bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of ‘Atlas’ Cotton to Variations in Plants Per Hill and Within‐Row Spacings1
Authors: Hawkins B. S. , Peacock H. A.
Published: July 2010

To determine the effects of variations in plants per hill, spacing arrangements, and plant populations on agronomic and fiber properties of cotton (Gossypium hirsutum L.) we conducted a 2‐year study at Experiment, Ga., using ‘Atlas’ cotton on Cecil scl. Each trial was a randomized block split‐plot with number of plants (2, 3, 4, or 5 per hill) as the main plots and within‐row spacings (20, 40, and 60 cm) as subplots. The variations in plants/ hill and spacings represent a range in population of 32,110 to 240,825 plants/hectare.

Significant differences in yield due to years and to within‐row spacings were found, but number of plants per hill did not affect yield. The plants in hills spaced 20 and 40 cm apart produced higher yields than the plants spaced 60 cm. A population range of 96,330 to 144,495 plants/ha produced best yields.

We found differences in lint percentage and boll size due to years, plants/hill, and within‐row spacings. Lint percentage was highest and bolls were largest from plants at the 60‐cm spacing and when there were 2 plants/hill. The only significant difference in seed size was that associated with years. Fiber length differences were due to years, plants/hill, and within‐row spacings; the longest fibers were produced by 3 plants/hill and by plants at 40‐cm spacing. Differences in fiber strength were due to years and within‐row spacings; the strongest fibers were produced by plants spaced 60 cm apart. Fiber fineness was influenced by years only.

The following interactions were found:

Years × plants/hill: boll size, fiber length, fiber fineness, yield, lint percentage, and seed size.

Years × spacings: lint percentage, boll size, and fiber fineness.

Plants/hill × spacings: lint percentage.

There were no significant second order interactions.

Although mean differences were statistically significant, they are so small that they may be of no practical value. However, results demonstrate the relative stability of the characters stodied over a wide range of planting patterns and population densities.
Relation of Weather to the Influence of Hay Crops on Subsequent Corn Yields on a Chalmers Silt Loam1
Authors: Barber Stanley A.
Published: July 2010

The effect of hay crops [alfalfa (Medicago sativa L.), bromegrass (Bromus inermus L.), and a mixture of the two] on soil productivity as measured by corn (Zea mays L.) yields was investigated in field experiments conducted from 1952 to 1969. Corn following hay yielded more than corn following corn. The greater the number of years of corn subsequent to hay, the lower the corn yield. There was a negative linear correlation between corn yield and log of year of corn subsequent to hay. The slope of this relation varied with year and was correlated with 8‐week precipitation and 4‐week degree days following corn planting. The slope was greater as precipitation decreased below 15 cm or increased above 20 cm and also as degree days increased.
Soil and Nutrient Losses in Runoff with Selected Cropping Treatments on Tropical Soils1
Authors: Barnett A. P. , Carreker J. R. , Abruna Fernando , Jackson W. A. , Dooley A. E. , Holladay J. H.
Published: July 2010

The soil and nutrient losses in runoff for selected cropping systems were studied using artificial rainfall techniques on three soils in Puerto Rico in 1967. This study was undertaken to determine the erosion control effectiveness of and nutrient removal in runoff from selected cropping systems. Soils were Humatas clay, Juncos silty clay, and Pandura sandy loam. Artificial rain was applied at 6.4 cm/hr fox 60 rain (Storm 1), followed 10 min later by 12.7 cm/hr for 60 min (Storm 2). Storms and 2 were combined and designated storm 3, representing less than 2‐ to more than 500‐year frequency storms. Cropping systems tested were fallow, conventional tobacco (Nicotiana sp.), mulch‐tilled tobacco, tobacco in grass strips, pangolagrass (Digitaria decumbens), and pangolagrass with all aboveground parts removed. Slopes ranged from 26 to 46%; plots were 10.7 m long. Test areas had been in grass for several years.

Final infiltration rates were 3.7, 0.9, and 6.2 cm/hr for Humatas clay, Juncos silty clay, and Pandura sandy loam, respectively. All soils were highly aggregated and remained so throughout all storms. The low infiltration rates of Juncos silty clay are misleading. Actually, most of the rainfall infiltrated this soil but returned as interflow at the lower end of the plots.

All soils were quite resistant to erosion due to their high degree of aggregation and in part to the grass grown in previous years. Tillage increased storage capacity in the soil and reduced runoff. All cropping treatments were effective in reducing erosion when compared with fallow, except on Humatas clay, where the fallow treatment permitted the least erosion. Average erosion on all treatments from Humatas, Juncos, and Pandura soils were: Storm 1 — 0.87, 0.51, and 0.06; storm 2 — 5.12, 1.20, and 6.63; and storm 3 — 6.00, 1.72, and 6.69 MT/ha, respectively.

Nitrogen, potassium, calcium, magnesium, sulfur, and chlorine in runoff were measured from conventionally tilled tobacco during storm 1. Treated plots received by broadcasting 1,120 kg/ha (2.27 kg/plot) of 12‐6‐16 (N, P2O5, K2O) fertilizer 1 kr before tests began. Concentrations were high at the initiation of runoff and decreased with time as the volume of runoff increased. The average concentration of N ranged from 0.01 to 2.02 ppm, which is well below accepted public health standards. Potassium ranged from 0.01 to 2.29 ppm. Concentrations were highest fox all nutrients in runoff from the fertilized Juncos silty clay plots, because almost all runoff from this soil was actually interflow—infiltrated water that moved through the tilled zone and along the tilled‐untilled interface and then surfaced at the lower end of the plot. Although measured as runoff, no surface flow occurred except at the lower 0.3 to 0.6 m of the plots.
Water Uptake and Radicle Emergence of Cottonseed as Affected by Soil Moisture and Temperature1
Authors: Wanjura D. F. , Buxton D. R.
Published: July 2010

Cottonseed (Gossypium hirsutum L.) germination was studied to estimate the effect of a wide range of constant soil temperatures and moisture tensions on seed water uptake and germination. This information was utilized in developing relationships expressing germination response as a function of the two soil parameters. Seed were placed in covered plastic cups containing soil, and seed moisture changes were measured until radicle emergence occurred. Constant temperatures were maintained by water‐bath tanks. Radicle emergence time decreased according to a Q10 relationship between 15.6 and 32.2 C with little change at 37.8 C. Water uptake rate increased with higher temperatures and lower soil moisture tensions (.3 to 10 bars). Seed moisture content at 3‐mm radicle emergence tended to be higher at the extreme temperatures (15.6 and 37.8 C) than at intermediate temperatures. Under some constant temperature and moisture environments, seeds apparently absorbed water in excess of the minimum requirement for radicle emergence. A temperature decrease of 6.2 C caused the same increase in variance of radicle lengths as an increase of 1.1‐bars soil moisture.
Interrelationships of Aluminum and Manganese on the Potato Plant1
Authors: Lee C. R.
Published: July 2010

Potatoes (Solanum tuberosum L.) var. ‘Netted Gem’ were grown in nutrient culture solutions and sand cultures to study the interrelationships of Al and Mn on plant growth, mineral nutrition, and tuber yield. Counteracting effects of Al and Mn levels in the growth medium were observed in the color of plant tops. Visual symptoms of Mn‐induced Fe deficiency in nutrient solution cultures were associated with Mn/Fe concentration ratios of 18 or more. Aluminum counteracted these symptoms by increasing plant Fe content and decreasing Mn/Fe ratios to less than 18. Absorption and translocation of P, Ca, and Mg were affected by the addition of either Al or Mn to the nutrient solution cultures. In sand cultures, Al stunted plant tops, while Mn lengthened plant tops. Potato tuber yields were reduced by Mn at a low Al level (0 ppm), not affected by Mn at intermediate Al levels (5 to 10 ppm) and increased by Mn at a higher Al level (20 ppm). The number, size, and specific gravtity of tubers produced were affected by Al levels but not by Mn levels. It is concluded that a more accurate evaluation of the influence of soil acidity on potato production can be obtained when the effects of both soluble Al and Mn in podzol soils are considered.
Nodulation and Nitrogen Fixation by Two Soybean Varieties as Affected by Phosphorus and Zinc Nutrition1
Authors: Demeterio Jefren L. , Ellis Roscoe , Paulsen Gary M.
Published: July 2010

Symbiotic N fixation by soybeans [Glycine max (L.) Merr.] is one factor determining yields of this important crop. Microelements have been shown to be important in metabolic processes in plants. This investigation was conducted to determine the effects of Zn and P on growth, nodulation, and N fixation, in two soybean varieties grown in solution cultures. Zinc deficiency decreased shoot weights, Zn concentrations in all plant parts, nodule weights, nodule leghemoglobin concentrations, and amounts of N fixed. Growth and P and Zn concentrations in one or more plant parts and nodule weights were greater for the P‐tolerant variety than for the P‐sensitive variety. Excess P decreased growth of all plant parts, nodule weights, nodule leghemoglobin concentrations, and amounts of N fixed. Nodule weights and amounts of N fixed were greater for the P‐tolerant variety, particularly at the higher P level. Zinc deficiency and excess P may influence N fixation directly by affecting nodule nutrition and indirectly by affecting host nutrition.
Effect of Aerial Environment and Soil Water Potential on the Transpiration and Energy Status of Water in Wheat Plants1
Authors: Yang S. J. , de Jong E.
Published: July 2010

Water stress is an important factor limiting wheat (Triticum aestivum L.) growth on the Canadian prairies. To determine the effect of evaporative demand and soil water potential on transpiration and leaf water status, Thatcher wheat was grown under four combinations of air temperature and relative humidity in a loam and a clay soil. Transpiration rate, leaf water potential, leaf water content, and soil water potential were determined. The relationship between transpiration rate and soil water potential depended on evaporative demand and soil texture. The decline in the transpiration rate from its maximum commenced at higher soil water potentials under conditions of higher evaporative demand and was more gradual on the clay than on the loam soil, presumably due to the higher capillary conductivity of the former. Permanent wilting occurred at soil water potentials of —20 to —25 bars on the loam soil and at —45 to —50 bars on the clay soil. At these potentials the capillary conductivities of both soils were about equal. Resistance to Water flow in the plant decreased with increased temperature, while changes in relative humidity had no consistent effect. The total resistance to water movement in the plant and the soil increased with decreasing soil water potential and decreasing air temperature. The relationship between leaf water potential and relative water content was affected by aerial environment and soil texture.
Water Use by Sugar Beets in a Semiarid Environment as Influenced by Population and Nitrogen Fertilizer1
Authors: Moraghan J. T.
Published: July 2010

Little information is available concerning the utilization of soil moisture by sugar beets (Beta vulgaris) under dryland conditions in a semiarid environment. The influence of population (26,400 and 70,700 plants/ha) and N fertilizer (0, 56, 112, and 224 kg N/ha) on water use by sugar beets under such conditions was studied. The growing season was characterized by long periods with little precipitation, and extensive use was made of stored soil moisture to a depth of at least 183 cm. The higher population and N fertilizer treatments increased water use by approximately 9.5 and 3.5%, and yield of sucrose by approximately 20 and 15%, respectively. The leaf area index was increased percentage‐wise much more markedly by both treatments. During the growing season the greatest effect of increasing population on water use was most evident in the deepest depths from which moisture was being utilized. The sugar beets apparently utilized soil nitrate to at least 152 cm.
Depletion of Nitrate Reductase Activity in Response to Soil Leaching1
Authors: Long R. C. , Woltz W. G.
Published: July 2010

Nitrate leaches readily from sandy soils. To test the sensitivity of nitrate reductase (a substrate‐inducible enzyme) as an indicator of nitrate leaching and restoration, low, normal, and high N treatments were imposed on young tobacco (Nicotiana tabacum L.) plants grown on a Durham sandy loam soil (Typic hapludult). Subsequent treatments imposed were soil leaching with and without a later application of replacement fertilizer. Plants were sampled at frequent intervals to determine the rapidity of changes in tissue nitrate concentration and nitrate reductase activity. Tissue nitrate concentration decreased within 24 hours after leaching in all N treatments in 1968. Nitrate reductase activity was decreased in the low and normal N treatments. The addition of replacement fertilizer resulted in increased nitrate reductase activity in the low and normal N treatments within 24 hours.
Influence of Salinity on Fe, Mn, and Zn Uptake by Plants1
Authors: Mass E. V. , Ogata Gen , Garber M. J.
Published: July 2010

This investigation was conducted to determine the influence of salinity on the uptake of Fe, Mn, and Zn by plants during the period of rapid vegetative growth. Relatively few data are available on the micronutrient status of salt‐stunted plants. Tomato (Lycopersicon esculentum Mill. ‘Heinz 1350’), soybean (Glycine max L. ‘Kanrich’), and squash (Cucurbita pepo ‘Golden Summer Crookneck’) were grown in the greenhouse in half‐strength Hoagland‘s solution salinized with 0, 25, 50, 75 and 100 meq NaCl/liter. Concentrations of Fe and Zn increased in the roots and tops of each species with increasing ambient levels of NaCl. Manganese concentrations increased in tomato and soybean tops but decreased in squash tops. Concentrations of Mn in the roots of tomato and squash were reduced at all salt levels, but they increased in all but the 100 meq/liter treatment in soybean. The changes in contents as a function of salinity were in the order of twofold or less and all were significant at the 5% level or better. Although the vegetative growth of the plant tops was depressed 45% or more by the highest saline treatment, the concentrations of these micronutrients in the tissue remained within the physiological limits necessary for normal plant growth. The influence of NaCl on the contents of Ca, Mg, K, Na, and Cl in the plant tops was comparable to that found in other investigations of salinity effects on plant mineral composition.
Corn for Silage as Influenced by Hybrid Maturity, Row Spacing, Plant Population, and Climate1
Authors: Cummins D. G. , Dobson J. W.
Published: July 2010

Most research on corn (Zea mays L.) silage production has been conducted in the northern United States and results do not necessarily apply to growing conditions in the South. Therefore in 1968 and 1969, corn was grown in the Piedmont (elevation 282 m) and Mountains (elevation 584 m) of Georgia to determine the influence of hybrid maturity row spacing, plant population, and climate on silage dry matter yields, percentage ears, leaves, and stalks, and in vitro dry matter digestibility (IVDMD). An early and late maturing hybrid was grown in 51 and 102 cm rows with 49‐, 68‐, and 86,000 plants/ha in the Piedmont, and a late maturing hybrid was grown in the Mountains in 61, 76, 91, and 107 cm rows with 30‐, 45‐, 59‐, and 74,000 plants/ha.

In the Piedmont, yields were not significantly different for the early and late maturing hybrids, significantly higher in 51 than 102 cm rows (11.9 vs 11.3 mt/ha), and increased significantly as populations increased from 49‐, 68‐, to 86,000 plants/ha (10.5, 11.6, to 12.3 mt/ha). In the Mountains yields were not significantly different for row spacing, and increased significantly as populations increased from 30‐, 45‐, 59‐, to 74,000 plants/ha (17.7, 21.1, 24.4, 26.0 mt/ha). As populations increased from 49 to 86,000 plants/ha at the Piedmont location, ear content decreased from 55 to 45 percent and stalk content increased from 27 to 32 percent. This resulted in significantly lower IVDMD at 86‐, than 68,000 plants/ha (63 vs 65.8 percent). In the Mountains as populations increased from 30‐ to 74,000 plants/ha, less change in ear (57 to 53 percent) and stalk (16 to 18 percent) content was observed with no change in IVDMD with varying papulations. Row spacing did not influence IVDMD at either location. These differences in response to management of corn grown for silage between these locations were attributed to more evenly distributed rainfall and lower temperatures at the Mountain location, and should be somewhat comparable to production response at average northern and southern locations.
Autumn Cutting Effects on Alfalfa Yield and Persistence in Alabama1
Authors: Mays D. A. , Evans E. M.
Published: July 2010

The research described herein was conducted to test the hypothesis that alfalfa (Medicago sativa L.) can be cut in September or early October in the southern United States without detrimental effects.

‘Williamsburg’ and ‘Dupuits’ alfalfa were planted at Muscle Shoals, Ala., in September 1963. From 1964 through 1966, 10 fall cutting regimes were imposed on the alfalfa. In 1967 residual yields were taken and stand densities were determined. Root carbohydrate analyses were made at the last autumn harvest and at 2‐week intervals until mid‐December each year.

Autumn cutting treatments had a greater effect on subsequent first harvest than on total yields. Total yields and stand density in 1967 showed that Williamsburg was quite tolerant to all cutting schedules and could safely be harvested in September or early October. The best yields and persistence of Dupuits were obtained where no fourth cut was taken. Date of third cut and consequent interval differences between the third and last cut affected subsequent growth and persistence of both varieties.

Root carbohydrate levels were slightly depressed for 2 to 4 weeks following harvest. However, the magnitude of fluctuation was much less than is usually reported. Carbohydrate levels did not drop from mid‐December to mid‐March.

It was concluded that a well‐adapted alfalfa variety could tolerate a wide range of fall managements in the climate typified by north Alabama.
Effectiveness of Two Nitrification Inhibitors for Anhydrous Ammonia Under Irrigated and Dryland Conditions1
Authors: Cochran V. L. , Papendick R. I. , Woody W. M.
Published: July 2010

Potassium azide (KN3) and 2‐chloro‐6‐(trichloromethyl) pyridine (N‐Serve) were evaluated as nitrification inhibitors for anhydrous NH3 field applied on irrigated and nonirrigated Ritzville silt loam and on nonirrigated Naff silt loam in eastern Washington. Formulations of KN3, N‐Serve in liquid NH3, or NH3 alone were applied to fallow soil in midsummer at a rate of 90 kg N/ha. Irrigations were 15 cm of water sprinkler applied 1 day or 2 weeks after fertilizer application, and 10 to 15 cm of water each time at 4, 8, and 13 weeks after NH3 application. The NH3 retention zone was sampled for NH+4 and NO−3 periodically through December for the Naff soil and through February for the Ritzville soil. Both KN3 and N‐Serve effectively inhibited nitrification of the applied NH3 on nonirrigated Ritzville soil when temperature and soil moisture were favorable for rapid nitrification. However, KN3 was completely ineffective following irrigation or, for the Naff soil, after rainwater penetrated below the retention zone 2 weeks after N application. Where irrigated 1 day or 2 weeks after fertilization application, all of the applied N had disappeared from the initial NH3 retention zone in the Ritzville soil in 8 to 13 weeks for both NH3 alone and NH3 + KN3. Results with the Naff soil for these applications were similar to results with the irrigated Ritzville soil. By contrast, N‐Serve effectively suppressed nitrification under leaching and nonleaching conditions.

For the Ritzville soil, total N uptake by the wheat (Triticum aestivum L.) crop for different rates of fertilizer application followed the order of NH3 + KN3 > NH3 + N‐Serve > NH3 alone, but grain yields with NH3 + inhibitor were not different from yields with NH3 alone. For the Naff soil there was no N‐uptake or grain‐yield response to N rates, and thus no response to the inhibitors.
Accumulated Heat Units for Classifying Corn Hybrid Maturity1
Authors: Mederski H. J. , Miller M. E. , Weaver C. R.
Published: July 2010

Previous studies comparing the accumulated heat unit (AHU) method with the calendar day method for classifying corn (Zea mays L.) hybrids with respect to maturity do not clearly show the superiority of the AHU method over the calendar day method. They appear to have two limitations: (1) the range of climatic conditions under which the studies were conducted was not broad enough to elicit wide variation in the rate of occurrence of plant development and maturity, and (2) the studies were truncated at silking because the time interval from silking to maturity was assumed to be constant.

The objective of the study herein was to determine, under a wide range of climatic conditions, whether AHU methods are superior to the calendar day method for classifying the maturity of corn hybrids and predicting the occurrence of phenological events. For a particular corn hybrid grown under a range of climatic conditions, the number of calendar days between any two phenological events may vary widely but the AHU should be constant.

Four plantings of three corn hybrids were made at weekly intervals at seven widely dispersed locations in Ohio in 1969 and 1970. Calendar days and AHU, calculated by six methods, were determined from planting to tasseling and silking, and from planting to 40, 35, 30, and 25% kernel moisture and black layer formation.

The coefficients of variation of AHU and calendar days to a particular phenological event for each of the three hybrids were determined on the pooled data from the four planting dates and seven locations for each of 2 years.

The differences in coefficients of variation among the six AHU methods were relatively small. However, as a group, the AHU methods were about half as variable as the calendar day method for classifying corn hybrid maturity. The data indicated that the AHU method of classifying corn hybrids was superior to calendar days.
Hydrocyanic Acid Potential of Black Cherry Leaves1
Authors: Smeathers Dan M. , Gray Elmer , James John H.
Published: July 2010

Black cherry (Prunus serotina L.) leaves have been reported to be a cause of hydrocyanic acid poisoning of livestock. It has been widely accepted that cherry leaves must be wilted before they are toxic to cattle.

A study was conducted during the 1971 growing season at Bowling Green, Kentucky to determine the level of hydrocyanic acid potential (HCN‐p) in black cherry leaves and to ascertain the effect of wilting of leaves on HCN‐p.

Average HCN‐p of fresh leaves from six black cherry trees was highest (2472 ppm) in the spring and decreased rather consistently during the growing season. Average HCN‐p was high in fresh leaves and was intermediate and low in leaves air‐dried for 24 and 48 hours, respectively. A negative relationship was found between level of HCN‐p and dry matter percentage. There were no consistent differences among the six cherry trees for HCN‐p of leaves.

These results indicate that wilted leaves should be safer than fresh leaves for cattle consumption.
Reaction of Tall Fescue to Frequent Summer Nitrogen Applications1
Authors: Hallock D. L. , Wolf D. D. , Blaser R. E.
Published: July 2010

The postulation that tall fescue (Festuca arundinacea L. var. ‘Ky. 31’) might tolerate and respond more favorably to higher rates of N in summer if applied frequently in small increments was studied at Holland, Va. from 1966 to 1970. Weekly N applications of up to 56 kg/ha, May through August each year, and one application of 168 kg/ha each March, totalling 1,120 kg/ha by September 1, thinned stands of tall rescue by only 30%. Rates of N up to 22.4 kg/ha per week increased density of stands.

Annual dry matter yields increased from 41 to 110 q/ha as N rates increased up to 39.2 kg/ha per week. Yields from the May harvests were highest with generally lower yields in successive cuttings taken every 4 to 6 weeks through September. Nitrogen content was lower in the May cuttings than in succeeding cuttings. Generally, protein concentrations increased in the summer cuttings as the rate of N increased to 22.4 kg/ha per week, above which no increase occurred. Nitrogen uptake by fescue increased from 90 to 375 kg/ha as weekly N rates increased from 0 to 56 kg/ha. The proportion of N removed in rescue forage relative to that applied was highest (61%) from 5.6 kg/ha per week of N and lowest (33%) from 56.0 kg/ha per week of N.

Use of tall rescue may be feasible as a vegetative cover for disposal of high N waste if applied frequently in small increments.

Soluble carbohydrate concentrations in the stubble probably were not low enough (7%) to influence regrowth and stand survival appreciably.
Quantitative Soil Moisture Use in Corn Grown Under Conventional and No‐tillage Methods1
Authors: Hill Jerry D. , Blevins R. L.
Published: July 2010

Experiments conducted at the University of Kentucky during 1969, 1970, and 1971 compared corn (Zea mays L.) production under conventional and no‐tillage systems. The presence of a killed‐sod mulch in the no‐tillage plots almost eliminated the loss of moisture by direct evaporation from the soil surface during the early growing period, but after a full crop canopy had developed, losses from both production methods were about equal. Water loss from the soil during the full‐canopy period was compared with open pan evaporation to determine the rate of loss under varying levels of soil moisture deficiency.

The average soil moisture deficiency during the period from about 3 weeks before to 6 weeks after silking was related to final grain yield, and a simple linear relationship indicated that each additional cm of water available to the plant increased yields by about 559 kg/ha. The relationship was tested on regional yield data for the years 1954 to 1968. Soil moisture status was simulated from precipitation and temperature data observed during the growing season by using the Palmer Crop Moisture Index method. The variation in predicted and observed yield follow each other very well, with a linear correlation coefficient of 0.81.
Cutting Management of Sericea Lespedeza for Forage and Seed1
Authors: Hoveland C. S. , Anthony W. B.
Published: July 2010

Sericea lespedeza (Lespedeza cuneata (Dumont) G. Don.) is being utilized for pasture to a greater extent than in previous years in the southeastern United States, yet information is lacking on the response of this species to frequent and close defoliation. ‘Serala’ sericea was harvested under various management systems in central Alabama for 3 years to determine the effect on forage yield and quality, seed yield, persistence, and root reserves. Harvesting was begun on April 21 each year and terminated in June, August, or October. Forage yields were highest, over 9,000 kg/ha, when sericea was cut at 9‐week intervals until August or October. Cutting at 6‐week intervals reduced forage yields 41% and 53%, respectively. Clipping at a 4‐cm stubble height reduced forage yields below that of a 10‐cm stubble for the 3 or 6‐week cutting intervals, but had no effect at the 9‐week interval. Seed yields were higher, over 600 kg/ha, when one hay harvest was removed to leave a 10‐cm stubble than when cut more frequently. Seed production was responsive to stubble height of forage cut early in the season. Frequent cutting and a short stubble height reduced new shoot development and root reserves but did not affect stands. Digestible dry matter (DDM) of forage was similar for a given treatment throughout the growing season. DDM was slightly lower for forage when cut at 9‐week intervals than at 3 or 6‐week intervals but was unaffected by stubble height.
Length‐Width Method for Estimating Leaf Area of Rice1
Authors: Palaniswamy K. M. , Gomez K. A.
Published: July 2010

The length‐width method for estimating leaf area has been evaluated with traditional Indica and Japonica rices (Oryza saliva L.); the leaves of modern semidwarf rices, however, are quite different in shape. We therefore evaluated the length‐width method using 11,356 leaves taken from 2 semidwarf varieties grown under 3 fertilizer levels for 2 crop seasons. Measurement of length alone was unsatisfactory. The use of length times maximum width, however, was found satisfactory under most test conditions except at 30 days after transplanting and at maturity. In other cases, leaf area could be determined from K(L ✕ W), where L is the leaf length, W is the maximum width of the leaf, and K is 0.73 for dry‐season crops and 0.75 for wet‐season crops. This method is unbiased; estimates should have no more than 5% error.
Persistence and Yield of 10 Grasses in Response to Clipping Frequency and Applied Nitrogen in the Allegheny Highlands1
Authors: Jung G. A. , Balasko J. A. , Alt F. L. , Stevens L. P.
Published: July 2010

This research was undertaken to assess the influence of harvest schedules and fertilization on the persistence and productivity of four warm‐ and six cool‐season grass species under minimal temperature and moisture stresses. The grasses were clipped three, five, or eight times during each of 2 years. The first clipping each year was taken on April 26, May 7, or June 10 and aftermath clippings were taken at 21‐, 35‐, or 55‐day intervals, respectively. Ammonium nitrate was applied in three equal applications during each growing season. A total equivalent of 168 or 336 kg/ha was applied to each plot. Persistence of Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb.), orchardgrass (Dactylis glomerata L.), and Timothy (Phleum pratense L.) improved as clipping frequency was increased from three to eight cuts per year, especially at the high rate of N. Reed canarygrass (Phalaris arundinacea L.) and smooth bromegrass (Bromus inermis Leyss.) stands were better if clipping was less frequent. Stands of bermudagrass [Cynodon dactylon (L.) Pers.], indiangrass [Sorghastrum nutans (L.) Nash], big bluestem (Andropogon gerardi Vitman) and switch‐grass (Panicum virgatum L.) had deteriorated badly after 2 years, regardless of treatment. Orchardgrass was the most productive species overall and was least affected by the clipping and fertilizer treatments.

Dry matter yields of grasses in the second harvest year were differentially influenced by clipping and nitrogen fertilizer (3‐factor interaction = P < .005). At the high rate of N, orchardgrass, reed canarygrass, and smooth bromegrass yields were highest with three clippings, tall fescue and timothy yields were highest with five clippings, and Kentucky bluegrass yields were highest with eight clippings. At the low rate of N all species, except Kentucky bluegrass and timothy, produced highest yields with three clippings. Timothy yields were highest with five clippings, and clipping frequency had little effect on bluegrass yields.

Yields were reduced most by infrequent clipping at the high rate of N (Kentucky bluegrass, tall fescue, timothy) and by frequent clipping at the low rate of N (all species except bluegrass).

Persistence and yield distribution responses to clipping and nitrogen fertilizer were different from those commonly reported for lower elevations and were attributed to less temperature and moisture stress. Management requirements for warm‐season grasses differ from those for cool‐season grasses and need to be studied in more detail.
Response of Corn and Soybeans to Field Applications of Copper1
Authors: Oplinger E. S. , Ohlrogge A. J.
Published: July 2010

Copper deficiencies have been recognized on muck soils for over 35 years. Cu deficiencies and responses under a wide range of growing conditions and soil types in Indiana have been identified by several workers. This study was initiated to establish the need for copper fertilization on certain Indiana soils and to investigate the utility of tissue analyses as a diagnostic tool for identifying such situations.

Spectrographic analysis of corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) tissue samples submitted by farmers and dealers in 1966 to the Purdue Soil and Plant Analysis Laboratory, were used to locate fields producing crops with copper levels below 5 ppm in the leaf tissue. In the spring of 1967, 44.8 kg Cu/ha was applied at 12 locations. These treatments were effective in increasing the leaf tissue copper level in both corn and soybeans. Corn yields were increased 3 to 12% on all five harvested locations and soybean yields 1.3% and 14.2% on both harvested locations.

In 1968 and 1969, increased copper uptake was indicated by higher tissue copper levels and by increased yields. Differences in treatments were more evident in corn tissue sampled 1 month prior to tasseling than when sampled at tasseling time. Yield increases as high as 22.5% in 1968 and 17.9% in 1969 were obtained even though tissue copper levels were not below the “critical level” of 5 ppm. Corn yields in 1968 on a “Chalmers” silty clay loam were increased an average of 6.7% with copper applied in 1968, while yields of corn grown on the same plots with no additional treatment were depressed 6.4% in 1969. In this instance, yields decreased more with cupric sulfate than with cuprous oxide.

The largest and most consistent yield increases were obtained on sandy loam and high organic matter soils. It was concluded that corn and soybean yields could be significantly increased with copper additions on selected mineral soils of northwestern and north central Indiana.
Comparison of Spring Wheat and Barley with Winter Wheat: Yield Components in Ontario1
Authors: Stoskopf N. C. , Nathaniel R. K. , Reinbergs E.
Published: July 2010

Studies were conducted to evaluate the reportedly high yielding Mexican and European spring wheat (Triticum aestivum L.) cultivars under different management systems under southern Ontario conditions. We evaluated the potential of selections from spring wheat crosses and crosses between spring and winter wheat. Spring wheat yielded 20 to 32% less than spring barley (Hordeum vulgare L.) and 40% less than winter wheat in tests at five locations over a 4‐year period. Spring wheat lacked yield stability over years and locations.

Tillering capacity, kernels per spike and kernel weight were lower in spring wheat than barley and winter wheat. The weakest component of spring wheat yield appeared to be the 20.6 average number of kernels per spike. A negative relationship was found between tillering and kernels per spike. This and the short period from seeding to maturity often associated with environmental stress may explain why management practices of increased nitrogen fertilization or reduced seeding rate had little influence on grain yield. Seeding delays reduced yields markedly.

Spring wheat in southern Ontario appears to be limited by environment so that superior genotypes may not express their full potential. Crosses between spring and winter wheat lines may, therefore, have a greater potential for winter wheat improvement in Ontario than for selection of spring wheat types.
Aluminum Tolerance of Wheat Cultivars Related to Region of Origin1
Authors: Foy C. D. , Lafever H. N. , Schwartz J. W. , Fleming A. L.
Published: July 2010

On certain acid soils of Ohio, certain Indiana‐developed wheat (Triticum aestivum L.) cultivars have performed poorly relative to Ohio cultivars. Preliminary observations suggested the possibility that Ohio cultivars, in general, have been indirectly selected for greater tolerance to Al toxicity than those from Indiana. This hypothesis was tested by growing 27 established cultivars and 19 experimental lines in greenhouse pots of acid (initial pH 4.2 to 4.4), Al‐toxic, Bladen clay loam treated with 0 or 3,000 ppm CaCO3

On the basis of relative yield (no lime/lime %), the maximum range of tolerance to the unlimed soil was 8‐ fold for tops and 12‐fold for roots. Cultivars showing greatest tolerance included ‘Thorne’ and ‘Seneca’ (Ohio origin); among those showing least tolerance were ‘Arthur’ and ‘Redcoat’ (Indiana origin). Differential Al tolerance among these four cultivars was also confirmed in nutrient solutions. With 4 ppm P in solution, the relative root yields (2 ppm Al/no Al %) were 42.7, 57.0, 13.3, and 5.4% for Thorne, Seneca, Arthur, and Redcoat, respectively. In this experiment the top yields of the four cultivars did not differ appreciably in response to Al. However, with a lower P level in solution (2 ppm) the cultivars differed in both top and root growth under Al stress. Relative root yields (3 ppm Al/no Al %) for Thorne and Redcoat were 48.4 and 14.9%, respectively; corresponding relative top yields were 45.1 and 34.5%. Under Al stress the Al‐sensitive Redcoat and Arthur maintained the pH of nutrient solutions at lower levels than the more tolerant Thorne and Seneca. Greater Al sensitivity in Arthur and Redcoat cultivars was not consistently associated with higher concentrations of Al or with lower concentrations of Ca or P within plant tops or roots.

We concluded that the older Ohio wheat cultivars have been selected, unknowingly, for greater Al tolerance than those in Indiana, and that this trait has been maintained in many of the newer Ohio lines which have been developed on more heavily limed sites, where Al toxicity is not a factor. The results suggest the possibility of breeding wheat cultivars for better adaptation to acid surface or subsurface soils in which the complete neutralization of acidity is mechanically difficult, economically unfeasible, or otherwise undesirable.
Relation of Soybean Leaf Water Potential to Soil Water Potential1
Authors: Brady R. A. , Powers W. L. , Stone L. R. , Goltz S. M.
Published: July 2010

Estimation of plant water potential is a possible aid in irrigation scheduling. This work examined the relation of maximum and minimum soybean (Glycine max (L.) Merr.) leaf water potential to soil water potential. Maximum readings were taken near sunrise and minimum readings were taken between 1300 and 1500 CDT. Leaf water potentials were measured with a pressure chamber and soil water potentials were estimated using moisture release curves and volumetric soil moisture measurements made with a neutron probe. Leaf water potentials decreased an average of 9 to 10 bars as a result of daily atmospheric evaporative demand during the vegetative stage. Soybean leaf water potential was as responsive to changes in soil water potential during the podding stage as during the vegetative stage. Data indicated the possibility of estimating soil water potential from early morning values of soybean leaf water potential.
Effect of Phosphorus and Ryzelan on the Growth and Mineral Composition of Chickpeas1
Authors: Maftoun M. , Bassiri A.
Published: July 2010

Phosphorus uptake, accumulation, and distribution have received much attention due to the increasing importance of fertilizer P in crop production. However, information concerning herbicide and P interaction is limited and there is no report available about the effect of P on the phytotoxicity of 3,5‐dinitro‐N4,N4‐dipropyl‐sulfanilamide (Ryzelan). Therefore, the present study was undertaken to determine the effects of P and/or Ryzelan on the growth and mineral contents of chickpea (Cicer arietinum L.).

Chickpeas were grown for 7 weeks in two arid region soils containing various levels of Ryzelan (O, 2 and 4 ppm) and P (0, 50 and 100 ppm). Dry matter yields and pant N, P, Ca, Mg, K, Na, and Fe contents were determined. Total N was determined by the micro‐Kjeldahl method; P by the ammonium molybdate‐stannous chloride method and Ca, Mg, K, Na, Fe, by atomic absorption spectrophotometer.

Application of herbicide suppressed growth, decreased total N and P uptakes and delayed emergence of seedlings as compared with control. In general, growth was more adversely affected in Maharloo soil than that in Kooshkak soil and in the former soil root growth was restricted more than top growth by Ryzelan treatment.

Addition of P increased the sensitivity of chickpeas to Ryzelan in Kooshkak. Moreover, application of P did not significantly affect plant height or dry weights in either soil, but increased total P uptake where no herbicide was added. Addition of Ryzelan increased the concentrations of N and P in the tops of chickpeas. The contents of Ca and Na by chickpeas were affected by P treatment and concentrations of K and Fe by Ryzelan treatment. Probably the unfavorable ratios of plant nutrients and/or the harmful influence of Ryzelan were the major factors which caused severe reduction of the dry matter yield.
Oven Drying of Small Herbage Samples1
Authors: Wolf D. D. , Ellmore T. L.
Published: July 2010

The method of preservation of forage tissue may influence the quality and quantity of the product. Oven drying with hot air is widely used; however, enzyme activity and respiration are stimulated during the moisture reduction process. Criterion for selecting efficient drying conditions, such as sample density, kind of container (cloth or paper), and size of container were investigated using alfalfa (Medicago sativa L.) herbage. The dry matter, total nonstructural carbohydrate (TNC), starch, reducing sugar, and nonreducing sugar percentages were related to drying rate.

Drying rate was linear until 80% dry weight was reached. Conditions requiring no more than 15 hours to reach 80% dry wt (density of 12 g dry wt per liter for paper sacks) were needed to hold loss within limits of experimental error for estimation of dry weight percentage. The TNC in all oven‐dried samples was less than in freeze‐dried tissue; however, data from cloth bags showed less loss and carbohydrate interconversion than paper sacks. Conditions requiring no more than 8 hours to reach 80% dry wt (density of 7 g per liter for paper sack) were required for sufficiently rapid drying to limit loss and interconversions of nonstructural carbohydrates within limits of experimental error. About twice this density was acceptable if cloth bags were used since the drying tune was reduced by about one‐half with cloth as compared to paper containers that had equal densities. Acceptable bulk densities will differ with efficiency of the drying equipment, but time needed for drying to 80% dry wt should not exceed these limits.
Soybean Yields and Lance Nematode Populations as Affected by Subsoiling, Fertility, and Nematicide Treatments1
Authors: Parker M. B. , Minton N. A. , Brooks O. L. , Perry C. E.
Published: July 2010

Soil compaction, nematode damage, and fertility problems occurring singly and in combination appear to be responsible for low yields of soybeans (Glycine max (L.) Merr.) in some Coastal Plain soils. This study was designed to determine if these conditions could be corrected with certain fertility treatments, subsoiling, and a nematicide.

A field study with ‘McNair 800’ soybeans was conducted in 1972–73 on a Marlboro sand (Typic Paleudult) which had a history of poor crop production. Treatments included: 1) lime, NPK, and a micronutrient mixture (B, Mn, Mo, and Zn) lime and NPK, lime and PK; 2) subsoiling under the row and no subsoiling; 3) a nematicide, 1, 2‐dibromo‐3‐chloropropane (DBCP), and no nematicide. Fertility, subsoiling, and nematicide treatments made up the main, split, and split‐split plots, respectively. Soil samples for nematode assay were taken at a depth of 0 to 20 cm in 1972 and depths of 0 to 20, 20 to 33, and 33 to 46 cm in 1973.

In 1972, subsoiling or DBCP increased yields more than 60% over those of the control (no subsoiling and no nematicide) and subsoiling plus DBCP increased yields 11.7 q/ha or 88%. In 1973, subsoiling without DBCP did not affect yields significantly, but DBCP without subsoiling increased yields yields 10.6 q/ha or 74%. Subsoiling plus DBCP increased yields 13.7 q/ha or 95%. The micronutrient mixture was the only fertility treatment which increased yields significantly, but the element(s) responsible were not identified. Lance nematodes (Hoplolaimus columbus., 1963) were numerous both years but populations were reduced in DBCP‐treated plots. In the nonsubsoiled plots without DBCP, the greatest number of nematodes occurred in the 0 to 20 cm depth and populations decreased at greater depths. In subsoiled plots, there was a relatively even distribution of nematodes for depths of 0 to 20, 20 to 33, and 33 to 46 cm. Results indicate the importance of DBCP and subsoiling for soybean production on compacted soils infested with lance nematodes.
Effects of Seed Size on Soybean Performance
Authors: Smith T. J. , Camper H. M.
Published: July 2010

A positive relation has been reported between size of seed planted and subsequent seed yield for several crop spcies, but limited research has produced inadequate information on this relationship in soybeans [Glycine max (L.) Merr.]. The potential for increased yield justifies further studies, especially in view of the relative ease of grading soybean seed for size. Use of more uniform seed also should result in greater uniformity of seed distribution by mechanical planters. Ten field experiments in 6 years compared effects of seed size on subsequent seed yield and certain plant characteristics that might be associated with yield of soybeans. Three or four seed size variables and three to eight genotypes were included in each experiment. Seed size variables were: (i) “large” — largest seed screened from each seed lot planted, (ii) “small” — smallest from each lot, (iii) “large‐small” — equal numbers of two sizes, and (iv) “field‐run” — un‐graded seed before removing large and small.

Seed size had little or no effect on initial plant stand, plant mortality, lodging, and mean size of harvested seed. Genotype and year had pronounced effects upon percentage of barren plants, but no meaningful relationship was established between percentage of barren plants and seed yield. Average seed yield of progeny from large seed planted alone exceeded the yield from small seed by 5.4% in 10 experiments, from large‐small by 4.7% in eight experiments, and from field run by 3.3% in four experiments. Average seed yield from small seed equalled the yield from large‐small in eight experiments and was 3.2% less than from field run in four experiments. When large and small seed were planted in the same row, progeny from large seed always produced more yield than those from small seed. No genotype ✕ seed size interaction effects on yield were obtained. Seed size effects on progeny performance apparently were a response to relative seed size within a population and not a response to seed size per se.