首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Abstract

Bragg soybeans [Glycine max. (L. ) Merill] were grown under field conditions near Sanford, Florida on a tile‐drained Immokalee fine sand (sandy, siliceous, hyperthermic Arenic Haplaquod). The objectives were: 1) to assess the K and P fertilizer requirements of soybeans grown in central Florida 2) to correlate soil and tissue nutritional levels with extractable soil nutrients and 3) to assess the influence of K application time on yield.

Experimental treatments were four K rates (0, 50, 100, and 200 kg K/ha), three P rates (0, 25, and 50 kg P/ha), and two sidedress K rates (0 and 50 kg K/ha) at early bloom. Treatments were arranged in a randomized complete block design and replicated four times.

Yield increased with each increase in applied K. Statistical maximum yield was obtained on plots which contained 103 ppm double‐acid extractable K during the pod‐filling stage of growth. Tissue K at early bloom exceeded 2.85% at maximum statistical yield. Potassium applied broadcast at early bloom did not significantly influence yield.

This soil contained approximately 390 ppm double‐acid extractable P prior to P application. No significant yield response to applied P was observed, indicating that the original extractable P content of the soil was adequate for the yield level obtained.

The quadratic regression of the ratio equivalents of double‐acid extractable K:Ca + Mg on the same ratio for the plant tissue is highly significant. This expression was a good predictor of tissue accumulation of these nutrients in that the coefficient for determination was 0.68.  相似文献   

2.
Abstract

Soil samples were obtained at 0–3, 3–6, 6–9 and 0–9 inch depths from experimental plots receiving five tillage treatments. Each of two samplers composited approximately six one‐inch cores from each plot. Soil samples were analyzed for acidity, P and K using routine analysis procedures in the University of Illinois Soil Testing Laboratory.

Few significant differences were attributed to sampler and it was concluded that samplers using similar sampling techniques were obtaining soil samples from the same population.

No significant differences in soil acidity at different depths were observed. The different tillage methods did significantly affect soil P at the 0–3 inch depth, but had no significant effect on soil P at deeper depths. Different tillage methods also significantly affected soil K values at different depths.  相似文献   

3.
Abstract

Results from a commercially available portable soil test laboratory were compared to standard soil test procedures used by a public soil testing laboratory. Standard soil tests examined were water extracted NO3‐N, pH, Acid‐P, NaHCO3‐P, and ammonium acetate extracted K. Approximately 35 to 55 different soils were used to compare methods for each soil test. Linear regression equations between the portable laboratory soil test values and those from the standard procedures were developed. The r2 values for NO3‐N, pH, Acid‐P, NaHCO3‐P, and K were 0.970, 0.891, 0.734, 0.742, and 0.887, respectively. The coefficient of variability values for NO3‐N, pH, Acid‐P, NaHCO3‐P, and K were 10, 1, 13, 15, and 6%, respectively for the portable laboratory, and 9, 2, 8, 9, and 5%, respectively for the public soil testing laboratory. Multiple regression was used to relate soil properties to soil test results. The R2 values for NO3‐N, pH, Acid‐P, NaHCO3‐P, and K were 0.970, 0.911, 0.860, 0.940, and 0.936, respectively.  相似文献   

4.
Abstract

The effect of soil pH on the exchangeability and solubility of soil cations (Ca, Mg, Na, K, and NH4‐N) and anions (NO3‐N, Cl, and P) was investigated for 80 soils, spanning a wide range in physical and chemical properties and taxonomic groups. This information is needed from environmental and agronomic standpoints to estimate the effect of changes in soil pH on leachability and plant availability of soil nutrients. Soils were incubated with varying amounts of acid (H2SO4) and base (CaCO3) for up to 30 days. Although acid and base amendments had no consistent effect on cation exchangeability (as determined by neutral NH4OAc), amounts of water‐soluble Ca, Mg, Na, K, NH4‐N, and P decreased, while NO3‐N and Cl increased with an increase in soil pH. The increase in cation solubility was attributed to an increase in the negative charge of the soil surface associated with the base addition. The change in surface electrostatic potential had the opposite effect on amounts of NO3‐N and Cl in solution, with increases in N mineralization with increasing soil pH also contributing to the greater amount of NO3‐N in solution. The decrease in P solubility was attributed to changes in the solubility of Fe‐, A1‐, and Ca‐P complexes. The logarithm of the amount of water‐soluble cation or anion was a linear function of soil pH. The slope of this relationship was closely related (R2 = = 0.90 ‐ 0.96) to clay content, initial soil pH, and size of the cation or anion pool maintaining solution concentration. Although the degree in soil pH buffering increased with length of incubation, no effect of time on the relationship between cation or anion solubility and pH was observed except for NO3‐N, due to N mineralization. A change in soil pH brought about by acid rain, fertilizer, and lime inputs, thus, affects cation and anion solubility. The impact of these changes on cation and anion leachability and plant availability may be assessed using the regression equations developed.  相似文献   

5.
Abstract

This research was undertaken on a paleudult soil in southern Brazil, 30° south latitude, to quantify lime and P effect upon soybean (Glycine max (L.) Merrill). A lime x P factorial experience with lime treatments of 0, 0.5, 1, and 2 times SMP interpretation to pH 6.5, and 0, 44, 88, 132, and 176 kg P/ha with 3 replications were installed. The experiment was conducted for 2 years (1973–74, 1974–75), with leaf‐N, P, and K; yield; seed‐N, P, and K; Bray P2 (0.03N NH4F + 0.1N HC1) avail‐able‐P and soil pH measurements completed each year. Data was evaluated with linear, quadratic, logarithmic, polynomial, segmented line, and multiple regression using the coefficient of determination as goodness of fit.

The best model fit between P treatment and Bray P2 available‐P was a quadratic equation; the model between relative yield and Bray P2‐P with 54% of the relative yield attributed to Bray P2 available‐P, a sigmented line. This model indicated point of maximum yield (91% relative yield) was obtained at 7.4 ppm‐P, with no increase in relative yield with increasing levels of soil available‐P. To calculate the P fertilizer necessary to increase available soil‐P to the level of maximum yield of equation Yp = [1639(7.4 ‐ xs)]1/2, where Yp = kg P/ha fertilizer needed; and xs = initial Bray P2 soil available‐P in ppm's. The lime effect upon soil pH was best described as a linear relationship. Yield increase with lime at this site was not significant at the 5% level.

The leaf‐N, P, and K increased significantly with soil available‐P levels. A second degree polynomial with logarithmic function best defined these relationships. The calculated DRIS indices and sum proved useful to evaluate the plant‐N, P, and K balance of each treatment.

Only seed‐P level was directly related to soil available‐P. Both seed‐N and seed‐K were highly correlated with indirect effects of soil available‐P levels.

Results from this study suggest the segmented line model would best interpret soybean yield response to Bray P2 available‐P for this soil. To obtain maximum yield using this model rather than the second degree polynomial would require less fertilizer P. Foliar analyses interpretation confirmed adequate plant‐P level would be supplied for maximum yield at this level of fertilization.  相似文献   

6.
Abstract

Corn (Zea mays L.) was grown for three consecutive years on Congaree loam to measure the effects of rates of N, P, and K fertilization and irrigation on the nutrient concentration of leaves, the level of available K in the soil, and on the yield of corn. Plant nutrients consisting of 0, 56, 140, 224, and 280 kg N/ha; 0, 15, 37.5, 60, and 75 kg P/ha, and 0, 28, 70, 112, and 140 kg K/ha were applied in a central composite rotatable design in each of the three years. All plant residue was removed each year when the corn was harvested, and the plots remained fallow during the winter months. One half of the experiment was irrigated when there was a 50% depletion of available soil moisture in the 0‐ to 46‐cm soil depth.

Leaf composition was affected by fertilization and irrigation. A rapid decrease in available soil K in the 0‐ to 15‐cm depth was evident the first year with all rates of added K. The decline in available soil K was unaffected by irrigation and levels of applied N and P.

There were consistent yield responses each year to added N, no response to added P, and a response to added K only during the second year.  相似文献   

7.
Abstract

An acid brown podzolic (pH 4.0) soil of wide distribution in Ireland was limed with Ca(OH)2 to pH values of 5.2 and 7.4. With each increment of lime significant increases in growth and F uptake by Italian ryegrass occurred, the increases being greatest with the first increment. Increasing soil pH resulted in decreased extractable aluminum and iron as well as exchangeable hydrogen. Available P as measured by various extractants increased with increasing soil pH.

The relative performance of three P fertilizers, superphosphate, phospal and basic slag was affected by liming. Basic slag was more effective than superphosphate at pH 4.0, was as effective at pH 5.2 and was less effective at pH 7.4. Phospal was poorest at each pH level. While growth and P uptake increased with increasing P levels the relative responses to the three fertilizers decreased with increasing soil pH.  相似文献   

8.
Abstract

Knowledge of the change in soil extractable phosphorus (P) as a consequence of soil P fertilization could be useful in discriminating soils with a potential for soil P release to runoff or movement of P along the soil profile. In this research, soils with low to medium P retention capacity were equilibrated for 90 days with soluble P (KH2PO4) at rate of 100 mg P kg‐1 soil. After this period, soil samples both with and without the P addition were analyzed using six conventional methods: 1) Olsen, 2) Bray 1,3) Mehlich3,4) Egner, 5) Houba, dilute CaCl2 solution, and 6) distilled water, and three “innovative”; P‐sink methodologies: 1) Fe oxide‐coated paper strip, 2) anion exchange resin membrane, and 3) cation‐anion exchange resin membrane. The soils without P addition had low levels of extracted P as determined by all nine procedures. Net increases in the amount of P extracted from the soils with added P ranged from 4.2 mg kg‐1 (CaCl2 extraction) to 57.6 mg kg‐1 (cation‐anion resin membrane extraction). Relationships between change in extracted P and i) physical and chemical characteristics, and ii) soil P sorption properties are also presented and discussed.  相似文献   

9.
Abstract

An understanding of how soil solution ionic strength (Is) and major cation activities influence crop growth is often limited by the extensive measurements required to characterize ionic composition and subsequent speciation exercises. Easily measured solution and soil attributes need to be identified that can predict these important solution parameters. Soil and soil solution chemical properties of four Ultisols in the Coastal Plain and Piedmont of North Carolina were used to develop models to predict ionic strength and solution cation attributes. GEOCHEM‐PC‐predicted Is was linearly related to electrical conductivity (EC) across soils (r2=0.92), confirming that Is for soil solutions with complex composition can be estimated from their electrical conductivity. Models of the form lnMs=a+blnEC+clnME, or modifications thereof, were developed for predicting solution aluminum (Al), calcium (Ca), magnesium (Mg), and postassium (K) levels (Ms) from a knowledge of EC and either soil exchangeable cation #OPME) or cation saturation (MSATE) attributes. For each cation, total and free solution concentration and activity in absolute and saturation terms were investigated. The best models explained, at most, 68% of the variability associated with total solution Al concentration (Als‐T) or 74% when Als ‐T was expressed as a percent of major solution cations. Greater than 85% of the variability associated with solution Ca and Mg could also be accounted for, but only 67% of the variability associated with solution K could be explained. Including soil pH and interaction terms (MExEC, MExpH, and ECxpH) in models improved the relationship for total Al concentration (R2=0.87) and solution Ca parameters (R2 ≥0.93), but not for solution Mg and K indices. None of the models could account for >30% of the variability associated with free concentration and activity of Al3+, suggesting that the prediction of these parameters for a particular Al species could not be made from a knowledge of soil pH, solution EC, and ME or MSATE data.  相似文献   

10.
Abstract

Commercial sugar cane (Saccharum qfficinarum) cultivation in Papua New Guinea started in 1979 at a plantation in the Ramu valley where Udifluvents and Hapluderts are the dominant soil types. The sugar cane is not irrigated and receives only nitrogen (N) fertilizers (±90 kg N ha‐1 y‐1). Changes in soil chemical fertility were assessed by comparing soil fertility data from the mid‐1980s and 1990s and by comparing soil fertility data from sugar cane and adjoining natural grassland. Between the mid‐1980s and 1990s the topsoil pH had declined significantly (p<0.001) by 0.3 units and this was accompanied by a decline in cation exchange capacity (CEC) of 34 mmolc kg‐1. Total N levels in the topsoils declined (p<0.001) from 2.5 to 1.9 g kg‐1 and available P from 36 to 27 mg kg‐1 during the same period. Exchangeable potassium (K) also declined significantly (p<0.05) with 1.3 mmolc kg‐1, but changes in exchangeable calcium (Ca) and magnesium (Mg) were not significant. The decline in soil fertility was highest in the topsoil although significant changes occurred up to 0.6 m depth. Total N decreased in the 0–0.15 and 0.15–0.30 m soil horizons, but increased in the lower horizons, possibly because of nitrate leaching. A similar degree of soil fertility decline was observed when soils under sugar cane and adjoining natural grassland were compared. However, the interrow had a slightly lower fertility level in comparison to within sugar cane rows. The decrease in total N, available phosphorus (P) and exchangeable K in the soil coincided with a decrease in the leaf N, P, and K concentrations of the sugar cane over the past 10 years. It was concluded that soil fertility had markedly declined under sugar cane monocropping although levels remained favorable for sugar cane cultivation. For sustainable soil management, nutrient inputs as well as small applications of lime may eventually be needed.  相似文献   

11.
Abstract

The relationship between water soluble and exchangeable cations (Ca, Mg, Na, and K) was investigated for surface horizons of 195 soils including many taxonomic categories and a wide range in physical and chemical properties from around the world. This will provide information on exchangeable soil cation solubility for use in estimating plant uptake and leaching potential. Amounts of water soluble and exchangeable cations were not consistently related (r2 of 0.50, 0.08, 0.77, and 0.49 for Ca, Mg, Na, and K). High correlations were biased by high water soluble and exchangeable cation levels of a few soils that had 3.8‐ and 2.5‐fold greater mean than median values. The ratio of exchangeable to water soluble cations was closely related to cation saturation (r2 of 0.87, 0.95, 0.95, and 0.93 for Ca, Mg, Na, and K, respectively). As the degree of saturation of the exchange complex by a certain cation increased, solubility Increased. A change in saturation had less effect on K than on Na, Mg, and Ca solubility. Only exchangeable soil cations (NH4OAc extractable) are routinely measured and reported in soil survey reports, thus, water soluble levels may be determined from cation saturation. This will allow estimation of the amounts of cation that can potentially move in solution through the soil or be taken up by plants. Use of cation saturation, in addition to exchangeable content, will better characterize soil cation availability by representing quantity, intensity, and buffer factors.  相似文献   

12.
Abstract

Irrigated potatoes were grown on a sandy soil which ranged in available P and K from 53 to 308 and 45 to 319 kg/ha, respectively. The levels of soil P and K as measured by soil test (Bray #1) were compared with yield, specific gravity of the tubers, and P and K tissue concentrations. The response of the potato crop was correlated to soil K but not to soil P. Yields increased with increasing soil K from 45 to 196 kg/ha in the surface sample and leveled off there after. The fact that the levels of subsoil K increased with increasing surface soil K may have had somewhat of an effect on the leveling off of potato yields at 196 kg/ha of K. The lack of a yield response to soil P was associated with adequate available soil P at the lowest soil test levels.  相似文献   

13.
Abstract

Phosphorus (P) and potassium (K) requirements of snap bean (Phaseolus vulgaris L.) in North Florida are not well defined in the literature. Response of a bush type snap bean to P and K was determined in a 2‐year test at NFREC, Quincy. The resulting data were used in site specific soil‐test interpretations. Residual soil‐P levels were 7, 11, 29, and 66 mg/kg the first yr and 7, 12, 21, and 42 mg/kg the second yr, no fertilizer K was added either yr. Residual soil‐K was 26, 60, and 73 mg/kg the first yr. Fertilizer K was added the second yr at 0,95, and 190 kg/ha. Soil samples were collected from each plot near the beginning of each growing season for determination of soil‐test P and K levels. Soil type was Norfolk loamy fine sand (fine loamy, siliceous, thermic, Typic Kandiudult). Maximum nutrient levels required for snap bean were: soil‐test P 30 mg/kg and soil‐test K 80 mg/kg. Soil‐test interpretations for P were: low <15 mg/kg, medium 15 to 30 mg/kg, and high >30 mg/kg. Potassium soil‐test interpretations were low <40 mg/kg, medium 40 to 80 mg/kg, and high >80 mg/kg.  相似文献   

14.
Abstract

Soil samples were collected under blight‐affected and healthy citrus trees at 30‐day intervals for 24 months, at 20‐to 50‐cm depth. Analyses of water extracts (1:1 soil: water) for K, Ca, Mg, Na, SO4, and Cl showed few differences in cations, but lower anion levels under blighted trees. The cation/anion ratio was significantly higher under blight‐affected trees. Samples collected once at different locations in the same time period showed the same differences. In one location, K was lower and Na higher under healthy trees than under blight‐affected trees, in others K was higher too.  相似文献   

15.
Abstract

Many soil extractants have been developed for determination of zinc (Zn) availability to plants. The optimum soil Zn extractant should be useful not only for prediction of plant Zn concentration but also for detection of applied Zn levels. The objectives of this study were: i) to compare soil Zn extradants for detecting applied Zn and for predicting peanut leaf Zn over a range of soil pH levels, and ii) to correlate other soil‐extractable Zn levels with Mehlich‐1. Soil and peanut leaf samples were taken from a field study testing pH levels as the main plots and Zn application rates in the sub‐plots. Extractable Zn was determined on soil samples using Mehlich‐1, Mehlich‐3, DTPA, MgNO3, and many dilute salt extradants of varied strength and pH. Correlation of extractable soil Zn to cumulative applied Zn levels revealed Mehlich‐1, Mehlich‐3, DTPA, and AlCl3 extradants to be among the best indicators of applied Zn. Leaf Zn concentration was best correlated with soil Zn extracted by dilute salts, such as KCl, CaCl2, NH4Cl, CaSO4, and MgCl2. Including soil pH as an independent variable in the regression to predict leaf Zn considerably improved R‐square values. The DTPA‐extractable soil Zn levels were very well correlated with Mehlich‐1‐extractable Zn. Mehlich‐3 extracted about 20% more soil Zn than Mehlich‐1, but Mehlich‐3 soil Zn was not as well correlated to Mehlich‐1 soil Zn as DTPA soil Zn. Lower pH solutions extracted more of the applied Zn, but more neutral solutions extracted Zn amounts which were better correlated with Zn uptake. On the other hand, Mehlich‐1, which had a lower pH, had better correlations with both applied Zn and leaf Zn than did Mehlich‐3. Shortening the DTPA extraction time to 30 minutes resulted in better correlations than the standard two hour extraction time. Chloride (Cl) was the best anion tested in relation to soil applied Zn recovery in combination with potassium (K), calcium (Ca), and aluminum (Al), and Cl optimized leaf Zn correlations for ammonium (NH4), K, Ca, and magnesium (Mg). The larger the valence of the cation, the better the correlation with applied Zn and the poorer the correlation with leaf Zn.  相似文献   

16.
Abstract

An established stand of Ranger alfalfa was topdressed with equal rates, but different combinations, of N, P, and K. Five harvests were taken and the material analyzed for cation concentrations.

Phosphorus application significantly increased P concentrations in alfalfa, but had little influence on concentration of other ions. Potassium applications showed striking effects by significantly increasing K levels of the forage while decreasing Ca, Mg, Cu, Zn, Al, and Mo levels.

Significant differences occurred among harvest dates for 14 of the 16 cations analyzed. Seasonal trends were evident for SiO2, Zn, Al, Co, and Na.

Applied N, P, and K and available soil P and K were associated with cation concentration of alfalfa and these interrelationships are discussed.  相似文献   

17.
Abstract

Selected chemical properties of an artificially acidified agricultural soil from northern Idaho were evaluated in a laboratory study. Elemental S and Ca(OH)2were used to manipulate the soil pH of a Latahco silt loam (fine‐silty, mixed, frigid Argiaquic Xeric Argialboll), which had an initial pH of 5.7. A 100 day incubation period resulted in a soil pH manipulation range of 3.3 to 7.0. Chemical properties evaluated included: N mineralization rate, extractable P, AI, Mn, Ca, Mg and K and CEC. N mineralization rate (assessed by anaerobic incubation) decreased with decreasing soil pH. Nitrification rate also decreased as NH4 +‐N accumulated under acid soil conditions. Sodium acetate extractable P was positively linearly correlated (R2= 0.87) with soil pH over the entire pH range evaluated. Potassium chloride extractable Al was less than 1.3 mg kg‐1of soil at pH values higher than 4.4. Consequently, potential Al toxicity problems in these soils are minimal. Extractable Mn increased with decreasing soil pH. Soil CEC, extractable Mg, and extractable K all decreased with increasing soil pH from 3.3 to 7.0. Extractable Ca levels were largely unaffected by changing soil pH. It is likely that the availability of N and P would be the most adversely affected parameters by soil acidification  相似文献   

18.
Abstract

An established stand of alfalfa was fertilized with different combinations of N, P and K. The rate used per nutrient was constant for all combinations. The study was conducted to evaluate the effect of fertilizer application, diurnal change and period to period fluctuation on the mineral composition of alfalfa. Two experiments were conducted at different stages of morphological maturity. Experiment one (E‐1) was initiated when regrowth after an initial hay harvest was in the late‐vegetative to early‐bud stage. The second experiment (E‐2) was initiated when regrowth from E‐1 was approximately 20 cm tall.

Phosphorus application significantly increased the P concentrations in alfalfa, but decreased the Cu levels in both experiments. Potassium applications significantly decreased the levels of Ca, Mg, Na, Cu, Zn, Mo and Co.

Levels of all minerals analyzed in E‐1 were significantly different from period to period while only seven of the sixteen were significantly changed in E‐2. Period to period differences were partially explained by rainfall pattern.

Significant diurnal variations were found for K, Ca, Mn, B, Sr, and Zn in E‐1 and for Ca, SiO2, and Sr in E‐2.

The N, P, and K applied and the P and K available in the soil were correlated with cation levels in alfalfa and the interrelationships were discussed.  相似文献   

19.
Abstract

Plots from a N, P, and K field fertility experiment were soil sampled each spring and fall from 1971 to 1979 to study the effect of cropping and different rates of added P and K on the content of available soil P and K (Bray I). Phosphorus and K fertilization was in the spring after soil sampling and before planting in 1971, 1972,and 1973 and in the fall after sampling in 1974, 1975, 1976, 1977, and 1978. Over the 8‐year period, available soil P increased 1 kg/ ha for every 2.3 kg/ha of added P; while available soil K increased 1 kg/ha for every 5.7 kg/ha of added K. However, within a growing season and between growing seasons, contents of available soil P and K showed cyclic patterns, increasing and decreasing to a greater extent than the long‐term response. Changes in available P and K from spring to fall and from fall to spring are presented. Variability in the content of available soil P and K for 32 plots receiving a similar treatment of either P or K was greater for P as compared to K.  相似文献   

20.
Abstract

Increasing soil bulk density has been shown to reduce root growth and decrease K uptake by soybeans (Glycine max L. Merrill). Changing soil bulk density also affects soil buffer power, b, and effective diffusion coefficient, De, which affect K influx. The relative decrease in K uptake due to reduced root growth as compared to reduced K influx is not known. Addition of P may affect root growth and P influx properties of plant roots. The objectives of this paper were (1) to use the Cushman mechanistic model to simulate the effect of changing soil bulk density and soil P on K uptake by soybeans, and (2) to determine the parameters that are changed by changes in bulk density and added P and their effect on K uptake. Plant and soil data of an experiment where Williams soybeans were grown for 21 days in pots of Raub (Aquic Argiudoll) silt loam with factorial treatments of two rates of K (0 and 100 mg K kg‐1 soil), two rates of P (0 and 100 mg P kg‐1 soil), and two bulk densities (1.25 and 1.45 g cm‐3 ) were used to verify the model. Plant and soil parameters for the model were measured independently of the verification experiment. Predicted K (y) uptake agreed with observed uptake (x) (y = 1.09x‐0.19; r = 0.97) for the P x K factorial and (y = 1.19X‐0.22; r = 0.90) for the K x soil bulk density factorial treatments. In a sensitivity analysis, the model predicted a maximal K influx at a soil bulk density of 1.38 g cm‐3. The greatest effect of soil bulk density on K uptake was due to reduction of root growth. Increased K uptake as a result of P addition was because of the effect on root growth.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号