Effect Of Potassium Fertilization Research Articles

Root characteristics response to N, P, and K fertilization in creeping bentgrass

AbstractTurfgrass roots are essential for growth and development by taking up water and nutrients from the soil. Therefore, improving root characteristics such as root length, root volume, root density, root diameter, and root dry biomass is crucial for improving turfgrass growth and quality. Greenhouse experiments were conducted in 2023 to document the effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizers on the root morphological responses of Penncross creeping bentgrass (Agrostis stolonifera) during establishment. Turfgrasses were grown from seeds in sand‐filled acrylic tubes for around three months. Fertilizer treatments included N, P, K, PK, NK, NP, all three macronutrients (NPK), and a non‐fertilized control (non‐NPK). NP treatment resulted in a greater total root length, root surface area, root volume, and root dry biomass of creeping bentgrass than the other treatments except for NPK treatment. While it is critical to provide sufficient N, P, and K for the optimal development of creeping bentgrass roots during the establishment period, reducing K fertilization had the least impact on the root morphological response of creeping bentgrass. NPK application during turfgrass establishment is context‐dependent, particularly with regard to nutrient availability in the soil. Based on this study, applying a balanced starter fertilizer with adjustments per the soil test results would ensure proper root growth.

Effects of potassium fertilization on grain yield, taste quality, and starch characteristics of rice (Oryza sativa L.) grain.

There is limited information on the effect of potassium (K) on the taste quality of rice. Field experiments with five K fertilizer application rates (0, 60, 120, 180, and 240 kg K2O ha-1) were conducted in 2019 and 2020 using two cultivars (Xiadao No. 1 and Shenliangyou 5814) to study the effects of K fertilization on grain yield, taste quality, starch components, and protein components in grains. Compared with a no-potassium treatment (K0), K fertilization increased the grain yield significantly: by 57.29% for Xiadao No. 1 and 33.51% for Shenliangyou 5814. It did this mainly by increasing the number of rice spikelets per panicle and improving the seed-setting rate. K fertilizationimproved the taste value by 12.64% for Xiadao No. 1 and 10.83% for Shenliangyou 5814. Starch components, protein components, and viscosity parameters were also influenced by K fertilization. With increased K application, the amylose content and the ratio of amylose content to amylopectin content tended to increase. K fertilization increased the peak viscosity and cool paste viscosity, while decreasing the prolamin content and pasting temperature. Principal component analysis highlighted the importance of amylose content and the ratio of amylose content to amylopectin content in determining taste value, texture, and appearance. Applying 180 kg K2O ha-1 of K fertilizer ensured high rice yields and taste quality, providing a basis for the production of high-yield and high-quality rice. © 2024 Society of Chemical Industry.

Potassium fertilization effects on dollar spot of annual bluegrass and creeping bentgrass

AbstractThe effect of potassium on dollar spot of annual bluegrass (ABG; Poa annua L. forma reptans (Hausskn.) T. Koyama) and creeping bentgrass (CBG; Agrostis stolonifera L.) is poorly understood. Two field trials were conducted in 2020 and 2021 to determine the effect of K fertilization on dollar spot of ABG and CBG turf grown on a sand mat layer overlying a sandy loam (fine‐loamy, mixed, semiactive, and mesic Typic Hapludults) and mowed at 2.8 mm. A 4 × 2 factorial, randomized complete block design evaluated K (potassium sulfate) applied at 0, 3.4, 6.9, and 13.8 kg ha−1 every 2 weeks and N (urea) applied at 4.9 kg ha−1 every 7 or 28 days over 20 weeks. Infection centers were counted over a 2‐week period each year after inoculation with Clarireedia jacksonii in mid‐September and used to calculate the disease severity. Increasing K fertilization rate consistently increased dollar spot severity on ABG and CBG. Higher N rate either slightly increased or did not affect disease severity on ABG, and either decreased or had no effect on CBG. This is the first study to document the impact of K fertilization on dollar spot severity of ABG turf. Regression analysis indicated that increases in both leaf tissue and mat layer K were associated with greater dollar spot severity on both species. Future research should determine whether the increased dollar spot response to K fertilization occurs at higher antecedent mat layer and leaf tissue K. Additionally, a broader range of N rates may clarify the dollar spot response.

Effects of potassium and boron fertilization on sunflower yield, oil content, and quality

Effects of potassium and boron fertilization on sunflower yield, oil content, and quality

Effects of Potassium Fertilizer on Sugarcane Yields and Plant and Soil Potassium Levels in Louisiana

Effects of Potassium Fertilizer on Sugarcane Yields and Plant and Soil Potassium Levels in Louisiana

Potassium Fertilization Alters the Morphogenetic, Structural, and Productive Characteristics of Panicum maximum Cultivars

The objective was to evaluate the effects of potassium fertilization on the morphogenetic, structural, and productive characteristics of Panicum maximum (cvs. Tanzania, Quênia, Mombaça, Zuri, Massai, and Tamani). The design was in randomized blocks with four doses of potassium (K) 0, 205, 410, and 820 mg dm−3, divided into 5 applications. The analyzed variables were leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), leaf senescence rate (LSR), leaf life span (LLS), phyllochron (PC), number of live leaves (NLL), final leaf length (FLL), tiller population density (TPD), and forage mass (FM). LAR increased by 0.00216 leaves tiller on day-1 (p = 0.0354) and LER increased by 0.00980 cm tiller on day-1 for each milligram of K (p = 0.0402). There was an increase in FLL of 0.16, 0.08, and 0.07 days for the cultivars Mombaça, Massai, and Tamani, respectively, for each milligram of K applied (p = 0.0034). The TPD of the cultivar Tamani increased linearly by 0.074 tillers/pot for each milligram of K (p = 0.0226), and the cultivar Massai showed a quadratic behavior. The TPD of the other cultivars was not influenced by the increase in the K doses. For forage mass (FM), the cultivars Mombaça and Quênia increased by 0.16 and 0.39 g DM/pot for each milligram of K added to the soil. The cultivars Tanzânia, Zuri, Massai, and Tamani showed maximum point at doses of 261.35, 279.45, 300.57, and 275.86 mg dm−3 K, respectively. Potassium fertilization linearly increased leaf appearance and elongation, with maximum productivity reached at a K dose of 430 mg dm−3, except for the cultivars Mombaça and Quênia, which responded up to a K dose of 820 mg dm−3.

Effect of sulfur and potassium foliar applications on wheat grain protein quality

ContextThe effects of sulfur and potassium fertilizers on wheat yield and quality have been well studied, but most of them are used as basal fertilizers. However, the root system is senescent at the later stages of wheat growth and cannot absorb sufficient sulfur and potassium fertilizers plant needed. It is still unclear whether sulfur and potassium foliar applications at the later stages can affect wheat yield and quality. ObjectiveThis experiment was conducted to investigate the changes of sulfur and potassium accumulation and transport, protein synthesis and flour processing quality after foliar application of sulfur and potassium fertilizers, transport and the relating physiological mechanisms. MethodsIn 2020–2021 and 2021–2022, a three-factor split plot experiment was carried out in the middle and lower reaches of Yangtze River, with wheat variety, concentration of sulfur fertilizer and potassium fertilizer served as main factor, subfactor and sub-subfactor respectively. ResultsIn the study from 2020 to 2022, the albumin protein content of both varieties decreased in the nutrient spraying treatment, particularly in the high potassium level. However, there was no significant effect on the globulin content. Moreover, the gliadin protein content decreased in the sulfur spraying treatment alone, but significantly increased the wheat gluten content, and thereby the total protein content. We also found significant genotypic differences in the composition and content of high molecular weight wheat glutenin subunits (HMW-GS) between the two varieties. The foliar spraying of sulfur and potassium fertilizers significantly increased the content of subunits 1 and 8 in Yangmai (YM15) and subunits 7 and 12 in Yangmai (YM16), and the effect of mixed spraying was better than single-nutrient spraying, especially the amount of 0.2 % sulfur and 0.3 % potassium fertilizer treatment. ConclusionsThe superimposed effect of sulfur and potassium effectively increased the total protein content by promoting the accumulation of sulfur in transit to the seeds, increasing the substrate supply level, and enhancing enzyme activity. Although sulfur and potassium combination can improve the grain protein quality and flour processing quality, too high spraying concentrations can decrease the flour processing quality. ImplicationsSpraying the appropriate amount of 0.2 % sulfur and 0.3 % potassium fertilizer can serve as an optimization measure for high-quality and efficient production of different types of wheat varieties.

HONEY PUMPKIN STEM BORER, Apomecyna saltator FABRICIUS (COLEOPTERA: CERAMBYCIDAE) CAN BE CONTROLLED WITH PHOSPHORUS AND POTASSIUM FERTILIZER

Apomecyna saltator, a notorious pest of honey pumpkin plants, poses a significant threat to both vegetative and generative phases, leading to considerable production losses. Despite its agricultural impact, there are limited studies on effective management strategies for this pest. This research investigates the effect of combined phosphorus and potassium fertilization on controlling A. saltator infestations in honey pumpkin plants. The study was conducted at the Teaching and Research Farm of the Faculty of Agriculture, Jambi University. A randomized block design with five treatments and five replications was used, testing different combinations of SP-36 phosphorus and potassium chloride (KCl) fertilizers: no fertilization (p0), SP-36 0.67 g/plant + KCl 1.25 g/plant (p1), SP-36 1.00 g/plant + KCl 1.88 g/plant (p2), SP-36 1.34 g/plant + KCl 2.51 g/plant (p3), and SP-36 1.67 g/plant + KCl 3.13 g/plant (p4). The variables observed included stem diameter, larval population, percentage of plant damage, number of attacked plant segments, fruit weight, and overall production. Data were analyzed using ANOVA and Duncan's Multiple Range Test (DMRT). The results indicated that combining phosphorus and potassium fertilizers significantly increased stem diameter, fruit weight, and yield while reducing larval populations, plant damage, and affected segments. The study demonstrates that phosphorus and potassium strengthen honey pumpkin plants and negatively impact A. saltator infestations. This research highlights a novel approach to pest control, showing that targeted fertilization promotes plant health and suppresses the honey pumpkin stem borer (A. saltator). This dual benefit of nutrient application provides a sustainable and efficient pest management strategy, offering a fresh perspective on integrated crop protection.

Potassium fertilization and defoliation intensity effects on forage characteristics of “BRS Zuri” guineagrass

Potassium fertilization and defoliation intensity effects on forage characteristics of “BRS Zuri” guineagrass

Effects of Potassium Fertilizer Base/Topdressing Ratio on Dry Matter Quality, Photosynthetic Fluorescence Characteristics and Carbon and Nitrogen Metabolism of Potato

Effects of Potassium Fertilizer Base/Topdressing Ratio on Dry Matter Quality, Photosynthetic Fluorescence Characteristics and Carbon and Nitrogen Metabolism of Potato

Effect of potassic fertilization on yield of fodder sorghum-sudan grass hybrid and selection of extractants for determination of plant potassium availability

The current study was carried out to assess the effect of potassium (K) fertilization on K-uptake and yield of fodder sorghum-sudan grass hybrid and to choose extractant(s), delineating the K-availability for routine soil testing method. Hybrid sorghum-Sudan grasses were grown in three different soils (red, alluvial, and black) with 100, 50, and 0% recommended K-doses for five seasons. Seven extractants, namely, cold H2SO4, Mehlich-1, 0.1 N CH3COONa, 1 N CH3COONH4 (pH 7), 0.1 N BaCl2, and sodium tetraphenylborate (NaTPB) with 5 and 15 minutes of contact times, were evaluated for elucidating forage K-availability. Results have revealed that biomass yields from all soils were higher (p < 0.05) in K-100% than in K-0%; whereas NaTPB (5 minutes) and ammonium acetate were found as better extractants for the determination of forage K-availability.

Potassium fertilizer promotes the thin-shelled Tartary buckwheat yield by delaying senescence and promoting grain filling.

The application rate of potassium fertilizer is closely related to the yield of crops. Thin-shelled Tartary buckwheat is a new variety of Tartary buckwheat with the advantages of thin shell and easy shelling. However, little is known about application rate of potassium fertilizer on the yield formation of thin-shelled Tartary buckwheat. This study aimed to clarify the effect of potassium fertilizer on the growth and yield of thin-shelled Tartary buckwheat. A field experiment to investigate the characteristics was conducted across two years using thin-shelled Tartary buckwheat (Miku 18) with four potassium fertilizer applications including 0 (no potassium fertilizer, CK), 15 (low-concentration potassium fertilizer, LK), 30 (medium-concentration potassium fertilizer, MK), and 45 kg·ha-1 (high-concentration potassium fertilizer, HK). The maximum and average grain filling rates; starch synthase activity; superoxide dismutase and peroxidase activities in leaves; root morphological indices and activities; available nitrogen, phosphorus, and organic matter content in rhizosphere soil; urease and alkaline phosphatase activities in rhizosphere soil; plant height, main stem node number, main stem branch number, leaf number; grain number per plant, grain weight per plant, and 100-grain weight increased first and then decreased with the increase in potassium fertilizer application rate and reached the maximum at MK treatment. The content of malondialdehyde was significantly lower in MK treatment than in other three treatments. The yields of thin-shelled Tartary buckwheat treated with LK, MK, and HK were 1.22, 1.37, and 1.07 times that of CK, respectively. In summary, an appropriate potassium fertilizer treatment (30kg·ha-1) can delay the senescence, promote the grain filling, and increase the grain weight and final yield of thin-shelled Tartary buckwheat. This treatment is recommended to be used in production to achieve high-yield cultivation of thin-shelled Tartary buckwheat.

Foliar applied potassium nanoparticles (K-NPs) and potassium sulfate on growth, physiological, and phytochemical parameters in Melissa officinalis L. under salt stress.

Salinity stress significantly constrains agricultural productivity and vegetation decline worldwide, particularly in Iran. Potassium, the second most prevalent nutrient in plants, is well known to be essential for cell metabolism. Here, the effects of potassium fertilizer in two biogenic nanoparticles (K-NPs) and conventional (potassium sulfate) forms (0.1 mg/ml) on Melissa officinalis L. under salinity (0, 50, 100, and 150 mM) were investigated. The results demonstrated that stress markers (electrolyte leakage, malondialdehyde, and hydrogen peroxide) increased as salinity levels increased. Plant growth parameters (shoot and root length, fresh and dry weight of shoot and root) and physiological and photosynthetic parameters (stomatal conductance, relative water content, chlorophyll fluorescence, and photosynthetic pigments) were reduced in salinized plants. The highest reduction in fresh weight root, dry weight root, fresh weight shoot, dry weight shoot, root length, and shoot length was recorded under 150 mM NaCl by 30.2%, 51.6%, 30.5%, 24.7%, 26.4%, and 21%, respectively. In contrast, bulk potassium sulfate and K-NPs increased these parameters. Furthermore, K-NPs improved M. officinalis tolerance to NaCl toxicity by enhancing the content of osmolytes such as proline, soluble sugars, and antioxidant enzymes, improving antioxidant contents such as phenols, tannins, anthocyanins, and flavonoids; increasing total protein; and lowering stress markers in plant tissues. Given the results of the physiological, biochemical, and phytochemical parameters obtained from this study, it can be stated that K-NPs, in comparison to the conventional form of potassium fertilizer, exhibit a greater potential to mitigate damages caused by salinity stress in M. officinalis plants.

Effects of phosphorus and potassium fertilization and fruit canopy position on sugar accumulation in mangifera indica cv. 'Kent' pulp

Sugar content is the key to mango quality and growers are constantly seeking methods to optimize it. In this study, fructose, glucose, sucrose, and maltose sugars were evaluated to determine how phosphorus and potassium fertilizers in varying amounts could affect these sugar levels and how sunlight exposure effects fruit. The experiments were conducted in the KALRO Orchard of Kiambu County, Kenya. Thirty-five healthy 7- to 8-year-old ‘Kent’ trees were selected and divided into five treatment groups with five replicates each. Treatment with 1 kg, 2 kg P, K and combined PK per tree resulted in a significantly higher fructose content than the control. In contrast, neither 1 kg nor 2 kg P resulted in significantly higher glucose contents than the control. Combined PK fertilizers at 0.5+0.5 kg per tree reduced fructose and increased glucose, sucrose, and maltose. A combination of PK fertilizers at 1.0+1.0 kg significantly increased only fructose, but not other sugars. Even after applying P and K fertilizers, the position of the fruit canopy did not affect fructose, glucose, or maltose contents. However, there was a trend towards a higher sucrose content in fruits exposed to sunlight (5.17 g/100 g) than in canopy fruits (2.29g/100g), although this difference was not statistically significant. The same trend was observed for the other sugars. The t-test revealed no significant differences between the two canopy positions (t = 1.01, p = 0.344). A significant difference in sugar content (p < 0.05) between fruits harvested at different canopy positions suggests that fruits harvested at different canopy positions did not ripen simultaneously. In contrast, neither 1 kg nor 2 kg of P produced a significant difference in the glucose content. Combining PK fertilizers at 0.5+0.5 kg per tree decreased fructose while increasing glucose, sucrose, and maltose. A combination of PK fertilizers at a rate of 1.0+1.0 kg significantly increased only fructose but not other sugars. Even after the application of P and K fertilizers, the position of the fruit canopy did not affect fructose, glucose, and maltose contents. However, there was a trend towards a higher sucrose content in fruits exposed to sunlight (5.17 g/100 g) than in crown fruits (2.29 g/100 g), although this difference was not statistically significant. The same trend was observed for the other sugars. The t-test revealed no significant differences between the two canopy positions (t = 1.01, p = 0.344). A significant difference in sugar content (p< 0.05) between fruits harvested at different canopy positions suggests that fruits harvested at different canopy positions did not ripen simultaneously.

Modeling the effect of fertilizers on cotton yields and cotton fiber quality on saline soils in so uthern Kazakhstan

Yntymak st.,26, Kazakhstan Cotton in Kazakhstan is one of the strategically important crops and is cultivated in the extreme south of the republic in the Turkestan region, in the northernmost cotton-growing zone on the globe. The aridity of the climate, the shortage of irrigation water and the growing threat of the risk of increasing saline lands in cotton plantations, on the one hand, and the insufficient and unjustified use of minerals, on the other, are the main limiting factors in cotton production. On the industrial plantations of the peasant farm "Sabyr", v. Atakent, Maktaaral district, Turkestan region, field experiments were carried out on serozems of slightly and moderately salinity in 2022. In experiments on two salinity backgrounds, 9 identical treatments of fertilizers with different doses and ratios of nitrogen, phosphorus and potassium were studied. During the phases of budding, flowering and fruit formation of cotton, biometric studies and selection of plant samples were carried out to study photosynthetic and yield indicators depending on fertilizers on 2 salinity backgrounds. The effect and interaction of fertilizers and the amount of salts in the soil on the formation of leaves in various phases of cotton development isquite accurately described (R2 = 0,957-0,972) by regression equations. At the same time, the effect of single action of nitrogen and potassium fertilizers was negative, and that of phosphorus fertilizers was positive. During the growing season, double combinations of all the studied factors, with the exception of nitrogen and potassium, had a negative effect on the dynamics of accumulation of cotton plant biomass. The gross cotton yield is 86% determined by the complex total influence of nitrogen, phosphorus and potassium fertilizers and the degree of soil salinity. At the same time, the unilateral effect of nitrogen and potassium fertilizers and soil salinity on cotton yield was negative, and that of phosphorus fertilizer was positive. There is a high correlation between potassium nutrition and fiber quality indicators (r = 0,38-0,62). Changes in fiber quality indicators generally had a strong relationship with the amount of salts in the topsoil (r = 0,51-0,61).

Comparative analysis of archival data on yields of main field crops from fertilizer experiments on different soil types in Bulgaria

The main aim of the study was to systematize and summarize archival data on yields from main field crops from multiple fertilizer experiments of Nikola Poushkarov ISSAPP on various soil types in Bulgaria. A large set of results from the field fertilizer experiments carried out on four different soil types: Calcareous Chernozem (Trastenik village), Haplic Chernozem (Gorni Dabnik village), Haplic Luvisol (Nikolaevo village) and Planosol (Sekirovo village) in the geographical network of Bulgaria of the Nikola Poushkarov ISSAPP has been accumulated. Eight fertilization variants were tested with annual application of potassium (0, 8, 16 and 32 kg/da K2 O) on two backgrounds of nitrogen (N) and phosphorus (P) fertilization. Crop rotation during the individual years was as follows: wheat (Triticum aestivum L.), maize (Zea mays L.), sunflower (Helianthus annuus L.) and sugar beet (Beta vulgaris L.), grown under non-irrigation conditions. Optimum rates of fertilization with the main nutrients, N, P and K have been established for the different soil types. There are complex interactions between the different rates of fertilization with the main macronutrients and this has a significant impact on the quantity and quality of agricultural crop yields. The difference in yields between the two investigated periods (1963-1970 and 1971-1975), at the same levels of fertilization, shows that the level of yields and accordingly, the use of nutrients are also determined to a significant extent by the climatic conditions. With an increase in the fertilizer rate, the yields also increase, and the rates of 16 kg and 32 kg K2 O remain the most effective, regardless of the occurrence of potassium accumulation in these variants. This was also confirmed by the results of the analysis of variance of the yields of cultivated crops. There was a pronounced increase of the effect of potassium fertilization in soils less supplied with this element, i.e. the Haplic Luvisol (Nikolaevo village) and Planosol (Sekirovo village). The effect of the potassium fertilization increases and expands in well supplied with potassium soils, but possessing unfavorable conditions for nutrition with this element, as in the case with the Calcareous Chernozem (Trastenik village). There was also an effect of potassium fertilization, although inconsistent, in soils well supplied with potassium, such as Haplic Chernozem (Gorni Dabnik village).

Effect of potassium fertilization on storage root number, yield, and appearance quality of sweet potato (Ipomoea batatas L.).

Increasing storage root number is a pivotal approach to enhance both storage root (SR) yield and appearance quality of sweet potato. Here, 2-year field experiments were conducted to investigate the effect of 0 (K0), 120 (K1), 240 (K2), and 360 (K3) kg ha-1 potassium fertilizer (K2O) on lignin metabolism, root growth, storage root yield, and uniformity. The results demonstrated that potassium (K) application led to a decrease in the activities of key enzymes involved in lignin biosynthesis, including phenylalanine deaminase (PAL), 4-coumarate coenzyme A ligase (4-CL), cinnamic acid dehydrogenase (CAD), polyphenol oxidase (PPO), and peroxidase (POD). This resulted in a significant reduction in lignin and G-type lignin contents in potential SRs compared to K0 treatment within 10-30 days after planting (DAP). BJ553 exhibited a significant decrease in PAL activity, as well as lignin and G-type contents at 10 DAP, whereas YS25 showed delayed effects until 20 DAP. However, the number and distribution of secondary xylem conduits as well as the mid-column diameter area in roots were increased in K2 treatment. Interestingly, K2 treatment exhibited significantly larger potential SR diameter than other treatments at 15, 20, and 25 DAP. At harvest, K2 treatment increased the SR number, the single SR weight, and overall yield greatly compared with K0 treatment, with an average increase of 19.12%, 16.54%, and 16.92% respectively. The increase of SR number in BJ553 was higher than that of YS25. Furthermore, K2 treatment exhibited the lowest coefficient of variation for both SR length and diameter, indicating a higher yield of middle-sized SRs. In general, appropriate potassium application could effectively suppress lignin biosynthesis, leading to a reduction in the degree of pericycle lignification in potential SRs. This promotes an increase in the number of storage roots and ultimately enhances both yield and appearance quality of sweet potato. The effect of potassium fertilizer on lignin metabolism in BJ553 roots was earlier and resulted in a greater increase in the SR number compared to YS25.

Effect of potassium fertilizer dose and compost dose of empty palm oil bunches (EFB) on the growth of lemongrass (Cymbopogon nardus L.)

This study aims to determine the effect of potassium fertilizer and compost of Empty Palm Oil Bunches (EFB) on the growth of citronella (Cymbopogon nardus L.). The research was started in February-June 2022 at BPTP Banten, and the Laboratory of the Department of Agroecotechnology, Sultan Ageng Tirtayasa University. This study used a factorial Randomized Block Design (RBD) method which consisted of two factors. The first of potassium fertilizer dose has 4 levels, 0 kg/ha potassium (K0), 15 kg/ha (K1), 30 kg/ha (K2) and 45 kg/ha (K3). The second factor of EFB compost has 4 levels, 0 tons/ha (T0), 20 tons/ha (T1), 30 tons/ha (T2) and 40 tons/ha (T3). The results showed the dose of potassium fertilizer 30 kg/ha gave the best results on plant height parameters at the age of 3, 4, 5, 6 weeks after planting (WAP). Dosage of 40 tons/ha of EFB compost gave the best results on the number of leaves aged 5 and 6 WAP. There was no interaction between the dose of potassium fertilizer and the dose of EFB compost on all.

Potassium fertigation and organic fertilisation in ‘Syrah’ grape in Northeastern Brazil: yield, must characteristics and phenolic compounds

The effect of both potassium and organic fertilisation on grape yield and must composition originating from wine grapevines cultivated in the São Francisco river basin, in the semi-arid region of Northeastern Brazil, is not well known. Since soils from that region usually have low organic matter content, we hypothesise that soil application of organic fertiliser and potassium application through drip irrigation enhances the availability of this nutrient in the soil, and it influences grape yield and quality. Hence, five doses of potassium (0, 20, 40, 80 and 160 kg ha-1) applied through a drip irrigation system and two doses of goat manure as organic fertiliser applied into the soil (0 and 7.5 m3 ha-1) after pruning were evaluated concerning yield and berry quality of grapevine ‘Syrah’ over four growing seasons (April 2013 to July 2015) in Petrolina, state of Pernambuco, Brazil. The experimental design was randomised blocks with 5 replications. We evaluated yield (t ha-1), weight of 100 berries (g), must volume (mL), total soluble solids (°Brix), pH and total titratable acidity (‰), K, Mg and Ca contents and phenolic compounds (total polyphenols, anthocyanins and flavonoids). The increasing application of potassium at the different doses of organic fertiliser did not alter the crop yield, except in the second season. Nonetheless, K concentration in grape must was influenced in the four growing seasons, with higher values at fitted K2O doses by polynomial regression of 83.62 kg ha-1 (first season), 101.25 kg ha-1 (second season), 120.00 kg ha-1 (third season) and 77.99 kg ha-1 (0 m3 ha-1 organic fertiliser) and 96.07 kg ha-1 (7.5 m3 ha-1 organic fertiliser) in the fourth season. The addition of increasing doses of potassium interfered with the wine grape quality, which is an important factor to be considered in relation to its acidity. Organic fertilisation did not affect the most quality characteristics of the grapes.

Effects of potassium fertilization on cesium-133 absorption by persimmon trees

In 2011, the Fukushima Daiichi Nuclear Power Station accident released radioactive materials, such as cesium (Cs), into the atmosphere and dropped onto agricultural land soil. Reducing radioactive Cs absorption from the soil is important for crop production. Therefore, persimmons were cultivated in pots with different amounts of potassium (K) fertilizer (+0 g, +20 g (standard level), and +40 g of K sulfate/pot), and the concentration of 133Cs in leaves and fruits was investigated. Additionally, the effects of phlogopite (materials expected to enhance K availability and radioactive Cs fixation in the soil) were investigated. K fertilization increased the exchangeable K concentration in the soil, and as the investigation continued, a significant difference in the K concentration in the leaves was observed. From the beginning of the 133Cs measurement, the 133Cs concentration in the leaves and fruits was significantly higher in the treatment without K fertilization. When the exchangeable potassium concentration in the soil was approximately 200 mg K2O kg−1 or less, the 133Cs concentration in the leaves tended to increase sharply. This suggests that controlling the Cs concentration in persimmon plants is possible by maintaining the exchangeable K concentration in the soil through K fertilization.