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Coffee in Western Ghats grown under shade, soils are enriched with all the nutrients except phosphorus. The areas receive high rainfall, which leads to leaching loss and surface runoff of applied nutrients causing low fertilizer use efficiency. Improved agronomic practices are essential to address these issues. Fertigation is one such practice, having the potential to reduce extra chemical load by improving nutrient use efficiency. Hence, an attempt was made to study the impact of long-term fertigation on soil-plant nutrition and productivity of Robusta coffee. The trial was laid out in randomized complete block design (RCBD) with six treatments and four replications. Data on yield parameters and coffee yield indicated that significantly higher total number of nodes/branches, number of bearing nodes/branches, number of fruits/branches and coffee yield (49.1, 35.0, 758, and 2117 kg ha−1, respectively) were recorded in fertigation block supplied with 100% recommended dose of fertilizer (RDF) as water soluble fertilizer (WSF) which were statistically on par with 75% RDF (44.1, 29.4, 679, and 1821 kg ha−1, respectively). Similarly, higher major, secondary, and micro-nutrient content were noticed in leaf with fertigation at 75 and 100% RDF and also it was observed that, leaf Nitrogen (N), Phosphorus (P), and Potassium (K) content played a highly significant role in increasing coffee yield. The study results revealed that the quantum of N, P, and K fertilizer requirement could be brought down to the tune of 25% through fertigation as compared to the conventional soil application. [ABSTRACT FROM AUTHOR]

Phonolite rock powder is an alternative to potassium fertilizer, having applicable K and Na content among rocks, as well as others nutrients (e.g. Ca, S and Si). The study tested the effects of replacing KCl with phonolite rock powder on tree growth, nutrition, and nutrient cycling in a Eucalyptus stand. We compared four top dressing fertilization treatments: PHO (91.7 kg ha− 1 of K and 47.5 kg ha− 1 of Na, applied via phonolite); SOD (54.2 kg ha− 1 Na, applied via NaCl); KCl (91.7 kg ha− 1 of K), and Control (no top dressing fertilization); where KCl and SOD present equivalent molar amount (2.33 kmol). Leaf K concentrations were elevated in the KCl treatment and leaf Na concentrations were elevated in the SOD treatment. Leaf K and Na concentrations in the phonolite rock powder treatment were similar to or lower than those in the KCl and SOD treatments. There were no differences among treatments in tree growth, volume, and aboveground biomass, probably due to a prolonged drought, during which precipitation was 27% below and the average temperature was 2.3ºC above the local historical average. Trees fertilized with KCl had the highest K deposition in litterfall, those fertilized with NaCl had the highest Na deposition, and phonolite rock powder fertilization was intermediate for both elements. We conclude that despite the use of phonolite did not significantly enhance the growth of eucalyptus plants, its application as a fertilizer yielded comparable leaf concentration, stem volume, and aerial biomass to that achieved with KCl, and in certain instances, even surpassed the results obtained with NaCl fertilization proving it applicability when compared to traditional sources, such as KCl. [ABSTRACT FROM AUTHOR]

Potassium (K) is the primary limiting nutrient for cassava, being essential to achieve sustainably satisfactory cassava yields in low K reserve sandy soils that require proper K fertilization to avoid depleting the soil K reserve. Soil K dynamics, the growth, and yield responses of cassava were investigated using varying K fertilizer rates (0, 25, 50, 75, 100, and 125 kg K2O/ha). Four on-farm experiments were conducted in major cassava-producing areas, Northeast Thailand during 2019–2021 year. Cassava responded positively to K, producing yield increases up to 132%, with the highest tuber yield obtained being in the range 100–125 kg K2O/ha. Mineral K was the main K source for cassava grown without K fertilization, which resulted in the poorest growth and yield quantities. Potassium fertilization significantly promoted the uptake of K by cassava, especially in the tuber, causing a negative K balance due to the large removal from the soil, even when the K fertilizer compensated to some degree. Potassium use efficiency of cassava was low, particularly with K fertilization at the highest rate, which reflected intense leaching of the soil. The critical level of soil-available K, identified using a linear-plateau model, was 40.55 mg/kg for 90% relative yield, suggesting the potential to increase K use efficiency through better fertilization guidelines. Our findings suggested that K fertilization of cassava annually is advisable for better yields and to avoid progressive depletion of the soil K capital, even though the residual K from K fertilizer contributed to available K in soils. [ABSTRACT FROM AUTHOR]

Introduction: Potassium deficiency significantly hinders cotton growth and development, adversely affecting yield and fiber quality. Applying potassium fertilizer is a common practice to address potassium deficiency in the soil. However, the effectiveness of potassium fertilizer application depends on the appropriate soil potassium levels in cotton fields. Methods: This study used a randomized block design with six different soil potassium levels and conducted experiments across 18 micro-zones in the field. This study aimed to investigate the response of cotton yield and quality to different soil potassium levels, to try to clarify the suitable soil potassium levels for cotton growth, so as to provide practical and effective help for determining the amount of potash fertilizer in the cotton field. Results: The results showed that the seedcotton yield was increasing, with the soil potassium level increased under no tillage. There was no significant difference among K4, K5, and K6 on seedcotton yield, which were significantly higher than K1 and K2. As soil potassium levels increased, the proportion of autumn boll and the proportion of outer boll also increased, indicating that higher soil potassium levels support the better growth and development of cotton in the middle and late stages, leading to increased boll sets and higher yields. Additionally, the available potassium content in the 0-40-cm soil layer was significantly correlated with yield and yield parameters but not with fiber quality indices. Discussion: It is concluded that K4 treatment could provide sufficient potassium to meet the growth and development needs of cotton. Potassium fertilizer application is recommended when the available potassium content in the 0-40-cm soil layer falls below 122.88 mg kg-1 in the cotton field. [ABSTRACT FROM AUTHOR]

Potassium (K) is one of the essential nutrients that play a crucial role in rice fields; however, its availability, transport, and balance components can be influenced by alternating wetting and drying (AWD) irrigation practice. This study used the Hydrus-1D solute transport model to simulate K transport and balance components in AWD irrigated rice fields. Thirty lysimeter field experiment plots with three different irrigation treatments (No: no soil water stress, MS: mild soil water stress (400 cm), and SS: severe soil water stress (750 cm)) were used for rice cultivation. Daily measurements of soil matric potential head (SMPH) and ponding water depth (PWD) were recorded. Throughout the rice-growing season, leachate water samples from the surface (ponding water) and soil profiles were collected to measure K content. Using the lysimeter field experiment data, the Hydrus-1D model simulated K transport in the AWD rice field. The simulation results indicate that the K distribution predominantly occurred within the top puddled soil layer (0–20 cm) in AWD practice. This suggests that the recommended K fertilizer dose with a 4–5 cm PWD and SMPH of 400 cm optimizes K availability for rice while limiting K leaching loss. The Hydrus-1D model proves to be a valuable management tool, aiding in determining optimal K application rates and ponding water depths for AWD irrigation, ensuring sufficient K nutrients for rice, and controlling K loss for sustainable rice production. [ABSTRACT FROM AUTHOR]

Introduction: In semiarid tropical locations, polyhalite (K2Ca2Mg(SO4)4H2O) and muriate potash (KCl) were tested for their ability to increase cane growth, yield, and recovery at potash (K)- and calcium (Ca)-deficient sites. Methods: The treatments involved control plots with no potash fertilizer (T1); T2 and T3 applied potassium through (muriate potash) MOP only at 80 and 120 kg K2O ha-1, whereas T4 and T5 applied potassium with half of MOP and polyhalite at 80 and 120 kg K2O ha-1, respectively. Results and discussion: At 35 days after harvest (DAH), T2 (10.82%), T3 (24.1%), T4 (34.9%), and T5 (34.9%) had a greater ratoon resprouting rate than did the control treatment, where it was just 37.0 out of 100 harvested canes. At 308 DAH, T2 (-5.9%), T3 (-5.7%), and T5 (-6.6%) presented greater leaf chlorophyll contents than did T1. The K-fertilized plots yielded 64.31 t ha-1 in T2 and 65.97 t ha-1 in T5, whereas the control plot yielded 61.5 t ha-1. Compared with the control plots, the T5 plots experienced fewer stalk borer (-28.6%), top borer (-23.3%), and early shoot borer (-23.3%) attacks. T2, T4, and T5 presented higher percentages of commercial cane sugar (CCS) (6.82, 8.83, and 8.74%, respectively) than did the control plots. T1 and T3 had similar CCSs (10.99 and 11.33%, respectively). The CCS weight per area ranged from 7.98 to 8.47 t ha-1 near maturity. T4 (8.59 t ha-1) and T5 (8.60 t ha-1) had significantly greater values than did T1-T3. Compared with the control, the applied potassium fertilizer increased the economic output by 8,711, 11,687, 13,485, and 13,857 INR ha-1 in the T2, T3, T4, and T5 plots, respectively. The higher cost of polyhalite than MOP has reduced its economic advantages. Thus, the T4 plots outperformed the other treatments in terms of growth, yield, and quality indices, but their higher values (120 kg K2O ha-1) were statistically equivalent. Conclusion: Finally, the study concluded that MOP and polyhalite at a 50% ratio of 80 kg K2O ha-1 may help improve sugarcane growth, yield, and quality in semiarid tropical locations. [ABSTRACT FROM AUTHOR]

AbstractRice cultivation in South Florida, especially within crop rotation systems, presents a promising avenue for mitigating phosphorus (P) levels in drainage water by optimizing nutrient absorption across varying flooding conditions. This study aimed to assess the impacts of different flooding depths on rice growth and nutrient efficiency while exploring the interrelationships among these factors. Conducted over a two-year period, the field study involved planting a single rice variety (Diamond: 95 kg ha−1, long-grain, short-season) at four distinct flooding depths (5, 10, 15, and 20 cm) without fertilizer application. Results revealed minimal effects of flooding depths on root and shoot length or dry matter accumulation. Additionally, concentrations of total P and potassium (K) in both shoot and root tissues remained consistent across the different flooding depths. Despite the absence of P and K fertilizer inputs, no significant changes were observed in P use efficiency (PUE), K use efficiency (KUE), or water use efficiency (WUE). Cultivating rice under optimal flood depths of 5 cm within the Everglades Agricultural Area (EAA) demonstrated potential for conserving water and essential nutrients such as P and K. These findings highlight the feasibility of rice cultivation in fertile soils as a means to decrease nutrient (P and K) concentrations in drainage water, thereby promoting sustainable agricultural practices in the region. [ABSTRACT FROM AUTHOR]

With the increasing focus on irrigation management, it is crucial to consider cost-effective alternatives for soil water monitoring, such as multi-point monitoring with low-cost soil moisture sensors. This study assesses the accuracy and functionality of low-cost sensors in a sandy loam (SL) soil amended with biochar at rates of 15.6 and 31.2 tons/ha by calibrating the sensors in the presence of two nitrogen (N) and potassium (K) commercial fertilizers at three salinity levels (non/slightly/moderately) and six soil water contents. Sensors were calibrated across nine SL-soil combinations with biochar and N and K fertilizers, counting for 21 treatments. The best fit for soil water content calibration was obtained using polynomial equations, demonstrating reliability with R 2 values greater than 0.98 for each case. After a second calibration, low-cost soil moisture sensors provide acceptable results concerning previous calibration, especially for non- and slightly saline treatments and at soil moisture levels lower than 0.17 cm3cm−3. The results showed that at low frequencies, biochar and salinity increase the capacitance detected by the sensors, with calibration curves deviating up to 30% from the control sandy loam soil. Due to changes in the physical and chemical properties of soil resulting from biochar amendments and the conductive properties influenced by fertilization practices, it is required to conduct specific and continuous calibrations of soil water content sensor, leading to better agricultural management decisions. [ABSTRACT FROM AUTHOR]

Nitrogen is a key nutrient for crop growth. Excessive or insufficient nitrogen affects crop growth, yield, and quality. Additionally, excessive nitrogen fertilizer can cause soil and water pollution. Applying panicle fertilizer during the late jointing stage can promote rice panicle growth. Therefore, accurately and timely monitoring of nitrogen status in rice fields during the late jointing stage and timely optimizing fertilization strategies is crucial for ensuring rice yield and environmental protection. This paper integrates multimodal data from unmanned aerial vehicle (UAV) remote sensing and ground observations to construct inversion models for leaf nitrogen content (LNC) and plant nitrogen content (PNC) of rice at the late jointing stage. The research was conducted at the Shapu Experimental Base of the Agricultural Science Research Institute in Zhaoqing City, Guangdong Province, with two field experiments carried out during the late rice seasons of 2021 and 2022. Each of Experiment 1 (2021) and Experiment 2 (2022) included 30 experimental plots, designed with 5 nitrogen fertilizer gradients, 2 planting densities, and 3 replications. Phosphorus and potassium fertilizers were applied uniformly across all plots. UAVs equipped with multispectral and RGB cameras were used to acquire remote sensing images of rice canopies during the late jointing stage. Vegetation indices (VIs) and texture feature values (TFVs) were extracted from the multispectral images, with TFVs derived using the gray level co-occurrence matrix (GLCM) method. Texture indices (TIs) were then constructed by combining TFVs. RGB images were used to generate digital surface models (DSM) for bare ground (pre-transplant) and rice fields (late jointing stage). These DSMs, combined with ground reference methods, were used to construct crop surface models (CSM) to derive estimated canopy heights (ECH) for each plot. Manually collected data included measured canopy height (MCH) and field nitrogen management data (FN) used as ground observations. For each experimental plot, three representative rice plants were selected as samples. After removing the roots, the leaves and stems were separated and dried at 85℃ to a constant weight, which was recorded as the aboveground biomass of the leaves and stems. The true values of leaf nitrogen content and stem nitrogen content were obtained using the Kjeldahl method. Combining these values with the dry weight data, the true values of plant nitrogen content were calculated. The maximal information coefficient (MIC) was used as an evaluation metric for feature assessment and selection. Random forest regression algorithms were employed to construct inversion models for rice LNC and PNC, respectively, using the coefficient of determination (R2), root mean squared error (RMSE), and mean absolute error (MAE) as model evaluation metrics. The analysis and experimental results indicate: TIs constructed using combinations of TFVs significantly enhanced the correlation between texture information and LNC and PNC. When the UAV flight height was 100 m, the Ratio Texture Index constructed using a 9×9 sliding window size in the GLCM method showed the best performance, improving the MIC value by 11.48% compared to the best TFV. For conventional machine-transplanted rice planting density, the correlation between TIs and LNC and PNC was best when the GLCM sliding window size was set to 9×9 or 11×11 at a UAV flight height of 100 m. The ECH derived from the CSM showed a high correlation with the manual MCH in the field. Including canopy height (MCH or ECH) as an input feature in the random forest regression model significantly improved the inversion accuracy of rice nitrogen content. The ECH extracted from the CSM showed high estimation accuracy (R² = 0.77, RMSE = 3.4 cm, MAE = 2.8 cm). The inclusion of canopy height (MCH or ECH) in the model construction improved the inversion accuracy for PNC more significantly compared to LNC. Integrating UAV remote sensing and ground observation multimodal data, the random forest regression algorithm significantly improved the inversion accuracy of rice LNC and PNC at the late jointing stage. Considering both inversion accuracy and operational convenience, it is recommended to use a feature combination of VI+TI+ECH+FN in field production. Compared to using VI alone, this feature combination improved R² by 6.73%, and reduced RMSE and MAE by 13.62% and 14.68%, respectively, for LNC inversion. For PNC inversion, R2 was improved by 12.53%, and RMSE and MAE were reduced by 22.09% and 19.80%, respectively. The results demonstrate that constructing random forest regression models by integrating UAV remote sensing and ground observation multimodal data can accurately detect rice LNC and PNC, providing a scientific basis for rice field management and fertilization decision-making. [ABSTRACT FROM AUTHOR]

To investgate the effects of potassium (K) application on the agronomic traits and fruit quality of Lycium barbarum L. (Goji), three levels of K fertilizer, namely LK (25 g/plant), CK (50 g/plant), and HK (75 g/plant), were applied to plants in phytotron for observing and measuring relevant indicators. The investigation involved seven agronomic traits: plant height, plant stem diameter, new branch increment, yield of fresh fruits per plant, dry fruit quantity within 50 g, ratio of different grade fruits, and ratio of longitudinal diameter to transverse diameter of Goji fruits. The results showed that K application level had significant effect on ratio of the longitudinal diameter to the transverse diameter of fresh Goji fruits, and that the influence on other agronomic traits was slight. In the meanwhile, the concentrations of amino acids, betaine, polysaccharides and flavonoids of Goji fruits in different levels of K fertilizer were tested. The K treatment increased the content of glutamic acid, and decreased that of flavonoids (P < 0.05), whereas the content of other amino acids, polysaccharides and betaine were unaffected. A total of 132 flavonoid metabolites was identified. Among them, K treatment up-regulated 36 metabolites and down-regulated 30 metabolites (P < 0.05). The results provided a basis for balanced K supply to regulate the agronomic traits and nutrients of Goji fruits. [ABSTRACT FROM AUTHOR]

Background: Potassium (K) is an essential nutrient for plant growth and development. Maize (Zea mays) is a widely planted crops in the world and requires a huge amount of K fertilizer. Arbuscular mycorrhizal fungi (AMF) are closely related to the K uptake of maize. Genetic improvement of maize K utilization efficiency will require elucidating the molecular mechanisms of maize K uptake through the mycorrhizal pathway. Here, we employed transcriptome and gene family analysis to elucidate the mechanism influencing the K uptake and utilization efficiency of mycorrhizal maize. Methods and results: The transcriptomes of maize were studied with and without AMF inoculation and under different K conditions. AM symbiosis increased the K concentration and dry weight of maize plants. RNA sequencing revealed that genes associated with the activity of the apoplast and nutrient reservoir were significantly enriched in mycorrhizal roots under low-K conditions but not under high-K conditions. Weighted gene correlation network analysis revealed that three modules were strongly correlated with K content. Twenty-one hub genes enriched in pathways associated with glycerophospholipid metabolism, glycerolipid metabolism, starch and sucrose metabolism, and anthocyanin biosynthesis were further identified. In general, these hub genes were upregulated in AMF-colonized roots under low-K conditions. Additionally, the members of 14 gene families associated with K obtain were identified (ARF: 38, ILK: 4, RBOH: 12, RUPO: 20, MAPKK: 89, CBL: 14, CIPK: 44, CPK: 40, PIN: 10, MYB: 174, NPF: 79, KT: 19, HAK/HKT/KUP: 38, and CPA: 8) from maize. The transcript levels of these genes showed that 92 genes (ARF:6, CBL:5, CIPK:13, CPK:2, HAK/HKT/KUP:7, PIN:2, MYB:26, NPF:16, RBOH:1, MAPKK:12 and RUPO:2) were upregulated with AM symbiosis under low-K conditions. Conclusions: This study indicated that AMF increase the resistance of maize to low-K stress by regulating K uptake at the gene transcription level. Our findings provide a genome-level resource for the functional assignment of genes regulated by K treatment and AM symbiosis in K uptake-related gene families in maize. This may contribute to elucidate the molecular mechanisms of maize response to low K stress with AMF inoculation, and provided a theoretical basis for AMF application in the crop field. [ABSTRACT FROM AUTHOR]

The negative impact of excessive fertilization on the sustainable development of agriculture has become the focus of universal attention. Thus, the aim is to maximize the yield of rice without imposing too much damage on the environment. This paper uses data regression analysis based on the statistical data (from 1990 to 2020) of a certain region to explore the impact of fertilizer application on rice yield, and adopts the sensitivity analysis to study the sensitivity of rice yield to the applied amount of chemical fertilizer. The results show that the average rice yield increased with increasing Nitrogen (N) and potassium (K) fertilizers application within the statistical data range; while the average rice yield decreased as Phosphorus (P) fertilizer application increased. Simultaneously, increasing the application of N and K fertilizers improved the average rice yield. Reducing the amount of P fertilizer and increasing the proportion of K fertilizer positively affected the average rice yield. The sensitivity analysis indicated that the average rice yield was most sensitive to K application amount. The sensitivity value maximized at a small amount of N fertilizer (11.25 kg hm-2) and a large amount of P fertilizer (6 kg hm-2). The findings reveal the interactive effect of multiple fertilizer application rates on grain yield and address the unclear mechanism of single fertilizer application on grain yield in the existing research. This paper provides a theoretical basis for scientific fertilizer use, agricultural quality, efficiency improvement, and sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

Biochar is a widely recognized soil amendment used to improve soil physicochemical properties and crop productivity. However, its compositive effects on soil water, fertilizer, and carbon in cropping systems are not extensively understood. A two-year field study was conducted to investigate the influence of integrating maize-residue-derived biochar on evapotranspiration, water and fertilizer utilization efficiency, soil organic carbon (SOC) content, and soil carbon emissions in maize farming, employing drip irrigation in conjunction with film mulching. The treatments included the following three biochar amendments: 15 (B15); 30 (B30); and 45 (B45) t ha−1. Biochar was exclusively incorporated prior to sowing during the initial year of the experiment, and no biochar was used as a control (CK). After two years, the biochar amendments, especially B30, improved crop water productivity and the partial factor productivities of nitrogen, phosphorus, and potassium fertilizer. Relative to CK, the biochar amendments significantly reduced soil CO2 and CH4 emissions during crop growth by 17.6–40.6% and −1.21–268.4%, respectively, averaged across two years. The best treatment effect was achieved by adding 15 t ha−1 of biochar. The biochar needed replenishing in the third year for B30 and in the fourth year for B45 to increase the SOC content by 20 g kg−1. An application rate of 22 metric tons per hectare of biochar is proposed to optimize water and fertilizer utilization efficiency, alongside augmenting the soil organic matter content, within maize farming under drip irrigation and mulching practices on sandy loam soil. However, the biochar must be added at 20 t ha−1 in the third year to counterbalance soil carbon losses and improve SOC. [ABSTRACT FROM AUTHOR]

Biochar application has received much attention because biochar can be used as an organic amendment. The nutrient release patterns and interactions in straw biochar produced at different temperatures are not well understood. In this study, we observed the release patterns of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) and the interaction between released C, N, P, and K from straw biochar prepared from 225 to 600 °C through a 180-day degradation experiment. The results showed that the degradation rate of the two kinds of straw biochar was faster in the first 30 days at different temperatures, and that of the straw biochar prepared before 300 °C was more rapid, indicating that 300 °C is an important turning point. The rule of nutrient release in the straw biochar showed that the K release rate was the highest and most rapid and was more than 60% in the first 30 days. The nutrient release rates for the two kinds of straw biochar were in the order K > N > P > C. The release of nutrients accompanied the decomposition of the straw biochar, and there was an exponential relationship between the amount of nutrients released from straw biochar and its degradation mass. There were collaborative or similar release processes indicated by significant positive correlations between the released C and N (R2 = 0.96) and P and K (R2 = 0.94) in the tobacco straw biochar and an obvious correlation between the released C and N (R2 = 0.76) in the rice straw biochar. These results indicated that the released C and N, P, and K in tobacco straw biochar, as well as C and N in rice straw biochar, have synergistic effects and the same degradation path. The application of straw biochar can provide a source of P and N in the short term and a source of P and C in the long term. This study suggests that returning straw biochar to the soil could appropriately reduce the input of K fertilizer in the early stage. [ABSTRACT FROM AUTHOR]

The present experiment was undertaken to characterize the K releasing pattern as well as the bioavailability of K in nine soils under three dominant soil orders of eastern India. Soils were extracted with 0.2 M sodium tetraphenyl boron (NaTPB) and perennial ryegrass (Lolium perenne L.) was grown repeatedly with and without the addition of K fertilizer to study the K release kinetics and bioavailability. The highest K release by 0.2 M NaTPB at 144 h incubation was recorded in Entisols, while the least in Alfisols. Cumulative K released was mathematically best described by a parabolic diffusion equation and the empirical constants up to a 2 h incubation period was significantly related to relative biomass yield and K uptake by ryegrass. Considering relative biomass yield and K uptake as indices of plant K availability, the sequence of K supplying capacity of the soils under different orders was: Entisols>Inceptisols>Alfisols. The K-release rate of 30.8 mg kg-1 h-1 and the ryegrass leaf K concentration of 32.1 g kg-1 were found to be critical for this experiment. Based on the critical K release rate, the maximum amount of K released for plant uptake before showing any K deficiency symptom ranged from 179.3 mg kg-1 to 596 mg kg-1 for soils under the order Entisols, 247.9 mg kg-1 to 687.84 mg kg-1 for soils under Inceptisols and 118.67 mg kg-1 to 184.25 mg kg-1 for soils under Alfisols. [ABSTRACT FROM AUTHOR]

A multiplicity of substantial disruptions in the physiological systems of the wheat crop (Triticum aestivum L.) are the result of a potassium deficiency.The foliar application of potassium improves the quality of wheat and the production of grains for end-use purposes. This study was carried out during the growing seasons of 2021-22 to investigate the response of winter wheat cultivars to foliar application of potassium (0, 1, and 2 g/L), at two growth stages (green up and heading) on the grain yield (t/ha), protein content (%), specific weight and plant vegetative indicators (chlorophyll content, flag leaf area and plant height). Foliar applications of potassium fertilizer were implemented at concentrations of (0, 1 and 2 g/L). The treatments were applied at both the tillering and flowering stages. Potassium treatments, wheat cultivars, and their interactions significantly differed in most measured parameters. Application of 2g/L of K increases grain yield, protein content, and plant height than 0, 1 g/L by 5.51 t/ha, 10.52% and 95.60 cm, respectively. Foliar application of nano-potassium timed at both tillering and flowering stages would be beneficial in improving the yield and its component. Furthermore, the various trait responses of cultivars to K application can be attractive to wheat breeders for selection. [ABSTRACT FROM AUTHOR]

Objective: This study aims to evaluate the effectiveness of Integrated Soil-Crop System Management (ISSM) and provide technical support for sustainable high yield and efficiency in regional agriculture. Methods: The study compared the effects of no fertilization (Control), conventional farmer practices (FP), high-yield management (HY), and ISSM on maize yield and plant nutrient uptake. Measurements included grain yield, plant biomass, plant nutrient absorption, and soil nutrient content across different management strategies. Results: Over the 12-year experimental period, a significant decline in grain yield was observed under the Control treatment, with a slight decrease in the FP treatment. In contrast, consistent yield increases were noted for the HY and ISSM treatments. The ISSM approach significantly enhanced the average yield and plant uptake of P and K by 26%, 24%, and 32%, respectively, approaching 98%, 91%, and 85% of the levels achieved in the HY treatment. Furthermore, the average use efficiency of P and K fertilizers in the ISSM treatment exceeded those in the FP treatment by 18.7% and 1.2%, respectively, and those in the HY treatment by 17.4% and 24.8%, respectively. The adoption of ISSM led to a significant increase in total and available P and K content within the 0-20 cm and 20-40 cm soil layers and enhanced the available P and K content across all aggregate size fractions within the 0-20 cm soil layer. Conclusion: ISSM is capable of achieving long-term high and stable yields for spring maize, enhancing the uptake and utilization of P and K in plants, and bolstering the soil's capacity to supply these nutrients, thereby fostering the sustainable development of the entire soil-crop system. [ABSTRACT FROM AUTHOR]

No-tillage is one of the most important technologies in conservation agriculture. It is also crucial to understand the impact of no-tillage on grain crop yields, in order to promote the no-tillage application for food security. In this study, a metaanalysis was carried out to determine the regional yield and influencing factors of no-tillage on the three major crops in China. The data was collected from the published literature in Chinese (English) between 1995 and 2023. Conventional tillage (plowing, rotary tillage, or harrowing, depth < 18 cm) was taken as a control. Meta-analysis was employed to quantitatively investigate the overall and regional effects of no-tillage on the yield and yield components of three major grain crops (wheat, maize, and rice). Results showed that there was no significant effect of no-tillage on the regional yields of wheat, maize, and rice on the national scale. However, the regional analysis revealed that the no-tillage significantly increased the wheat yield by 4.1% and 2.2% in the Southwest and Northwest, respectively. There was a significant decrease in the maize yield by 2.4%, 2.6%, and 3.5% in the Northeast, Northwest, and Southeast, respectively. The rice yield was reduced by 1.0% in the Southeast. No significant effects were observed on the wheat and maize yields in North China, or on the wheat and rice yield in the rest regions. The yield components showed that the primary yield effect of no-tillage was attributed to the variation in the effective spikes. The influencing factors were examined on the regional crop yield. The mean annual precipitation was the main contributor to the wheat and maize yield, with the contribution rates of 12.7% and 13.6%, respectively. Soil organic carbon (SOC) content was the primary influencing factor (approximately 16.2%) on regional rice yield under no-tillage. The northwest region was characterized by mean annual temperatures <10 °C, annual precipitation <400 mm, and low soil nutrient content (SOC <10 g/kg, and total nitrogen <1 g/kg). Furthermore, no-tillage significantly increased the wheat yield under single and continuous cropping. Low annual precipitation (< 400 mm) promoted the maize yield in the Northwest, while the high soil pH (>8) and single or triple cropping in two years significantly reduced the crop yield. Specifically, the maize yield decreased in the Northeast and Southeast, which were influenced by the low (< 10 °C) and high (> 15 °C) temperatures, respectively. In the Southeast, the rice yield effects were influenced by the high annual precipitation (>800 mm), soil nutrient content (SOC >15 g/kg, and total nitrogen >1.5 g/kg), as well as the nitrogen and potassium fertilizer inputs. No-tillage was combined with the straw returning and scientific fertilization, in order to minimize the negative yield effect or even increase crop yield. The notillage technology was required to fully consider the crop types, regional climate, soil fertility, and cropping systems. These findings can provide a scientific basis to promote no-tillage technology in different agricultural regions in China. [ABSTRACT FROM AUTHOR]

Late spring coldness (LSC) is the main limiting factor threatening wheat yield and quality stability. Optimal nutrient management is beneficial in mitigating the harms of LSC by improving wheat root physiology. This study proposed a nutrient management strategy that postponed the application of phosphorus (P) and potassium (K), effectively strengthening wheat's defense against LSC. This experiment used the winter cultivar "Yannong19" (YN 19) as plant material for two consecutive years (2021–2022 and 2022–2023). Two fertilizer treatments were used: traditional P and K fertilizers application (R1: base fertilizer: jointing fertilizer = 10:0) and postponed P and K fertilizers application (R2: base fertilizer: jointing fertilizer = 5:5); wheat plants at the anther connective formation stage shifted to temperature-controlled phytotrons for normal (T0, 11 °C/4 h) and low temperatures (T1, 4 °C/4 h; T2, −4 °C/4 h) as treatments of LSC. The results showed that under low temperature (LT) treatment, compared with R1, the R2 treatment increased the concentrations of osmotic adjustment substances (soluble sugars and soluble protein contents by 6.2–8.7% and 3.0–8.9%), enhanced activities of antioxidant enzymes (superoxide dismutase, peroxidase and catalase activities by 2.2–9.1%, 6.2–9.7% and 4.2–8.4%), balanced the hormone concentrations (increased IAA and GA3 contents by 2.8–17.5% and 10.4–14.1% and decreased ABA contents by 7.2–14.3%), and reduced the toxicity (malondialdehyde, hydrogen peroxide content and O2·− production rate by 5.7–12.4%, 17.7–22.8% and 19.1–19.1%) of the cellular membranes. Furthermore, the wheat root physiology in R2 significantly improved as the root surface area and dry weight increased by 5.0–6.6% and 4.7–6.6%, and P and K accumulation increased by 7.4–11.3% and 12.2–15.4% compared to R1, respectively. Overall, the postponed application of P and K fertilizers enhanced the physiological function of the root system, maintained root morphology, and promoted the accumulation of wheat nutrients under the stress of LSC. [ABSTRACT FROM AUTHOR]

[Objective] The paper aimed to gain an in-depth understanding of soil nutrient characteristics and fertilizer supply capacity in the main distribution areas of temperate climate types in Yunnan province, to facilitate scientific guidance on fertilization and to ensure steady improvement in the level of soil fertility and stable crop yield. (Method) From 2019 to 2022, 1880 topsoil samples were collected from the northwest, northeast, and central northern regions in Yunnan province, which were the main temperate climate types, in order to analyze the current status of soil nutrient and fertility, and to clarify the spatial distribution of and differences in soil nutrients in the main distribution areas of the climate types. (Result) The soil organic matter, total nitrogen, available phosphorus and available potassium all belonged to the rich level or above in the main distribution areas of temperate climate type in Yunnan province, with average contents of 39.86 g/kg, 2.09 g/kg, 29. 17 mg/kg and 166.31 mg/kg, and the proportion of the rich level or above were 66.85%,73.19%,54.11% and 40.25%, respectively. There was a good linear positive correlation between soil organic matter content and total nitrogen content, and soil nutrient changing trends among different soil types were similar. Brown soil had the highest organic matter and total nitrogen content, followed by yellow brown soil, paddy soil, while purple soil and dry red soil had lower levels. The total nitrogen, available phosphorus, available potassium, slowly available potassium, and pH in soil of cultivated land in the northwest region in Yunnan province were significantly higher than those in northeastern and north-central Yunnan (P<0.05), and the contents of total nitrogen, available potassium and slowly available potassium in soil in the central-north region were also significantly higher than those in the northeastern region in Yunnan province. The soil available potassium in the northeastern and central northern regions in Yunnan province was deficient, with a deficiency ratio of 36.99% and 45.69%, respectively. (Conclusion】 It was necessary to pay attention to balance fertilization in the northwest regions in Yunnan province to ensure the balanced absorption and utilization of nutrients by crops. Organic fertilizer should be increased in the northeast and central northern regions in Yunnan province, and potassium fertilizer should be appropriately increased according to crop types to steadily improve the soil fertility of cultivated land and crop yield. [ABSTRACT FROM AUTHOR]

Cocoa is one of important commodities for the economy of Indonesia. However, national exports of the commodity has declined due to decreasing of domestic cocoa production. For enhancing cocoa production, potassium fertilization is required. Potassium (K) is an essential macronutrient in the physiology, anatomy, and yields processes. Anatomically, K is needed in the elongation of meristem tissue as well as for increasing the yields of fruit and seed. The objectives of this research included the study of the effect of K fertilizer dose and determination of optimum K doses on root anatomy development as well as the yield of cocoa pods. This research was conducted on the cocoa plantation of PT. Pagilaran. Applied doses of K fertilization consisted of 0, 150, 300, 450, and 600 g KCl/plant in Randomized Complete Block Design (RCBD) with 5 replications. Observed variables consisted of root anatomy and yield of cocoa pods. The results indicated that the dose of K fertilization significantly influenced both stele and xylem diameters of cocoa roots but insignificantly effected the thickness of cork tissue, phloem diameter, and the thickness of cambium tissue. Moreover, the dose also showed significant effect on the number of beans per pod, the weight of 100 beans, as well as the fresh and dry weight of beans per plant. It was also revealed that the dose showed no significant effect on length, diameter, and weight of the cocoa pods. It implied that K fertilization dose had effect on root anatomical properties and yield of cacao. [ABSTRACT FROM AUTHOR]

The effect of long-term use of mineral fertilizers on changes in the content of total phosphorus and its organic, mineral, and mobile compounds in soddy-podzolic heavy loamy soil (Albiс Retisol (Abruptic, Aric, Loamic)) was analyzed. The studies were performed in a long-term stationary experiment initiated in Perm krai in 1978. The variants were: 0 (without fertilizers), N90, P90, K90, N90P90, N90K90, P90K90, N90P90K90, N30P30K30, N60P60K60, N120P120K120, and N150P150K150. Ammonium nitrate or urea, double or simple superphosphate, and potassium chloride were used in the experiment. It was established that long-term use of superphosphate during five eight-field crop rotations (P90, P90K90, N90P90, and N90P90K90) resulted in a significant increase in the contents of the total phosphorus, mineral phosphorus (by 1.3–1.8 times), and mobile phosphorus (by 1.9–2.7 times) compounds in the plow layer (0–20 cm). The use of nitrogen fertilizers (N90, N90K90, N90Р90, and N90Р90K90) affected the accumulation of organic phosphorus compounds in the soil. The increase in the content and reserves of both mineral and organic phosphorus compounds was significant only in the case of using complete mineral fertilizer N90P90K90. Different combinations of superphosphate with nitrogen fertilizers and potassium chloride, as well as the rate of fertilizer application, affected the accumulation intensity of mobile phosphorus compounds in the soil during rotations and the changes in their contents in the soil profile. The application of low fertilizer rates ((NPK)30–60) resulted in an increase in the content of mobile phosphorus compounds mainly in the plow layer, whereas higher rates ((NPK)90–150) caused changes in the 80-cm-thick soil layer. Long-term use of nitrogen and potassium fertilizers resulted in an increase in the content of mobile phosphorus compounds in the plow layer over time. [ABSTRACT FROM AUTHOR]

Plant nutrition through fertilizer application plays a crucial role in enhancing crop quality and yield, necessitating a balanced fertilization approach. Sweet cherry, esteemed as one of the most prized crops worldwide, was the focus of this three-year study spanning from 2019 to 2021, involving the sweet cherry cultivar Burlat. This study investigated the foliar application of magnesium (Mg) and potassium (K) to enhance fruit quality parameters. Different doses of Mg (250 g hL−1 and 125 g hL−1) and K (100 g hL−1 and 50 g hL−1) and a control treatment were administered to sweet cherry trees to assess their impact on fruit quality. At the commercial ripening stage, fruits from each treatment were harvested for comprehensive evaluation, including biometric and chromatic parameters, fruit firmness, routine parameters, sensory profile, and nutrient content analysis. Results from the study revealed notable enhancements in fruit weight and dimensions, particularly in the control treatment in 2020. Furthermore, Mg125 and Mg250 treatments exhibited improved color development and accelerated maturity by increasing the total soluble solids content while decreasing titratable acidity. Sensorial profiling indicated that Mg125 and Mg250 treatments intensified color intensity and sweet taste while mitigating sour taste perceptions. Conversely, potassium fertilization, especially the K50 treatment, led to increased fruit firmness and nutrient content. These findings offer valuable insights into optimizing sweet cherry production practices globally. [ABSTRACT FROM AUTHOR]

To assess the effect of pure castor meal and a mixture of castor meal with ground hydrothermalized phonolite rock (CM+HP mixture) in providing nutrients, particularly N and K, and optimizing yield and quality of sweet potato, a field experiment was conducted using a randomized block design. Treatments were the absence and presence of synthetic N and K fertilizers (ammonium nitrate and KCl) combined with rates of organic fertilizers (1.2 and 2.4 Mg ha−1 of castor meal, 2.25 and 4.5 Mg ha−1 of CM+HP mixture, plus a treatment without organic fertilizers). The CM+HP mixture maintained adequate N and K status in plant leaves. Organic fertilizers increased the number of storage roots per plant and the sweetness of the storage roots, while synthetic fertilizers increased the storage root mean weight. Castor meal combined with synthetic fertilizers improved soil health (increased organic matter and enzyme activity in the soil). The combined application of synthetic fertilizers with 2.4 Mg ha−1 of castor meal or 4.5 Mg ha−1 of CM+HP mixture had the greatest benefit on storage root yield, with an average increase of 128% (10.9 Mg ha−1) on marketable storage root yield, and the nutrient removal compared with the sole application of organic fertilizers. [ABSTRACT FROM AUTHOR]

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Plants acquire potassium (K) not only from exchangeable K fractions but also from non-exchangeable K fractions. However, factors affecting the amount of K supplied from the non-exchangeable K fraction have not been well understood. In this study, the effects of soils and exchangeable K on the amount of K supplied to rice from the non-exchangeable K fraction were investigated for six Japanese paddy soils diluted with different rates of quartz sand. The amounts of K supplied from the non-exchangeable K fractions (recharged K) ranged from 14.4 to 137 mg K2O kg−1, equivalent to 10 to 61% of the total K acquired by rice. The amounts of recharged K were affected by the exchangeable K levels in three out of six soils. Although the cultivation experiments were conducted under various K conditions including severe K deficiency, exchangeable K was detected after cultivation in all soils, and the contents of exchangeable K were almost identical for each soil regardless of the dilution ratio of soil with quartz sand. Accordingly, there would be at least three types of non-exchangeable K fractions which dissolve into soil solution to attain a specific level of exchangeable K: (i) a non-exchangeable K fraction that releases K regardless of the exchangeable K level; (ii) a non-exchangeable K fraction that easily releases K with the decrease in exchangeable K under sufficient K conditions without inducing K-deficient symptoms in rice; and (iii) a non-exchangeable K fraction that releases K with the decrease in exchangeable K only under severe K-deficient conditions with accompanying deficient symptoms in rice. The application of K fertilizer would reduce the amount of recharged K acquired by rice from fractions (ii) and (iii), whereas fraction (i) would remain unaffected by the fertilized K until the level of exchangeable K reaches a specific level for each soil. The release of K from a fraction (iii) only occurred under conditions of severe K deficiency; hence, farmers should not rely on this fraction for K supply. [ABSTRACT FROM AUTHOR]

The online detection of fertilizer solution information is a crucial link in the implementation of intelligent and precise variable fertilization techniques. However, achieving simultaneous rapid online detection of multiple fertilizer components is still challenging. Therefore, a rapid detection method based on spectrophotometry for qualitative and quantitative identification of four fertilizers (typical N, P, and K fertilizers: KNO3, (NH4)2SO4, KH2PO4, and K2SO4) was proposed in this work. Full-scan absorption spectra of fertilizer solutions at varying concentrations were obtained using a UV–visible/near-infrared spectrophotometer. By assessing the linear fit between fertilizer concentration and absorbance at each wavelength within the characteristic band, the characteristic wavelengths for KNO3, (NH4)2SO4, KH2PO4, and K2SO4 were identified as 214 nm, 410 nm, 712 nm, and 1708 nm, respectively. The identification method of fertilizer type and the prediction model of concentration were constructed based on characteristic wavelength and the Lambert–Beer law. Based on the above analysis, a four-channel photoelectric sensor was designed with four LEDs emitting wavelengths closely matched to characteristic wavelengths for fertilizer detection. A detection strategy of "qualitative analysis followed by quantitative detection" was proposed to realize the online detection of four fertilizer types and their concentrations. Evaluation of the sensor's performance showed its high stability, with an accuracy of 81.5% in recognizing fertilizer types. Furthermore, the relative error of the sensor detection was substantially less than ±15% for the fertilizer concentrations not exceeding 80 mg/L. These results confirm the capability of the sensor to meet the practical requirements for online detection of four fertilizer types and concentrations in the field of agricultural engineering. [ABSTRACT FROM AUTHOR]

Soybean is a crucial crop utilized for both food and oil production, with balanced crop nutrition being a key determinant of soybean yield throughout its growth cycle. Sulfur, an essential nutrient for crop growth, substantially impacts soybean yield. In this study, two soybean cultivars, Laidou 2 and Hefeng 55, were used to study the changes in nitrogen, phosphorus, potassium, and sulfur contents in soybean plants at different growth stages. Additionally, the effects of dry matter accumulation under five different sulfur levels were examined. The results showed that the sulfur levels had varying effects on the nitrogen, phosphorus, potassium, and sulfur contents and accumulation in different parts of the soybean plants. There were marked differences in the accumulation and distribution of dry matter in different parts of the soybean plant. Soybean dry matter weight shows the best overall performance under the S80 treatment. With increasing sulfur nutrition, the nitrogen, phosphorus, potassium, and sulfur contents in various plant parts exhibited an unimodal trend, reaching maximum values when the sulfur content was 80 mg/L. This study elucidates the dynamic changes in nutrient elements in soybeans under different sulfur levels and is important in guiding the rational application of sulfur fertilizers in agricultural production. [ABSTRACT FROM AUTHOR]

Background: Striga asiatica (L.) O. Kuntze is a traditional medicinal plant rich in flavonoids, which has various pharmacological effects such as anti-hepatitis and antioxidant activities. However, there is a scarcity of resources, and artificial cultivation has not yet been achieved. This study explored the association between flavonoid metabolites and soil physicochemical properties and trace elements in different habitats, with the aim of offering theoretical guidance for the high-quality artificial cultivation of S. asiatica. Results: The results showed that S. asiatica has low requirements for soil fertility and prefers to grow in acidic soil with high contents of potassium and available potassium, while low contents of phosphorus, nitrogen and alkali hydrolyzed nitrogen. Additionally, 1592 kinds of metabolites were identified from S. asiatica, including 78 flavonoids. Conclusions: The flavonoid metabolites were strongly related to soil factors. Reasonable application of nitrogen and potassium fertilizers as well as controlling the contents of sodium, manganese and boron in the soil, can promote the synthesis of flavonoid metabolites in the plant. Moreover, kaempferide, glycitein, luteolin, apigenin and genistein may be the metabolic markers for identifying different regions. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the impact of multifunctional microbial fertilizer and inorganic macronutrient fertilizers N, P, K on plant biomass, essential oil yield, chemical composition, antimicrobial and antioxidant activities of tulsi (Ocimum tenuiflorum L.) grown in Hanoi, Vietnam. Among the four formulas tested, F2 emerged as the most favourable, comprising a basal fertilization of 10 tons of decomposed manure, 15 kg of multifunctional microbial fertilizer, 150 kg of P fertilizer, and 75 kg of K fertilizer, together with top dressing of 200 kg of N fertilizer and 75 kg of K fertilizer per hectare.  This formula yielded the highest tulsi dry biomass (4.73 ton/ha), essential oil yield (0.831%), and essential oil production (39.29 L/ha), which were significantly different (p < 0.001) from those of the remaining formulas. In addition, the concentration of the essential oil main compound - eugenol (63.1%) of tulsi in F2 was also the highest, which may be the cause of the strongest antibacterial activity against Bacillus subtilis, Escherichia coli (IC50 of 320, 273 µg/mL, respectively), and antifungal activity against Candida albicans (IC50 of 400 µg/mL), as well as antioxidant activity (IC50 of 0.165 µg/mL) compared to the other formulas tested. The results suggested the role of both multifunctional microbial fertilizer and inorganic macronutrient fertilizers N, P, K on growth and essential oil biosynthesis in tulsi. These findings are important in identifying the most efficient fertilization formula for cultivating tulsi, serving the needs of the cosmetic and medicinal industries. [ABSTRACT FROM AUTHOR]

The bacterial communities that harbour the pyrroloquinoline quinone gene (pqqC‐harbouring bacteria communities) play a pivotal role in the mobilization of inorganic phosphorus (Pi). However, there is limited knowledge regarding the connection between soil pqqC‐harbouring bacterial communities and Pi fractions, as well as the factors that can regulate them, particularly under different fertilization strategies in the agricultural soil. High‐throughput sequencing was used to investigate the pqqC‐harbouring communities from the wheat (Triticum aestivum L.)–sweet potato (Ipomoea batatas L.) season in a 9‐year field experiment, including without fertilization (control), nitrogen (N) and potassium (K) fertilization (NK), NPK fertilization (NPK) and the combined application of chemical NPK and organic fertilizer (NPKM), and to explore their relationships with Pi fractions and their regulatory factors. Long‐term N fertilization and crop type substantially changed the community composition of pqqC‐harbouring bacteria but had no effect on their diversity. In two crop seasons, long‐term N fertilization significantly increased the content and proportion of moderately labile Pi (aluminium‐ and iron‐bound P) and available P (AP) and significantly decreased the proportion of recalcitrant Pi (calcium‐bound P) compared with the control. Specifically, AP increased by 79%–778%, Fe‐P by 64%–88%, and Al‐P by 71%–308%, while Ca‐P decreased by 10%–59%. N fertilization increased the relative abundance of Micromonospora, which was significantly positively correlated with moderately labile Pi and AP. Moreover, the relative abundance of some Streptomyces increased by 391% in the sweet potato season, and they were positively correlated with AP. Structural equation modelling revealed that the interplay between the pqqC‐harbouring community composition and Pi mobilization was mainly governed by pH, underscoring the role of pH in shaping the communities of Pi‐mobilizing microbes and their effect on Pi mobilization processes. This study emphasized how N fertilization and crops reshape Pi‐mobilizing microbial communities, which in turn affects Pi mobilization and P availability. Overall, these findings offer valuable insights into optimizing P cycles and availability through N fertilization strategies. [ABSTRACT FROM AUTHOR]

Tree species can have great impacts on soil. Since the rhizosphere is more responsive to external inputs than the surrounding bulk soil, we investigated the rhizosphere effect of the exotic slash pine and the native araucaria in long‐term conifer monocultures in southern Brazil. Araucaria trees in a natural section of a nearby mixed araucaria forest were taken as the control. We assessed physical, chemical, and mineralogical properties of the underlying subtropical highly weathered soil. We did not find rhizosphere effects for most chemical and physical soil attributes, yet principal component analysis clearly distinguished the effects of the exotic and native conifers on rhizosphere properties by separating slash pine cluster from reforested and native araucaria clusters. Reductions in silt and sand contents under slash pine reforestation led to increases in clay and well‐crystallized iron oxides contents. The clay mineralogy comprised kaolinite, mica/illite, and hydroxy‐interlayered minerals, with kaolinite enrichment in the rhizospheres of both araucaria sites, mica/illite depletion in the rhizospheres of both araucaria and pine monocultures, and prevalence of well‐crystallized iron oxyhydroxides in the slash pine rhizosphere. This study demonstrates a tendency toward increasing soil weathering in the conifer monocultures, potential negative impacts of the faster growing slash pine reforestation on soil organic carbon, available P, and total K possibly by mica/illite depletion, while araucaria had lower impacts on soil properties. These results show long‐term potential loss of soil fertility and quality, which should be considered when monitoring soil changes in human modified ecosystems. Core Ideas: Monoculture of conifers slightly increased soil particle fragmentation.Conifer monocultures that had not received K fertilizers promoted mica/illite depletion in the rhizospheres.Monoculture of slash pine caused more negative impact on soil in the long term than did monoculture of araucaria. [ABSTRACT FROM AUTHOR]

Potassium (K) is an essential macronutrient for the healthy growth and development of crops but their conventional resources are only limited to a few countries. Deficiency of potash fertilizer in soil is a widespread problem for countries with no such potash deposits to meet the present as well as future food demands. In view of this, the present work investigates a novel interdisciplinary approach for the recovery of potash fertilizer from widely available glauconitic rocks. The rock sample containing ~ 6–8% K2O can be considered a potential alternative source of K-fertilizer. The characterization study revealed that the quartz, glauconite and K-feldspar are the major mineral phases, and the glauconite occurs in the form of ovoidal-shaped pellets. As potassium is trapped between di-octahedral T-O-T stable structure of glauconite, a combined process involving hydrogen gas reduction followed by mild hydrochloric acid leaching was developed to enhance the effective recovery of potassium. More than 99% of potassium dissolution was achieved with 20% (v/v) hydrochloric acid leaching at 80ºC for the sample reduced at 500ºC in the presence of 20 mL/min of H2 gas flow rate for 2 h. The leach liquor was further treated to recover potassium as muriate of potash (MOP). [ABSTRACT FROM AUTHOR]

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Researchers have extensively studied and documented the effects of potassium (K) fertility on alfalfa (Medicago sativa L.). Yet, additional research is needed to determine how interactions of K, cultivar, and harvest management influence the K needs of alfalfa. To explore these interactions, we conducted 5 years of field research at the University of Wyoming James C. Hageman Sustainable Agriculture Research and Extension Center in Lingle, WY. Treatments were (a) four K rates (0, 56, 112, and 168 kg K2O ha−1 year−1) applied before planting in the fall of 2016 and after the final harvest in the fall of 2017–2020, (b) two cultivars (Hi‐Gest 360 and AFX 457), and (c) two harvest times (early harvest, late bud to early [10%] bloom, and late harvest, 7 days after early harvest), arranged in a 4 × 2 × 2 factorial under random complete blocks with four replications. At 168 kg K2O ha−1 year−1 and early harvest, a consistently significant (p < 0.05) higher yield response was observed. The same response was seen at 112 kg K2O ha−1 year−1 and late harvest. This occurred at a site with moderate‐to‐high soil K levels throughout the study period. There was a linear (p < 0.001, R2 = 0.66) and quadratic (p = 0.006, R2 = 0.61) response of forage accumulation to K rate at early and late harvest, respectively. Similar trends were also seen for stem count, relative water content, root uptake of K, and tissue K. Time of harvest showed immense potential for optimizing K's effect for a consistent high‐yield response. However, fertilizing alfalfa with 112 kg K2O ha−1 year−1 gave the most profitable production under both harvest times. If K fertilizer prices drop over time, high profits could be attained with higher K fertilization rates. After 3 years of production, average forage accumulation increased under an early harvest system and decreased under a late harvest system. Growers in Wyoming and similar regions are encouraged to consider fertilizing alfalfa with moderate K rates (∼112 kg K2O ha−1 year−1) on soils testing moderate‐to‐high in soil test K, implement a late harvest system for the first 3 years after planting, and transition to an early harvest system after the initial 3 years to maximize alfalfa profits. Core Ideas: There have been conflicting reports on the effect of potassium (K) fertilizer on alfalfa (Medicago sativa L.) production.Research is needed to quantify the K needs of alfalfa as influenced by the interactions of K rates, cultivar, and harvest time.Alfalfa responded significantly to K fertilizer even in a moderate‐to‐high exchangeable K soil environment.Alfalfa cultivar did not influence K requirements, and late harvest reduced K requirements by 56 kg K2O ha−1 year−1 for optimal yield response.The 112 kg K2O ha−1 year−1 rate was most economically optimal for both early and late harvests, suggesting that K rates can be similar for both harvest times. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) 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.)

Plant available potassium (K) content is very low in K-bearing mineral ores present in Sri Lanka and that restrict their use in crop production as K fertilizer sources. Heating of minerals can increase their plant available forms of nutrients. The objective of this experiment was to study the effect of direct heating of K-bearing minerals at different temperatures and co-pyrolyis with poultry litter (PL) at different rates on their total and available K contents. Poultry litter was co-pyrolyzed with 0, 1 and 5% (w/w) of feldspar and mica at 350, 500, 650 and 900 ℃. K-bearing minerals were also directly heated at these temperatures. With direct heating the mineral, total K contents of feldspar (6.2%) and mica (4.5%) were significantly (p<0.001) increased by 10% and 18%, respectively at 500 ℃ and then decreased by 33 and 65%, respectively at 900 ℃. Available K contents in feldspar (0.05%) and in mica (0.03%) either decreased significantly (feldspar) or did not change (mica) upon direct heating. Increasing pyrolysis temperature up to 650 ℃ increased both total (4.2 to 6.4%), and available K (3.2 to 6.1%) contents in poultry litter biochar (PLB). Co-pyrolysis of PL with feldspar or mica at 1 or 5% rates did not improve the total or available K contents in PLB at these temperatures. We concluded that heat treatment of locally available feldspar and mica or co-pyrolyzing them with PL are not effective technologies to increase their utilization in agriculture. [ABSTRACT FROM AUTHOR]

Background: Green manure is an important source of organic fertilizer. Exploring green fertilizer and nitrogen fertilizer reduction is important for agricultural production. However, few studies have been conducted, especially on the effects of different green fertilizers along with reduced nitrogen fertilizer application on soil ammonia volatilization emissions, rice yield, and nitrogen fertilizer uptake and utilization. Methods: In this study, the effects of different types of green manure and reduced nitrogen fertilizer application on soil ammonia volatilization emissions, aboveground population characteristics of rice, and nitrogen fertilizer uptake and utilization were explored. This study was based on a field-positioning experiment conducted between 2020 and 2022. Six treatments were established: no nitrogen fertilizer application (CK), conventional fertilization in wheat-rice (WR), villous villosa-rice (VvR), vetch sativa-rice (VsR), rapeseed seed-rice (RR), and milk vetch-rice (GR), with a 20% reduction in nitrogen fertilizer application. The amounts of phosphorus and potassium fertilizers remained unchanged. The characteristics of ammonia volatilization loss in rice fields, agronomic traits of rice, yield traits, and nitrogen uptake and utilization were investigated. Results: The results indicated a significant difference (P < 0.05) in the impact of different treatments on ammonia volatilization emissions from rice in the two-year experiment. Compared with WR treatment, VvR, VsR, RR, and GR treatments reduced the total ammonia volatilization loss by 23.58 to 39.21 kg ha−1, respectively. Compared with the conventional WR treatment, other treatments increased rice yield by 0.09 to 0.83 t ha−1. GR treatment was significantly higher than other green fertilizer treatments, except for VsR (P < 0.05). It increased the nitrogen uptake of rice by an average of 4.24%–22.24% and 13.08%–33.21% over the two years, respectively. The impact of different types of green manure on the nitrogen uptake and utilization of rice varied greatly, indicating that the combination of green manure and fertilizer is a sustainable fertilization model for crops to achieve high yields. In particular, the Chinese milk vetch as green manure was more beneficial for ammonia volatilization reduction in paddy field and stable grain production of rice. [ABSTRACT FROM AUTHOR]

This article explores the impact of boron contamination on spinach plants and the potential mitigating effects of silicon and NPK fertilizer. The study found that increasing levels of boron in the soil led to a decrease in plant growth and various physiological parameters. However, the addition of silicon and fertilizer helped alleviate the negative effects of boron toxicity and improved plant growth. The research suggests that silicon and NPK application can be effective in reducing boron toxicity in spinach plants. [Extracted from the article]

Potassium (K) fertilization guidelines often oversimplify, overlooking factors like soil mineralogy and K application methods. This study aimed to evaluate the influence of K fertilizer rates and application methods on crop yields and the forms of K in soils with different textural and mineralogical features. In 2020, two field trials were conducted to evaluate the impact of varying K rates, added through band or broadcast methods, in Planosol and in Ferralsol. Soybean yield was evaluated in both trials, while flooded rice yield was evaluated only in the Planosol. Soil samples collected from the 0–10 and 10–20 cm layers and soil K content was determined using Mehlich-1, nitric acid (HNO3), and sodium tetraphenylborate. In the Ferralsol, K desorption by HNO3 in the 10–20 cm soil layer was 1.4 times higher the in band application (171 mg kg−1) compared to broadcast method (92 mg kg−1). The Mehlich-1 extractor proved insensitive to detecting K rates in the Planosol (91 and 43 mg kg−1 in the 0–10 and 10–20 cm layers, respectively), while it exhibited responsiveness in the Ferralsol, demonstrating positive increases with K rates. Using a proper chemical extractor is crucial for accurate detection and recovery of applied K in the soil. Grain yields were 4.50 Mg ha−1 for soybeans in the Ferralsol and 9.72 and 5.55 Mg ha−1 for rice and soybeans, respectively, in the Planosol. The findings reveal that applied K distributes into preexisting pools, persisting in the applied location, thereby reducing the anthropogenic K gradient with band reapplication. [ABSTRACT FROM AUTHOR]

The application of potassium fertilizer application and straw return are effective agronomic measures for increasing crop productivity; however, information on how straw return—when substituting potassium fertilizer—affects crop yield, efficiency, and quality in dryland remains limited. In this study, an experiment on a dryland summer maize and winter wheat rotation system was initiated in 2007. This study included four treatments: CK (no fertilizer and no straw return), NP (nitrogen and phosphorus fertilizer application without straw return), NPK (nitrogen, phosphorus, and potassium fertilizer application without straw return), and NPS (NP treatment with straw return, substituting potassium fertilizer as used in the NPK treatment). These treatments were employed to assess grain yield and fertilizer agronomic efficiency in 2015–2020. Additionally, we evaluated the content of nitrogen (N), phosphorus (P), and potassium (K), as well as the protein content and protein yield in maize and wheat grains and the protein components in wheat grains in 2019–2020. The results showed that compared to the CK treatment, NP, NPK, and NPS treatments not only significantly increased the yield, protein yield, and fertilizer agronomic efficiency in both maize and wheat but also increased the content of protein and protein components in wheat grains. Compared to the NP treatment, the NPK treatment significantly increased the contents of N, K, globulin, and gluten in wheat grains by 5.11%, 21.59%, 10.06%, and 15.14%. Compared to NPK treatment, NPS treatment significantly increased the average yield of summer maize by 21.33% and 20.91%, respectively, as well as the annual yield by 9.99% and 13.59%, the N fertilizer agronomic efficiency of summer maize by 132.47%, and the annual N and P fertilizer agronomic efficiency by 42.83% and 64.36%, over the five-year period. The NPS treatment also significantly increased the summer maize protein yield and annual protein yield by 10.43% and 23.08%, as well as the content of protein components, the protein content, and P content in wheat grains by 4.93–13.58%, 7.81%, and 28.89%, respectively. In conclusion, NPS treatment can not only enhance crop yield, protein yield, and fertilizer agronomic efficiency in summer maize annually but also has the advantage of promoting wheat quality. NPS is an efficient strategy to improve crop yield, efficiency, and quality in a dryland maize–wheat rotation system. [ABSTRACT FROM AUTHOR]

To compare the differences in the soil microbial community structure in yellow soil paddy fields after the long-term application of chemical fertilizer, the role and mechanism of chemical fertilizer in maintaining soil microbial diversity were analyzed, and a theoretical basis for fertilization management in farmlands was provided. In this study, long-term experiments were conducted at the Scientific Observation and Experimental Station of the Arable Land Conservation and Agricultural Environment (Guizhou), Ministry of Agriculture and Rural Affairs. Soil samples were collected from five treatments: fertilizer N, P, and K (NPK); fertilizer P and K (PK); fertilizer N and K (NK); fertilizer N and P (NP); and no fertilizer (CK). High-throughput sequencing technology was used to analyze the microbial composition and diversity of the colonies, and the influencing factors are discussed. An analysis of the soil bacterial α diversity indices under the different fertilization treatments revealed that the long-term application of NPK fertilizers had less of an effect on the soil bacterial α diversity indices than did the CK. The long-term application of chemical fertilizers significantly reduced the soil bacterial Chao1, Shannon, and Simpson indices, while there was no significant difference in the bacterial Pielou e index among the treatments. The long-term application of chemical fertilizers significantly increased the soil fungal Chao1 index, but the effects on the other indices were not significant (p < 0.05). An analysis of the bacterial and fungal species under different fertilization treatments showed found that compared with CK, the long-term application of chemical fertilizer increased the relative abundance of Proteobacteria to varying degrees while reducing the relative abundance of Chloroflexi. The impact of other phyla was relatively small, and the difference in the relative abundance of fungi was not significant (p < 0.05). Principal component analysis revealed that, at the genus level, the bacterial and fungal community structures in the CK and NK treatments were relatively independent, while those in the NPK, PK, and NP treatments were similar. Random forest analysis revealed that OM, TP, and TK are the dominant factors that affect soil bacteria α diversity. The dominant factors affecting fungi α diversity are pH, OM, and AK. Redundancy analysis indicated that AK and TP were the main factors affecting bacterial community structure, while AP, AK, and pH were the main factors affecting fungal community structure. The conclusion drawn from this study is that the long-term application of nitrogen, phosphorus, and potassium fertilizer; phosphorus and potassium fertilizer; and nitrogen and phosphorus fertilizer can improve soil fertility, alter the soil environment, enhance microbial diversity, and improve the microbial community structure in yellow soil paddy fields, promoting soil ecosystem stability and health. [ABSTRACT FROM AUTHOR]

To reach the target yield of crops, nutrient management is essential. Selecting the appropriate prediction model and adjusting the nutrient supply based on the actual situation can effectively improve the nutrient utilization efficiency, crop yield, and product quality. Therefore, a prediction model of the NPK fertilizer application rate for greenhouse tomatoes under the target yield was studied in this study. Under low, medium, and high soil fertility conditions, a neural network prediction model based on the sparrow search algorithm (SSA-NN), a neural network prediction model based on the improved sparrow search algorithm (ISSA-NN), and a neural network prediction model based on the hybrid algorithm (HA-NN) were used to predict the NPK fertilizer application rate for greenhouse tomatoes. The experimental results indicated that the evaluation indexes (i.e., the mean square error (MSE), explained variance score (EVS), and coefficient of determination (R2)) of the HA-NN prediction model proposed in this study were superior than the SSA-NN and ISSA-NN prediction models under three different soil fertility conditions. Under high soil fertility, compared with the SSA-NN prediction model, the MSE of the ISSA-NN and HA-NN prediction models decreased to 0.007 and 0.005, respectively; the EVS increased to 0.871 and 0.908, respectively; and the R2 increased to 0.862 and 0.899, respectively. This study showed that the HA–NN prediction model was superior in predicting the NPK fertilizer application rate for greenhouse tomatoes under three different soil fertility conditions. Due to the significance of NPK fertilizer application rate prediction for greenhouse tomatoes, this technique is expected to bring benefits to agricultural production management and decision support. [ABSTRACT FROM AUTHOR]

Background: Wheat is staple diet for majority of people of world and requires several nutrients for optimum growth like Nitrogen, Potassium and Zinc etc. These nutrients when added in the form of chemical fertilizers definitely increase production but at the cost of negative impact on soil, air, water and living beings. Nanoformulations can provide a possible solution to this problem. The current study tried to assess the impact of foliar application of Nano-N, K, Zn on morphological and yield related parameters of wheat. Methods: Wheat plants were grown up to harvesting stage for two consecutive years from 2018 to 2020. Pots grown plants were treated with three different concentrations of Nano-N, K, Zn and bulk/chemical N, K, Zn along-with a control setup having no external nutrients supplement. Several morphological and yield related parameters were recorded. Result: Application of Nano-N, K, Zn resulted in statistically significant increase in plant height, seeds per spike, root length, 100 seed weight, yield and biomass accumulation compared to the control and bulk/chemical N, K, Zn. Highest yield per pot of 23.87 g was obtained under nano-N, K, Zn treatment while yield under bulk fertilizers and control setup was only 7.54 g and 4.38 g respectively. Our work presents a novel combination of nitrogen, potassium and zinc nanofertilizers which not only increase quality of wheat produce but also environment friendly too. [ABSTRACT FROM AUTHOR]

This study assesses the elemental composition of Egyptian glauconite sediments, focusing on potentially toxic elements (PTEs) and macronutrients. The primary aim is to evaluate the feasibility of utilizing these sediments as a natural source of potassium for agricultural purposes, besides conventional chemical fertilizers like potassium sulfate. To quantify elemental content, chemical analysis was employed across five distinct grain size fractions after grinding glauconite rock. The assessment included potassium, calcium, sodium, and PTE concentrations, utilizing potassium chloride (KCl) and ammonium acetate lactate (AL Solution) as single extractants, and the BCR extraction protocol, in addition to measuring the pseudo-total content of these elements. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) facilitated a comparative analysis of elemental concentrations. Results indicate PTE concentrations within European Union regulations, with an absence of cadmium. Glauconite samples contain approximately 3–3.3% potassium by weight, alongside significant amounts of essential macronutrients (calcium, magnesium) and micronutrients (copper, nickel, zinc) crucial for agriculture. BCR sequential extraction protocol results closely align with or slightly surpass pseudo-total content results. Notably, the AL Solution demonstrates high efficiency compared to KCl or acetic acid in the first step of the BCR method. BCR sequential protocol provides valuable insights into various elemental forms and potential mobility. Overall, this study reveals that glauconite has the potential to serve as a promising alternative potassium fertilizer without causing adverse environmental impacts. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) 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 Plant Production is the property of Egyptian National Agricultural Library (ENAL) 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.)

The essential role of fertilization in the management of oil palm plantations cannot be overstated, with the understanding that effective strategies must be finetuned to accommodate the diversity of soil types present. The nuanced response of oil palm to fertilization under different soil conditions underscores the critical nature of this research. This study investigates the relationship between oil palm farming practices and agro-environmental performance of plantations. This research aims to understand the complex mechanisms influencing plantation productivity. Five agronomic field experiments were carried out on various soil types (Podzol, Inceptisol, Peat) during 2022. These experiments involved various types of soil and used different plant materials in a total land area of 33 hectares. The results of the peat soil trials revealed a positive effect of RP fertilizer on leaf phosphorus (P) content and a visible gradient in potassium (K) content with different doses of KCl. Average plantation yields peaked in 2022, showing the best yields ever recorded. On the contrary, experiments in podzolic soils showed that oil palm responded better to organic fertilizers than to mineral fertilizers in podzolic soils. The inceptisol soil revealed a significant increase in leaf potassium (K) content with KCl dose, confirming the positive effect of fresh oil palm empty fruit bunches (EFB) on potassium levels. In particular, EFB acts as a good K fertilizer, positively influencing the K content but negatively affecting the calcium content (Ca) due to K/Ca antagonism. These findings emphasize the need for diversified agricultural strategies to optimize oil palm cultivation, increase productivity, and reduce dependence on external input. [ABSTRACT FROM AUTHOR]

Coastal regions provide excellent ambience for agricultural practices in terms of their weather conditions. However, the presence of salinity in such areas affects crop growth and productivity by restricting the accessibility to vital nutrients. Potassium (K) is one such key nutrient, whose absorption, transport, and distribution to crops are greatly affected by salinity. Conventional use of huge amounts of potash fertilizers in such areas failed to serve the purpose due to their poor mobility, non-availability to the crops and soil precipitation leading to the search for alternate and sustainable approaches. One such approach is the use of potassium-solubilizing microorganisms (KSMs) as plant prebiotics which are capable of solubilizing mineral potassium from insoluble components and thus facilitates the K intake to the crops. Many species such as Aminobacter, Bacillus, Burkholderia, Cladosporium, Enterobacter, Paenibacillus and Sphingomonas are effective K solubilizers. These groups of bacteria are primarily converting the insoluble K to its solubilized form by various mechanisms including the production of organic/inorganic acids, protons via acidolysis mechanism and hydrogen ion-facilitated cation-exchange mechanism. The present review is primarily intended to report comprehensive information on the various negative effects of salinity on crop growth and yield. Also, scientific discussions on the feasibility of sustainable agricultural practices using KSMs were systematically analyzed in the context of their role in actions along with their mechanistic elucidation. Conclusively, this review has critically identified the potential challenges/gaps in the augmentation of KSMs in the coastal regions and provided significant research hotspots to be addressed in future prospects. [ABSTRACT FROM AUTHOR]