Differential potassium buffer behavior of individual soils related to potassium corrective treatments

Abstract

Although the basic chemistry and behavior of potassium in the soil is well understood, little of this knowledge is used in soil testing and practical soil fertility mangement. In this study the K buffer behavior of three individual soils (Hagerstown silt loam (Typic Hapludalf), Gatesburg sand (Entic Haplorthod) and Gilpin channery silt loam (Typic Hapludult)) was investigated. The buffer relationships determined indicated very different K behavior for these soils even though exchangeable K soil tests indicated similar K levels. It was also determined that for these soils the buffer relationship was apparently independent of previous K management, indicating that the K buffer behavior could be included as part of soil characterization data.

The role of nonexchangeable K in determining K buffer behavior was also investigated. It was found that the levels of solution K where the release of nonexchangeable K becomes measurable (0.27 ‐ 0.83 × 10^‐4 M) are similar to solution K levels reportedly required for crop growth (0.02 ‐ 0.95 × 10^‐4 M). It was also found that these soils were capable of maintaining a relatively high level of exchangeable K even after extraction of significant amounts of nonexchangeable K with sodium tetraphenyl boron.

It was concluded that K buffering behavior of individual soils could and should be included in K management decisions involving corrective soil treatments and/or crop removal estimation. Otherwise, based on current soil tests, soils with very different K buffer behavior will be treated similarly.     

Potential potassium buffer capacity of Kamchatka volcanic soils

The volcanic soils of Kamchatka are characterized by low and very low values of their potential potassium buffer capacity. The largest amount of readily exchangeable potassium (-ΔK ₀) is observed in the surface layers of the natural soils and is due to the active biogenic accumulation. The soddy horizons have a high content of strongly fixed potassium (K _X ). The main factors determining the content of the labile potassium and its mobility are the contents of physical clay, humus, and exchangeable potassium. The extremely nonuniform distribution of all the potassium status parameters throughout the soil profile reflects the discrete character of the volcanic pedogenesis. The low values of the potential buffer capacity for the potassium (PBC^K) at the high values of the equilibrium potassium potential (AR ₀) and the medium content of the labile potassium in the light-textured synlithogenic soils simultaneously indicate both the good potassium supply of the plants and the incapability of the soils to resist potassium exhaustion under agricultural production conditions for a long time.     

Effect of increasing potassium levels for alleviating sodium chloride stress on the growth and yield of tomato

Abstract

The efficacy of using various levels of potassium (K) (4, 8, and 16 mM) under saline conditions to alleviate the detrimental effects of salt‐stress were studied using five tomato (Lycopersicon esculentum Mill) cultivars, ‘Strain 19’, ‘Pearson’, ‘Montecarlo’, ‘Maruthuam’, and ‘Pusa Rub’. Results of the study revealed that 50 mM sodium chloride (NaCl) in a Hoagland nutrient solution significantly reduced stem height, fruit weight, and whole plant dry weights, but increased number of fruits/plant and improved fruit quality by increasing total soluble solids. It did not significantly affect leaf count, percent fruit set, or dry weight. The addition of 4, 8 and 16 mM potassium nitrate (KNO₃) to the nutrient solution containing 50 mM NaCl resulted in sodium/potassium (Na/K) ratios of 12.5, 6.3, and 3.1, respectively. The Na/K ratios of 12.5 and 6.3 produced significant improvement in stem height, percent fruit set, number of fruits/plant, fruit weight, and whole plant dry weight. The Na/K ratio of 3.1 was found to be detrimental as it resulted in sharp reduction of plant dry weight compared to the control. Percent total soluble solids was not significantly affected by the addition of any level of K to the saline nutrient solution. The performance of the tomatoplant grown under saline conditions supplemented with K in the nutrient solution indicated a higher response at the lowest K concentration used in this study.     

Influence of surfactants on potassium uptake and yield response of cotton to foliar potassium nitrate

Foliar potassium (K) applications are intended to supplement soil K uptake, and thereby, increase cotton (Gossypium hirsutum L.) yields. Considerable research has been conducted to evaluate yield response to foliar K, but research evaluating surfactant effects on foliar uptake has been limited. Research was initiated in West Tennessee in 1991 to evaluate effects of foliar applied potassium nitrate (KNO₃) with and without surfactants on leaf and petiole K concentrations and on lint yield. Field research was conducted on three sites over a four year period using upland cotton ‘DPL 50’. Treatments included a check (no foliar treatment), 4.1 kg K/ha in water, 4.1 kg K/ha with Penetrator Plus, 4.1 kg K/ha with X‐77, 2.0 kg K/ha with Penetrator Plus, and 2.0 kg K/ha with X‐77. Surfactants were added to KNO₃ solutions at 1.25% v/v for Penetrator Plus and 0.5% v/v for X‐77. Kinetic was substituted for X‐77 after 1991 and was applied at 0.12% v/v. Cotton leaves and petioles were collected one, three, and seven days after each foliar application for K concentration determinations. Applying 4.1 kg K/ha (high‐K rate) as KNO₃ in water increased four‐year average leaf K but not petiole K concentrations in tissue collected 24 h after treatment relative to the check. Applying the high‐K rate with a surfactant increased the four‐year average concentration of leaves and petioles collected one, three, and seven days after application relative to the check or to the high‐K rate applied with water. Increases in both leaf and petiole K concentrations varied with year, with significant increases in two of the four years of the study. Yearly K concentrations of the day‐one and day‐three petioles were higher after applying the high‐K rate with Penetrator Plus relative to the check. Petiole K was not increased by applying low‐K rates with surfactants or the high‐K rate in water. First harvest lint yields were generally unaffected by foliar treatments. Second harvest and total yields were increased by applying the high‐K rate with Penetrator Plus relative to the other treatments. Yield responses may have been due in part to the nitrate anion (NO₃‐) being applied with the K+ cation, but higher K concentrations generally accompanied higher yields. These results suggest that surfactants may enhance K uptake and yield, but that more research is needed to determine why responses vary from year to year.     

The relationship between grain yield and plant potassium concentration in Lupinus angustifolius cv. Unicrop

Abstract

The relationship between potassium concentration in the plant at various growth stages and the grain yield of L. angustifolius cv. Unicrop was derived from a rates and times of application of KCl field trial.

Critical levels were defined as those associated with 90% of maximum yield. Critical % K levels in the whole tops were 3.1 at the 4–6 leaves stage, 2.9 at 8–10 leaves, 1.5 at first flowering, 1.2 with flowers on higher order laterals and 0.9 post flowering.

The effect of plant part sampled was examined at early flowering. Critical levels at that stage were 1.2% K for petioles 1–5, 0.6% K for petioles 6–10, 1.3% K for leaves 1–5, 0.5% K for leaves 6–10 and 2.1% K in the growing point of the plant.

Grain K concentrations were very insensitive to changes in supply, and are of little use as a diagnostic tool. The ratio of K concentration in pods to that in seeds increased from 0.5 under extreme deficiency to 1.3 under conditions of adequate supply, and should be a useful diagnostic tool at maturity.     

Potato yield and quality under potassium and gypsum levels in southeastern Brazil

Abstract

This work was established to study the effects of sources and levels of potassium (K) along with gypsum and the residual effects of K on growth and yield of two potato (Solanum tubrosum L.) cultivars. Two experiments were conducted under field conditions at the experimental station of “Sao Sebastião do Paraíso”; Southeastern Minas Gerais, Brazil. Tuber quality, yield components, and branches and leaves mineral composition were analyzed. In the first year, using the ‘Monallsa’ cultivar, there were significant effects of treatments on plant height, tuber dry matter, and plant mineral composition. In the second year, using the ‘Achat’ cultivar, the K application plus residual gypsum from the first year reduced plant physiological anomaly known as tuber cracking.     

Effects of crop residue incorporation and inorganic potassium fertilization on soil potassium supply power

Crop residues can be used as an effective replacement for inorganic potassium (K) fertilizers. However, the impact of the type and quantity of crop residue on soil K supply capacity in different soil types remains poorly known. To investigate the effects of crop residue incorporation rate and inorganic K fertilization on apparent K balance and soil K supply capacity in cotton-wheat cropping system, we conducted two, six-year field experiments on two soil types in Nanjing and Dafeng, China. At both sites, crop residue incorporation ameliorated the negative K balance and improved the soil water-soluble, exchangeable, and non-exchangeable K (WSK, EK, and NEK) contents. The soil WSK, EK and NEK contents were positively correlated with the net K accumulation at both sites across two soil layers. However, the correlations between net K accumulation and quantity-intensity related parameters varied with the soil types. Treatment with wheat straw (9000 kg ha^?1) + cotton residue (7500 kg ha^?1) at both sites performed better than the 300 kg K₂O ha^?1 treatment in terms of balancing soil K depletion and keeping adequate K fertility status. Incorporation of adequate crop residues performed similarly to inorganic potash in improving the soil K supply power.     

Effect of potassium and boron upon yield and nutrient concentration of alfalfa

An alfalfa experiment was conducted to determine the effect of rates of K applied in the fall and rates of K applied, one‐half in the fall and one‐half after first harvest, upon yield and chemical composition. Three rates of B applied in the fall and also one‐half in the fall and one‐half after first harvest at the highest K rate (560 kg/ha) were also included. Herbage samples were taken from each plot at each harvest and analyzed for N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn. Significant effects of fertility upon yield and nutrient content were observed. Harvest x fertility interactions also affected many parameters. The Cu concentration of herbage was relatively uniform and not significantly affected by any factors studied.     

Diversity of boron-toxicity tolerance in lentil growth and yield

Boron (B) toxicity is increasingly being recognized as a problem in arid areas of West Asia, where lentil is widely grown. This study investigated whether or not: (1) phenotypic variation of B-toxicity tolerance exists at the seedling stage in lentil, (2) such variation persists to affect adult performance, and (3) there is geographical diversity in seedling tolerance. Four experiments were conducted in a greenhouse. Boric acid was added and mixed uniformly into the soil-mix to prepare high-B soil. Experiment I screened 77 lentil lines randomly selected from ICARDA's international nurseries. Visual growth scores and foliar B-toxicity symptom scores were taken 4–5 weeks after sowing, and used as an indicator for B-toxicity tolerance. In Experiments II and III, four selected lines were studied beyond the seedling stage. In Experiment IV, 231 lentil accessions from seven different countries/regions of the world were screened. There were highly significant differences between the 77 lines in B-toxicity tolerance at the seedling stage as indicated by their degree of B-toxicity symptom, and plant growth. The two tolerant and two sensitive selections from Experiment I showed diverse performance up to maturity as reflected by their differences in leaflet loss, dry mass reduction, and seed yield when grown in high-B soil. There were significant differences in B-toxicity tolerance between the 231 accessions. On average, accessions from Afghanistan were the most tolerant, followed by those from India, Iraq, Syria, Europe, Ethiopia, and Nepal.     

氮磷钾不同用量对马铃薯产量和淀粉含量的影响

采用311－A最优设计与田间试验方法,研究了氮、磷、钾施肥用量对马铃薯产量和淀粉含量的影响,建立了宁夏雨养农业区马铃薯产量、淀粉含量与氮、磷、钾施肥用量之间的数学模型。分析了马铃薯产量及淀粉含量试验因子的主效应和互作效应,优选了马铃薯目标产量在30000 kg/hm2时最高产量的最佳施肥量组合为氮、磷、钾(kg/hm2)：267.3－139.0－82.1,最佳经济施肥用量组合为氮、磷、钾(kg/hm2)：258.6－131.1－71.1;淀粉含量最高时最佳组合氮、磷、钾( kg/hm2)：183.9－106.4－87.6。     

The growth and the respiration in roots of sweet potato plants under a moderate potassium deficiency

A seven days' culture of sweet potato plants under a deficient potassium application induced various metabolic disturbances in the roots (1,2) and the leaves (3). Prolonged cultures of taro (4), broad bean plants (5), and barley (5) suggested that a half level of the normal potassium content in roots might be a critical point of K -deficiency resulting in a higher respiration rate than its normal status. Such a temporary enhancement of respiration accompanied by accumulation of amino-N and reducing sugars may not necessarily contribute to the accumulation and the assimilation of salts, but accelerate the disturbance of plant metabolism to cause early death of the tissues. This work deals with supplemental data on the effects of K -deficiency on the plant growth and the respiration in roots, comparing these effects in a 15 days' culture of sweet potato plants with those in a longer term culture of other plant species (4,5).     

The effects of foliar applied potassium in the mineral form and complexed with amino acids on pistachio nut yield and quality

A two-year field experiment was conducted to investigate the effects of foliar-applied K in the form of mineral compound (K₂SO₄) and complexed with lysine (KL) and lysine plus methionine (KLMet) with or without ascorbic acid (A) on nut yield and quality of bearing pistachio (Pistachio vera L. cv. Owhadi). Results showed that foliar application of K, regardless of applied source, significantly increased leaf and nut K concentration in comparison with control. In both experimental years, the trees supplemented with K provided higher total yield, fresh and dry mass of shelled and unshelled 100-nut, and 100-kernel dry mass and lower percentage of non-split shells in comparison with those un-supplemented with K. In both years, foliar application of K significantly decreased the percentages of blank nuts. The effectiveness of K-amino chelates in improving nut yield and quality was, in general, higher than that of K₂SO₄. The highest yield and the best nut quality was obtained with foliar application of KLMet-1. The critical leaf and nut K concentration for optimum pistachio nut yield and quality was 2.27 and 1.87%, respectively. Foliar application of K particularly in the form of KLMet-1 during nut filling is recommended to obtain optimum yield and quality of pistachio.     

Enhancement of salinity tolerance in tomato: Implications of potassium and calcium in flowering and yield

Abstract

Five tomato (Lycopersicon esculentum Mill) cultivars were grown in sand nutrient culture experiment in a greenhouse to investigate the effects of salinity on growth and yield. Nutrient solutions were made saline with 50 mM NaCl (EC = 5.5 mS/cm or supplemented with 2 mM KNO₃ (EC = 6.8), 20 mM Ca(NO₃)₂ (EC = 7.5), and combination of potassium (K) and calcium (Ca) (EC = 8.0). Seedlings were irrigated with saline treatments commencing two weeks after transplanting. Determination of sodium (Na) and K in tomato leaves and fruits were by flame photometry. Accumulation of Na in tomato fruits was higher than in leaves under control or saline conditions for all tomato cultivars. The amount of K in the tomato leaves was higher in control than in saline‐grown plants. Addition of K and Ca to the nutrient solution resulted in a 3 to 7 fold increase in K accumulation in all cultivars tested. Stem and leaf growth were significantly reduced with salinity but growth was enhanced following irrigation when K was added to the nutrient solution. Flowering and fruit set were adversely affected by NaCl stress. Reduction of flower number was 44% relative to the control plants. Fresh fruit yield decreased by 78% when plants received 50 mM NaCl. Growth and development of tomatoes under saline conditions was enhanced in this study following the application of K to the saline nutrient solution. Amelioration in growth was also achieved when Ca was used but to a lesser extent. Our results suggest that ion accumulation and regulation of K and Ca contribute to salt tolerance and growth enhancement.     

Effects of nitrogen,phosphorus, and potassium nutrition on yield,rates of kernel growth and grain filling periods of two corn hybrids

Abstract

Depression of corn grain yields from nutrient stress has been studied extensively, but effects of nutrient stress on rates of corn development and yield determinants are less well understood. Nutritional effects on the number of kernels/unit area, growth rate/kernel, and duration of growth have implications concerning fertilization practices and yield potentials of crops. Two corn hybrids with equivalent silking dates but having different grain filling periods were grown in a field experiment. Fertility treatments consisted of a N series receiving 0, 112, or 336 kg of N/ha and a P‐K series receiving factorial combinations of 0, 22, or 112 kg of P/ha and 0, 56, or 224 kg of K/ha. Dates for grain initiation and maturity were determined for each plot along with tissue analyses of ear leaves, grain yields, and kernel weights. Concentrations of N and K in ear leaves generally corresponded to treatment levels of these nutrients, although Pioneer Hi‐bred 3390 appeared to be less efficient than Pioneer Hi‐bred 3334 in K uptake. Effects of nutrient stress on yield determinants depended on the determinant and nutrient under consideration. Severe N stress did not change length of grain filling periods, but decreased kernel numbers 30 to 70%. Stress for K, on the other hand, shortened grain filling periods about 13% and had only a slight effect on kernel number. Negligible P stress occurred in the experiment. The two hybrids produced equal quantities of grain/ha/day but the hybrid with a longer filling period (Pioneer 3334) filled many more kernels at a slightly slower rate and for a longer period of time to give a significantly greater grain yield compared to Pioneer 3390.     

The influence of soil microorganisms on growth of cereal seedlings and on potassium uptake

The comparative influence of soil microorganisms, aerial contaminants and Bacillus subtilis on growth and potassium nutrition was studied in Zea mays and other cereals under aseptic growth conditions. Soil microorganisms, but not aerial contaminants, markedly modified root morphology and growth. Potassium uptake and translocation, measured by ⁸⁶Rb as a tracer, were enhanced by growth in the presence of a soil inoculum although the relative influence on uptake and translocation varied from inoculum to inoculum. Similar metabolic changes were not found in seedlings inoculated with aerial contaminants.     

氮、钾肥运筹对马铃薯经济性状与产量的影响

为优化马铃薯氮、钾肥运筹,提高产量和商品薯率,2009年进行在施肥总量一定的情况下,马铃薯氮、钾肥不同时期不同比例配合施用的试验。结果表明,不同氮、钾肥运筹对马铃薯生育期影响较小,但对马铃薯经济性状和产量影响较明显,优化氮、钾肥运筹,能有效改善经济性状和提高产量,采用氮40%作基肥、40%作齐苗肥、20%作现蕾肥,钾60%作基肥、40%作现蕾肥时效果最佳,马铃薯综合经济性状和商品性好,产量最高。     

Root growth,nutrient uptake and yield of soybean cultivars grown in the field

Abstract

Soybean (Glycine max L. Merr.) cultivars differ in their root morphology and their nutrient uptake capabilities. The relation between root growth, P and K uptake, and grain yield was investigated using eight cultivars grown in the field on Raub (Aquic Argiudoll) silt loam which received 49 kg P/ha and 93 kg K/ha. Hobbit (maturity group III, determinate) was among the highest in grain yield, P and K uptakes, and root system length. However, this cultivar was intermediate in its relative efficiency to utilize P and K to produce grain yield; among the most efficient cultivars were Asgrow 3127 (maturity group II) and Williams‐79 (maturity group III). The hay cultivar, Wilson‐6, was the least efficient. It was concluded that even though grain yield was correlated with nutrient uptake, selection for higher yields was not necessarily a selection for higher efficiency in utilization of fertilizer for grain production.     

Effect of nitrogen on growth,flower yield,oil composition,and yield in boronia megastigma nees

Four forms of nitrogen (N), isobutylidene diurea (IBDU), urea, ammonium nitrate (NH₄NO₃), and calcium nitrate [Ca(NO₃)₂] were applied to boronia plants at three rates of application (25, 50, and 100 kg N/ha) either as a single application in late October or in two equal applications, one in October and the other in early January. Two sites and two clones were investigated, growth measurements were taken on one site on a regular basis throughout the year, and flowers were harvested in September. Leaf N, flower N number of nodes, and flower and oil yields as well as the percent volatiles and ß‐ionone content of the oil were positively correlated with increased rates of N application. Ammonium nitrate and Ca(NO₃)₂ gave the highest yields for both clones. IBDU and urea were partially toxic to Clone 5 at 100 kg N/ha which was thought to be due to an inability to detoxify ammonium (NH₄) rather than a low nitrate reductase activity. This results of this experiment provides guide lines for N management in the future.     

Effect of nitrogen application on growth and yield of pumpkin

Evaluation of any crop response to different nitrogen amounts is important for determining the amount that can be considered as optimum from economical and environmental point of view. This study was conducted to (1) evaluate the growth and yield of pumpkin (Cucurbita pepo L.) under different nitrogen rates and (2) determine the nitrogen use efficiency (NUE) of pumpkin in two growing seasons (2013 and 2014). In both growing seasons, nitrogen fertilizer (at three rates including 50, 150, and 250 kg ha^?1) was band-dressed on the planted side of each furrow, coinciding with 4–6 leaves stage and flowering. Crop performance over 2 years was evaluated by measuring shoot dry matter, crop growth rate (CGR), leaf area index (LAI), leaf area duration (LAD), intercepted PAR (PAR_i), radiation use efficiency (RUE), shoot nitrogen uptake, water use efficiency (WUE), NUE, and fruit and seed yield. The results showed that in both growing seasons, the highest growth and yield of pumpkin were obtained by applying 250 kg N ha^?1 (using urea fertilizer containing 46% nitrogen). Increased nitrogen rate from 50 to 250 kg ha^?1 resulted in 87.3%, 27.0%, 62.1%, 87.5%, and 84.5% increase in shoot dry weight, RUE, WUE, fruit yield, and seed yield of pumpkin, respectively, across both growing seasons. However, higher application nitrogen rate decreased the NUE of pumpkin, i.e., the NUE decreased by 62.5% when the nitrogen rate increased from 50 to 250 kg ha^?1. The effect of nitrogen applied in 2014 growing season on growth and yield of pumpkin was higher than that in 2013 growing season, which might be due to more suitable weather condition. In conclusion, the nitrogen rate of 250 kg ha^?1 produced the highest amount of fruit and seed yield in pumpkin.     

The buffer effect and the selection of protected areas for waterbirds in Britain

The buffer effect predicts that where the reproductive success and survivorship of a species vary between potential habitats, sites will be sequentially filled according to a preference hierarchy. Once favoured sites reach saturation, numbers on the less-suitable/poorer quality sites will show a greater rate of increase compared with those on favoured sites. Supporting evidence for a buffer effect is readily available in the literature for many species, although this is generally restricted to small-scale analyses. In this paper we test for a buffer effect on a national scale for 19 species of waterbirds regularly wintering in the UK for which populations have increased nationally. The results provide little support for the effect, with only four species showing significant negative correlations. Nonetheless, a number of factors are likely to confound the occurrence/identification of a buffer effect for these species, including site area and data limitations. By contrast, for the majority of these 19 species, those sites where initial population totals are largest are also those with the fastest rates of population increase. Encouragingly, these sites are, therefore, more likely to be classified and managed as Special Protection Areas (SPAs) or Ramsar sites using the current numerical criteria for identifying such conservation areas.