bluuebunny/crossref_metadata_2025 huggingface dataset:
Salt Response of Chickpea as Influenced by N Supply1
Authors: Lauter D. J. , Munns D. N. , Clarkin K. L.
Published: July 2010

Production of chickpea (Cicer arietinum L.) in semiarid and coastal areas may be limited by the salt sensitivity of the chickpea symbiosis. Accordingly, this study was done to analyze effects of salt on the symbiosis by comparing the NaCl tolerance of chickpea‐specific strains of Rhizobium with tolerance of the chickpea plant grown either with combined N or dependent on symbiotic N2‐fixation. Effects of supplemental N on the salt response of symbiotic chickpea were also tested.

In greenhouse sand cultures, growth of chickpea was depressed by NaCl at only 20 mM concentration unless mineral N was provided. With no added NaCl 22 strains of rhizobia were all effective, producing plant yields comparable with NH4NO3 control treatments; but with NaCl added at 75 mM only 1 strain did significantly better than controls with no N or inoculum. Poor symbiotic performance was not due to salt limitation of growth of rhizobia. Rhizobial growth rates determined by viable counts in yeast mannitol medium were unaffected by NaCl at 120 mM and only moderately depressed by 250 mM.

Effects of supplemental N were studied in a solution culture experiment with four levels of NaCl (0, 15, 23, and 31 mM) combined factorially with four different N treatments: NH4NO3 absent, present continuously, present only during the first 31 days, or present only after onset of vigorous fixation at 31 days. The growth of both N‐fertilized and symbiotic plants was inhibited by salt. Ammonium nitrate moderated salt stress most strongly during the later period of growth (after 31 days). Growth inhibition of N‐fertilized plants was associated with excess Cl accumulation in shoots, which occurred regardless of N treatment. Additional effects could account for the greater inhibition in symbiotic plants. Salt delayed nodulation, and N‐treated plants showed greater retention of Na in roots and lower concentrations of Na in shoots than completely symbiotic plants

The data indicate a clear need for greater salt tolerance in chickpea. And since the nature of the salt response changed markedly with N‐source, selection of cultivars and testing of management procedures should be done with both N‐fertilized and symbiotic plants.
Fate of Tagged Urea N in the Field with Different Methods of N and Organic Matter Placement
Authors: Tomar J. S. , Soper R. J.
Published: July 2010

A field experiment of factorial randomized block design was conducted with barley (Hordeum vulgare L.) to evaluate the effect of organic matter and fertilizer N placement on the efficiency and immobilization of applied N. Also, the experiment was to determine whether immobilization was a factor in causing the differences in efficiencies for broadcast and banded N. The plots used consisted of open‐ended iron cylinders 35 cm in diameter pressed into the soil to a depth of 25 cm. Labelled urea containing 19.15 atom %15N was either banded at 10 cm soil depth or surface broadcast at a rate of 100 kg N/ha. Oat straw (Avena sativa L.) was used us the organic matter source and applied at 5,000 kg/ha and was either mixed throughout the soil to a 10 cm depth or spread evenly on the soil surface. Fertilizer N removed by the above‐ground portion of the crop and that remaining in the 100 cm soil depth at harvest time was determined.

Nitrogen uptake and barley yield were greater from banded N than from broadcast N. The differences in uptake for the two methods of N placement were enhanced by adding organic matter to the soil. Recovery of fertilizer N in plant tops varied between 22.8 and 42.8% for urea surface broadcast and between 42.0 and 53.1% for urea applied in a band. About 83 to 87% and 82 to 95% of the applied N was accounted for in the soil and plant at the end of the experiment for broadcast and band‐N applications, respectively. Leaching losses of applied N were negligible for both methods of N application. Significantly more labelled N was found in soil from the broadcast than from the banded fertilizer (40.3 vs. 34.0% of added N) at the end of the experiment and the effect was particularly enhanced by mixing straw with the soil.

Since leaching losses were negligible and unaccountable differences probably as gaseous losses were essentially the same for broadcast and banded N applications (13 and 15%, respectively), the superiority of banded N over broadcast N applications with respect to barley yields and N uptake was largely due to the reduced immobilization of banded N.
Population Density and Planting Date Effects on Kenaf Performance1
Authors: Campbell T. A. , White G. A.
Published: July 2010

Population density and planting date can have substantial effects on kenaf (Hibiscus cannabinus L.) performance in temperate climates. The effects of population densities of up to 395,000 plants/ha on kenaf have been evaluated in Maryland. Because positive yield responses have been derived from higher populations at other locations, the effects of five population densities [247,100 (PI), 370,700 (P2), 494,200 (P3), 617,800 (P4), and 741,300 (P5) plants/ha] on ‘Cuba‐2032’ and ‘Tainung‐1’ were studied in 1976 and 1977 on the Eastern Shore of Maryland. Soil was a Bertie silt loam (fine‐loamy, mixed thermic Aquic Hapludult). Yields of Tainung‐1 were maximized at approximately 370,000 plants/ha whereas yields of the less vigorous Cuba‐ 2032 were maximized at approximately 500,000 to 700,000 plants/ha. Plants grown at P1 and P2 generally achieved greater height and stem diameter than those grown at P3 to P5; stand reduction was generally higher at P3 to P5 than at P1 and P2. Neither height nor stem diameter was significantly correlated with percent stand reduction. The primary cause of stand loss was probably greater intraspecific competition at the higher populations.

Early (28 April) and late (19 May) planting of kenaf led to comparable dry matter yields in a 1970 study in Maryland. We concluded that a more detailed study of planting date was needed and experiments were conducted in 1976 and 1977 on the Eastern Shore of Maryland. Soil and cultivars were the same as for the density studies. Planting dates were 5 May in 1976 and 11 May in 1977 (D1), 19 May (D2), 2 June (D3), 16 June (M), and 30 June (D5). Planting on D1 and D2 generally led to significantly (0.01 level) greater yields than did planting on D3 to D5. Date of planting had no substantial effect on height; stem diameter and stand reduction responses were erratic.
Use of Paired Sampling to Quantify Soil Productivity1
Authors: Munn L. C. , Schweitzer B. D. , Lund R. E. , Nielsen G. A.
Published: July 2010

Variations in management inputs and climatic conditions between fields and from year to year are major complicating factors in attempts to quantify soil productivity. A study of soil productivity for spring wheat (Triticum aestivum) in northcentral Montana is used to illustrate the advantage of the paired sampling technique as compared to a non‐paired design for evaluating yields on contrasting soils. The two soils in the study were both Aridic Argiborolls which occur as a complex in the same fields. Relative efficiency of the paired design compared to nonpaired sampling ranged from 0.9 to 6.5 for the 11 crop and soil variables measured (mean relative efficiency was 2.0).
Small‐Scale Dryer Design1
Authors: Navratil R. J. , Burris J. S.
Published: July 2010

High ear corn (Zea mays L.) drying temperatures are known to affect subsequent seed quality. In addition, genotypes have been known to differ in their tolerance to higher drying temperatures. Therefore, in order to experimentally test some of the most widely grown public inbred lines for tolerance to dryer induced injury at 35, 40, 45, and 50 C, four small‐scale, single‐pass movable dryers were constructed. Each unit consists of a cap and stackable trays on top of a base, which houses the thermostat, fan, and a resistance heat source. Units were operated during the 1979 and 1980 harvest seasons. Measured mean temperatures both years were within 0.3 C of the desired temperatures.

The dryers are quite flexible. They are capable of drying shell corn or bulk soybeans [Glycine max (L.) Merrill] as well as earn corn. By connecting the exhaust ports of two adjacent stacks, these units can be used to recycle exhaust air in a two‐pass arrangement through the second stack. Convenient unstacking of the trays facilitates rapid addition or removal of samples and transfer of samples from one drying environment to another. These units can not only be used to screen germplasm for tolerance to high drying temperatues, but can also serve to supply seed that have been dried under defined conditions for physiological studies.
Impact of Simulated Land Treatment with Oily Sludges on Ryegrass Emergence and Yield1
Authors: Brown K. W. , Brawand H. , Thomas J. C. , Evans G. B.
Published: July 2010

The proper design and management of facilities for the land treatment of hazardous industrial wastes require information on the effects of the oily wastes on the soil and on the growth of vegetation. Measurements were made on the impact of two oil‐water separator sludges (a refinery sludge which originated from a petroleum refinery, and a petrochemical sludge which originated from a petrochemical plant) on the emergence and dry matter yield of ryegrass (Lolium multiflorum Lem.) grown on four diverse soils in the greenhouse. Each sludge was applied at 0, 5, 10, and 20% v/v to each of four soils to determine the influence of application rates. After growth periods of approximately 6 weeks, the grass was harvested and the soil‐sludge mixture was air‐dried, remixed, and reseeded. A total of eight sequential harvests were made. Measurements of soil wettability were made twice to evaluate physical problems.

Concentrations of refinery sludge at 5% v/v and above depressed ryegrass emergence and yield through two mechanisms. Phytotoxic constituents initially acted to retard plant growth. Several months were required for the sludge to degrade sufficiently to allow normal plant growth. Subsequent yield reductions resulted from impaired water relations associated with residual hydrophobic hydrocarbons.

The petrochemical sludge had higher concentrations of both organic carbon and aromatics and suppressed emergence and yield proportional to the amount of sludge applied. The suppression lasted longer than that caused by the refinery sludge. Seedling emergence from soils treated with 20% refinery sludge did not differ from those in the unamended control by the second planting, while the corresponding treatments using petrochemical sludge were less than those in the control for the first five replantings. Grass yield from the 20% refinery sludge treatment required 13 months to reach control levels. The corresponding petrochemical treatment yield increased to only 47 % of the control, 17 months after application.

Thus, while oily sludge may initially be phytotoxic and may reduce the yield of vegetation that managed to emerge, the toxicity diminishes with time, so that soils used for land treatment of oily sludges can eventually be revegetated.
Reseeding Crimson Clover as a N Source for No‐Tillage Grain Sorghum Production1
Authors: Touchton J. T. , Gardner W. A. , Hargrove W. L. , Duncan R. R.
Published: July 2010

Nitrogen fertilizer is an expensive but essential input for optimum production of non‐leguminous crops. The use of N fertilizer for summer grain crops can be reduced and possibly eliminated by double cropping with leguminous winter crops. Costs of seeding winter legumes, however, are often as expensive as the commercially produced N that they replace. Allowing the legumes to produce seed prior to planting the summer crop may potentially eliminate costs associated with seeding the legume each fall. The purpose of this field study, conducted on a Cecil sandy loam soil (Typic Hapludult), was to determine N fertilizer requirements for no‐tillage grain sorghum (Sorghum bicolor L. Moench) double cropped with reseeding crimson clover (Trifolium incarnation L.) and effects of N treatments on nutrient uptake and on insect populations. Nitrogen treatments were 0, 15, 30, 45, 90, and 135 kg N/ha and the clover tissue was either removed or left on the soil surface as a no‐tillage mulch.

No‐till planting sorghum into clover or removing the clover top growth at maturity had no apparent effect on clover stand establishment the following fall. Clover dry matter production was essentially equal among years and averaged 4,762 kg/ha/yr. When averaged over years, the N, P, and K concentrations in the clovertops were 2.02, 0.24 and 2.40%, respectively. The only essential nutrient in sorghum leaves at the bloom stage affected by applied N was Cu which increased linearly as applied N increased. The only effects that removing clover had on nutrient content in the sorghum leaves were to reduce K in 1979 (from 2.47 to 2.31%), N in 1980 (from 2.85 to 2.69%) and P in 1979 (from 0.36 to 0.34%) and 1980 (from 0.34 to 0.29%). The reductions, however, were not sufficient to create a deficiency of either element. Some differences were found among common insect populations and their subsequent damage among treatments but the populations were not great enough to be considered economically damaging. Nitrogen produced by the clover was sufficient for maximum sorghum grain yield (5,760, 7,098, and 2,924 kg/ha in 1978, 1979, 1980, respectively) without supplemental applications of inorganic N. Removing the clover had no effect on sorghum grain yield in 1978 or 1979, but in 1980 this treatment reduced grain yield 601 kg/ha. Even though removing the clover which contained 62 kg/ha N in 1980 reduced sorghum yield, there was no response to applied N which suggests that the yield reduction was not due to a shortage of N.
Soil Compaction Effects on Soybean Nodulation, N2 (C2H4) Fixation and Seed Yield1
Authors: Lindemann W. C. , Ham G. E. , Randall G. W
Published: July 2010

Often soil compaction is considered undesirable for plant growth and may limit soybean yield. The objective of this study was to determine the effect of soil compaction on soybean plant growth, yield, nodulation, and N2 (C2H4) fixation. Field experiments were conducted for 2 years (1976 and 1977) on a Webster clay loam soil (fine‐loamy, mixed, mesic Typic Haplaquolls). Plots were compacted by 0, 1, 2, or 3 tractor passes over the same area approximately 2 weeks before planting. Soybean biomass and plant height were measured in 1977, but soil bulk density and soybean seed yield were measured in both years. Nodulation and acetylene reduction activity were measured four times during the season for taproots and two times for lateral roots in both years. Bulk density was increased significantly both years by tractor compaction. In 1976, when extremely dry conditions existed throughout the growing season mean seed yield values were greater on the tractor compacted plots (2,161, 2,106, and 2,283 kg/ha for the 1, 2, and 3 tractor pass treatments, respectively) than on the non‐compacted plots (1977 kg/ha), but the yields were not statistically significant. Taproot nodulation and acetylene reduction were also significantly greater on the 2 tractor pass treatment than on the non‐compacted plots, but little difference in lateral root nodulation and acetylene reduction was noted.

In 1977, when greater than normal precipitation occurred, compaction decreased significantly plant growth and taproot nodulation and tended to decrease lateral root nodulation. Acetylene reduction was not affected by compaction. The mean seed yield value was greatest in the non‐compacted plot (4,117 kg/ha) and the mean values declined with increasing tractor compaction (4,105, 3,955, and 3,854 kg/ha for the 1, 2, and 3 tractor pass treatments, respectively), although the yields were not statistically different. The effect of soil compaction in the spring prior to planting appeared to be dependent on the amount of precipitation in the growing season.
Three Tillage Systems Affect Selected Properties of a Tiled, Naturally Poorly‐Drained Soil1
Authors: Costamagna O. A. , Stivers R. K. , Galloway H. M. , Barber S. A.
Published: July 2010

Reduced tillage systems for corn (Zea mays L.) have seldom shown a yield advantage on naturally poorly drained soils. This research was intended to further test this hypothesis and to find other advantages of reduced tillage on tiled, naturally poorly drained soils. The effects of three systems of tillage on selected soil properties, and growth and yield of corn were compared for 7 years on a tiled, naturally poorly drained Chalmers silty clay loam (Typic Argiaquoll) soil. Conventional or plow tillage consisted of fall moldboard plowing to about 20 cm, two diskings in spring, planting, and one cultivation; field cultivation included field cultivation in spring to about 15 cm followed by two diskings, planting, and one cultivation, and “light disking” included one disking in spring and planting behind fluted coulters but no cultivation. After 7 years organic matter percentages under field cultivation (4.68%) and light disking (4.89%) systems were higher (p < 0.05) than that under plow (3.79%) tillage at the 0 to 5 cm depth. Mean weight diameters of water‐stable soil aggregates were higher (p < 0.05) for field cultivation (2.74 mm) and light disking (2.48 mm) systems than for the plow tillage (1.51 mm) system. In early October, after a summer of low rainfall, soil moisture was higher (p < 0.05) with field cultivation (35.9%) than with the plow tillage (32.3%) system. Even though tasselling was generally later (5 days in 1974) with the field cultivation and light disking systems than with the plow tillage system, annual (1968‐1974) corn grain yields were 97.1 and 98.9% respectively, of those obtained with plow tillage (8,700 kg/ha).
Effects of Applied Mechanical Stress on Plant Growth and Nutrient Uptake1
Authors: Castillo S. R. , Dowdy R. H. , Bradford J. M. , Larson W. E.
Published: July 2010

The ever‐increasing size of farm tillage machinery is contributing to increased soil compaction. Does this compaction affect dry matter production and nutrient uptake of growing plants? To better understand the consequences of increased mechanical stress on the root system, the effects of confining external stresses on root growth and nutrient uptake by pregerminated pea seedlings (Pisum sativum L. cv. Alaska) were studied in the laboratory. The application of stresses up to 269 kPa around the rooting medium (Dickinson loam, Typic Hapludoll) of pea seedlings reduced root growth and nutrient uptake. In relatively loose soil (1.16 g cm−3), the application of a 90 kPa stress (post‐planting) which resulted in a bulk density of 1.28 g cm−3, reduced Ca, K, Mg, and Mn uptake compared to another treatment where the soil was compacted to 1.30 g cm−3 before seeding. Such stresses, which are often applied to soils during field cultivations, also resulted in reduced root growth and distribution. In another experiment, the increased soil strength of a naturally dense subsoil, which resulted from lowering the soil water potential from −10 to −33 kPa, was associated with a 50% reduction in root length and a 21% reduction in K uptake by pea seedlings. The slower root development and reduced nutrient accumulation will affect the plant's ability to withstand environmental stresses during later stages of development.
Fall Growth and Cold Acclimation of Winter Wheat and Rye Differentially Fertilized with Phosphorus1
Authors: Fowler D. B. , Gusta L. V.
Published: July 2010

Phosphorus deficiencies and imbalances are among the factors that have been reported to result in poor cold acclimation of plants. Many soils in the Great Plains are deficient in P. Therefore this study was initiated to determine the effect of P on fall growth and cold acclimation of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) under field conditions.

Trials were located (52°N, 104°W) on phosphate deficient udic haploboroll soils in the northeastern corner of the agricultural area of Saskatchewan, Canada. Added P increased the P content of the crown, leaf and root tissue of wheat and rye plants. In all cases P content was higher in the crowns and leaves than in the roots. Added P increased the crown and root fresh weight and dry weight for both wheat and rye. Root growth in particular was stimulated by added P. Shoot dry weight and leaf fresh and dry weight of rye were also increased by added P. Similar trends were evident for wheat; however, differences were not significant. In spite of this obvious effect on plant growth, soil P deficiency had little effect on the ability of winter wheat and rye to cold acclimate as reflected by measurements of crown cold tolerance.
Critical Nutrient Ranges for Petiole Phosphorus Levels of Sprinkler‐Irrigated Russet Burbank Potatoes1
Authors: Roberts S. , Dow A. I.
Published: July 2010

Two field experiments were conducted for the purpose of establishing critical nutrient range (CNR) values for P in petioles of Russet Burhank potatoes (Solanum tuberosum L.) for use as standards in assessing plant nutrient status. The CNR is defined as the range of nutrient concentrations in plant tissue at a selected growth stage, above which the crop has an ample nutrient supply and below which the crop is nutrient‐deficient. The experiments were conducted under center‐pivot irrigation on soils classified as Quincy and Winchester loamy sands (mixed, mesic, Xeric Torripsamments). Five treatment levels from 0 to 269 kg P/ha were applied broadcast and incorporated before planting in April. Petioles were analyzed for P six times through the season, and potato yield was determined at harvest in late September. Adequate P fertilization produced maximum yields of 64 metric tons/ha on Quincy soil and 73 metric tons/ha on Winchester soil as compared with yields of only 79 to 86% of maximum without P fertilization. It was concluded that for 95 to 100% of maximum yield the estimated CNR was 0.38 to 0.45% P at the 2‐cm tuber stage in June and generally decreased with time to give a CNR of 0.14 to 0.17% P toward the end of the season 10 weeks later.
Effects of Deep Tillage on N Response by Corn on a Sandy Coastal Plain Soil1
Authors: Chancy H. F. , Kamprath E. J.
Published: July 2010

Tillage pans in sandy coastal plain soils often restrict utilization of subsoil moisture and nutrients and may limit corn (Zea mays L.) yields. Field experiments were conducted for 2 years on a Wagram loamy sand (Arenic Paleudult) with a tillage pan to evaluate deep tillage treatments and preplant N applications containing nitrapyrin (NI) on corn. Experiments were arranged in a split plot design containing three tillage treatments as the main plots with four N‐treatments as the subplots. The three tillage treatments were: a) disking to a 15 cm depth, designated as conventional, b) chisel‐plowing to a depth of 30 cm at 30 cm intervals, and c) subsoiling in the row to a depth of 45 cm and bedding over the subsoil slit. Four N‐treatments consisted of preplant applications of 0, 112, and 168 kg N/ha broadcast as urea and a urea‐NI solution at a rate of 112 kg N/ha plus 1.12 kg NI/ha. Measurements were made of soil NH+4 and NO‐3 concentrations, leaf N, stover weight, stover N concentration, grain yield, grain N content, and recovery of fertilizer N.

Use of NI in 1978 resulted in more of the total inorganic soil N in the 0 to 15 cm depth being in the NH+4 form; however, this did not significantly increase total inorganic soil N content at any depth. Nitrapyrin had no significant effect on inhibition of nitrification in the top 45 cm depth in 1979. Inorganic soil N was moved below the tillage pan into the subsoil by leaching rains. Ineffectiveness of NI to significantly suppress nitrification in 1979 was probably due to the differential movement of NH+4 and NI. Subsoiling significantly increased leaf N concentration above that obtained from conventional tillage in 1979, suggesting root extraction of soil N below the tillage pan. Chisel‐plowing and subsoiling increased corn stover dry matter production above that of the conventional tillage in both seasons.

Disruption of the tillage pan by subsoiling or chisel‐plowing increased corn yields above that obtained with conventional tillage. Highest yields were obtained with subsoiling. In 1978, higher grain yields with the deep tillage treatments were thought to have resulted from the utilization of moisture below the tillage pan. Increased yields with deep tillage in 1979 were due to utilization of both moisture and N below the tillage pan. Yields in 1978 were significantly higher with 168 kg N/ha as compared with 112 kg N/ha rate. Yields in 1979 were not significantly different at the 112 and 168 kg N/ha rates. Nitrapyrin had a positive effect only on yields with the chisel‐plow treatment.
Calculation of the Length of Day1
Authors: Keisling T. C.
Published: July 2010

With the advent of sophisticated computing capability many tables and curves that were standard methods of obtaining values in the past can be computed directly with the appropriate formulas. The photosensitivity of many agronomic crops makes knowing the length of hours that the light intensity is above a certain critical level useful. A formula for calculating daylength is presented and methods indicated for obtaining the desired beginning and ending light intensity at any location. The only information necessary to utilize the formula is the latitude of the location and the critical light intensity of interest for the particular crop being used.
Evaluation of Inoculant Viability on Commercially Inoculated Legume Seed1
Authors: Vincent Jean E. , Smith M. Scott
Published: July 2010

The objective of this study was to evaluate the viability of rhizobia on retail samples of preinoculated seed. Sixty‐two samples of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) seed were evaluated by growing in plastic growth pouches and observing nodulation. This convenient test procedure gave results which related well to percent N in plants grown from preinoculated seed in nonsterile soil (pH 6.1). The merits of this test procedure, relative to other plant infection methods and plate counts, are discussed. Coated (pelleted) alfalfa seeds produced plants with more nodules in infection assays, higher plate counts of rhizobia, and higher N percentages in soil‐grown plants than did uncoated preinoculated seed. Coated red clover seed was not significantly different from uncoated. During storage of preinoculated seed, viability of inoculant on uncoated seed decreased faster than on coated seed. The results suggest the conclusion that many retail samples of preinoculated seed do not carry optimum levels of viable inoculant.
Seasonal Variation of Water Soluble and Total Zinc in Cool‐Season Grasses1
Authors: Belesky D. P. , Jung G. A.
Published: July 2010

Zinc concentrations in temperate origin perennial grasses do not always meet recommended nutritional requirements for animals. Availability could be affected by factors which contribute to lignification which reduce forage digestibility, and possibly, availability of minerals including Zn. A field plot study was established on Hagerstown silt loam (Typic Hapludalf fine, mixed, mesic) where Zn concentration and Zn water solubility was determined in vegetative material of two cultivars of each of six temperate origin perennial grasses collected in May, August, and October of 1971 and 1972. Total Zn concentrations were positively correlated (P < 0.01) with water soluble Zn especially in material produced in August and October. Total Zn concentrations and percentage Zn solubility [(water soluble Zn/total Zn) ✕ 100] were inversely related among species; for example, reed canarygrass (Phalaris arundinacea L.) ranked first among the species for total Zn (23 ppm) and last for percent solubility (61%), while tall fescue (Festuca arundinacea Schreb.) ranked last among the cultivars for total Zn (15 ppm) and first for solubility (84%). Total Zn concentrations were positively correlated (P < 0.01) with in vitro dry matter digestibility; Zn solubility (%) was not. The data show Zn concentrations vary with season and that all species and cultivars do not exhibit the same pattern of variation. Therefore, careful species and cultivar selection should be considered, particularly where there is evidence of Zn inadequacy in ruminant diets.
The Effect of Seeding Depth, Soil Moisture Regime, and Crust Strength on Emergence of Rape Cultivars1
Authors: Nuttall W. F.
Published: July 2010

Emergence of rape seedlings Brassica napus L. and B. campestris L.) on Typic Cryoboralf (Gray Wooded, Luvisolic) soils may be reduced by the formation of hard crusts. Twelve of these soils were sampled from the surface horizon (Ap) to examine the effect of soil type on emergence of rape and determine if particle‐size distribution and organic matter or organic carbon percentage were related to soil crust hardness. Four split plot greenhouse experiments were conducted to examine the effect of seeding depth and moisture regime on seedling emergence of rape cultivars.

Multiple regression analyses showed that silt percentage (0.05‐0.002 mm size) was positively related to crust strength measured by modulus of rupture and that organic matter and organic carbon percentage were negatively related to crust strength.

The seedling emergence of rape cvs. ‘Target’, ‘Zephyr’, ‘Span’, ‘Regent’, and ‘Candle’ was significantly higher at the shallow seeding depth of 1.5 cm than the 3.0 cm depth (18, 38, 49, 14, 16 vs. 7, 35, 42, 7, and 7% respectively, at 6 days after seeding). Emergence of rape seedlings campestris species, Span was 69% vs. 61% napus species, Zephyr 13 days after seeding. However, with the low glucosinolate Candle (campestris) and Regent (napus) on the average emergence was 56 vs. 74%, respectively, under a high moisture regime (watered to 100% field capacity). Under low moisture regime (50% field capacity) emergence was 15% for both species. Under the low moisture regime, there was no emergence of Regent on seven soils, whereas with Candle there was no emergence on four soils. These results indicated a different threshold soil condition under which these two cultivars would emerge and resulted in significant soil and crop by moisture interactions.

The greater percentage emergence of the smaller seeds of Span than the larger seeds of Zephyr was attributed to less energy required to push the smaller cotyledons of Span through the soil crust. Similarly, under dry soil conditions, the smaller seeds of Candle emerged on more soils than the larger seeds of Regent.

Seedling emergence of Candle and Regent grown on Typic Cryoboralf soils was significantly related by regression analyses to soil crust strength measured by penetrometer and by modulus of rupture under different seeding depth and moisture regime conditions.
Indirect Estimation of Grass‐Legume Ratios in Mixed Swards1
Authors: Johnson K. D. , Lechtenberg V. L. , Vorst J. J. , Hendrix K. S.
Published: July 2010

The legume to grass ratio in mixed pasture and hay swards is an important determinant of forage yield and quality. Ratio measurements, determined on the basis of the relative weight of the grass and legume components, are time‐consuming and tedious. Studies were conducted to evaluate a method for estimating the grass and legume ratios in mixed swards on the basis of neutral detergent fiber percentages. Samples of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and ladino clover (T. repens L.) were mixed with tall fescue (Festuca arundinacea Schreb.) in known proportions. Samples were analyzed to determine neutral detergent fiber percentages. The legume and grass proportions were estimated by solving simultaneous equations for each mixture. Coefficients of determination (r2) between known and predicted values ranged from 0.92 to 0.98. The standard deviation (SD) between known and estimated values ranged from 2.26 to 5.56 percentage units. When the difference between the neutral detergent fiber percentage of the grass and that of the legume was altered mathematically, the SD increased exponentially as the difference between the neutral detergent fiber percentages of the grass and the legume approached zero. Acid detergent fiber did not accurately assess legume and grass proportions in mixed swards.
Yield and Composition of Field Bean and Adzuki Bean in Response to Irrigation, Compost, and Nitrogen1
Authors: Robinson Robert G.
Published: July 2010

Nutritionists expect bean seed to provide a nutritious, high‐protein food. Consequently, production practices, that alter nutritive composition and yield, affect both human health and economic profit. Field bean (Phaseolus vulgaris L.) and adzuki bean [Vigna angularis (Willd.) Ohwi and Ohashi] were grown on Udorthentic Haploborolls, sandy, mixed soils in central Minnesota to measure the effects of irrigation, rhizobial inoculant, and N on seed yield, protein concentration, and nutritive value. Main plot treatments were rainfall of 16 to 36 cm during June, July, and August and rainfall plus irrigation of 24 to 30 cm. Subplot treatments for fieldbean were untreated, compost at 3 to 6 metric tons/ha, rhizobia, inorganic N at 74 to 310 kg/ha, soybean [Glycine max (L.) Merr.] meal at 112 kg N/ha, corn (Zea mays L.) grits plus inorganic N at 112 kg N/ha, and compost plus inorganic N. Subplot treatments for adzuki bean were untreated, rhizobia, and inorganic N at 112 kg/ba. Seed harvested from the treatments was analyzed by standard methods for amino acids, N, P, K, S, Ca, Mg, Fe, Zn, Mn, AI, B, Cu, Na, Mo, Ni, Pb, Cr, and Cd. Yield increases from irrigation ranged from 1,198 to 1,940 kg/ha. Yields from the subplot treatments differed significantly under irrigated but usually not under dryland treatment. Highest yields of fieldbean were obtained from compost plus inorganic N. The effect of compost on seed yield and quality was equivalent to that of 74 to 112 kg/ha of inorganic N fertilizer. Soybean meal, corn grits plus N, and N fertilizer treatments at equal rates of N did not differ in fieldbean yield or protein percentage. Irrigation resulted in low‐protein bean seed but compost and/or inorganic N at high rates usually maintained protein at acceptable levels. Amino acid composition of bean protein was not significantly affected by irrigation or other treatments. Bean seed from dryland plots was superior to seed from irrigated plots in protein and Zn concentrations. Nitrogen to protein conversion factors among treatments ranged from 6.19 to 6.26 for fieldbean and from 6.06 to 6.24 for adzuki bean.
Estimating Emergence Date of Spring Small Grains Using Landsat Spectral Data1
Authors: Badhwar G. D. , Thompson D. R.
Published: July 2010

Remotely acquired data using the Landsat satellite system provide a means for initiating crop growth simulation models and crop phenology models at a field level over a large geographic area. A model based on Landsat spectral data has been developed that estimates a spectral emergence of the crop at a pixel (field) level. This spectral emergence date is evaluated using dates of planting and emergence reported by farmers for their fields of spring wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) located in North and South Dakota. The differences between model predicted emergence date and farmer reported is found to be 4.9 ± 7.7 days. The model can provide a means of understanding the distribution of crop emergence across all pixels of a region. This knowledge of emergence date of spring grains from satellite data provides an ability to run crop development and yield prediction models at field level.
Sugarcane Response to P, K, and DRIS Corrective Treatments on Florida Histosols1
Authors: Elwali A. M. O. , Gascho G. J.
Published: July 2010

Nutritional imbalances in sugarcane (a complex trispecies hybrid of Saccharum) on Florida Histosols (Medisaprists) were suggested in earlier studies. In order to eliminate possible imbalances among nutrients, the Diagnosis and Recommendation Integrated System (DRIS) was adapted to monitor the nutritional status of sugarcane in an experiment with varying P and K levels. Standard DRIS reference norms were established for nine nutrients (N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu) in the top visible dewlap leaf laminae of sugarcane. Factorial P and K levels were applied with the seed cane at planting (January). Soil and leaf samples were collected during the grand growth period (July) and the DRIS indices for nutrients in the leaves were calculated. In order to correct nutritional imbalances indicated by DRIS indices at each PK‐treatment, each plot was split into two subplots. One subplot did not receive additional fertilizer while the other subplot was fertilized with the required nutrients as indicated by DRIS indices for that whole plot. Leaf samples were collected again close to the end of the grand growth period (end of September). Sugarcane and sugar yields were not affected by the rates of P applied at planting but were significantly affected by the rates of K applied at planting and by the DRIS treatments. The highest rate of K (560 kg/ha) reduced both sugarcane and sugar yields compared with the other rates. Plots which received 280 kg of K/ha at planting yielded significantly more cane but no more sugar than plots with 0 K at planting. Application of nutrients during the grand growth period (July) as indicated by DRIS indices significantly increased both cane and sugar yields over those obtained from plots which did not receive fertilizers in July. The DRIS indices for leaf nutrients during the grand growth period revealed that a shortage of P and an excess of K had been applied at planting, a fact which would have gone undetected by conventional nutrient level monitoring. The increase in cane and sugar yields from the DRIS corrective treatment resulted primarily from better nutrient balance as revealed by DRIS indices for leaf nutrients late in the season.
Field Evaluation of Selected Rhizobium in an Improved Legume Inoculant1
Authors: Kremer R.J. , Peterson H. L.
Published: July 2010

Increased grain legume production depends on effective symbiotic dinitrogen fixation through successful legume inoculation. Inoculants containing high numbers ≥ l07/g of effective Rhizobium must withstand adverse field conditions. Field studies were performed to determine the effects of selected rhizobia in two different inoculant carriers on nodulation and performance of three grain legumes. The soil at the 1979 site (Vertic Haplaquept) contained = 103 cowpea Rhizobium and = 102 Rhizobium phaseoli per g of dry soil. The soil at the 1980 site (Typic Paleudalf) contained < l02 R. phaseoli per g of dry soil. Selected strains of R. phaseoli and cowpea Rhizobium were incorporated in peat or vegetable oil. Seeds of bean (Phaseolus vulgaris L.), cowpea [Vigna unguiculata (L.) Walp.], and peanut (Arachis hypogaea L.) were inoculated (ca. 108 Rhizobium/seed) and planted. Nodulation, plant growth, and yields were determined in all experiments. Strains of Rhizobium in oil‐base inoculants generally formed a greater percentage of nodules on plants than did the same strains applied in peat‐base inoculants. Rhizobium phaseoli 971A occupied 93% of bean nodules when applied as oil‐base inoculant but only 82% when applied as peat‐base inoculant. Fresh weight bean yields of 5,620 kg/ha were obtained with strain 971A (oil‐base) compared to 3,370 kg/ha for the peat‐base treatment. Similar significant yield increases were obtained for cowpeas and peanuts inoculated with oil‐base inoculants. These experiments indicate that an improved inoculant provided high numbers of effective Rhizobium at planting. Through subsequent effective nodulation, oil‐base inoculants increased yields and nitrogen fixation by the legumes due to increased nodulation by the superior N2‐fixing strains of Rhizobium.
A Computerized Process for Soil Test Data Acquisition1
Authors: Hue N. V. , Evans C. E. , Patterson R. M. , Bailey A. C. , Schafer R. L. , Cope J. T.
Published: July 2010

A mini‐computer with 64K words of memory and a real‐time clock was interfaced to pH meters, AA spectrometers, and colorimeters to measure pH, buffer pH, K, Mg, Ca, and P. The data acquistion process is assisted by custom‐made, manually operated, operator‐and‐instrument interfaces (0II), which allow technicians to command the mini‐computer to perform certain tasks. These operations are controlled by a memory resident program in the mini‐computer named MONITOR, which monitors the state of the 011 switches. When MONITOR senses a switch closure, it causes B proper program to he loaded for execution from a moving head disc. Most of the user real‐time software routines are written in FORTRAN, but some routines are written in ASSEMBLY. Data collected are transmitted to an IBM 3031 for execution of the fertilizer recommendations program.
A Comparison of Plant Digestion Methods for Identifying Soil Contamination of Plant Tissue by TI Analysis1
Authors: Cherney J. H. , Robinson D. L.
Published: July 2010

Five plant tissue digestion procedures were evaluated for their ability to extract Ti from soil. Sulfuric‐selenous and nitric‐perchloric acid procedures each extracted large amounts of Ti from soil, and therefore, soil contamination of plant tissue samples can be identified by using either of these digestion procedures. Both of these procedures also extracted relatively large amounts of Al, Fe, Mg, and Ca from soil. Nitric acid and dry ash plus HCI extraction methods were inadequate for determining soil contamination by Ti analysis.
Fertilizer and Salty Water Effects on Phaseolus1
Authors: Wagenet R. J. , Rodriguez R. R. , Campbell W. F. , Turner D. L.
Published: July 2010

The response of legumes such as Phaseolus to adverse salt or water regimes is relatively unstudied as a function of soil nutrient status. Greenhouse studies, involving interactive effects on snap bean (P. vulgaris L.) yield of three levels of irrigation water salinity, three frequencies of irrigation water application, two levels of N applied in the irrigation water, and seven levels of P and K fertilization, were conducted to determine if the adverse effects of saline conditions or water stress on Phaseolus could be overcome by enhanced fertility status and/or improved saline water management on an Argixeroll. Dry matter and bean yields were reduced with decreasing irrigation frequency (2 to 8 days) and increasing salinity of irrigation water (0.5 to 8.0 mmho/cm). Percentage yield decrements were measured for both salt and irrigation regimes. Yield increases were noted for all fertilizer treatments so long as salinity did not become too high (8 mmho/cm). Plant N content and root weight were shown to be responsive to irrigation frequency and salinity, but not to fertilizer form. Nitrogen applied in the irrigation water produced increased yield across all treatment in one set of experiments where greenhouse conditions were hot, dry, and of high potential evapotranspirational demand, No N effect was measured in a second series of experiments with low potential ET.
Ammonia Volatilization: Soil, Plant, and Microclimate Effects on Diurnal and Seasonal Fluctuations1
Authors: Harper L. A. , Catchpoole V. R. , Davis R. , Weir K. L.
Published: July 2010

Nitrogen balance studies in pastures have shown unexplained losses of applied N with much of the loss assumed to be denitrification and NH3 volatilization. This project studied soil, plant, and microclimate effects on diurnal and seasonal fluctuations of gaseous NH3 flux in a subtropical pasture fertilized with urea. Soil and microclimate measurements were taken concurrently with NH3 flux density determinations to relate these factors to magnitude and direction of NH3 transport. Average daily NH3 volatilization varied with seasonal soil and microclimate conditions and time after area application. A short period of large NH3, efflux was observed after urea application during warmer seasons whereas smaller efflux for longer duration was observed during cooler seasons. Soil water content and rainfall after urea application modified seasonal NH3 losses. Diurnal NH3 cycling was apparent, with large efflux occurring during daytime and small efflux or influx at night. Prior to each urea application, average diurnal NH3 transport was into the soil‐plant system possibly due to low soil mineral and plant N. Brief periods of NH, influx were common throughout all seasons, particularly around sunset and sunrise. Soil surface temperature was the most highly correlated factor influencing NH3 flux density during the summer season. During the remainder of the year evapotranspiration had the highest correlation, although the increased midday fluxes were probably due to paralleled increase in soil temperature and windspeed. All of the major influencing factors are. interrelated through their dependence on solar radiation. Rainfall distribution and amount after urea application appeared to control the total NH3 losses from applied urea. The rainfall influence was probably the result of rainfall dispersing urea which prevented high concentrations of NH3 and NH4+ from building up around urea‐prills.
Light Penetrating a Bahiagrass Canopy and Its Influence on Establishing Jointvetch1
Authors: Kalmbacher R. S. , Martin F. G.
Published: July 2010

Bahiagrass (Paspalum notatum Flügge) is important in the southeastern USA and is Florida's major perennial grass, but low protein content and digestibility can limit cattle performance. Mixing bahiagrass with a legume such as jointvetch (Aeschynomene americana L.) would improve animal grazing performance. This 3‐year study was conducted at Ona, Fla. (27°25 N, 81°55 W) on a sandy, siliceous, hyperthermic Alfic Haplaquod to determine the effect of light on legume seedling establishment and yield to develop management guidelines that would enhance seeding success. Bahiagrass was treated each year by: i) spraying paraquat (1,1' dimethyl‐4,4' bipyridinium dichloride) at 0.56 a.i. kg. ha−1, desiccating for 72 h, then burning the residue and drilling seed into the sod; ii) disking sod three times followed by broadcasting seed; iii) grazing to 3 to 5 cm stubble, drilling seed and grazing until jointvetch was 2.5 cm tall; iv) spraying glyphosate [(N‐phosphonomethyl) glycine] at 0.84 a.i. kg. ha−1 in 15 cm wide bands, 22.9 cm apart, drilling seed; v) spraying dalapon (2,2 dichloropropionic acid) at 3.32 kg. −1 in 15 cm wide bands, drilling seed; vi) drilling seed in untreated hahiagrass (check). More light penetrated through the canopy of the paraquat‐burn (21 to 33 E m−2 day−1) and graze treated (20 to 30 E m−2 day−1) bahiagrass than in any other treatment. These treatments also had the greatest number of seedlings (3‐year average was 86 m−2), the highest dry matter yield of jointvetch (2,200 kg ha−1), and they produced the grass‐legume mixtures with the highest protein content (10.6%) and digestibility (49.1 %). Glyphosate treated sod allowed 17 to 24 E m−2 day−1 to penetrate the canopy, and good legume stands developed (80 seedlings m−2). The canopy from dalapon and check treatments was too dense (7 to 20 E m−2 day−1) to permit good legume establishment. Studies with saran shade screen indicated that 45% incident light, 20 E m−2 day−1, was the minimum light level for good jointvetch establishment. These data indicated that grazing was the most practical and successful method of removing and controlling the bahiagrass pasture canopy during legume establishment.