Alfalfa Responses to Combined Use of Lime and Limiting Nutrients on an Acidic Soil

An on-farm field experiment was conducted on an acidic soil to investigate the effects of combined use of lime and deficient nutrients on herbage yield of alfalfa (Medicago sativa L.). Omitting lime and limiting nutrients led to elevated concentrations of aluminium (Al), iron (Fe), and manganese (Mn) in alfalfa leaves and stems and caused severe reductions in herbage yield of alfalfa. Combined use of lime (2 t ha^?1) and nutrients [phosphorus (P): 20 kg ha^?1, sulfur (S): 20 kg ha^?1, zinc (Zn): 4 kg ha^?1, and boron (B): 2 kg ha^?1] had the maximum increase in groundcover, root biomass, nodulation, leaf retention, leaf-to-stem ratio, herbage yield, crude protein, and nutrient composition of alfalfa. These beneficial effects were due to raised soil pH; improved calcium (Ca), P, S, Zn, and B nutrition; and reduced Al, Mn, and Fe toxicity. Aluminium and all the nutrients except copper (Cu) were more concentrated in alfalfa leaves than stems.

Aluminum concentration was about three times greater in the lower leaves than in upper leaves. Lower leaves also had much greater concentrations of Ca, Mg, K, S, Fe, Mn, Cu, and B compared with upper leaves. In contrast, P and Zn concentrations were greater in the upper leaves than in lower leaves. Results suggest that the combined use of lime and all the limiting nutrients may realize potential beneficial effects of alfalfa on acidic soils where more than one essential nutrient is deficient. This may increase growth potential, nitrogen contributions, and groundcover by alfalfa and reduce soil erosion and runoff.     

Pressurized Hot Water and DTPA‐Sorbitol as Viable Alternatives for Soil Boron Extraction. II. Correlation of Soil Extraction to Responses of Boron‐Fertilized Alfalfa

Abstract

Pressurized hot water and DTPA‐Sorbitol are two relatively new, proposed alternative soil boron (B) extraction methods for which no data on yield or plant nutrient uptake have been reported for validation. Both methods initially have shown significant correlation with the hot water extraction method in untreated soils as well as soils incubated with various levels of B. The objective of the research was to extract samples of B‐treated soils by using all three extraction methods and correlate the B values obtained to yield, B tissue concentration, and total B removal of alfalfa (Medicago sativa). Greenhouse and field experiments on alkaline and limed acid soils naturally low in hot water‐extractable B were conducted to test alfalfa response to B fertilizer. In the greenhouse, highly significant relationships exist between plant uptake and extractable B with all three methods at varying levels of applied B, but no alfalfa yield response was observed. All three methods result in accurate predictions of plant B tissue concentrations and total B removal. The field experiment exhibited a significant positive relationship between total alfalfa yield and extractable B using hot water and pressurized hot water extractions. Extractable B using DTPA‐Sorbitol was not related to total alfalfa yield in the field experiment. This work, coupled with the earlier incubation studies, supports the pressurized hot water extraction method as an improvement over hot water in diverse soil types. The lack of relationship in the acid soil supports DTPA‐Sorbitol as an improvement over hot water in alkaline soils.     

Improvement of boron soil test

Abstract

Boron soil tests often do not adequately reflect B plant uptake or deficiency levels in the Eastern United States. In an attempt to develop a better test, the following systems were studied: Silicic acid replacement of boron; B soil buffering power; and the addition of small quantities of boron (0.175 ugB/g‐soil) to each soil sample to overcome some of the stronger boron fixing sites prior to hot water extraction.

Boron extracted with B spiked hot water (r=0.80 for plant tissue B vs. extractable B, opposed to r=0.76 for nonspiked hot water) was the only new test that showed promise.

The results appear to explain why hot water extractable B correlates well with plant uptake for soils previously treated with boron fertilizer (e.g. alfalfa fields); but why, on the other hand, hot water extractable B fails to correlate well with plant boron uptake for soils not having a recent history of boron fertilization. . . in which some fixing sites apparently have to be satisfied before the hot water test will work well.     

Micronutrient topdressing of alfalfa (medicago sativa L.) on a udollic albaqualf

Abstract

An established stand of alfalfa (Medicago sativa L.) was topdressed with two rates each of borax, zinc sulfate, and copper sulfate at two levels of applied P and K. Yields and plant composition were determined at five harvests over two seasons. Treatments were not effective in increasing yields but topdressing with B and Zn increased the concentration of these elements in the plant tissue. The Cu concentration in alfalfa tissue was not affected by topdressing with copper sulfate. Phosphorus application rates of about four times removal rates were needed to maintain the Bray 2 soil test level of the soil.     

Boron,molybdenum and selenium status in different plant parts in forage legumes and vegetable crops 1

This study was conducted in Prince Edward Island (P.E.I.), Canada to characterize the levels of B, Mo, and Se in the various plant parts of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), broccoli (Brassica oleracea var. italica Plenck.), Brussels sprouts (Brassica oleracea var. gemmifera Zenker), cauliflower (Brassica oleracea var. botrytis L.), and rutabaga (Brassica napobrassica Mill). The three micronutrient anions were consistently highest in the leaves and lowest in the stems. The lower halves of the vegetable crops usually contained close to the highest amounts of B and Mo. In forage legumes, the B concentration was higher in the bottom than in the upper leaves, but B was lower in the bottom than upper stems. Since leaves consistently contained the highest amounts of B and Mo, it is recommended that most recently matured leaves in the Brassica species, and young leaves in forage legumes be sampled to characterize the B and Mo status of these crops. Selenium is of significance to livestock, but not in plant nutrition; therefore, only the parts fed to animals, e.g. the whole vegetative tops of forage legumes, should be used to determine the crop Se status.     

Inclusion of nitrate and nitrite in the Kjeldahl nitrogen determination of soils and plant materials using sodium thiosulphate

Abstract

Soil applications of boron were applied shortly before transplanting dormant strawberry plants into the field in early April. Composite samples of ‘Benton’ and ‘Tristar’ grown under soil applied B fertilizer rates of 0, 1.1, 2.2, and 4.5 kg/ha B were taken during June, August, and September in 1985. ‘Benton’ plants were resampled in April 1986. Tissue concentrations and dry weights were determined for up to ten plant parts. Concentrations decreased over time. Differences in B content between treatments were greatest early in the season and gradually disappeared. The amounts of boron in different plant parts were similar by September for ‘Tristar’ and in the following spring for ‘Benton’. Even though total boron content in strawberry plants could be doubled with the high boron application, little change occurred in nonleaf tissues. Approximately 90% of the additional boron in a plant resulting from soil application of B was found in the leaves. Total B content of nonleaf tissues was similar regardless of B treatment. Interpreting boron concentrations was difficult because all plant parts were signficantly correlated to leaf concentrations, even though total boron uptake of nonleaf tissues did not differ between treatments. Elevated B concentrations were partly due to decreases in dry weight. Leaf tissue analysis did not accurately indicate B status of other plant parts and tissue concentrations can be misleading if total B contents are not evaluated.     

Alfalfa responses to foliar and soil applications of manganese

Abstract

Manganese (Mn) deficiency often occurs in crops grown on well‐limed sandy soils of the Atlantic Coastal Plain region of the United States. This study was conducted to compare the responses of established alfalfa (Medicago sativa S.) to various application methods of manganese sulfate (MnSO₄) fertilizer. Experiments conducted in farmers’ fields at three New Jersey locations determined the effects of applied Mn on forage yield, tissue Mn concentration, and leaf chlorophyll meter readings. An untreated control was compared to the following treatments: foliar Mn applied once before each harvest, foliar Mn applied twice before each harvest, and a one‐time broadcast Mn application in April Or May at 22.4 kg Mn/ha to the soil surface. The rate of foliar Mn used in 1990 was 1.12 kg Mn/ha and in 1991 was 0.56 kg Mn/ha at each treatment time. Forage yield increases were greater with foliar than soil‐applied Mn but there were no differences between foliar‐applied Mn treatments. Total seasonal forage yields were increased (P<0.05) at all three locations with foliar‐applied Mn but at only one location with soil‐applied Mn. When averaged across all locations, forage yields were 6.4% higher than the control for the foliar‐applied Mn treatments compared to 2.9% higher for the soil‐applied Mn treatment. A Mn concentration of 21 mg/kg was determined as the critical level in the upper 15 cm of alfalfa tissue at the early bloom growth stage. Foliar Mn applied twice between harvests most effectively increased tissue Mn concentrations. Soil‐applied Mn initially increased tissue Mn concentration, but there was little long‐term benefit from this treatment. Applied Mn was observed to improve leaf color and chlorophyll meter readings of Mn‐deficient alfalfa. Results indicate that foliar Mn applied before each harvest was a more effective treatment for correction of Mn deficiency of alfalfa than a one‐time soil application of Mn.     

Boron toxicity of strawberry

Abstract

Radlands Crimson strawberries were grown in a glasshouse with 7 rates of applied boron. Wood shavings mulches with different boron concentrations were also applied as separate treatments. Boron toxicity symptoms were produced in leaves by boron rates of 0.32 kg ha^‐1 and greater on a soil containing 1.6 ug B g^‐1 of hot water extractable boron. Concentrations greater than 123 μg B g^‐1 in old leaves were associated with boron toxicity symptoms.

In the B rate experiment, soil boron concentrations greater than 1.9 μg B g^‐1 soil were associated with leaf toxicity symptoms which increased in severity with increasing soil boron concentrations up to 4.1 μg B g^‐1 soil. Wood shavings mulch containing 17 μg B g^‐1 caused boron toxicity symptoms in older leaves whereas mulches containing less than 6 μg B g^‐1 did not produce toxicity symptoms.     

EARLY DIAGNOSIS OF BORON DEFICIENCY IN CHESTNUT

This study aims to identify an alternative plant tissue to be used in the early diagnosis of boron (B) deficiency in chestnut (Castanea sativa Mill.). A B-deficient orchard was selected, and 16 trees were submitted to two levels of B fertilization. When flowers were in bloom, the following tissues were sampled: leaves, androgynous catkins and flowers. There was a significant increase in B content in plant tissues due to B application. In July, the highest B content was observed in flowers in B0, but leaves had the greatest content in B1. Boron content in the tissues collected in July was positively correlated with B contents in leaves sampled in September. Foliar B concentrations, irrespective of the sampling period, were correlated with chestnut productivity, while the other tissues did not. These results suggest that the leaves, sampled in bloom, were the most efficient tissue for the early diagnosis of B deficiency.     

Lithium toxicity in plants

Abstract

The toxicity of Li to three plant species was studied to determine if there were interactions with other elements and to determine if a chelating agent modified Li toxicity. Bush beans (Phaseolus vulgarls L. C.V. Improved Tendergreen), grown in solution culture, were sensitive to 0.5 X10^‐3Li which resulted in 10 μg/g in leaves, 48 in stems, and 24 in roots. Higher concentrations of Li produced marked reductions in plant yield accompanied by increased Li concentrations in leaf, stem, and root tissues. For most treatments, root concentrations of Li were lower than those in shoots, but those in stems were higher than those in leaves. Higher levels of Li decreased Zn in leaves, increased Ca in stems, and generally increased Fe and Mn in all plant tissues. Ethylenediamine tetraacetic acid (EDTA) resulted in slightly increased Ii levels in leaves, stems, and roots. Bush bean plants were injured slightly with 25 μg Li/g of Yolo loam soil applied as LiCl; 50 μg Li/g soil caused more severe injury. Leaf concentrations of about 200 μg Li/g resulted in significant yield reduction and around 600 μg//g of leaves resulted in severe toxicity. There were some interactions of Li with other elements which resulted in an increase of them in both leaf and stem tissues. Barley plants (Hordeum vulgare L. C.V. Atlas 57) were severely stunted when grown with 500 and 1000 μg Li/g soil as Li oxalate. Increasing the soil pH even further with lime and decreasing it with S had no influence on the toxicity. Shoot concentrations of Li ranged from 800 to over 2000 in the various treatments resulting in severe disruption of the Ca and K balance. Leaf concentrations of Li were higher than those for stems in cotton (Gossypium hirsutum L. C.V. Acala 442). Cotton was tolerant of a leaf concentration of 587 μg Li/g. High levels of Li increased concentrations of several elements in cotton leaves and in stems. Cotton leaves accumulated more Li than did bush beans.     

Growth and plant zinc distribution in two navy bean varieties fertilized with zinc

Abstract

Sanilac and Saginaw varieties of navy beans were grown on Wisner silty clay loam. Treatments of no added Zn and 3 ppm Zn were applied to the soil fertilized with N, K, and 500 ppm P. Selected plant tissues were harvested two, four, six, or eight weeks after planting.

The weights and Zn contents of some tissues were not affected by Zn application regardless of variety but the growth of the plant parts above the primary leaves and the Zn contents of the trifoliolate leaves increased with Zn rate. The three oldest trifoliolate leaves and younger tissues showed equal or greater increases in growth and Zn contents than the total plant tops, but the primary leaves and the lower portions of stems were less influenced by available Zn in the soil. These responses indicated that the three oldest trifoliolate leaves were the most reliable indexes for available Zn throughout the growing period.

As the plants matured, the growth and Zn contents of the young tissues of the Saginaw variety responded more to Zn fertilization than did the young tissues of Sanilac. This differential response appeared to be partially due to the lower plant weights of the Saginaw than the Sanilac variety where no Zn had been applied to the soil.     

Zinc‐boron interaction effects in oilseed rape

The interaction effect of applied zinc (Zn) and boron (B) on early vegetative growth and uptake of Zn and B by two oilseed rape (canola) (Brassica napus L.) genotypes was investigated in a sand culture experiment under controlled environmental conditions. Two genotypes (Yickadee and Dunkeld) were grown at three Zn levels (0.05, 0.25, and 2.0 mg kg^‐1 soil) and two B levels (0.05 mg kg^‐1 soil and 0.5 mg kg^‐1 soil). Dunkeld produced significantly higher shoot and root dry matter than Yickadee at low Zn and low B supply indicating the superiority of Dunkeld over Yickadee for tolerance to both low Zn and low B supply. Chlorophyll content of fresh leaf tissue was increased significantly by an increase in Zn and B supply. Zinc deficiency enhanced B concentration in younger and older leaves. Boron concentration was higher in older leaves than in the younger leaves irrespective of B deficiency and sufficiency indicating immobility of B in two oilseed rape genotypes tested. Zinc concentration was higher in younger leaves than in the older leaves indicating mobility of Zn. An increased supply of Zn enhanced B uptake under high boron supply only. Zinc uptake in Dunkeld was enhanced significantly with an increased rate of B supply under high Zn supply, while the effect was not significant in Yickadee. Dunkeld proved to be more efficient in Zn and B uptake than Yickadee.     

Shoot growth,plant tissue elemental composition,and soil salinity following irrigation of alfalfa and tall fescue with high‐sulfate waters 1

Groundwater contaminated with sulfate (SO₄ ^2‐) at concentrations higher than allowable for drinking water might still be usable for irrigation. Objectives were to determine the growth response and mineral uptake of two forage crops irrigated with waters containing SO₄ ^2‐ at concentrations ranging from 175 to 1743 mg/L, and with electrical conductivities (EC) ranging from 1.2 to 3.6 dS/m. Plants were grown for 12 weeks in 8‐L pots containing a calcareous sandy loam and were harvested at 4, 8, or 12 weeks for plant growth measurements and tissue analysis. Digested leaves, stems, and reproductive tissues were analyzed by inductively coupled plasma (ICP) spectroscopy at each harvest, as were saturated soil paste extracts. Shoot growth of tall fescue (Festuca arundinacea Schreb.) was not affected by irrigation water treatment, whereas shoot growth of alfalfa (Medicago sativa L.) was increased by a moderate level of soil solution SO₄ ^2‐ Sulfur (S), boron (B), magnesium (Mg), sodium (Na), and zinc (Zn) concentrations in shoot tissues of both species showed a tendency to increase with increasing SO₄ ^2‐ content of irrigation water. Shoot tissue concentration of molybdenum (Mo) increased with maturation in both species, while the concentrations of B, potassium (K), manganese (Mn), Na, and Zn decreased. Soil saturated paste extract concentrations of Mg and Na increased with irrigation water Mg and Na concentrations, while Ca and S concentrations in the soil solution became saturated at the higher irrigation water concentrations of these elements.     

A miniaturized curcumin method for the determination of boron in solutions and biological samples

Methods for the determination of boron require either sophisticated and expensive equipment (e.g. ICP-OES or ICP-MS) or a relatively large sample volume (e.g. spectrophotometric methods). A modified and miniaturized spectrophotometric curcumin method is presented which allows the determination of boron in sample volumes of 50—150 μl with a detection limit of 0.010 mg B l¹. The calibration curve is linear up to a concentration of 3 mg B l¹. Interferences with other ions are eliminated by extraction of boron with 2-ethyl-1,3-hexanediol in chloroform. Simultaneously, enrichment of boron in the sample can be performed within the same extraction step. Results show good reproducibility with a relative standard deviation of 15% at B concentrations between 0.05 and 0.40 mg B l^—1. In different types of solutions, recovery of added boron was in the range of 98 to 99%. For several plant materials containing from 18 to 58 μg B (g dw)¹, an overall relative standard deviation of 4.5% was established. So far, the method has been successfully applied to determine boron in waters, nutrient solutions, different plant parts (roots, stems and leaves) as well as in phloem sap and apoplastic washing fluid of several plant species.     

In situ labeling of legume residues with a foliar application of a 15N‐enriched urea solution

Abstract

Conventional methods for labeling of legume residues with ¹⁵N for the measurement of the transfer of nitrogen (N) to a succeeding crop are inadequate for zero‐tillage management where the residue is chemically desiccated. The study tests the feasibility of in situ labeling of legumes with ¹⁵N for the study of N transfer to a succeeding crop. A single foliar application of ¹⁵N‐labeled urea was misted onto the stems and leaves of second cut red clover and alfalfa in the field in 0.75 x 0.75 m microplots. Nitrogen content and ¹⁵N enrichment were determined for above‐ and below‐ground plant parts. Overall, recovery of the foliar applied ¹⁵N in the forage was 30% and 57% for the alfalfa and red clover, respectively. Of the nitrogen recovered, approximately 70% and 30% were recovered in the above‐ and below‐ground plant parts, respectively, for both forage species. Atom % ¹⁵N was similar for the red clover and alfalfa for each of the above‐ground plant parts and was slightly lower in the crown and roots for the red clover than for the alfalfa. Values of atom % ¹⁵N ranged from 0.5 for fine roots to 1.5 for leaves above 0.20 m from the ground. Labeling of the plant material was not uniform between plant parts but was adequate for many studies of N transfer to a succeeding crop.     

Mineral composition of tobacco leaf samples part I: As affected by soil fertility,variety, and leaf position

Abstract

Three tobacco varieties were grown under four soil fertility conditions. Leaf samples were taken at bloom stage from upper and lower positions and analyzed for eleven elements. Results show how leaf position and variety affect leaf mineral composition with variable soil conditions. Therefore, variety and leaf position should be clearly defined before leaf nutrient levels can have a suitable degree of diagnostic value. However, variety differences were of less importance because nutrient concentration differences were generally related to appropriate changes in yield measurements.     

Sampling water from alfalfa (Medicago sativa) for analysis of stable isotopes of water

Abstract

The isotopic composition of water extracted from various parts of alfalfa (Medicago saliva) plants was compared with that transpired by the plants to validate water extraction procedures, and to define the degree of alteration of the isotopic composition of water that occurred in different plant parts. The mean δ²H and δ¹⁸O values of water extracted from the upper tap root and lower crown regions were < 1‰ and 0.3‰ different from that of water transpired, respectively, with an analytical precision similar to that found in previous studies on soils and trees. Water from other plant parts closer to the leaves was enriched in ²H (up to 12.6 in upper stems) and ¹⁸O (4.2‰) with respect to that transpired. The enrichment was associated with a greater variability in δ²H values between replicate plants. δ²H‐δ¹⁸O data indicated that the isotopic enrichment was due to evaporation during transpiration. The study showed that azeotropic distillation is an accurate means of extracting water from alfalfa, although care is required when obtaining plant samples for comparison with water from the root‐zone.     

Determining critical limit of boron in soil for wheat (Triticum aestivum L.)

Abstract

Critical values of boron (B) for wheat nutrition in soil and plant were determined through a pot experiment with twenty-one surface soils of Alluvial flood plain and Red-latertic belt comprising three major soil orders (Entisols, Alfisols, Inceptisols) with four levels of boron. Application of boron significantly increased the dry matter yield as well as uptake of B by plants. Critical concentration of hot calcium chloride (CaCl₂) extractable B in soil for wheat was found to be 0.53?mg?kg^?1. The critical plant B concentration varied with growth stages and values were 7.4?mg?kg^?1 at panicle initiation and 4.18?mg?kg^?1 at maturity, respectively. The findings of this investigation also recommend the application of 2?kg?B^?1?ha^?1 for ensuring B sufficiency to wheat in Indo-gangetic alluvial and Red-Lateritic soils.     

Evaluation of the NH4HCO3‐DTPA soil test for assessing boron availability to wheat

Abstract

The NH₄HCO₃‐DTPA (AB‐DTPA), 1 MNH₄HCO₃, 0.005 M DTPA, pH=7.6, was proposed as a multi‐element extractant, for evaluating macro and micronutrients availability to plants. AB‐DTPA was also evaluated as a soil test, for assessing boron availability and toxicity to alfalfa. In a pot experiment, ten soils of Northern Greece were used to assess AB‐DTPA as an extractant of available boron to wheat (Triticum aestivum L., cv. Yecora), in comparison with hot water and saturation extract. Boron (B) was added as borax (Na₂B₄O₇*10H₂O) to the ten soils, at rates equal to 0, 3, and 5 mg B kg^‐1. Wheat was grown in pots containing the boron amended soils to the stage of tillering, and dry aboveground biomass, B concentration and B uptake by wheat were determined. AB‐DTPA extractable B was significantly greater than saturation extract and similar to hot water at each B application rate, and was correlated significantly with hot water (r=0.84), or with saturation extract (r=0.48). Extractable boron by all extractants, boron concentration in wheat and boron uptake were significantly affected by the soil x B application rate interaction. In assessing B availability to wheat using AB‐DTPA as a soil test, CEC should be included in the regression equation for B concentration, or pH for B uptake. However, the corresponding adjusted coefficients of determination for B concentration (adjusted R²=0.46) and B uptake (adjusted R²=0.48) were similar or lower to those of hot water (adjusted R²=0.45 and 0.60, respectively) and the saturation extract (adjusted R²=0.70 and 0.49, respectively), when the latter two soil tests were used in the regression equations without the inclusion of any soil property.     

Clarification of water movement properties in a multi-soil-layering system

Maize (Zea mays L.) cv. T42 was grown in refined sand at low (0.1 μM) and normal (30 μu) concentrations of boron each under low (1 mM), normal (4 mM), and excess (8 mM) supply of calcium. Visible symptoms of boron deficiency which appeared first, were accentuated by calcium deficiency and were least evident when calcium was added in excess. The yield was maximum at normal levels of boron and calcium and was the lowest under boron and calcium deficiency.

In maize leaves when both calcium and boron were deficient together the activity of starch phosphorylase increased markedly and that of ribonuclease and polyphenol oxidase also increased. The increase in the calcium content inhibited the starch phosphorylase activity when boron was deficient. The activity of peroxidase was stimulated under boron deficiency at all levels of calcium and that of ATPase was depressed significantly when calcium was deficient alone.

A decrease in the tissue boron (except in old leaves) and tissue calcium content as well as sugar and starch contents was observed under the combined deficiency of calcium and boron.

Excess calcium at both levels of boron increased the tissue boron and calcium contents and decreased the concentration of starch, sugars, nucleic acids, total and inorganic phosphorus, and the activities of starch phosphorylase and ATPase.

The activity of ATPase increased upon the addition of calcium to plants deficient in calcium and boron respectively. The tissue concentration of the element added increased when the element was applied to calcium or boron deficient maize plants.