scholarly journals Potassium Rates Affect Yield of Two Muskmelon Varieties in Florida

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 593a-593 ◽  
Author(s):  
Alvaro O. Pacheco ◽  
G.J. Hochmuth ◽  
D.N. Maynard ◽  
A.A. Csizinszky ◽  
S.A. Sargent
Keyword(s):  
Maximum Yield ◽  
Essential Elements ◽  
Soil Test ◽  
Current Recommendation ◽  
Marketable Yield ◽  
Minor Crops ◽  
Significant Yield ◽  
Yield Responses ◽  
Spring Yield ◽  
K Fertilization

Optimum economic yield is produced when nutrients in the proper amounts are supplied to the crop. Crop nutrient requirements (CNR) of essential elements have been determined for the major vegetables produced in Florida. However, for minor crops, such as muskmelon, little research has been conducted to determine the CNR, especially potassium. In many vegetables, yield has responded to increasing K rates when other elements were not limiting. Our objective was to determine the K fertility requirement for optimum yield of muskmelon and to evaluate the Mehlich-1 soil test calibration for soil testing low in K (<20 mg·kg–1). Experiments were conducted in the spring and fall seasons of 1995. Potassium at five rates (0, 56, 112, 168, and 224 kg·ha–1) was injected weekly, approximating the growth curve of `Galia' and `Mission'. There were significant yield responses to K fertilization for both cultivars during both seasons. During spring, average marketable yield was 14.5, 26.1, 31.9, 31.5, and 36.3 Mg·ha–1 and for fall, average marketable yield was 15.8, 32.9, 37.8, 37.2, and 36.4 Mg·ha–1 for the previously described K treatments, respectively. The cultivar response for both seasons was described by a linear-plateau model. In spring, yield was maximized with K at 116.8 and 76.3 kg·ha–1 for `Galia' and `Mission', respectively. In fall, K at 73.3 and 68.3 kg·ha–1 produced the peak response for the same cultivars. These results indicate that maximum yield of muskmelon in Florida can be obtained at considerably less K than the current recommendation of 140 kg·ha–1.

Phosphate and potash requirements of sugar cane in relation to soil chemical analysis and soil type

1966 ◽  
Vol 6 (23) ◽  
pp. 409
Author(s):  
ICR Holford
Keyword(s):  
Sugar Cane ◽  
Soil Type ◽  
Field Experiments ◽  
Soil Phosphorus ◽  
Soil Test ◽  
Mitscherlich Equation ◽  
Percentage Yield ◽  
Significant Yield ◽  
Highly Correlated ◽  
Yield Responses

The superphosphate and potassium chloride requirements of sugar cane were studied in relation to soil test levels on 25 different soil types in Fiji. Soil phosphorus was determined by a modified Truog method and soil potassium by extraction with 0.5N acetic acid. Percentage yields of sugar cane in fertilizer field experiments harvested over a five-year period were highly correlated with soil test levels in the control plots. The regressions of percentage yield on soil test level were curvilinear, and a modified Mitscherlich equation gave an excellent fit to the points. Critical soil test levels were found to exist, below which soils gave significant yield responses to applied nutrients. Critical soil test levels ranged over 5 to 20 p.p.m, for phosphorus and 51 to 150 p.p.m. for potassium. Within the deficient range of each nutrient there were only weak relationships between optimum fertilizer requirements and soil test levels. There was some evidence to suggest that soil type may be a useful complementary criterion for predicting fertilizer requirements.

scholarly journals Effects of repeated phosphorus fertilisation on field crops in Finland 1.Yield responses on clay and loam soils relation to soil test P values

2008 ◽  
Vol 15 (2) ◽  
pp. 106 ◽  
Author(s):  
I. SAARELA ◽  
Y. SALO ◽  
M. VUORINEN
Keyword(s):  
Ammonium Acetate ◽  
Field Studies ◽  
Soil Test ◽  
P Values ◽  
Extractable P ◽  
Soil Test P ◽  
Significant Yield ◽  
The Mean ◽  
Yield Responses ◽  
Phosphorus Fertilisation

In order to update phosphorus (P) fertiliser recommendations for the Finnish clay and loam soils enriched with applied P, the effects of repeated P fertilisation on the yields of cereal and other crops were measured at eight sites over a period of 12-18 years. Yield results of some earlier field studies were also used in calibrating the soil test P values determined by the Finnish acid ammonium acetate method (PAc). Significant yield responses to P fertilisation were obtained on soils which had low PAc values or medium levels of PAc and too low or too high pH values (< 6.0 or 7.5 in water suspension). The mean relative control yield (RCY, yield without applied P divided by yield with sufficient P multiplied by 100) of the eight sites was 94.6% (n = 128, mean PAc 15.5 mg dm-3) varying from 87% at PAc 2.8 mg dm-3 to 100% at high PAc. A PAc level of 5-7 mg dm-3 was adequate for cereals, grasses and oilseed rape on the basis of the RCY value of 95% at optimal pH. At this PAc replacing the amounts of P in the crops (14 kg in 4 t grain) and the fixation of extractable P (about 6 kg ha-1 a-1) produced almost maximum yields in favourable seasons and were considered optimal.;

Determining the fertiliser phosphorus requirements of intensively grazed dairy pastures in south-western Australia with or without adequate nitrogen fertiliser

2007 ◽  
Vol 47 (7) ◽  
pp. 801 ◽  
Author(s):  
M. D. A. Bolland ◽  
I. F. Guthridge
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Maximum Yield ◽  
Dairy Herd ◽  
Yield Response ◽  
Soil Test ◽  
Mineral N ◽  
P Leaching ◽  
The Many ◽  
Yield Responses

Fertiliser phosphorus (P) and, more recently, fertiliser nitrogen (N) are regularly applied to intensively grazed dairy pastures in south-western Australia. However, it is not known if applications of fertiliser N change pasture dry matter (DM) yield responses to applied fertiliser P. In three Western Australian field experiments (2000–04), six levels of P were applied to large plots with or without fertiliser N. The pastures were rotationally grazed. Grazing started when ryegrass plants had 2–3 leaves per tiller. Plots were grazed in common with the lactating dairy herd in the 6-h period between the morning and afternoon milking. A pasture DM yield response to applied N occurred for all harvests in all three experiments. For the two experiments on P deficient soil, pasture DM yield responses also occurred to applications of P. For some harvests when no fertiliser N was applied, probably because mineral N in soil was so small, there was a small, non-significant pasture DM response to applied P and the P × N interaction was highly significant (P < 0.001). However, for most harvests there was a significant pasture DM response to both applied N and P, and the P × N interaction was significant (P < 0.05–0.01), with the response to applied P, and maximum yield plateaus to applied P, being smaller when no N was applied. Despite this, for the significant pasture DM responses to applied P, the level of applied P required to produce 90% of the maximum pasture DM yield was mostly similar with or without applied N. Evidently for P deficient soils in the region, pasture DM responses to applied fertiliser P are smaller or may fail to occur unless fertiliser N is also applied. In a third experiment, where the soil had a high P status (i.e. more typical of most dairy farms in the region), there was only a pasture DM yield response to applied fertiliser N. We recommend that fertiliser P should not be applied to dairy pastures in the region until soil testing indicates likely deficiency, to avoid developing unproductive, unprofitable large surpluses of P in soil, and reduce the likelihood of P leaching and polluting water in the many drains and waterways in the region. For all three experiments, critical Colwell soil test P (a soil test value that was related to 90% of the maximum pasture DM yield), was similar for the two fertiliser N treatments.

PREDICTION DES BESOINS EN ENGRAIS N, P et K DES LEGUMES CULTIVES EN SOL MINERAL: LES CHOUX

1983 ◽  
Vol 63 (1) ◽  
pp. 113-123
Author(s):  
EMILE CHAMBERLAND
Keyword(s):  
Maximum Yield ◽  
Field Trials ◽  
N Fertilization ◽  
Yield Response ◽  
Brussels Sprouts ◽  
High K ◽  
Fertilizer Recommendations ◽  
Mineral Soils ◽  
Yield Responses ◽  
K Fertilization

The objective of this study was to verify and improve the accuracy of fertilizer recommendations for growing cole crops on mineral soils. To achieve this end, 21 field trials were conducted on 12 soils during 1978–1981; of these trials, 13 were performed with late cabbage and Brussels sprouts and eight early cabbage and brocoli. The test crops were fertilized at four rates of N, P and K, and yield responses were related to soil test values. The Cate-Nelson iteration method was used to partition soils into three different classes according to their yield response to fertilization. Furthermore, polynomial and Mitscherlich equations were fitted to yield versus soil K and P data. These procedures suggested that fertilizer recommendations would be more precise by classifying these crops into early- and late-maturing groups. Accordingly, the recommended fertilization rates for soils containing a deficient or medium P supply were 70 and 80 kg P/ha for early and late crops, respectively. A clear yield response by early cabbage to K fertilization was indicated for soils containing a medium K supply; on these soils maximum yields would be achieved with an application of about 180 kg K/ha. On the other hand late cabbage and Brussels sprouts apparently only needed about 120 kg K/ha to achieve maximum yields on the same class of soils. While an increase in yields attributable to K fertilization is unlikely on soils containing a low and high K supply, a rate of 120 kg K/ha is nonetheless recommended to ensure maximum yield and maintain soil fertility levels. As regards N-fertilization, maximum yields early and late crop were produced with 160 and 180 kg N/ha, respectively. Key words: Fertilizer, N, P, K, vegetables, cabbages

Soil properties as predictors of yield response of clover (Trifolium subterraneum L.) to added P in soils of varying P sorption capacity

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 653 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland
Keyword(s):  
Soil Properties ◽  
Response Curve ◽  
Maximum Yield ◽  
Trifolium Subterraneum ◽  
Stepwise Multiple Regression ◽  
Yield Response ◽  
Soil Test ◽  
Organic Carbon Content ◽  
Soil Test P ◽  
Yield Responses

Thirty-five unfertilised soils collected in south-western Australia were used to measure the effect of soil properties on (i) shoot yield responses of 50-day-old clover (Trifolium subterraneum L. cv. Nungarin) plants to applied phosphorus (P), and (ii) extractability of bicarbonate soil test P (slope of the linear relationship between Colwell P and the amount of P applied). Data for the relationship between shoot yield and the amount of P applied were fitted to a rescaled Mitscherlich equation to calculate the amount of P required to produce 50% and 90% of the maximum yield (P50% and P90%) and determine the curvature (c) and n coefficients of the equation. When the value of n is 1.00, the response curve is exponential, and as the value of n increases above 1.00 the response curve becomes more sigmoidal. The c, n, P50%, P90%, and extractability values were related to properties of the 35 soils.There was a significant (P < 0.05) trend for the values of c and extractability to decrease as the capacity of the soil to sorb P increased. Consequently, as the soil sorbed more P, the trend was that (1) more P needed to be applied to produce the same yield, so both P50% and P90% tended to significantly (P < 0.05) increase; (2) shoot yield responses to applied P became more sigmoidal so the value of the n coefficient tended to significantly (P < 0.05) increase; (3) more P needed to be applied to a soil to produce the same soil test P value; and (4) larger soil test P values were needed to produce the same yield. No single soil property adequately predicted P50%, P90%, extractability, c, or n. Stepwise multiple regression indicated that (1) clay content and P buffer capacity (PBC) of soil together accounted for 48% of the variation in P50%, 56% of the variation in P90%, and 52% of the variation in c; (2) PBC and soil pH together accounted for 17% of the variation in n; and (3) PBC, percentage clay and percentage organic carbon content of soil together accounted for 68% of the variation in extractability.

EFFET DE LA FERTILISATION POTASSIQUE SUR LE RENDEMENT DE LA POMME DE TERRE EN RELATION AVEC L’ANALYSE DU SOL

1982 ◽  
Vol 62 (2) ◽  
pp. 259-266 ◽  
Author(s):  
MARCEL GIROUX ◽  
W. VAN LIEROP
Keyword(s):  
Soil Fertility ◽  
Tuber Yield ◽  
Solanum Tuberosum L ◽  
Maximum Yield ◽  
Soil Test ◽  
Exponential Equation ◽  
Potassium Fertilization ◽  
The Relationship ◽  
K Fertilization

The effects of potassium fertilization on potatoes (Solanum tuberosum L.) grown on 40 experimental sites were related to tuber yields and soil test values. The data used in this work were gathered by seven research groups over a 25-yr period. Concentrations of exchangeable potassium (1 N NH4OAc, pH 7.0) in soils ranged from 28 to 462 kg K/ha. About 68% of the soils were classed as having a poor supply of available potassium, according to the criteria used until now in Quebec, because they contained less than 200 kg K/ha. A Mitscherlich exponential equation was fitted to the relationship between the percent of maximum yield and the concentration of available K in soils (R2 = 35.9%). The Cate-Nelson procedure was also used for ranking soils in three potassium fertility classes as indicated by their relative yields without K fertilization. The following classification of soil K levels was obtained: poor, soils containing less than 140 kg K/ha; intermediate, those containing between 141 and 300 kg K/ha; and sufficient, those containing more than 300 kg K/ha. The percent of maximum yield ranges obtained without K fertilization by these different soil fertility classes were: poor, from 34 to 98% with an average of 74%; intermediate, from 88 to 100% with an average of 95: and sufficient, from 93 to 100% with an average of 98%. The fertilization rates required to obtain or maintain maximum yields by these respective classes were 175, 130 and 80 kg K/ha. Potassium fertilization increased yields significantly on the soils that had a poor K supply only. Nonetheless, the average tuber yield indicated that a 5% increase in yield might be obtained with K fertilization on the intermediate soils and this increase would easily be profitable. Potassium fertilization of the soils classed sufficient would, however, only maintain soil fertility by supplying part of the K requirement of this crop.

Soil and tissue tests to predict pasture yield responses to applications of potassium fertiliser in high-rainfall areas of south-western Australia

2002 ◽  
Vol 42 (2) ◽  
pp. 149 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. J. Cox ◽  
B. J. Codling
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Test Method ◽  
Yield Response ◽  
Soil Test ◽  
Test Procedures ◽  
Pasture Production ◽  
Yield Responses

Dairy and beef pastures in the high (>800 mm annual average) rainfall areas of south-western Australia, based on subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum), grow on acidic to neutral deep (>40 cm) sands, up to 40 cm sand over loam or clay, or where loam or clay occur at the surface. Potassium deficiency is common, particularly for the sandy soils, requiring regular applications of fertiliser potassium for profitable pasture production. A large study was undertaken to assess 6 soil-test procedures, and tissue testing of dried herbage, as predictors of when fertiliser potassium was required for these pastures. The 100 field experiments, each conducted for 1 year, measured dried-herbage production separately for clover and ryegrass in response to applied fertiliser potassium (potassium chloride). Significant (P<0.05) increases in yield to applied potassium (yield response) were obtained in 42 experiments for clover and 6 experiments for ryegrass, indicating that grass roots were more able to access potassium from the soil than clover roots. When percentage of the maximum (relative) yield was related to soil-test potassium values for the top 10 cm of soil, the best relationships were obtained for the exchangeable (1 mol/L NH4Cl) and Colwell (0.5 mol/L NaHCO3-extracted) soil-test procedures for potassium. Both procedures accounted for about 42% of the variation for clover, 15% for ryegrass, and 32% for clover + grass. The Colwell procedure for the top 10 cm of soil is now the standard soil-test method for potassium used in Western Australia. No increases in clover yields to applied potassium were obtained for Colwell potassium at >100 mg/kg soil. There was always a clover-yield increase to applied potassium for Colwell potassium at <30 mg/kg soil. Corresponding potassium concentrations for ryegrass were >50 and <30 mg/kg soil. At potassium concentrations 30–100 mg/kg soil for clover and 30–50 mg/kg soil for ryegrass, the Colwell procedure did not reliably predict yield response, because from nil to large yield responses to applied potassium occurred. The Colwell procedure appears to extract the most labile potassium in the soil, including soluble potassium in soil solution and potassium balancing negative charge sites on soil constituents. In some soils, Colwell potassium was low indicating deficiency, yet plant roots may have accessed potassum deeper in the soil profile. Where the Colwell procedure does not reliably predict soil potassium status, tissue testing may help. The relationship between relative yield and tissue-test potassium varied markedly for different harvests in each year of the experiments, and for different experiments. For clover, the concentration of potassium in dried herbage that was related to 90% of the maximum, potassium non-limiting yield (critical potassium) was at the concentration of about 15 g/kg dried herbage for plants up to 8 weeks old, and at <10 g/kg dried herbage for plants older than 10–12 weeks. For ryegrass, there were insufficient data to provide reliable estimates of critical potassium.

EFFECTS OF NITROGEN, PHOSPHORUS, POTASSIUM, AND MANURE FACTORIALLY APPLIED TO POTATOES IN A LONG-TERM STUDY

1973 ◽  
Vol 53 (2) ◽  
pp. 205-211 ◽  
Author(s):  
W. N. BLACK ◽  
R. P. WHITE
Keyword(s):  
Solanum Tuberosum L ◽  
Starch Content ◽  
Leaf Tissue ◽  
Soil Test ◽  
Term Study ◽  
Long Term Study ◽  
Soil Test P ◽  
Yield Responses ◽  
Nitrogen Phosphorus

The effects of N, P, K, and manure factorially applied to potato (Solanum tuberosum L.) yields, starch content, and soil and tissue nutrient levels were evaluated on continuous plots over 12 yr in a 4-yr potato, grain, hay, hay rotation. Although yield responses were observed with N, P, and K applications, manure application substantially increased yields above yield levels due to applied N, P, and K. Increasing rates of KCl strongly depressed tuber starch contents. Soil test P and K levels increased with repeated fertility applications, and leaf tissue levels were increased with N, P, and K treatments.

Effects of Application Method and Rate on Control of Sclerotinia Blight of Peanut with Iprodione and Fluazinam1

2001 ◽  
Vol 28 (1) ◽  
pp. 28-33 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson
Keyword(s):  
Disease Control ◽  
Disease Incidence ◽  
Maximum Yield ◽  
Wide Band ◽  
Yield Response ◽  
Application Method ◽  
Sclerotinia Blight ◽  
Progress Curve ◽  
Application Methods ◽  
Yield Responses

Abstract Two trials with iprodione and three trials with fluazinam were conducted to assess the effects of application method and rate on the control of Sclerotinia blight of peanut with fungicide. In order to concentrate the fungicides near the crown area where the disease causes the most damage, applications were made through a canopy opener with a single nozzle centered over the row to achieve a 30.5-cm-wide band (canopy opener), and through a single nozzle centered over the row to achieve a 46-cm-wide band (band). Broadcast applications were compared to these methods at rates of 0, 0.28, 0.56, and 1.12 kg/ha on the susceptible cultivar Okrun. Sclerotinia blight was severe, with &gt; 70% disease incidence and &lt; 2000 kg/ha yield for the untreated controls in each trial. Linear reductions in area under the disease progress curve (AUDPC), but not final disease incidence, with iprodione rate were significant (P &lt; 0.05) for all methods of application. However, the rate of decrease did not differ among application methods. Linear increases in yield with rate of iprodione were greater for canopy opener compared to the band or broadcast applications. Only a 50% reduction in AUDPC and a maximum yield of &lt; 2700 kg/ha was achieved with iprodione using the best method. At the maximum rate of 1.12 kg/ha, fluazinam provided &gt; 75% disease control and &gt; 4000 kg/ha yield for all application methods. Differences in disease control and yield among application methods only occurred at the 0.28 and 0.56 kg/ha rates of fluazinam. Reductions in AUDPC with fluazinam rate were quadratic for all application methods, but AUDPC values were less for the canopy opener and band methods at 0.28 and 0.56 kg/ha compared to the broadcast methods. The yield response to rate for broadcast applications of fluazinam was linear. However, predicted yield responses to fluazinam rate were quadratic for the band and canopy opener methods and approached the maximum response at 0.84 kg/ha. Targeting fungicide applications using the band and/or canopy opener methods was beneficial for fluazinam at reduced rates. Disease control with iprodione was not adequate regardless of application method.

scholarly journals Finnish trends in phosphorus balances and soil test phosphorus

2008 ◽  
Vol 16 (4) ◽  
pp. 301 ◽  
Author(s):  
R. UUSITALO ◽  
E. TURTOLA ◽  
J. GRÖNROOS
Keyword(s):  
Agricultural Soils ◽  
Animal Production ◽  
Plant Production ◽  
Major Influence ◽  
Soil Test ◽  
P Loss ◽  
P Concentration ◽  
Soil Test P ◽  
Soil Test Phosphorus ◽  
Yield Responses

Soil test phosphorus (P) concentration has a major influence on the dissolved P concentration in runoff from agricultural soils. Thus, trends in soil test P partly determine the development of pollution potential of agricultural activities. We reviewed the changes of soil test P and P balances in Finnish agriculture, and assessed the current setting of P loss potential after two Agri-Environmental Programs. Phosphorus balance of the Finnish agriculture has decreased from +35 kg ha–1 of the 1980’s to about +8 kg P ha–1 today. As a consequence, the 50-yr upward trend in soil test P concentrations has probably levelled out in the late 1990’s, as suggested by sampling of about 1600 fields and by a modelling exercise. For the majority of our agricultural soils, soil test P concentrations are currently at a level at which annual P fertilization is unlikely to give measurable yield responses. Soils that benefit from annual P applications are more often found in farms specialized in cereal production, whereas farms specialized in non-cereal plant production and animal production have higher soil test P concentrations. An imbalance in P cycling between plant (feed) and animal production is obvious, and regional imbalances are a result of concentration of animal farms in some parts of the country. A major concern in future will be the fate of manure P in those regions where animal production intensity is further increasing.;

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