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1.
Abstract

In a fertilizer trial in a Valencia orange orchard, two soil types were distinguished: a poorly aerated loamy sand (A) and sandy clay loam (B). Mineral composition of leaves and fruit quality characteristics differed significantly in the two soil types, regardless of the fertilizer treatments. Fruits on the sandy clay loam were larger, had a thicker peel, and contained more total acids and vitamin C in the juice, and were less affected by a peel disorder (creasing). The leaves of such trees contained more K and Mg and less Ca and P.  相似文献   

2.
Abstract

Variations in the plant growth media were achieved by combining kaolinite clay (<lμm esd.), silt (2–50μm esd.) and sand (100–250 μm esd.) in various ratios. Peds of different sizes were separated from an Okolona clay soil and used as a growth media. A layer (3 cm thickness) of the sand, silt or clay and their combinations were intercalated between sandy loam soil material in a lucite coated cardboard carton. After 21 days the plants were harvested and analyzed for a number of growth parameters and related to the physical and micromorphology of the central control layer.

Germination and emergence of sorghum seed were delayed in the finer aggregates. An increase in aggregate size increased the root elongation. An examination of thin sections showed that most of the roots in the finer aggregates were grown in interpedal regions whereas in the larger aggregates roots were found in both the intrapedal as well as interpedal regions.

An increase in clay content of the central layer reduced the root growth. Silt also reduced root growth but not to the extent of the clay. Maximum root growth and penetration occurred in the mixture containing about 50 percent sand. Better root growth was observed in a sandy to sandy loam texture than clay to clay loam texture.  相似文献   

3.
Abstract

Field trials were established on a loamy fine sand and a silt loam using snapbeans and soybeans as test crops, respectively. Row fertilizer was placed with the seed (seed‐placed). Treatments were arranged in a 3×3×3 factorial experiment, and N, P, and K were applied in all combinations at three rates (0, 3.4, and 6.8 kg/ha). Ammonium nitrate (AN), monoammonium phosphate (MAP), concentrated superphosphate (CSP) and potassium chloride (KCl) were used as sources of N, P and K. Additional treatments compared MAP with diammonium phosphate (DAP) and KCl with potassium nitrate (KNO3).

The salt index of each treatment was inversely related to emergence, i.e. as the salt index increased, the emergence decreased. Level of N was more important than level of P or K in regards to reduction in emergence. Snapbeans grown on a loamy fine sand were extremely sensitive to damage from seed‐placed fertilizer, even at rates as low as 3.4 kg/ha of N, P or K. Soybeans planted on a silt loam soil were less sensitive than snapbeans planted on a loamy sand. The soybeans were able to tolerate up to 10.2 kg/ha of seed‐placed P plus K or 6.8 kg/ha of seed‐placed N plus P or N plus K without causing a significant delay in emergence.  相似文献   

4.
Abstract

A greenhouse experiment was conducted to determine the effect of peat moss‐shrimp wastes compost on barley (Hordeum vulgare L.) grown on a limed loamy sand soil. A control, four rates of compost applied alone and in combination with three rates of nitrogen, phosphorus, and potassium (NPK) chemical fertilizer were evaluated. Applications of compost to limed soil substantially enhanced the growth of barley over the control. When considering all treatments, the main effect of compost rates on straw yield, numbers of tillers, plant height, and number of ears was more important than that of fertilizer. A significant interaction on barley growth parameter values was obtained with compost and fertilizer rates. A combination of moderate application of compost and fertilizer gave in some instances, more yield than compost or fertilizer applied alone. Nutrient content of barley increased with rate of compost applied to soil over the control. A significant relationship was found between soil organic carbon (C) and straw yield, number of tillers, plant height and number of ears whereas grain yield was correlated with soil total N. Results from this study indicate that peat moss‐shrimp wastes compost could represent a potential means of renovating low fertility sand soils.  相似文献   

5.
Abstract

Field experiments were conducted on Maraval clay loam (fine, kaolinitic, isohyperthermic Oxic Tropudalfs) and River Estate sandy clay loam (fine loam, micaceous, isohyperthermic Fluventic Eutropepts) in Trinidad and Tobago to determine the effect of rate of nitrogen (N) in the presence and absence of phosphorus (P) and potassium (K) on the growth, yield, and plant tissue nutrient content for chive (Allium spp.) grown for the fresh market. Nitrogen had a significant effect (p<0.001) on the average number of tillers/plot, the average number of leaf blades/plot and subsequently on the marketable yield (p<0.05) of the crop. Application of low rates of applied N (67 kg/ha) gave the highest values although there being significant differences (p<0.005) between soils with higher values recorded on the River Estate clay loam. On the Maraval clay loam, application of increased N had no positive effect on tissue N except in the presence of P and K fertilizers. Significant differences (p<0.05) were obtained for the plant tissue nutrient content between treatment and between soils, except in the case of plant tissue K content where no significant differences were obtained between soils.  相似文献   

6.
Abstract

Coker 7473 wheat (Triticum aestivum L.) was grown on Keo silt loam (coarse‐silty, mixed, thermic Dystric Fluventic Entrochrepts) with four S sources applied at various rates for two years. The innate S level of this soil was not adequate for optimum grain yield; therefore, additional S significantly increased grain yield and S concentration and decreased N/S ratios in wheat tissue. Minimum S concentration and N/S ratios in plant tissue for maximum yield ranged from 1.3 to 2.73 g S/kg and 9.5 to 19.2, respectively.  相似文献   

7.
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   

8.
Abstract

Extraction of soil zinc with routine chemical extractants does not always reflect differences in Zn availability as detected by plant uptake. This study was undertaken to explore and compare the use of an ion exchange resin and diethylenetriaminepentaacetic acid (DTPA) for extracting soil Zn as related to plant Zn uptake. Beans were grown in 1989 following differential cropping with corn and beans or fallow in 1988 on a Portneuf silt loam near Kimberly, Idaho. Two Zn fertilizer treatments were imposed across previous cropping treatments. A batch method for determining resin extractable soil Zn was established.

Both plant Zn concentration and Zn uptake by beans in 1989 were significantly higher in Zn fertilized than unfertilized treatments regardless of previous crop; and higher in plots previously cropped with corn than beans or fallow, regardless of Zn treatment. DTPA and resin extractable soil Zn were significantly higher in Zn fertilized plots compared to unfertilized plots but did not differ between previous cropping treatments. Resin and DTPA extractable soil Zn concentrations were positively correlated. Resin extracted soil Zn correlated better with plant Zn concentration and Zn uptake throughout the growing season than DTPA extracted soil Zn, particularly in plots that had been fallowed or previously cropped with corn. Resin may be extracting labile soil Zn not extracted with DTPA and, therefore, be better simulating plant uptake. Both extraction methods correlated better with Zn uptake when evaluated within cropping treatments, emphasizing the need to consider previous crop when calibrating soil tests.  相似文献   

9.
ABSTRACT

A greenhouse experiment was conducted to determine the bioavailability of copper (Cu) in clay loam and sandy clay loam soil. Lettuce (Lactuca sativa) and spinach (Spinacia oleracea) were grown in pots for 45 d. When mature, plants were treated for 15 additional days with 0, 100, 250, 500, or 1000 mg Cu kg?1 as CuSO4·5H2O. After harvest, Cu in soils and plant tissues was determined. In soils, applied Cu raised total and EDTA-extractible Cu. Results also revealed that the amounts of Cu extracted from sandy clay loam soil (80%) were higher than those extracted from clay loam soil (70%). In plants, increasing soil Cu concentration increased plant concentration of the metal. Plant species vary in their capacity for Cu accumulation: Lettuce has a relatively higher potential for Cu uptake and translocation than does spinach. Cu accumulation also differs among plant organs. In lettuce, metal accumulation is higher in roots than in shoots, where 60% to 80% of the total Cu of the plant is located in the roots. However, in spinach, there is no significant difference in Cu content between roots and shoots. The transfer of the metal from soil to plant is higher for plants grown on sandy clay loam soil. For a given rate of applied Cu, metal content in plant tissues is higher on sandy clay loam soil due to its higher transfer coefficient (CT) from soil to plant. Nevertheless, all crops studied showed a positive linear relationship between extractible soil Cu and plant Cu.  相似文献   

10.
Agriculture is a major source of phosphorus (P) and suspended sediment (SS) losses to aquatic ecosystems promoting eutrophication. Mechanical soil loosening equipments such as topsoil looseners or aerators have been reported to improve the physical quality and infiltration of soils susceptible to livestock damage resulting from treading. We hypothesized that soil aeration would significantly decrease the volume of surface runoff and consequent losses of P and SS compared with non‐aerated soil (control) in cattle‐grazed pasture on a poorly structured silt‐loam soil. Hydrologically isolated plots (2 m long × 1 m wide × 0.15 m deep) were installed in aerated and control plots to collect surface runoff following irrigation or rainfall and analysed for P and SS losses for 1 year. Soil physical properties [% macroporosity, bulk density, saturated hydraulic conductivity (Ksat) and unsaturated hydraulic conductivity (Kunsat at ?1kPa)] were measured in the aerated and control treatments and taken before each irrigation event (n = 12). Six months after mechanical aeration was employed, but before cattle grazing commenced, no significant differences in soil physical quality were found between aerated and control treatments, with the exception of a minor increase in Kunsat for the control plots. This lack of treatment difference continued after grazing and was largely attributed to the re‐settling of the poorly structured and dispersive soil. Flow‐weighted mean concentrations and annual loads of dissolved reactive P (DRP) on the mechanically aerated soil (2.24 kg DRP/ha) were approximately double those from the control treatment (1.20 kg DRP/ha). However, no significant differences were observed between treatments for surface runoff volumes and losses of total P and total SS, which may reflect the similar soil physical conditions exhibited between treatments throughout most of the trial. As observed elsewhere, time (days) since grazing or fertilizer application was found to influence P and/or SS losses. We conclude that aeration did not decrease P and SS losses. Any changes in soil physical properties such as macroporosity were short‐lived and therefore unlikely to influence surface runoff and subsequent P and SS losses for this soil type.  相似文献   

11.
Abstract

The relationship of Cu and Zn fractionation in soils to plant growth was investigated on a Sassafras sandy loam (fine‐loamy, siliceous, mesic Typic Hapludult) and a Joppa gravelly sandy loam (loamy‐skeletal, siliceous, mesic Typic Hapludult). Pot studies were conducted in the greenhouse exposing corn (Zea mays cv. Silver Queen) to concentrations of 0, 100, 200, and 400 mg brass powder/kg soil. The corn was grown over a two week period, during which time individual plant heights were taken to note differences in plant growth. Data showed that plant height was reduced when the concentration of brass powder in the soil was increased. Total and fractionated Cu and Zn levels in the soils were analyzed and compared to height. Regression equations showed a more explicit relationship between height and exchangeable Cu levels rather than other Cu and Zn levels in the two soils. Additionally, a more pronounced effect was seen in plants grown on the Sassafras sandy loam, which was attributed to differences in soil physicochemical properties.  相似文献   

12.
Abstract

Sudangrass (Sorghum sudanense, ‘Piper’ Stapf) was grown in the greenhouse in a slightly calcareous sample of Shano silt loam. The purpose of the study was to evaluate plant response to Mg and to determine any changes in Mg nutrition following individual or composite application of Mg, Ca, K and Na as nitrate compounds. The concentration of Mg in plant tissue decreased following K application and increased with each increment of Mg applied irrespective of variations in the proportions of Ca and Na included in the treatments. A base treatment including Ca, Na, and K applied with or without Mg showed a significant yield response to Mg. The Mg response was attributed to a more favorable ionic balance in the growth medium with respect to Mg because the soil was not particularly Mg deficient. Application of Mg in this case lowered the plant K concentration significantly, increased the concentration of Mg, and gave a lower K/(Ca+Mg) ratio in the foliage than was obtained without Mg. Results suggest that high levels of other nutrient cations may adversely affect the Mg nutrition of crops growing on alkaline soils not abundantly supplied with available Mg.  相似文献   

13.
Abstract

A new method was proposed for assessing the difference in the capacity of soils to supply Cd to plants. The relation of tissue (tc) to soil (sc) Cd concentrations can be expressed as; log(tc) = α+βlog(sc), where α and β are the regression coefficients. When the same plant is grown on another soil, the equation will change to; log(tc) = α'+β'log(sc’). Based on both equations, the relationship between sc‘and sc becomes; log(sc’) = (α‐α')/β’ + (β/β') log(sc). Set p = (α‐α')/β’ and q = β/β’, then the difference of Cd availability between two soils can be evaluated according to the values of p and q. The p and q values were determined among four treatments in which radish was grown on a sand soil and a silty loam soil at two pH levels. The values showed that the Cd present in the sand soil (pH 5.6) and the metal in the silty loam soil (pH 7.5) were the most and least available, respectively. It was therefore considered that the parameters p and q could be used as criteria for selecting an ideal extractant capable of removing the actually available Cd from soils.  相似文献   

14.
Abstract

Treatments of P, Zn and Fe fertilizers were added to a Zn deficient Wisner silty clay loam soil. Sanilac bean plants were grown as the Zn responsive test crop and tissue samples were taken 5 weeks after planting for early growth and Zn uptake responses. At maturity, yield data were obtained and composite samples of beans were taken for determination of protein quality as evaluated by percentage of N, percentage of crude protein and relative contents of essential amino acids. A growth and Zn uptake response was obtained to ZnSO4, ZnNTA and FeNTA fertilization at both P levels, while a yield response to the same treatments was obtained only at high soil P (448 kg/ha) levels. The percentage N, percentage crude protein and relative contents of essential amino acids did not change as a result of P, Zn or Fe fertilization even when yields were tripled due to Zn fertilization.  相似文献   

15.
Abstract

Field studies were conducted to determine the influence of ammonia fertilization on cotton grown in conservation tillage systems. The studies were located on a Decatur silt loam (Rhodic Paleudult) in the Limestone Valley and a Norfolk sandy loam (Typic Paleudult) in the Coastal Plain of Alabama. Winter annual legumes, crimson clover (Trifolium incarnatum L. at the Norfolk site) and hairy vetch (Vicia villosa Roth at the Decatur site) were established as whole plots along with a winter fallow area. Sources of fertilizer differing widely in their NH4+‐N contents were used for split plot treatments applied at time of cotton (Gossypium hirsutum L.) planting. Fertilizer treatments included calcium nitrate, ammonium nitrate, urea, urea with dicyandiamide, and a no N check. The cotton was planted with a strip‐till conservation planter. Nitrogen production by winter legumes was adequate to meet N requirements for cotton on the Decatur silt loam (67 kg N/ha) but not at the Norfolk sandy loam site (101 kg N/ha). Cotton populations were 24% higher in fallow than legume whole plots. Differences in plant growth and N concentrations were highly variable and treatment trends were not found. Seed cotton yields were 4% higher in fallow than legume plots. Maximum populations and yields were achieved with ammonium nitrate in fallow area and urea in legume areas.  相似文献   

16.
Abstract

The effect of different concentrations of cobalt added to two soil types, a sandy and a sandy loam soil, was studied on growth performance and tissue cobalt concentration of wheat plants. DTPA‐extractable cobalt was significantly higher in the sandy soil than in the sandy loam soil. Plants grown in the sandy soil accumulated significantly higher amount of cobalt in comparison to plants grown in the sandy loam soil. Roots were significantly richer in cobalt than shoots in both the soil types. Lower (1 μg g‐1) administration of cobalt resulted in an enhancement in the growth whereas higher (5–625 μg g‐1) addition inhibited growth. A significant inverse relationship between relative wheat yield and tissue cobalt concentration was observed. The results indicate a possible requirement of cobalt for higher plants.  相似文献   

17.
《Journal of plant nutrition》2013,36(12):2591-2602
ABSTRACT

No boron (B) deficiencies have been reported for rice (Oryza sativa L.) grown in the United States and, when occurring elsewhere, reports often lack details of deficiency symptoms and leaf-B critical values. An experiment was conducted to determine the effect of B and lime on yield, pollen viability, and to determine diagnostic symptoms of B deficiency in rice. Rice cv. “Bengal” was grown in the greenhouse on a soil acquired from a rice farm from SW Louisiana in the United States, a Caddo silt loam (Caddo sl) (Typic Glossaqualf, fine-silty, siliceous, thermic), treated with 0.44?mg?B?kg?1 (+B) or no B (?B). Split plots were limed at rates of (i) none; (ii) 224?mg?kg?1 CaO+40.3?mg?kg?1 MgO; and (iii) 673?mg?kg?1 CaO+121?mg?kg?1 MgO. Rice was also grown in ?B and +B potting media and in ?B sand culture using nutrient solution identical to that used in other studies of ours. Rough-rice yields from the +B Caddo sl treatment was 11% higher than from the ?B treatment (29.3 vs. 26.3?g?pot?1; P=0.02). The yield increase was likely due to fewer damaged pollen (8%) found from the +B than the ?B treatment (17%; P=0.014). Leaf-B at tillering was 11.3?mg?kg?1 for the B-treated rice and 7.1?mg?kg?1 from the ?B treatment. Liming did not significantly affect leaf B or yields. Boron deficiency symptoms were found only in the ?B sand-culture where yields were 1.1?g?pot?1, 96% less than that from the +B Caddo sl. Symptoms were like those found in our earlier hydroponic studies with twisted and whitish leaf tips starting at tillering and 1-cm white bands across the width of leaves. Maturity was delayed about four weeks. Boron deficiency from the Caddo sl and sand treatments occurred with leaf B≤7?mg?kg?1 and with a Caddo sl soil B of 0.18?mg?hws (hot-water soluble) B?kg?1. Given that no B deficiency symptoms were found in rice experiencing moderate yield loss grown on the rice soil, one must rely on soil and plant analyses to help detect likely candidates for moderate B deficiency.  相似文献   

18.
Abstract

The objective of this study was to evaluate the usefulness of measures of mineralized sulfur (S), soil sulfate‐sulfur (SO4‐S), concentration of S in plant tissue, and the N: S ratio in plant tissue as predictors of the need for S in a fertilizer program for corn (Zea mays L.). Data to evaluate the use of plant analysis for S as a predictor were obtained from ten sites where various rates of N and S were applied to corn. Regression analysis was used to relate the S concentration in the ear leaf tissue as well as the N: S ratio in the same tissue to relative yield when the rate of applied N was held constant at a rate of 168 kg/ha. These measures of S in plant tissue were not significantly related to relative yield at sites where there was no response to fertilizer S as well as sites where added S increased yield.

Data from the same sites were used to assess the ability of soil tests to predict the need for fertilizer S. A measurement of extractable SO4‐S in the surface soil (0–15 cm) was not reliable for predicting the need for S for corn grown on soils with a silt loam texture.

Static incubation techniques were used to evaluate the amount of S mineralized from soil collected from seven sites. The amount of SO4‐S measured after four and twelve weeks of incubation was curvilinearly related (p <.05) to yield increase from a S fertilizer. Net mineralized S was less than 2.1 and 3.7 ppm SO4‐S after four and twelve weeks of incubation, respectively, for soils taken from sites where response to fertilizer S was obtained. Data collected in this study indicate that a measure of mineralized S could improve the ability to predict S needs for corn production on soils with a silt loam texture and a low organic matter content.  相似文献   

19.
Abstract

A discrete and an integrated sampling procedure were used to determine ‘ L ‘ values for maize plants grown in a soil. In the discrete procedure a plant was grown in a sand culture labelled with 33P solution and then transferred in a soil which was labelled with 32P. In the integrated sampling procedure plants were grown entirely in a P label led soil.

The discrete procedure permits point of time observation so that changes in the equilibrium between solution and surface P and mineralization rates can be monitored.  相似文献   

20.
Abstract

Winter wheat (Triticum aestivum L.) occupies large hectarage and is important in crop rotations on the highly weathered, low organic matter silt loam soils common in southern Illinois and the southern midwest United States region. Sulfur (S) is an essential element with some potential for deficiency, but it is not commonly applied to winter wheat grown on these soils. This study was conducted to determine if S nutrition is limiting winter wheat growth and grain yield. Interactive effects of topdressed fertilizer S (0 and 28 kg S/ha), tillage (disk‐till, DT and no‐till, NT), and wheat variety on plant growth, nutrient concentration, and grain yield were investigated for three crop years on two soils in southern Illinois; Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualf), Brownstown site, and Grantsburg silt loam (fine‐silty, mixed, mesic Typic Fragiudalf), Dixon Springs site. Grain yield was unaffected by S application although flag leaf and whole plant S concentrations increased. Lack of yield response to S application was consistent each year on both soils and across all varieties and tillage systems. Equivalent yields were produced with both tillage systems at Brownstown, but slightly lower yield occurred with no‐till at Dixon Springs. Plant S concentrations and soil sulfate levels indicated sufficient S was available from sources other than fertilizer S, including extractable soil S and atmospheric deposition. Wheat variety consistently influenced plant nutrient composition and grain yield more than tillage or application of S fertilizer. If, in the future, wheat grain production, atmospheric S deposition, and extractable soil S remain at levels measured in this study, then S fertilizer applications would not be expected to increase winter wheat grain yield.  相似文献   

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