Compared to the N90 × K120 treatment, the N120 × K160 and N180 × K210 combinations resulted in substantial increases in grain yield (12.0% and 21.1%, respectively) and RUE (11.9% and 21.4%, respectively). The YLY900 variety showed notable yield improvement due to enhanced aboveground biomass production resulting from increased IPAR and RUE. In contrast, the QYHZ variety's aboveground biomass accumulation was primarily influenced by RUE rather than IPAR, resulting in higher RUE and grain yields of 9.2% and 5.3%, respectively, compared to YLY900. Importantly, fertilization led to significant increases in yield, biomass, and RUE, while HI remained relatively constant. Both varieties demonstrated a positive relationship between grain yield and IPAR and RUE. Multiple regression analysis indicated that increasing RUE was the primary driver of yield improvement in hybrid rice varieties. By promoting sustainable agriculture and enhancing fertilizer management, elevating nitrogen and potassium levels from a low base would synergistically enhance rice yield and RUE, emphasizing the critical importance of RUE in hybrid rice productivity compared to HI. [ABSTRACT FROM AUTHOR]

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