Levels Of Potassium Fertilization Research Articles

The Management of Irrigation and Potassium Fertilization to Mitigate the Effect of Light Frosts on the Phenolic and Volatile Compounds in Virgin Olive Oils.

The frequency of early frosts has increased in recent years, which are injurious to olive growing, causing losses in the yield and quality of virgin olive oil. In this research, it was studied how the management of agronomic factors mitigates frost damage in Arbequina olives, minimizing the loss of phenols and volatiles in virgin olive oil, at different fruit ripening stages. A Box-Behnken design and multivariate analysis were performed, with three levels of irrigation, potassium fertilization, and foliar copper application (15 treatments). Virgin olive oil was extracted from fresh and frozen olives. Light frost caused a significant decrease in the total phenols and secoiridoid compounds in and the antioxidant capacity of the frost-affected oils, which were perceived as more pungent and had the slight defect of "frostbitten olives". According to the Box-Behnken design, an 86% reference evapotranspiration (ET0) or higher with 100 potassium oxide units (UK2O) and a 100% ET0 or higher with 250 UK2O would be required to minimize the effect of light frost on phenols and volatiles. Partial Least Squares Regression-Discriminant Analysis (PLS-DA) differentiated the virgin olive oils according to their ripening stage and fresh and frost conditions. Moreover, PLS-DA positively correlated a 75-100% ET0 and 0 Uk2O with the dialdehydic form of the decarboxymethyl ligstroside aglycone (p-HPEA-EDA), the dialdehydic form of the decarboxymethyl oleuropein aglycone (3,4-DHPEA-EDA), the dialdehydic form of the ligstroside aglycone (p-HPEA-EDA-DLA), and with fruity, pungent, and bitter attributes. Precision agronomic management based on the needs of the crop itself would avoid unnecessary stress on olive trees and oil damage.

Evaluating the Efficiency of Potassium Fertilizer Sources and Levels on Sesame Growth and Yield in Two Different Gypsum Soils

To investigate the effect of potassium fertilizer sources and level on sesame growth and yield in two different gypsum soils, two experiments were applied throughout the summer of 2022. The experiments included three factors, which were sources of potassium, potassium sulfate (KK2SO4) and potassium chloride (KKCL), potassium levels, 0 (K00), 75 (K75), 150 (K150), and 300 (K300) kg ha-1, and levels of gypsum in the soil, 6.02 (Soil06.02) and 15.87 (Soil15.87) %. Completely Random Block Design (CRBD) with three replications was used to apply the experiments. The results indicated that KK2SO4 significantly impacted plant height (18%), plant dry weight (8%), branch no (11%), capsules no. (5%), 1000 seeds weight (13%), yield (13%), and oil percentage (9%) compared with KKCL. Similarly, potassium at K300 was significantly higher compared with the other potassium levels. Also, gypsum Soil15.87 significantly impacted plant height (11%), dry weight (11%), capsules no. (5%), 1000 seeds weight (19%), yield (11%), and oil percentage (12%) compared with gypsum soil with 6%. The interactions between the two study factors and among the three study factors effected significantly all the study traits. These results will be beneficial for sesame production and management in the Saladin area, Iraq.

Metabolomics Reveals the Effects of Nitrogen/Phosphorus/Potassium (NPK) Fertilizer Levels on Cucumber Fruit Raised in Different Nutrient Soils.

Fertilizers are widely used to improve the quality of fruits and vegetables. However, the overuse of fertilizers has become an issue because it causes environmental problems and negatively affects productivity and fruit quality. In this study, we examined the effects of nitrogen, phosphorus, and potassium (NPK) fertilizer levels on the metabolism of cucumber fruit in low- and high-nutrient soils using mass-spectrometry-based metabolomics approaches. Cucumber metabolite content was notably different depending on the initial soil nutrient status. Most amino acids and phenylpropanoids were abundant in the cucumbers raised in low-nutrient soil, whereas organic acids, some amino acids (aspartate, glutamate, and ornithine), and carbohydrates were comparatively higher in fruits from high-nutrient soil. The fertilizer supply resulted in an alteration in the metabolite profile, while no change in fruit yield was observed in either low- or high-nutrient soils. Fertilizer treatment perturbed the metabolite contents in cucumbers from low-nutrient soil. In contrast, treatment with higher concentrations of fertilizer in high-nutrient soil increased phenylpropanoid content in the cucumbers, while most metabolites decreased. In conclusion, fertilization levels should be carefully determined, considering culture conditions such as the original soil status, to increase product yield and fruit quality and avoid environmental problems.

The improvement of antioxidant contents and fruit quality of Sukkary date cultivar using various Potassium levels and Irrigation interval

Sukkary date palms (Phoenix dactylifera L.) were treated with three levels of potassium fertilizer combined with three irrigation intervals regime, five replicates were allocated per treatment, to enhance better date peel color; decrease loose crust, and subsequently, improve high market ability. Potassium sulfate (49% K2O) was applied annually at a rate of 490 g (as common fertilization applied in the farm in which this experiment was carried out, therefore, it was considered as a control treatment), 735 g, or 980 g K2O per palm tree, each level was divided into three equal doses. The first dose was added one month after pollination; the other two doses were added at two month interval, whereas the irrigation treatments were as follows: 24 hrs (as common irrigation application in the farm used for this study, and it was considered as a control treatment), 48 hrs, or 72 hrs. The results showed a great decrease in the loose crust dates at harvesting time. An inverse proportional relationship between irrigation intervals and loose crust of dates was observed. The High potassium fertilizer treatment accompanied with 72 hrs irrigation interval treatment produced a significantly higher date quality regarding with bright yellow color, less darkening, and loose crust. High potassium fertilizer treatments (735, or 980 g K2O per palm) increased total yield, improved date weight, size, and color. Moreover, increasing potassium level affected significantly the date total antioxidant. This study showed that, a potential means to control peel darkening and loose date crust and improve quality of cv. Sukkary dates, which ultimately improves its market ability, through implementing appropriate potassium and irrigation regimes.

Production and postharvest quality of <i>Passiflora edulis</i> Sims under brackish water and potassium doses

<abstract> <p>The aim of this research was to assess the yield and postharvest characteristics of 'BRS Sol do Cerrado' sour passion fruits based on irrigation with varying levels of saline water and potassium fertilization. The study was conducted under field conditions at an experimental farm in São Domingos, Paraíba, Brazil. A randomized block design was implemented in a 5 × 4 factorial arrangement, with five levels of electrical conductivity of water (ECw): 0.3, 1.1, 1.9, 2.7, and 3.5 dS m<sup>−1</sup>, and four potassium doses (KD): 60, 80,100, and 120% of the recommended amount, with 3 replications. The potassium dose equivalent to 120% of the recommended dose in combination with low-salinity water resulted in the highest fresh mass accumulation in the sour passion fruit. Water electrical conductivity up to 2.7 dS m<sup>−1</sup>, along with the lowest recommended KD, led to increased levels of soluble solids and ascorbic acid in the sour passion fruit. Irrigation with water of 3.5 dS m<sup>−1</sup> and using 80 to 100% of the recommended KD enhanced the total sugar content in the sour passion fruit. On the other hand, irrigation with water of 3.5 dS m<sup>−1</sup> combined with 60% of the recommended KD resulted in a higher pulp yield in the 'BRS Sol do Cerrado' sour passion fruit 160 days post-transplantation. Adjustments in potassium fertilization management at different irrigation water salinity levels played a crucial role in maintaining both the production and quality of the sour passion fruit.</p> </abstract>

Study of Genotypic and Phenotypic Correlation and Path Analysis Under Potassium Fertilization in Maize (Zea mays)

During the autumn season of 2018, a field experiment was carried out. The study’s goal was to evaluate phenotypic and genotypic correlation as well as path coefficient analysis under varied degrees of potassium fertilization. The study included nine different maize genotypes. Planted with three levels of potassium fertilization (75, 100, and 125 K2SO4 Kg Hectare-1). The split plot arrangement was done according to RCBD with three replications. The most important findings were summarized as follows: The genetic analysis revealed that genotypes differed significantly in all analyzed variables under the three levels of potassium fertilization. The grain yield genetically, phenotypically, and positively correlated with plant height, leaf area index, number of rows per ear, number of grain in a row and weight of 300 grain. The trait of a number of grains in a row showed genetic, phenotypic, and significant correlation with the three levels of potassium fertilization and the highest reached 0.95 and 0.89 respectively at the third level. Path analysis showed that the direct effects for a Leaf area index, number of rows per ear, Number of grains per row and weight of 300 grain were negative at the first level of potassium and highly positive at the other two levels. the direct selection for a number of rows per ear and Number of grains per row will incredibly effective in enhancing yield. However, the highest indirect effect for Number of grains per row was through plant height (1.76) at the first levels of potassium fertilization.

Response of Three Garlic Allium Sativum L. Genotypes to Potassium Fertilization Levels

A field experiment was carried out at the Agricultural Research Station of the College of Agriculture, the University of Anbar for the season (2021-2022) in order to study the effect of different levels of potassium fertilization on the growth, yield and quality of bulbs for three garlic genotypes. The experiment included the use of four levels of potassium fertilization (0, 150, 200, 250) kg/ha, respectively, it was added to three garlic genotypes (local, Chinese, and Egyptian). The study was carried out as a factorial experiment in a randomized complete block design (R.C.B.D) with three replicates. The results showed that the local cultivar was immunologically superior in vegetative growth characteristics (plant height, leaf area) and reached 100.44 cm and 7.08 cm2 compared to the lowest plant height achieved by plants of the Egyptian cultivar, which amounted to 55.17 cm and the lowest leaf area achieved by the Chinese cultivar plant, which reached 6.96 dm2. The local cultivar and the level of fertilization 250 kg / ha also excelled in the yield trait, as it achieved the highest weight of heads, the highest number of cloves and the highest yield per unit area 91.93 g per clove, 36.24 clove per plant, 36.24 ton / ha compared to the lowest amount achieved by plants of the Chinese cultivar without fertilizing.

Impact of planting dates and potassium levels on sunflower grain yield and fullness (Helianthus annuus L.) Shampoos variety

The study was conducted during the spring season (2022) to determine the effect of early planting for four planting dates (18/1, 2/2, 17/2 and 4/3) and four levels of potassium fertilizer (30, 60, 90 and 120) kg ha-1 , on the yield and fullness of sunflower grains, cultivar Shamoos, was carried out by arranging the split panels according to a Randomized Complete Block Design with three replicates. The results of the experiment showed significant effects of planting dates on yield and its components, as the planting date exceeds D1 on the grain filling period, the number of grains filled, the weight of 1000 grains, the yield of the individual plant, the biological yield and the percentage of fertilization, the results of the experiment also showed a significant effect of potassium levels on yield traits, the K4 fertilization treatment gave the highest average of the duration of grain filling and the number of filled grains, whereas, the K2 fertilization treatment gave the highest mean for the 1000 grain weight, regarding the interaction between the two factors of the study, the results showed significant differences between the experimental treatments on the yield, the D1K4 interference treatment gave the highest mean of the grain filling time. Keywords: planting dates, potassium levels, sunflower grains (Helianthus annuus L.), Shamoos cultivar.

The effect of potassium fertilizer and planting dates on growth, yield, and quality of wheat (Triticum aestivum L.)

The field experiment was conducted during the winter season of 2021-2022 in one of the farmers' fields in the village of Al-Budayab, affiliated Ramadi city . The study aimed to investigate the effect of potassium fertilizer levels (120, 160, and 200) kg K ha1- and planting dates (November 15th, December 1st, December 15th) on the growth, yield, and quality characteristics of wheat . The experiment was carried out using a randomized complete block design (RCBD). Statistical analysis revealed significant differences among the levels of potassium fertilizer, with the 200 kg K ha-1 level superior to other levels in plant height 94.25 cm, leaf area 48.16 cm², number of spikes per square meter 285.60 m-², number of grains per spike 65.50 grains, 1000-grain weight 34.10 g and grain yield 6.40 ton ha-1 . Additionally, the planting dates showed significant differences, where 15th of December record a significant yield significantly higher results for the above-mentioned characteristics, measuring plant height 82.30 cm, leaf area 43.31 cm², number of spikes per square meter 270.94 m-², number of grains per spike 58.94 grains, 1000-grain weight 32.64 g and 5.36 tons. The interaction between the level of potassium fertilizer and planting dates also had a significant effect on grain yield, as the 200 kg K ha-1 level combined with the December 15th planting date resulted in the highest grain yield of 7.30 tons ha-1. Regarding the grains protein content in, the 120 kg K ha-1level recorded the highest percentage of 12.57%, and the November 15th yielded the highest percentage of 12.12% compared to the other planting dates.

Effect of spraying with organic nutrients and adding levels of potassium fertilizer on the growth and yield of red cabbage

The research was conducted at Research Station (A) of the College of Agricultural Engineering Sciences - University of Baghdad in the autumn season 2022-2021 to know the effect of spraying the organic fertilizer Fertiorgan and adding potassium fertilizer on the growth and yield of red cabbage. The research was done using a randomized complete block design R.C.B.D. with three replications. The first factor included spraying with the organic nutrient (Fertiorgan) with three concentrations (0, 1.5 and 3 ml. L-1 ) symbolized by F0, F1, and F2, respectively. The second factor included the addition of potassium fertilizer in the form of potassium sulfate at four levels (0, 100, 135 and 170 kg.ha-1 ) with a symbol K0, K1, K2, and K3, respectively. The results showed the superiority of the concentration (3 ml. L-1 ) of the organic nutrient in the characteristics of plant height (47.53 cm), stem length (18.83 cm), number of outer leaves (18.74 leaves. plant-1 ) and leaf area (1214.96 dm2 .plant-1 ). The dry weight of the vegetative total was (225.92 g) and the total yield (45.53 tons. ha-1 ), and the level (170 kg. ha-1 ) of potassium fertilizer showed a significant increase for the same trait above, reaching (45.80 cm) and (17.72 cm) and ( 18.18 leaves. plant-1 ), (1171.02 dm2.plant-1), (208.11 g) and (40.48 tons. ha1 ), As for the two working interactions, the interaction treatment (F2K3) was excelled in giving it the highest values for these traits, as it reached (52.62 cm), (21.39 cm), (21.55 leaves. ) and (1296.97 dm2 .plant-1 ) and (248.33 gm) and (50.00 tons.ha1 ) Keywords: organic nutrients, red cabbage, potassium fertilizer, Fertiorgan.

Responce of European Wheat to Weed Competitiveness as Affected by Potassium Fertilizer Levels

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 methods: 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.

Effect of Potassium on the Growth and Yield of Different Varieties of Mustard (Brassica juncea L.) under Poplar (Populus deltoides) Based Agroforestry System

A field experiment was conducted to find out the "Effect of potassium on the growth and yield of different varieties of Mustard (Brassica juncea L.) under Poplar (Populus deltoides) based agroforestry system" at Forestry Nursery, the research farm of the College of Forestry, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, U.P., India. Experiment was laid out in randomized block design with 3 different varieties of Mustard viz. T59-Varuna, Pioneer 45s 42s, and Jugni in 3 replications and 5 levels of Potassium per variety (50% kg/ha), (75% kg/ha), (100% kg/ha), (125% kg/ha) and (150% kg/ha) as of total 15 treatments in all. The result shows that the application of increased levels of potassium fertilizers showed high growth and yield of Mustard. It was recorded from the application of potassium fertilizers in treatments applied with (MOP @ 150% kg/ha) resulted in increased pre-harvest observation viz., plant height (cm), dry weight (g/plant), crop growth rate (g/m2/day) and increased relative growth rate (g/g/day). It was also concluded from the trail that the application of fertilizers in treatment with (MOP @ 150% kg/ha) was found in increasing post-harvest observations viz., number of siliqua/plants, number of seeds/siliquas, test weight (g), seed yield (t/ha), stover yield (t/ha), harvest index (%). Also, after the economic analysis, the returns as compared to investment were found to be more profitable.

Rye Production under Acid Soils and Drought Conditions: An Alternative for the Sustainability of High Andean Livestock Farming in Peru

The rye (Secale cereale L.) crop shows a high potential to contribute to the sustainability of high Andean livestock because it supports the agroclimatic conditions and acid soils in the Peruvian Andes. The production of green forage, hay, and grain from the rye crop in acid soils was studied with the use of different levels of phosphorus and potassium fertilization in four local rye ecotypes (CBI-001, CSM-001, CJS-001, and CCE-001). The green forage yield (GFY) ranged from 32.35 to 53.62 t ha−1, dry matter from 6.05 to 8.56 t ha−1, and hay from 7.0 to 10.36 t ha−1; nutritional levels ranged from 9.02% to 13.56% protein and 6.50% to 7.75% ash levels, mainly with differences between ecotypes (p < 0.05). No differences existed between fertilization levels for the number of stems per plant, spikes per plant, and grains per ear (p > 0.05). Also, CBI-001 and CCE-001 were superior with 1868.4 and 1797.8 kg ha−1 of grain, respectively (p = 0.0072); the use of 60 kg ha of nitrogen, 120 kg ha−1 of P2O5, and 80 kg ha−1 of K2O gave higher grain and residue yields. The high nutritional value and yield of the rye ecotypes studied in acid soil conditions and without irrigation can be an alternative for livestock feeding and grain production in the rainy season in the Andes as a dual-purpose crop.

Sustainable production ofSaussurea costus under different levels of nitrogen, phosphorus and potassium fertilizers in cold desert region of Western Himalaya.

Saussurea costus, an important critically endangered medicinal herb native to the Himalayan region, is commonly used in various ailments, viz. asthma, ulcer, inflammation, and stomach problems. In the international market, the dry roots and essential oil of S. costus has become an important drug. The lack of appropriate fertilizer dose recommendations is one of the limiting factors for its ex-situ conservation and large-scale cultivation, as plant nutrition is vital in determining crop growth and productivity. The study aimed to understand the comparative impact of different levels of fertilizer nutrients on growth, dry root and essential oil yield, and essential oil profile of S. costus. A field experiment was conducted in Himachal Pradesh, India's cold desert region (Lahaul valley), during 2020-21. The experiment comprised three levels of nitrogen (60, 90, and 120 kg ha-1), three levels of phosphorus (20, 40, 60 kg ha-1), and two levels of potassium (20 and 40 kg ha-1) in a factorial randomized block design. The fertilizer application had an immense effect on growth attributes, root yield attributes, dry root yield, and essential oil yield over control. The treatment combination N120, P60, and K40 had the largest effect on the plant height, number of leaves per plant, leaf length and width, root length and diameter, dry matter per plant, dry root yield, and essential oil yield. However, the results were at par with the treatment comprising N90, P40, and K20. Dry root yield increased by 108.9%, and essential oil yield increased by 210.3% with fertilizer applications over unfertilized plots. The regression curve shows an increasing trend in dry root yield till N90, P40, and K20; after that, it nearly stabilized. The heat map showed that applying fertilizer significantly affected the chemical constituents of S. costus essential oil. Similarly, the plots fertilized with the highest level of NPK recorded the utmost value of available N, P, and K, as compared to unfertilized plots. The results emphasize that for sustainable cultivation of S. costus, the application of N90, P40, and K20 combinations is the most suitable one.

Response of Sweet Sudan Grass to Graded Levels of Phosphorus and Potassium Fertilization

Background: Green fodder yield potential of the landmark multi-cut sweet sudan grass (SSG) variety SSG 59-3 was influenced due to the poor fertility status at many places in Haryana. The performance of sweet sudan grass under different P and K treatments was assessed by measuring fodder yield, agronomic efficiency, physiological efficiency and net income. Methods: A two-year (2018 and 2019) field study was conducted at Hisar, Haryana to assess the effect of four P levels (0, 6.6, 13.2 and 19.8 kg/ha P) and four K levels (0, 12.5, 25.0 and 37.5 kg/ha K) on growth, yield and quality of sweet sudan grass (SSG-59-3). The sixteen treatment combinations were replicated thrice in a factorial RBD. The sandy-loam soils of the experimental field was low in organic carbon (0.47%) and available nitrogen (141 kg/ha) and medium in available P (12.9 kg/ha) and K (225 kg/ha). The nutrients P and K were applied through di-ammonium phosphate and muriate of potash just before sowing. Result: The graded levels of P and K gave significantly better results up to 13.2 kg/ha P and 37.5 kg/ha K. The agronomic efficiency, physiological effecicency and apparent nutrient recovery (%) of nutrients were highest with lower levels of P and K (6.6 and 12.5 kg). The application of K had complementary effect on the uptake of P as appropriate ratios of N, P and K fertilizer improved absorption and utilization of nutrients.Therefore, farmers can apply 13.2 kg P/ha plus 37.5 kg K/ha along with recommend N for increased dry fodder yield and net income in sweet sudan grass.

Effect of Common Bean (Phaseolus vulgaris L.) Varieties and Variable Rates of Potassium Fertilizer on Yield and Yield-Related Traits at Areka, Southern Ethiopia

Yield and yield components of common bean varieties reacted differently in response to variable levels of potassium (K) fertilization under different growing areas. Hence, it is necessary to integrate varieties with optimum K rates in order to maximize bean yield. On the other hand, insufficient K supply has a negative influence on stomata’s functionality, delaying stomatal closure and leaving pores partially closed. Thus, it is essential to find high-yielding varieties with balanced K fertilization. To evaluate common bean varieties at various K rates, a field experiment was carried out during the 2019/20 cropping seasons at the Areka Agricultural Research Center Experimental Field in Southern Ethiopia. Treatments consisted of three common bean varieties (SER 119, SAB 736, and Awassa Dume) and five K rates (0, 10, 20, 30, and 40 kg/ha K2O) combined in factorial and laid out in a randomized complete block design with three replications. The phenological, growth, yield components, and yield of common bean varieties reacted differently to the varieties, K rates, and their interactions. Parameters such as branches per plant, leaf area, LAI, pods per plant, biomass, and grain yield were significantly affected by varieties, K rates, and their interactions. Conversely, plant height, seeds per pod, and HI were significantly affected only by the main effects of varieties and K fertilizer rates. This investigation indicated that variety SER 119 exhibited superior performance over others with the highest grain yield at K rate of 40 kg/ha. Hence, variety SER 119 at K rate of 40 kg/ha could be used for production in the study area and similar agroecologies.

Identification of Key Genes Induced by Different Potassium Levels Provides Insight into the Formation of Fruit Quality in Grapes.

Inadequate potassium (K) availability is a common abiotic stress that limits the growth and quality of fruit trees. Few studies have investigated the physiological and molecular responses of grapes at different potassium levels. In this study, an integrated approach was developed for grapevines grown at four different potassium fertilization levels [0 (K0-CK), 150 (K150), 300 (K300), and 450 (K450) g/plant] in combination with metabolite measurements and transcript analysis. The results showed that different K levels affected the accumulation of sugars and anthocyanins in the fruit. At 78 days after bloom (DAB), the K150, K300, and K450 treatments increased soluble sugar content by 37.39%, 31.10% and 32.59%, respectively, and anthocyanin content by 49.78%, 24.10%, and 13.06%, respectively, compared to K0. Weighted gene co-expression network analysis (WGCNA) of DEGs identified a network of 11 grapevines involved. During fruit development, potassium application promoted the accumulation of anthocyanins and sugars in fruit by regulating the up-regulation of GST, AT, UFGT and SPS, HT, PK gene expressions. These results suggest that potassium deficiency inhibits anthocyanin and sugar metabolism. In addition, it promotes the up-regulation of KUP expression, which is the main cause of K accumulation in fruits. Together, our data revealed the molecular mechanism in response to different K levels during fruit quality formation and provides the scientific foundation for the improvement of fruit quality by adding K fertilizer.

Using Optimized Three-Band Spectral Indices and a Machine Learning Model to Assess Squash Characteristics under Moisture and Potassium Deficiency Stress

Moisture and potassium deficiency are two of the main limiting variables for squash crop performance in many water-stressed places worldwide. If major output decreases are to be avoided, it is critical to detect signs of crop stress as early as possible in the growth cycle. Proximal remote sensing can be a reliable technique for offering a rapid and precise instrument and localized management tool. This study tested the ability of proximal hyperspectral remotely sensed data to predict squash traits in two successive seasons (spring and fall) with varying moisture and potassium rates. Spectral data were collected from drip-irrigated squash that had been treated to varied rates of irrigation and potassium fertilization over both investigated seasons. To forecast potassium-use efficiency (KUE), chlorophyll meter (Chlm), water-use efficiency (WUE), and seed yield (SY) of squash, different commonly used and newly-introduced spectral index values for three bands (3D-SRIs), as well as a Decision Tree (DT) model, were evaluated. The results revealed that the newly constructed three-band SRIs based on the wavelengths of the visible (VIS), near-infrared (NIR), and red-edge regions were sensitive enough to measure the four tested parameters of squash in this study. For instance, NDI558,646,708 presented the highest R2 of 0.75 for KUE, NDI744,746,738 presented the highest R2 of 0.65 for Chlm, and NDI670,628,392 presented the highest R2 of 0.64 for SY of squash. The results further demonstrated that the principal component analysis (PCA) demonstrated the ability to distinguish moisture stress from potassium deficiency stress at the flowering stage onwards. Combining 3D-SRIs, DT-based bands (DT-b), and the aggregate of all spectral characteristics (ASF) with DT models would be an effective strategy for estimating four observed parameters with appropriate accuracy. For example, the model’s approximately 30 spectral characteristics were extremely important for predicting KUE. Its outputs with R2 were, for the training and validation datasets, 0.967 (RMSE = 0.175) and 0.818 (RMSE = 0.284), respectively. For measuring Chlm, the DT-DT-b-20 model demonstrated the best. In the training and validation datasets, the R2 value was 0.993 (RMSE = 0.522) and 0.692 (RMSE = 2.321), respectively. The overall outcomes showed that proximal-reflectance-sensing-based 3D-SRIs and DT models based on 3D-SRIs, DT-b, and ASF could be used to evaluate the four tested parameters of squash under different levels of irrigation regimes and potassium fertilizer.

Effect of potassium fertilization levels on rice yield, yield attributes and rice stem borer infestation of Giza 178 rice cultivar grown under nitrogen fertilizer levels

Effect of potassium fertilization levels on rice yield, yield attributes and rice stem borer infestation of Giza 178 rice cultivar grown under nitrogen fertilizer levels

Effect of potassium on yield and some qualitative and physiological traits of safflower (Carthamus tinctorius L.) under drought stress conditions

Improving the pattern of water consumption in the agricultural sector is one of the necessary measures to manage the water crisis in the country. The present study was conducted to investigate the effects of drought stress on yield and physiological characteristics of safflower under different amounts of potassium fertilizer. The experiment was performed as a combined analysis in a randomized complete block design with three replications during 2018 and 2019. The main plot consisted of drought stress at three levels of 45%, 65%, and 85% of permissible moisture drain and the subplot consisted of potassium fertilizer at four levels of zero, 75, 150, and 225 kg of potassium sulfate per hectare. In the second year compared to the first year, the amount of proline and seed oil were significantly higher by 23.4% and 4.43%, respectively, and the amount of carbohydrates and chlorophyll a were significantly lower by 11.9% and 27.4%, respectively. With increasing potassium intake, the amount of chlorophyll a increased significantly, and the highest amount of chlorophyll a at the rate of 16.7 mg/L was obtained in the treatment of 225 kg of potassium per hectare. With increasing the intensity of stress from 45% to 85% of moisture drain in different levels of potassium fertilizer, seed yield decreased significantly. Treatment of 85% moisture drain in no application of potassium showed the highest amount of proline. The application of potassium is effective in modulating the negative effects of drought stress on seed yield, qualitative, and physiological characteristics of safflower.