bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield and Quality of Herbage Harvested Under Various Rainy−Season and Dry−Season Managements1
Authors: Omaliko C. P. E. , Obioha F. C.
Published: July 2010

Livestock production potentials in tropical areas are often unattainable because of limited availability of good quality herbage. Rates of herbage growth and lignification are high resulting in production of poor quality herbage during the rainy season and severe herbage scarcity during the dry season. Factors other than depleted soil moisture, which may contribute to the decreased production in the following dry season, needed investigation. This experiment, therefore, studied the influence which harvesting interval used during the rainy season may have on dry−season herbage production of three well−adapted herbage species.

Two−year−old swards of guinea (Panicum maximum, Jacq.), elephant (Pennisetum purpureum, Schum.), and star (Cynodon nlemfnensis, Vanderyst) grass were used in the experiment from March 1977 to March 1979. The grasses were grown on fine, sandy loam soil of the Nipologuri series (an chesol). Plots were mowed either every 3, 4, 5, 6, 8, or 10 weeks between 10 March and 27 October each year. Beginning the end of November until the end of March the following year, each plot was mowed at 4−week intervals irrespective of the rainy−season management. Results showed that infrequent rainy−season harvesting encouraged dry−season dry matter production. Mean dry matter yields were 1,022, 1,103, 1,108, 1,119, 1,171, and 1,189 kg/ha/month for 3, 4, 5, 6, 8, and 10−week intervals, respectively. Quality of the dry−season herbage was largely unaffected by the rainy−season management. Significant species differences existed with star grass being inferior to the others (cf. 10.0, 10.6, and 6.2% CP for elephant, guinea, and star grass, respectively). Quality decreased with the advance of the dry season, for example, 13.8 vs. 7.9; 29.2 vs. 33.0; and 40.1 vs. 43.1 for November vs. February guinea grass's percent crude protein, percent crude fiber, and percent acid−detergent fiber, respectively.

Use of a 6−week harvest interval and either guinea or elephant grass, but not star grass, was considered the best management combination for improved all−year quality herbage production in this tropical area.
Design and Construction of a Rhizotron‐Lysimeter Facility at the Ohio State University1
Authors: Karnok K. J. , Kucharski R. T.
Published: July 2010

A rhizotron‐lysimeter was constructed at the Ohio State University in 1979. This entirely below ground‐level facility consists of three main rooms: (1) An instrument room equipped with climatological and data acquisition instrumentation, (2) a water reservoir room used in the lysimeter portion of the facility, and (3) an observation area consisting of two rows of 15 observation‐lysimeter cells (60 ✕ 60 ✕ 90 cm high.)

The lysimeter portion of the facility operates on a Mariotte supply system which allows evapotranspiration rates to be determined concurrently with root observations. When the Mariotte supply system is not in use, leachates can be drawn under vacuum from each cell. The rhizotron‐lysimeter is initially being used to monitor the seasonal rooting responses and water use rates of several cool season turfgrasses.
Fuel Characteristics of Vegetable Oil from Oilseed Crops in the Pacific Northwest1
Authors: Bettis B. L. , Peterson C. L. , Auld D. L. , Driscoll D. J. , Peterson E. D.
Published: July 2010

In recent years, the agricultural industry has been threatened by the increased costs and limited supplies of petroleum fuels.

The purpose of this research was to evaluate vegetable oil from various oilseed crops adapted to the Pacific Northwest as a potential source of liquid fuel for diesel engines. Sunflower (Helianthus annuus L.), oleic and linoleic safflower (Carthamus tinctorius L.), and low and high erucic acid rapeseed (Brassica napus L.) oils were evaluated for fatty acid composition, energy content, viscosity, and engine performance in short‐term tests. During 20‐min engine tests power output, fuel economy, and thermal efficiency were compared to diesel fuel. The long‐term effect of using linoleic safflower oil as a fuel was evaluated in a single cylinder diesel engine operated for 830 hours.

Vegetable oils contained 94 to 95% of the energy content (KJ/L) of diesel fuel, but were 11.1 to 17.6 times more viscous. Viscosity of the vegetable oils was related to fatty acid chain length and number of unsaturated bonds (R2 = 0.99). During short‐term engine tests, all vegetable oils produced power outputs equivalent to diesel, and had thermal efficiencies 1.8 to 2.8% higher than diesel. After 830 hours of operation, linoleic safflower oil formed extensive carbon deposits in the combustion chamber and exhaust port and heavy gum deposits on the injector and compression rings. The development of an additive package to inhibit carbon and gum formation is essential before pure vegetable oils can be used for long‐term operation of diesel engines.
Nutritional Value of Hard Red Spring Wheat Grain Protein as Influenced by Fertilization and Cultivar1
Authors: Syltie Paul W. , Dahnke William C. , Harrold Robert L.
Published: July 2010

Cereal grains often vary sufficiently in protein content or amino acid composition to produce significant growth differences in experimental animals. A study was undertaken to determine the influence of fertilization and cultivar on the nutritional value of wheat. Two relatively unrelated hard red spring wheat (Triticum aestivum L.) cultivars, Era and Waldron, were grown during 1977 and 1978 on Heimdal (coarse‐loamy , mixed, thermic Udic Haploborolls) soils in eastern North Dakota. Fertilizer N, P, and K were applied in several combinations to determine if differences would occur in grain protein. Sprague‐Dawley albino rats were fed vitamin and mineral‐fortified grain diets from 11 of the fertility treatments and the two cultivars each year to determine if treatment and cultivar would result in differences in diet consumed, rate of gain, feed per gain, protein efficiency ratio (PER), and protein digestibility coefficient (PDC). In 1977, with relatively high initial available N, additions of fertilizer N increased grain protein 1.6 percentage units and caused highly significant increases in diet consumed and rate of gain, and a decrease in feed per gain; PER and PDC were not affected. In 1978, with low initial available soil N, fertilizer N increased grain protein by 2.1 percentage units, reduced PER and increased PDC values. Adding micronutrients and S to the soil after planting did not affect PER values but significantly improved PDC values. The fact that the grain from the low N treatments and the low residual N site tended to have low protein contents, but higher nutritive value of the protein, tends to support the widely acknowledged inverse lysine‐protein relationship. Improved protein utilization at lower dietary protein levels may also have been a factor in improving PER values.
Yield Component Comparisons between USA and USSR Winter Wheat Cultivars1
Authors: Black A. L. , Aase J. K.
Published: July 2010

Information is needed to improve our understanding of the USSR literature regarding cultural and climatic influences on winter wheat (Triticum aestivum L.) production. Effect of seeding rates, N‐fertilization rates, and growing season precipitation on tiller formation and grain yield components of winter wheat were investigated by growing one US cultivar (‘Roughrider’) and two USSR cultivars (‘Mironovskaya’ and ‘Bezostaya’) on a Williams loam (fine‐loamy mixed, Typic Argiborolls). Plant population densities ranged from 148 to 480 plants/m2 as a result of low and high seeding rates. With below average growing season rainfall, grain yield of these cultivars was not influenced appreciably by seeding rate or N‐fertilization. Number of tillers and head‐producing stems/unit area were about 20% higher on high population density plots than on low population density plots whereas number of kernels/head was about 20% less. With above average growing season rainfall, at respectively 0 and 45 kg/ha of fertilizer N, all high seeding rate plots had about 10 and 20% more heads/m2, respectively, than low seeding rate plots. Nitrogen‐fertilization alone increased number of head‐producing stems about 30%. At high plant population densities, number of kernels/head for Roughrider was 21 and 27% less than at low plant population densities with and without N‐fertilization, respectively, whereas both Mironovskaya and Bezostaya maintained higher kernel numbers than Roughrider with only about 8 and 12% respective decrease independent of N‐fertilization. Over the 2‐year period, grain yields ranged from 1,820 to 4,260 kg/ha. Grain yield could be predicted from leaf area indices at growth stage 10.4 of the Feekes scale (r2 = 0.960), from total dry matter production at maturity (r2 = 0.835), or from straw production (r2 = 0.908). Grain yields could not be predicted from number of tillers/m2 or from total dry matter production at any growth stage before maturity. Differences between US and USSR winter wheat cultivars in maintaining kernel numbers at high plant densities are apparently the product of breeding programs conducted under different environments and plant cultures.
Single‐Cross Bermudagrass Seed Production under Different Management1
Authors: Ahring R. M. , Taliaferro C. M. , Richardson W. L.
Published: July 2010

The ease with which bermudagrass [Cynodon dactylon (L.) Pers.] plants are vegetatively propagated, combined with their usual high degree of sexual self‐incompatibility, provides a simple mechanism for producing single‐cross seed. Such seed could be produced using two cross‐compatible, self‐incompatible plants vegetatively propagated in alternate rows in a production field. The feasibility of the system depends firstly on the seed yield potential of the parental plants and secondly on the acceptability of the hybrid plant population. This experiment was conducted to measure single‐cross seed yields and seed yield components from such a production block, as influenced by N fertilization and early‐season forage removal.

The cross‐compatible, self‐incompatible bermudagrass plants were Oklahoma Agric. Exp. Stn. accessions ‘A‐9959’ (PI 253302) and ‘Guymon’. Four levels of N fertilization (N = 22, 34, 67, and 101 kg/ha) and two spring mowing treatments were used in each of the 3 years of the experiment. The experimental design was a Latin Square, split‐block, replicated four times. The soil was a Brewer clay loam (fine, mixed, thermic Pachic Arguistolls). The mowing treatments consisted of mowing and removing all growth on or about 1 May (Management A) or mowing and removing all growth on or about 1 May and again on about 20 May (Management B). Nitrogen fertilizer was applied at the selected rates in single annual applications soon after the plots were mowed on or about 1 May. Seed yield (kg/ha) and seedhead density (seedheads/m2) were measured for 3 years (1975–1977), and florets/raceme and % seed set were measured for 2 years.

Seed yields (kg/ha) averaged over treatments ranged from 658 in 1975 to 818 in 1976 and had a 3‐year average of 743. Nitrogen fertilizer rates had no significant (P > 0.05) or discernible effect on any of the response variables. Significant effects due to management occurred for seed yield (P < 0.05) and seedheads/m2 (P < 0.05) in 1975 and for florets/raceme (P < 0.01) in 1976. Differences attributable to years were significant (P < 0.01) for seed yield and seedheads/m2. The only significant interaction was management x years for seedheads/m2 (P < 0.05). Seed yields were higher under Management A during each year of the experiment, though the difference was significant only in 1975. Management A plots had significantly more seedheads/m2 than Management B plots in 1975, but slightly fewer in 1976 and 1977. Management A plots also bore racemes with significantly more florets in 1976.

While the elucidation of management effects on bermudagrass seed production will require further experiments conducted over time, our results support the feasibility of using presently available germplasm to produce new single‐cross seed propagated cultivars.
Availability of Rock Phosphate as Measured by an Acid Tolerant Pasture Grass and Extractable Phosphorus1
Authors: Yost R. S. , Naderman G. C. , Kamprath E. J. , Lobato E.
Published: July 2010

As agricultural development intensifies in tropical countries and as costs of superphosphate production increase, the need for further evaluation of rock phosphates has become apparent. An acid tolerant pasture grass (Brachiaria decumbens Stapf.) was used to evaluate the initial and residual (3 years) availability of P from several phosphate materials. A field study was conducted on a Typic Haplustox of the Cerrado of Central Brazil. Initial availability of P supplied as normal superphosphate, Hyperphosphate, Thermalphosphate, and North Carolina rock phosphate was similar when the soils were not limed (pH = 4.3, Al = 1.4 meq/100g). Where lime had been added and pH was increased to 5.4 the P in Hyperphosphate and N.C. rock phosphate was initially less available than P added as superphosphate and Thermalphosphate. After 10 months of contact, lime no longer significantly depressed P availability in these relatively soluble rock phosphates as measured by forage dry weight. The P in the other phosphate rock of low citric acid solubility, Araxá, was virtually unavailable during the 3 months after application. However, within 13 months, maximum forage yields were attained where this material had been applied to unlimed soil and at 25 months maximum yields were obtained on both limed and unlimed soil. Higher rates of Araxá material were required to obtain maximum yields than with normal superphosphate. Forage yields were 2 to 4 times greater where superphosphate was surface applied each year than where similar amounts were incorporated prior to planting. A comparison of extractant methods for soil P indicated that highly acidic extractants (e.g., 0.05 N HC1 + 0.025 N H2SO4) overestimated available P where rock phosphate had been applied. Where superphosphate or rock phosphate had been applied, P availability was better assessed by extractants such as 0.5 M NaHCO3 and Bray 1. The results emphasize the need to supplement laboratory and short‐term studies with long‐term evaluations of P materials with acid tolerant perennial crop species available in tropical countries.
Effect of Amendments on Microhydrologic Properties of Compact Basal Till Soil and Yield of Alfalfa1
Authors: Chow T. L. , Saini G. R.
Published: July 2010

Greenhouse and field experiments were conducted to evaluate the efficacy of various amendments (lime, farm manure, and sawdust), alone and in combination, for improving hydrologic properties of a dense basal till soil (Fera Luvic Gleysol in the Canadian system of classification which is equivalent to Typic Ochraqualf in the U.S. system) and for increasing alfalfa (Medicago sativa L.) yield.

The amendments used in the experiments were mixed with sub‐soil samples fragmented to < 5 mm at a rate of 16 g/kg of sub‐soil on a dry basis and packed into PVC columns in which minature ceramic cups at various depths were installed to measure soil water matric potential during the growth period of crop planted in the columns. After the harvest of the crop the columns were used to determine bulk density and various hydrological properties of the soil.

The hydrological data of the soil indicated that the saturated hydraulic conductivity of sawdust‐treated sub‐soil was six times higher than the manure treatment and over 53 times higher than the control. Moisture retention curves suggested that an increase in percentage of pores > 29 micron was the major difference in pore size distribution between the organic matter treated and the nontreated sub‐soils.

The greenhouse, as well as the field experiments, showed that all organic amendment treatments gave significantly higher yields than the compacted and loosened sub‐soils but were not significantly different from each other. The increase in yield was much more pronounced in the field experiments as compared to the greenhouse ones. It was concluded from these experiments that the incorporation of farm manure and sawdust in the dense subsoils of basal till Fera Luvic Gleysols will improve their physical properties and hence the yield of alfalfa.
Dinitrogen Fixation Measured by 15N Isotope Dilution in Two Canadian Soybean Cultivars1
Authors: Rennie R. J. , Dubetz S. , Bole J. B. , Muendel H.-H.
Published: July 2010

Adapted cultivars must be developed if significant production of soybeans [Glycine max (L.) Merr.] is to be realized in western Canada. Selection and breeding for ability to support symbiotic N2 fixation is important in this development.

15N isotope dilution techniques were used to determine the percent plant N derived from the atmosphere (%Ndfa), i.e., fixation, and actual amounts of N fixed by two promising cultivars, X005 and Maple Presto. Precent Ndfa for the two cultivars was almost identical under comparable conditions. Depending on soil type and plant growth stage, %Ndfa varied from 38 to 70% in lysimeter experiments and maximized at 67% in the field. X005 fixed significantly more N2 (115 kg N/ha) than Maple Presto (82 kg N/ha) in the field because X005 had a higher N yield, possibly due to a slightly longer growing season. The N yield of both cultivars, when inoculated, did not respond to increasing rates of fertilizer N [Ca (NO3)2]. The highest percent fertilizer use efficiency (%FUE) was 51% when uninoculated and 44% when the seed was inoculated. Although N2 fixation occurred in both cultivars when fertilizer up to 160 kg N/ha was provided, the cultivars differed in their tolerance to fertilizer N with respect to N2 fixation. For X005, N2 fixation was constant as N fertilizer increased from 0 to 80 kg/ha but decreased by 24% where 160 kg N/ha was applied. For Maple Presto, N2 fixation was constant as N fertilizer increased from 0 to 40 kg/ha but decreased by 21% where 80 or 160 kg N/ha was applied. Both cultivars had similar %Ndfa and amount of N fixed/ha to soybeans in other countries.
Prediction of Wheat Grain Protein Content from Climatic and Edaphic Variables1
Authors: Porter Michael A. , Paulsen Gary M. , Feyerherm Arlin M. , Milliken George M.
Published: July 2010

Grain protein in wheat (Triticum aestivum L.) has important funtional and nutritional roles and methods to predict its content would be valuable to both producers and users. We developed statistical models to predict grain protein content of hard red winter wheat from soil fertility conditions during anthesis and climatic conditions during grain filling. Soil and grain samples were collected from two irrigated field locations and nine dryland field locations containing 12 wheat cultivars during three growing seasons. A number of models were constructed using SAS procedures. In the best model, five edaphic parameters—P, K, and nitrate concentration from 15 to 46 cm in the profile and organic matter contents from 0 to 15 cm and 15 to 46 cm in the profile—significantly predicted the response surface. There were significant location, year, and location × year effects, but climatic variables did not significantly affect the prediction surface in the set of experiments. The model can be used to predict wheat grain protein content, to identify factors that influence protein content, and to aid in managing wheat for higher protein content.
Second‐Brood Southwestern Corn Borer Infestation Levels and Their Effect on Corn1
Authors: Williams W. Paul , Davis Frank M. , Scott Gene E.
Published: July 2010

The southwestern corn borer, Diatraea grandiosella (Dyar), is recognized as a serious pest of corn, Zea mays L.; however, no data relating level of second‐brood southwestern corn borer infestation of corn and the resulting damage have been reported. To determine the effects of varying levels of second‐brood southwestern corn borer infestation, corn plants were infested at anthesis with 0 to 35 southwestern corn borer eggs in a field study grown at Mississippi State, Miss, on a Leeper silty clay loam (fine, montmorillonitic, nonacid, thermic, Vertic Haplaquepts) in 1974, 1976, and 1977. Grain yields were measured and stalks were dissected after harvest to determine the extent of tunneling. Infestations with increasing numbers of southwestern corn borer eggs were accompanied by a linear decline in yield. A quadratic type curve best described the relationship between number of eggs and number of tunnels in a plant and between number of eggs and extent of stalk tunneling. Damage sustained by corn plants infested with 25 to 35 eggs was heavy and differences among treatments were slight. These results indicate that investigators involved in the evaluation of corn genotypes for southwestern corn borer damage should consider applying approximately 30 eggs per plant in order to achieve a uniform, heavy infestation.
Phosphorus Fertilization and Sugar Yields of Fall Planted Sugarbeets1
Authors: Abbott J. L. , Nelson J. M.
Published: July 2010

Fall planted sugarbeets (Beta vulgaris L.) are commonly subjected to low winter soil temperatures which contribute to low available soil P. Two field experiments were conducted near Phoenix, Ariz. to determine the effects of P fertilizer and feedlot manure on residual available P and sugarbeet production. Sugarbeets grown on a Laveen clay loam (Coarseloamy, mixed, hyperthermic Typic Calciorthid) soil that had not received P fertilizer for 10 years were compared with those grown on the same soil that had received annual applications of P fertilizer prior to that crop. The effect of residual P was studied at four levels of N (0 to 300 kg N ha‐1). Another experiment on the same soil type evaluated residual P from manure applied at rates of 22,45, and 67 Mg ha‐1 two seasons prior to that crop. Maintaining a high level of residual P by applying P fertilizer to other crops in the rotation was an effective method of avoiding P deficiency in sugarbeets. Both sucrose concentration and sugar yield were influenced by high residual soil P. Soluble P measurements in petioles collected when soils were cold were generally related to sucrose concentration. Winter month soil temperatures as low as 6 C were observed in the Phoenix area. Sugarbeets responded equally to P fertilized soil relatively high in residual soil P compared with soil having residual P from feedlot manure with P fertilizer applied 2 Years earlier.
Tillage and Cultural Management of Irrigated Potatoes1
Authors: Buxton D. R. , Zalewski J. C.
Published: July 2010

Many intensively row‐cropped, irrigated soils are compacted and have slow water infiltration rates. This study was conducted to evaluate the relationship among soil compaction, water infiltration rates, and potato (Solanum tuberosum L.) yield and quality; and to determine the influence of tillage and other practices on soil compaction, water infiltration rates, and potato response. Twenty‐two commercial, irrigated potato fields were monitored and several tillage practices evaluated on soils from seven great groups. Soil compaction was evaluated by measuring penetrometer resistance. Although penetrometer resistance and water infiltration rates showed a large amount of variation in the 22 fields, they were not significantly correlated with each other. The correlation coefficient between penetrometer resistance 0.2 m below furrows and tuber yield was −0.38. Water infiltration rate was not associated with tuber yield nor quality. In the 18 fields with less than 600 g kg−1 sand, soil texture had little association with water infiltration rates, however, soil organic matter greater than 12 g kg−1 was positively associated with water infiltration rates. In the 22 fields, number of years between successive potato crops accounted for 33% of the variation in tuber yield with greatest yields when at least 4 years occurred between potato crops. In replicated tillage experiments, chiseling reduced penetrometer resistance to a deeper depth than moldboard plowing. Chiseling did not result in greater water infiltration rates, tuber yield, nor tuber quality than plowing. Chiseling and plowing in combination showed no advantage over either practice alone. Additionally, chiseling bed centers showed no yield advantage over an unchiseled check in fields that were previously plowed even though penetrometer resistance was reduced by chiseling. This study indicates that with proper irrigation management some deep tillage operations can be eliminated by many growers.
A Controlled Environment System for Turfgrass Research1
Authors: Augustin B. J. , Karnok K. J.
Published: July 2010

A need exists for a system capable of providing a realistic and controlled environment for conducting research on turfgrass swards. Therefore a controlled environment system was constructed for evaluating the morphological and physiological responses of turfgrass swards to laboratory controlled environmental conditions. The system consists of three basic components: (1) An acrylic plastic assimilation cell which covers a 1,000 cm2 sward of turf, (2) a four‐sided, glass root observation cell, and (3) an open gas exchange system with accompanying instrumentation. The system has the capability of controlled light intensity, light quality, daylength, diurnal air temperature, soil temperature, and relative humidity. The design of the facility allows continuous and concurrent monitoring of both morphological (shoots and roots) and physiological (photosynthesis, dark respiration, and evapotranspiration) responses of turfgrasses to a variety of laboratory simulated environmental conditions.
Use of Box‐Cox Transformation Technique for Fitting Crop Yield Trends
Authors: Lin Kuang‐Hsing T. , Huang Chung‐Liang
Published: July 2010

There is a need for a more general approach to selecting appropriate models for transformation of long‐term crop yield data prior to statistical analysis without a priori restrictions about the mathematical form of the model. A least restrictive formulation about the functional specification of a model is less likely to lead to erroneous results. The objective of the study is to illustrate a general approach to model selection via application of the Box‐Cox transformation technique to estimate national yield trends for corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] during the period 1960‐1979. Results suggest that corn and wheat yields were approaching a plateau level whereas soybeans showed no indication of levelling off of yields.
Device for Removing Mini – Rhizotrons from the Field1
Authors: McMichael B. L. , Brashears A. D.
Published: July 2010

Mini‐rhizotrons (glass or acrylic tubes) are gaining widespread usage as an acceptable means for observing in situ plant root growth under field conditions. These transparent tubes are placed in the soil to various depths, and roots growing against the surface of the tube are observed throughout the season. It is difficult to remove intact mini‐rhizotrons from the field for reuse to reduce cost because close contact between the soil and glass surface must be maintained. An inexpensive extraction device for the removal of mini‐rhizotrons with minimum breakage or marring of the surface is described. The unit consists of a shaft to which an expandable, spring‐loaded foot mechanism is attached. Foot plates expand and engage the bottom edge of the mini‐rhizotron tube after the foot mechanism is lowered to the bottom of the tube. A tractor lift or other suitable hydraulic lifting apparatus is then attached to the other end of the rod and the tube is lifted out intact. Modifications of the device to accommodate tubes of different sizes and lengths and to assure that the inner surface of the tube is not scratched by the device are discussed.
Central Appalachian Hill Land Pasture Evaluation Using Cows and Calves. III. Treatment Comparisons of per Animal and Hectare Responses1
Authors: Burns J. C. , Harvey R. W. , Giesbrecht F. G. , Cope W. A. , Linnerud A. C.
Published: July 2010

The productivity of hill land pastures using cow‐calf testers in formal grazing trials is not well documented. This study determined animal response and per hectare productivity of improved hill land pasture [mainly Kentucky bluegrass (Poa pratensis L.), and white clover (Trifoolium repens L.)], crownvetch (Coronilla varia L.), and birdsfoot trefoil (Lotus corniculatus L.) subjected to various pasture and animal management treatments during 6 years of evaluation. Soils ranged from primarily a fine loamy micaceous mesic, Typic Hapludult on the uplands to primarily a fine loamy mixed mesic Hapludult in the low lands. Treatments evaluated in April through June (period 1) consisted of N rates (0, 67, 112, and 224 kg ha−1) and continuously grazed crownvetch. From July through October (period 2) two additional legume rotational treatments and early weaning (0, 67, or 112 kg of N ha−1) were evaluated. Cow and calf daily gain (kg), calf gain (kg ha−1), and total digestible nutrients (TDN) (kg ha−1) from improved hill land pasture (IHP) in period 1 averaged 0.74, 0.97, 156, and 1470, respectively. The respective values for period 2 were 0.13, 0.72, 97, and 1100 and for the season were 0.44, 0.84, 245, and 2420. Cow‐calf units were stocked on IHP to average 2.11 ha−1 in period 1, 1.29 in period 2 and 1.54 for the grazing season. Continuous grazing of crownvetch compared with IHP during periods 1 and 2 or rotational grazing of crownvetch and birdsfoot trefoil in period 2 increased only cow daily gain. Calf daily gain in period 1 declined linearly with N rates while calf gain (kg ha−1) and stocking rate increased at a declining rate (quadratic term) at the higher N levels. Maximum calf gain ha−1 occurred at the 224 kg N rate, averaging 109 kg when pastures were stocked at 1.90 cow‐calf units ha−1. Calf gain ha−1 was not altered in period 2 by N rates while stocking rate increased linearly. Pasture productivity was increased by N rate in both periods 1 and 2 with 1 kg of applied N ha−1 yielding 2.47 kg of TDN ha−1 (Ŷ = 1507 + 2.47 X) in period 1 and 1.83 kg of TDN ha−1 (Ŷ = 1109 + 1.83 X) in period 2. Early weaning increased calf daily gain, calf gain and TDN ha−1 compared with conventional grazing, but calf daily gains were variable and less than expected.
Cowpea Response to Row Width, Density, and Irrigation1
Authors: Herbert S. J. , Baggerman F. D.
Published: July 2010

The interrelationships among row width, plant density, and irrigation are not well understood for cowpea [Vigna unguiculata (L.) Walp.], as shown by previous conflicting results describing the sensitivity of cowpea to drought. Two experiments, a three factor central composite, second order design in incomplete blocks, and a two factor split plot randomized block design, were used to quantify the yield responses of ‘California No. 5’ cowpea established at five row widths (25 to 125 cm), five plant densities (4 to 34 plants m−2), and five (0 to 200 cm) and two levels of irrigation at planting. Cowpea was grown on sandy clay loam soils (fine, mixed thermic families of Aridic and Torrertic Paleustolls) on the research farm in Lubbock and the Slab farm in Hereford, Tex. Seed yield was very dependent on irrigation, increasing linearly from 635 kg ha−1 to 2043 kg ha−1 at the Lubbock site without evidence of diminishing returns. At the second site more water was available from rainfall and irrigation and yields were greater (2837 kg ha−1). Highest yields were obtained with the combination of wide rows and high plant density while lowest yields resulted with high plant density in narrow rows. Of the components of seed yield, pod number per plant and seed number per pod were important regulators of seed yield, while seed size remained reasonably constant. Seed yield and harvest index results suggested that, in narrow rows, the more uniformly spaced plants explored the complete soil volume earlier, extracting more of the available soil water during vegetative growth, and leaving less available for reproductive growth than in wide rows. This restriction on reproductive development in narrow rows was accentuated most when plant densities were highest. Our study shows the need to examine plant interactions before management recommendations can be firmly established.
Nitrate and Total Alkaloid Concentration of 11 Pearl Millet Lines1
Authors: Krejsa Beverly B. , Rouquette F. M. , Holt E. C. , Camp B. J. , Nelson L. R.
Published: July 2010

Pearl millet [Pennisetum americanum(L.) Leeke] forage has been reported to become unpalatable under drought stress conditions in east Texas. This unpalatable millet has been found to contain high levels of nitrate and total alkaloid relative to palatable, apparently unstressed, pearl millet. This study was conducted to determine if alkaloid and nitrate levels vary among pearl millet lines. Eleven lines were evaluated in the field on a Darco soil (loamy, siliceous, thermic Grossarenic Paleudult). Chemical analyses were conducted on leaf blades, and stems plus sheaths of vegetative plants. Millet lines differed for total forage alkaloid concentration as well as for total forage nitrate concentration (P < 0.05). Though alkaloid levels of the lines were relatively low, they ranged six‐fold (from 17 to 101 mg kg−1) among millet lines. Nitrate levels ranged from 2.4 to 9.8 g kg−1among the lines. Total forage alkaloid and nitrate levels were positively correlated (r = 0.45, P < 0.05). Leaf blades contained more total alkaloid than stems plus sheaths, 75 vs. 17 mg kg−1, respectively; while stems plus sheaths contained more nitrate than leaf blades, 10.8 vs. 3.9 g kg−1, respectively. It may be possible to develop lines that have both low alkaloid and low nitrate accumulations.
Yield and Yield Components of Sorghum and Soybeans of Varying Plant Heights when Intercropped1
Authors: Elmore R. W. , Jackobs J. A.
Published: July 2010

A 2‐year field study was conducted to examine the effects of different sorghum (Sorghum bicolor L. Moench) plant heights on yield and yield components of both sorghum and soybeans (Glycine max L. Merr.) and to compare production of intercrop and monoculture cropping systems. In 1977, ‘Amsoy 71’ soybeans were planted with a short (1.2 m) and a tall (1.6 m) sorghum cultivar in alternate 0.38 m rows on a Drummer silty clay loam (Mollisol, fine‐silty, mixed, mesic Typic Haplaquoll). In 1978, two short (1.3 m) and two tall (1.6 m) sorghum cultivars were intercropped with four soybean cultivars in 0.4 and 0.8 m rows on a Coto clay (Oxisol, clayey, kaolinitic, isohyperthermic Tropeptic Haplorthox). Soybean yields with tall sorghum were 71 and 18% less than those with short sorghum for 1977 and 1978, respectively. These reductions were due to fewer pods/plant in both years, fewer seeds/pod in 1978, and decreased seed weight in 1977. Narrow rows increased soybean yields 50% with short sorghum and by 35% with tall sorghum in 1978. Intercrop tall sorghum yields were greater than short sorghum yields by 86% in 1977 and 74% in 1978. All yield components except plants/ha contributed to the increase in 1978. Intercrop soybean yields were 37 and 69% of monoculture yields in 1977 and 1978, respectively. Intercrop sorghum yields were 40 and 45% of monoculture yields in 1977 and 1978, respectively. Land equivalent ratios were not different in 1977, but in 1978 they were greater with tall sorghum than with short sorghum, 1.17 vs 1.10, and were greater in intercrop than in monoculture, 1.14 vs 1.00.
Mefluidide‐Induced Nitrate Accumulation in Pearl Millet Forage1
Authors: Fales S. L. , Wilkinson R. E.
Published: July 2010

Several recent studies have reported that mefluidide {N‐[2,4‐di‐methyl‐5‐[[(trifluoromethyl)sulfonyl]sulfonyl]amino]phenyl]acetamid} can improve the forage quality of perennial cool‐season grasses; however, there is no published information concerning the response of summer annual grasses to this growth regulator. The purpose of this study was to examine the influence of different rates of mefluidide application on growth, total‐N, and NO3N concentration in pearl millet [Pennisetum americanum(L.) Leeke]. In controlled environment experiments, mefluidide inhibited the growth of pearl millet when applied at the vegetative stage. On a whole plant basis, total N increased linearly with mefluidide rate from 1.3 mol kg‒1in control plants to 2.4 mol kg‒1in 1.12 kg ha‒1mefluidide‐treated plants. Nitrate‐N concentration increased linearly from 14.3 mmol kg‒1in control plants to 278.6 mmol kg‒1in 1.12 kg ha‒1mefluidide‐treated plants. Similar results were obtained for leaf tissue, the largest differences occurring as mefluidide rate was increased to 1.12 kg ha‒1. Total N increased from 1.7 mol kg‒1in control leaves to 2.7 mol kg‒1in 1.12 kg ha‒1mefluidide leaves, and to 2.8 mol kg‒1in 2.24 kg ha‒1mefluidide‐treated leaves. Nitrate‐N increased from 42.8 mmol kg‒1in control leaves to 314.3 mmol kg‒1in 1.12 kg ha‒1mefluidide‐treated leaves and declined to 250 mmol kg‒1in 2.24 kg ha‒1mefluidide‐treated leaves. Concentrations of total N and NO3‐N were inversely related to dry matter yield, implying that accumulations were a result of sustained nitrate uptake in the absence of growth. Levels of NO3‐N were reached that could be potentially hazardous to livestock, indicating that mefluidide should be used with caution on pearl millet.
Effect of Dimethyl Sulfoxide on Forage Digestibility1
Authors: Forwood J. R. , Owensby C. E.
Published: July 2010

Dimethyl sulfoxide (DMSO) has found use in agriculture as a carrier for plant toxicants and nutrients mainly due to its membrane penetrating properties. Our objective was to determine the effect of DMSO on forage digestibility. Effects of DMSO on digestibility were determined by adding 0.0, 8.5, 42.3, and 423 mM DMSO L−1 to in vitro dry matter digestion tubes (IVDMD) containing big bluestem (Andropogon gerardi Vitman) harvested in mid‐July. Concentrations of 0.0, 4.2, 8.5, and 423 mM DMSO L−1 were also added to tubes containing mid‐ and late July harvested big bluestem and late July harvested indiangrass [Sorghastrum nutans (L.) Nash]. The latter DMSO rates were also added to in vitro tubes containing fall harvested tall fescue (Festuca arundinacea Schreb.) cultivars Kentucky 31, Kenhy, MO 96, and ‘Hallmark’ orchardgrass (Dactylis glomerata L.). Rates of 0, 1.12, 5.60, and 22.4 kg DMSO ha−1 were foliarly applied to potted big bluestem plants in the late vegetative stage and to fieldstanding (uncut) ‘Kentucky 31’ tall fescue and ‘Hallmark’ orchardgrass in mid‐October. Soil type was a Mexico silt loam (fine, montmorillonitic, mesic Udollic Ochraqualf). Forage from the foliar application studies were harvested 24, 48, and 168 h after DMSO application. Dimethyl sulfoxide at 8.5 and 42.3 mM L−1 significantly increased big bluestem in vitro digestibility while 42.3 mM L−1 was most effective on indiangrass. The 423 mM L−1 rate severely reduced digestibility of big bluestem. In vitro digestibility of cool‐season grasses was significantly increased by 8.5 and 42.3 mM DMSO L−1, but not as greatly as with warm‐season grasses. There was no significant digestibility increase of warm or cool‐season grasses due to foliarly applied DMSO.
Calorific Energy Distribution within the Corn Plant1
Authors: Girardin Philippe
Published: July 2010

The distribution of dry matter and nutrients within the corn (Zea mays L.) is well documented, however this is not the case for the distribution of calorific energy. The calorific value of different above ground crop components (blades, sheaths, internodes, tassel, husks, shank, cob, and grains) was measured during both the vegetative and reproductive phases of corn growth under field conditions. The mean energy content (per unit of dry weight), calculated at the sixth leaf stage, at silking and at maturity averaged 4.35, 4.11, and 3.98 kcal g−1, respectively. When ash content was taken into consideration, the calorific values averaged 5.18, 4.65, and 4.14 kcal g−1 of dry organic matter, respectively. These values are useful for calculating the efficiency of solar energy conversion into chemical energy of dry matter.
Tripartite Symbiosis of Stylosanthes scabra Vog. Influenced by Soil Fertility Treatments of a Typic Eutrustox1
Authors: Purcino A. A. C. , Lynd J. Q.
Published: July 2010

Stylosanthes scabra Vog. is a drought tolerant forage legume with potential for improved pasturage within extensive subhumid, neotropical regions of the world. The objective of these studies was to determine effects of Glomus fasciculatum and soil fertility treatments on growth, nodulation, nitrogenase activity (NA), and nodule cytosol composition of the anthracnose resistant Seca cultivar, inoculated with Rhizobium leguminosarum, and grown on a Typic Eutrustox. The differential endomycorrhizal fungi experiment included levels of Ca3(PO4)2 and KCl. Top growth, nodule weight, and nitrogenase activity increased significantly with mycorrhizal fungi inoculation, P and K soil amendment. The interaction between endomycorrhizal fungi and Ca3(PO4)2 fertilization indicated that G. fasciculatum improved effectiveness of indigenous soil P, but not of P added as Ca3(PO4)2. Nodule cytosol of G. fasciculatum treated plants had higher contents of P, Ca, Mg, and K, but reduced Na. Ca3(PO4)2 fertilization increased cytosol content of P, Ca, and Mg, and significantly decreased Na. Potassium fertilization increased cytosol content of P and K, but decreased Ca, Mg, and Na. These results indicate practical means to attain improved growth and N2 fixation of inoculated S. scabra. with favorable effects from G. fasciculatum colonization when combined with proper soil fertility treatments.
Optimum Time of Day for Maximum Flower Opening of Faba Bean1
Authors: De Pace C. , Geng Shu , Filippetti A. , Ricciardi L.
Published: July 2010

The success of cross pollination by bees (Apis melliferaL. and Bombusssp.) depends on the number of flowers and the pattern of flower opening of a plant. Four cultivars of faba bean, Vicia fabaL. (‘Wierboon,’ ‘Minica,’ ‘Black Russian,’ and ‘Violetta di Policoro’) were studied for their patterns of flowering time and the implications on seed yield. Diurnal observations were made on 20 plants of three replications for each cultivar and for every 2 h from 0900 to 1700 h on 5 consecutive days. Time series models were used to fit the data, and the second‐order autoregressive model was found adequate. The fitted models indicated that Minica had a sharp daily flower‐opening peak compared with the other cultivars and that the peak flowering time was less regular in Wierboon than in other cultivars. These implied that Minica produced the most new flowers to display to bees but they were concentrated in a few hours; Wierboon tended to prolong its flowering peak when bees had decreased their visits to flowers. Although the flower patterns varied according to cultivars, the peaks of flowering time were similar. Usually, the number of flower openings increased from 0900 to 1500 h and then decreased. The number of new flowers opening peaked between 1500 and 1700 h.
The Segregation of Homogeneous and Blended Granular Fertilizers from a Rotary Spreader1
Authors: Karnok Keith J.
Published: July 2010

In recent years there has been much discussion regarding the use of homogeneous granular fertilizers vs. blended granular fertilizers on turfgrass. The common thought being that homogeneous fertilizers will provide a more uniform coverage when delivered from a rotary spreader than blended fertilizers. The objective of this study was to determine the relative particle dispersion of seven commonly used turfgrass fertilizers delivered from a rotary spreader. Seven complete fertilizer materials were tested: three homogeneous and four blended. The test procedure involved the spreading of fertilizer over a series of specially designed collection trays. A chemical and physical analysis was conducted on the material collected from each tray. Considering all fertilizers tested, there was relatively uniform dispersion of particles in the 1‐mm or greater size range. Particle sizes smaller than 1‐mm showed less uniform distribution across the effective spread pattern. For all fertilizers, P showed the greatest CV(5.0) along the spreader swath, followed by K (4.0) and N (1.6). The lowest overall CV (N, P, K combined) was exhibited by a homogeneous fertilizer (1.2), but was closely followed by a blended fertilizer (CV 1.6). Fertilizers having a small particle size range had the lowest overall CV. This study showed that when considering uniformity of fertilizer dispersion from a rotary spreader, a uniform particle size is more important than whether the fertilizer is homogeneous or physically blended.
Steer Performance and Productivity of ‘Kenhy’ Fescue and Persistence of Fescues in the Central Appalachians1
Authors: Burns J. C. , Harvey R. W.
Published: July 2010

Kentucky bluegrass (Poa pratensisL.), intermediate white clover (Trifolium repensL.), and orchardgrass (Dactylis glomerataL.) are the main hill land pasture (HP) species in the Applachian Mountains region, but frequently are semidormant during midsummer, which results in reduced animal gains. ‘Kenny‘ fescue (Festuca arundinaceaSchreb.) has characteristics that may permit greater productivity than HP at the higher elevations (920 m). This study compared steer (Bos taurus) daily gain and yield of total digestible nutrients (TDN) from Kenhy fescue and HP in summer and early fall of 1975 and 1976. The grazing trial, on a fine loamy, micaceous, mesic Typic Hapludult (Watauga silt loam), was discontinued after the second year. Invasion of Kenhy by Kentucky bluegrass and white clover reduced Kenhy stands from 97% in 1975 to 72% in 1977 and to 17% by 1978. From July through fall, steers grazing Kenhy gained less (0.34 vs. 0.59 kg day−1than steers grazing HP (P≤ 0.09), but in the dry summer (1976) Kenhy was more productive (1300 kg TDN ha−1vs. 1030). A subsequent 5‐yr small‐plot study verified stand changes noted in the grazing trial. Kenhy and ‘Kentucky 31’ fescue (K‐31), receiving two or four N applications of 56 kg ha−1each year were equally invaded by HP grass species. Kentucky bluegrass appeared in the fescue sods by the third year (12% for Kenhy and 6% for K‐31) and all treatments were less than 55% fescue by the fifth year. Productivity of Kenhy was less sensitive to summer stress than that of HP in the Central Applachian region, but neither Kenhy nor K‐31 were competitive with HP species at this elevation.
Indirect Estimation of Wheat‐Hairy Vetch Ratios in a Mixed Stand1
Authors: Twidwell E. K. , Johnson K. D. , Cherney J. H.
Published: July 2010

Forage researchers often times work with mixed grass and legume stands. The relative proportion each species contributes to the stand is an important determinant of forage yield and quality, but handseparating species is a time‐consuming and tedious task. A study was conducted to evaluate a laboratory technique for estimating wheat (Triticum aestivumL.) and hairy vetch (Vicia villosaRoth.) ratios in a mixed stand. Pure samples of two wheat cultivars and hairy vetch collected at the boot, milk, and soft dough stages of wheat maturity were mixed in known proportions and analyzed for total N concentration. The wheat and hairy vetch proportions were estimated by solving simultaneous equations for each mixture. The total N method was an effective means of estimating grass‐legume ratios in this two‐component mixture. The deviation of a predicted individual observation ranged from 1.46 to 5.50 percentage units. Precision of the method was not influenced by the wheat cultivar utilized or by the maturity stages selected. Total N determination is commonly done as a part of forage quality assessment in many experiments. Only a few additional total N determinations on the pure grass and legume components are necessary to estimate grass‐legume ratios.