bluuebunny/crossref_metadata_2025 huggingface dataset:
A Differential Fluid Manometer for Hydraulic Lysimeters1
Authors: McLaughlin N. B. , Davidson H. R.
Published: July 2010

A manometer that uses two fluids of different densities is described. The manometer is similar to the conventional manometer except that it has an enlarged reservoir at the top of the tube. The lower density fluid floats on the higher density fluid so that the interface between the two fluids is in the manometer tube and the free surface of the lower density fluid is in the reservoir. The manometer is read at the interface. The differential manometer has a greater sensitivity than the conventional manometer and is useful for measuring mass changes in a hydraulic lysimeter.
Irrigated Corn Yield Response to Nitrogen and Water1
Authors: Eck Harold V.
Published: July 2010

Irrigated corn (Zea maysL.) is a relatively new crop on the Southern High Plains where the groundwater supply for irrigation is declining. Field studies were conducted to determine the plant nutrient needs for corn on a predominant soil of the area, the effects of timing and duration of drought stress periods, and the interacting effects of N levels and drought stress on N nutrition and production of corn. Fertilizer N rates ranged from 0 to 350 kg/ha. Irrigations were applied or deleted to allow the crop to be unstressed (I‐1), stressed 2 weeks during late vegetative growth (I‐2), stressed 2 weeks during early vegetative growth (1‐2a), stressed 4 weeks during vegetative growth (I‐3), stressed about 4 weeks during grain filling (I‐4), and stressed about 2 weeks during grain filling (1‐5). The soil was Pullman clay loam (fine, mixed, thermic Torrertic Paleustolls). Fouryear average data (three with graded furrow irrigation, one in level borders) showed that 140 kg N/ha were sufficient for maximum yields. However, simultaneous experiments conducted on graded furrows and level borders showed that while 140 kg N/ha gave maximum yields on graded furrows, 210 kg N/ha were required in level borders. This comparison illustrates the possible fallacy in conducting fertilizer trials under one method of irrigation and extrapolating results to another. Two and 4 weeks of plant water stress during vegetative growth reduced yields of adequately fertilized (210 kg N/ha) corn 23 and 46%, respectively. Two‐week stress periods during late (1‐2) and early (I‐2a) vegetative growth had similar effects on grain yields. Relationships between lengths of stress periods during grain filling and yield showed that yields were reduced 1.2% for each day stress was imposed during grain filling; however, as indicated by the r2(0.31), there was considerable variation in the data. A N × water stress interaction occurred on grain yields. Adequate N slightly increased corn grain yield under stress and greatly increased yield with full irrigation. Excessive N did not reduce yield even with severe water stress, thus, there would be no reason to reduce N rates to reduce water stress. As grain yields increased, the ratio of grain yield to N yield decreased until maximum yields were attained and then remained constant, indicating little luxury consumption of N. At maximum yield, typical grain yield/N yield ratios were about 52:l. At harvest soil NO−3‐N levels showed that plants had removed most of the N applied at rates up to 140 kg/ha, but increasing amounts remained when N application rates were above 140 kg/ha.
Effect of Soil Acidity Factors on Nodulation and Growth of Vigna unguiculata in Solution Culture1
Authors: Hohenberg J. S. , Munns D. N.
Published: July 2010

Effects of low pH, low Ca, and high Al were tested on nodulation of Vigna unguiculatacultivars by the tolerant Rhizobiumstrain CB 756 in solution culture. Both pH (4.5) and Al (100 µM) caused delays in nodulation, particularly at low Ca (0.3 mM). At high Ca (3.0 mM) cultivar and treatment differences diminished with time. Cultivars differed in nodulation delay. In cultivar TVu 990 nodulation was most tolerant of acidity alone; in California Blackeye‐5 it was tolerant to Al; and in TVu 1190 it was sensitive to both stresses. Nodulation in three other cultivars was sensitive to Al. “Starter N” improved nodulation and plant growth. Cultivars whose growth was Al tolerant (in +N media) recovered more rapidly from effects of nodulation delay. Three types of symbiotic failure were observed. In TVu 1190, nodulation failure at high (100 µM) Al caused N deficiency. In TVu 990, host plant sensitivity to Al decreased N2fixation despite adequate nodule numbers. In Blackeye 5, nodulation was tolerant to Al and plant N was maintained, so that relative yields of +N and symbiotic plants were similarly decreased by Al.
Establishment, Dry Matter Yield, and Crude Protein of Fertilized Smooth Bromegrass on a Cleared Alaskan Soil1
Authors: Michaelson G. J. , Loynachan T. E. , Woodling F. J.
Published: July 2010

A study was established to evaluate the fertilizer responses of smooth bromegrass (Bromus inermis Leyss. cv. Polar) during the first 3 years of growth on a newly cleared soil (Typic Cryochrept) in interior Alaska. The fertilization rates in the N4 by P4 by K4 complete factorial experiment were N at 0, 45, 90, and 135 kg/ha, and P and K each at 0, 34, 68, and 102 kg/ha. Yield responses to N were minimal without application of the first 34 kg/ha increment of P, and a significant N by P interaction occurred each of the 3 years of the study. During establishment (1979), the first increment of N (45 kg/ha) increased growth over sixfold above the level of the nonfertilized control. Growth was improved throughout the 0 to 102 kg/ha range of P, with over an eightfold increase in total production. Potassium (0 to 102 kg/ha) also improved growth but to a lesser extent than N or P, giving just over a 150% increase in production. In 1980 and 1981, total dry matter yields from the two cuttings increased with added N from 0.26 and 0.21 Mg/ha at the 0 N rate to 2.6 and 2.0 Mg/ha with 45 kg/ha N, respectively. Comparable yields at 90 and 135 kg/ha N were 3.8 and 4.3 Mg/ha in 1980 and 3.4 and 4.7 Mg/ha in 1981. Multiple regression equations were developed to predict bromegrass yield and N uptake for the 1980 and 1981 seasons. Relatively high coefficients of determination were obtained for dry matter yield (R2 = 0.845 for 1980 and 0.857 for 1981) and for N uptake (R2 = 0.861 for 1980 and 0.872 for 1981). Linear responses to N suggest that rates above 135 kg/ha N may provide even higher yields and protein contents.
Introduction of Effective N2‐Fixing Rhizobia1 Strains into the Soybean Plant by Use of Fungicide Resistance1
Authors: Jones Roger , Giddens Joel
Published: July 2010

Experiments were designed to determine if thiram seed treatment reduces populations of competing rhizosphere microorganisms and enhances nodule formation by an effective inoculant strain. Soybeans [Glycine max (L.) Merr.] inoculated in a greenhouse experiment with an effective, fungicide‐resistant mutant of Rhizobium japonicum USDA 110 were shown to produce a greater proportion of nodule isolates that were fungicide resistant. Populations of fungicide resistant rhizobia in the rhizosphere were also found to be higher with fungicide treated than with untreated seed. Rhizosphere total bacterial counts and protozoan populations were lower with treated seed but seed treatment did not significantly affect plant growth. The use of fungicide seed treatment and inoculation with effective (high N2‐fixing) fungicide resistant R. japonicum may offer an improved method of soybean inoculation.
Bermudagrass, Tall Fescue, and Orchardgrass Pasture Combinations with Clover or N Fertilization for Grazing Steers. II. The Species Composition Index and Variability in Forage Growth and Consumption, and Animal Performance1
Authors: Fribourg H. A. , Carlisle R. J. , McLaren J. B.
Published: July 2010

Forage growth and consumption, animal gain, and beef production were estimated in a steer (Bos sp.) backgrounding experiment concurrently with several environmental, plant, and animal characteristics. This paper describes a technique that combines the dynamic changes in species composition in pastures over time into a Species Composition Index (SCI). This index can then be related to the effects of season, grazing periods, stocking rates, forage crude protein, precipitation, and air temperature on forage growth and consumption, and beef production. The SCI was compared to the traditional classification variable treatments to describe seven differently managed pasture combinations of different forage species. It was superior to treatments in explaining variability and appeared to be a sensitive tool for characterizing dynamically changing pasture compositions. It could be a useful and flexible tool in quantifying species cover in many other situations.
Corn Irrigation Scheduled by Tensiometer and the Lambert Model in the Humid Southeast1
Authors: Hook J. E. , Threadgill E. D. , Lambert J. R.
Published: July 2010

A need for a grower acceptable irrigation scheduling technique was brought about by rapid expansion in irrigated land in the Southeast. A modified Jensen‐Haise evapotranspiration formula was adapted by Lambert et al. into an irrigation scheduling and forecasting model for this region. The purpose of this study was to determine if the Lambert model was as effective as tensiometer scheduling in meeting irrigation needs of field corn (Zea mays L.). Corn was grown in seven replicated field experiments and two nonreplicated production scale experiments. Yield and water were compared after irrigation was applied either when soil water pressure in the 150 to 300 mm zone fell below −30 kPa as indicated by tensiometers or when called for by the model. The comparisons were conducted for 3 years on two soils, Tifton loamy sand (fine‐loamy, siliceous, thermic Plinthic Paleudult) and Bonifay sand (loamy, siliceous, thermic, grossarenic Plinthic Paleudult). In five of the comparisons a nonirrigated check was included. The treatment irrigated by the Lambert model yielded 11.1 Mg ha−1 over all seven experiments; the tensiometer irrigated treatment yielded 11.0 Mg ha−1, and the nonirrigated treatment yielded 4.3 Mg ha−1. There were no significant differences between the two irrigated treatments within any year on either soil. The mean yearly water required by the model was 285 mm, compared to 237 mm for the tensiometer. In four of the seven experiments the model called for more water than the tensiometer treatment. Model predicted soil water content was generally greater than measured soil water content for the Bonifay soil but was not significantly different for the Tifton soil. Experience with the Lambert model indicated that it was difficult to determine some of the required model inputs but with correct inputs the model could accurately predict soil water content and corn water requirements.
Planting Method and Plant Population Influence on Soybeans1
Authors: Wright D. L. , Shokes F.M. , Sprenkel R. K.
Published: July 2010

No‐tillage planting of crops usually results in fewer plants per unit of row than the same planting rate with conventional planting. This research was conducted to relate soybean [Glycine max (L.) Merr.] population density under conventional and no‐till plantings to yield and plant growth differences on a Norfolk sandy loam soil (fineloamy, siliceous, thermic Typic Paleudult). ‘Bragg’ soybean were planted in the field with conventional and no‐till planters in 0.76 m wide rows during 1979, 1980, and 1981. Highest yields usually occurred at 20 plants m−1. Yield, plant height, seed weight, and stem diameter differed little in relation to planting method except that seed weight was lower for no‐till plantings in the driest year (1981). Yield and plant height increased and seed weight and stem diameter decreased in relation to population density between 1.5 and 13 plants m−1 row, and then changed gradually to populations of 27 plants m−1 row. Adequate rainfall received during the pod‐fill period of 1979 (August and September) increased yield, plant height, and seed weight more than the planting method in any year.
Battery‐Operated Color Video Camera for Root Observations in Mini‐Rhizotrons1
Authors: Upchurch D. R. , Ritchie J. T.
Published: July 2010

A previously described system (Upchurch and Ritchie, 1983) for observing roots in situ has been modified to include a color video camera. The previous system used a black and white video camera and borescope for observations and included several bulky components which caused damage to the crop and made maneuvering difficult. To allow differentiation of new and old roots and improve field performance and picture quality, a color camera and battery‐operated components were added. The new system involved lowering a small video camera and optics system into 51 mm inside diameter (ID) clear, acrylic tubes, which are buried in the soil, and observing the roots intersecting the tubes on a video monitor. All components were battery operated and mounted on a backpack facilitating use of the system in the field. The new system requires approximately 0.3 person h per scan of a 2.4 m mini‐rhizotron. Use of a color camera allowed easier identification of smaller diameter roots and provided an indication of relative root age. As noted in other reports, the technique underestimates root length density near the soil surface. The overall average coefficient of variation was 100%, but when the near surface zone and zone near the rooting front are not considered this was reduced to 30%. Statistically significant differences in rooting between irrigated and water‐stressed maize (Zea mays L.) could be shown for several depths and dates.
Effect of Spray/Planting Intervals and Various Grass Sods on No‐Till Establishment of Alfalfa1
Authors: Eltun Ragnar , Wakefield R. C. , Sullivan W. M.
Published: July 2010

Consistently successful legume establishment using sod‐seeding techniques has been difficult to achieve. There is increasing evidence that substances released from herbicide‐treated grass swards have an inhibitory effect on legume germination and seedling growth. Field, greenhouse, and laboratory studies were undertaken to evaluate the effect of spray/planting intervals of 1, 7, 14, and 28 days on the establishment of alfalfa [Medicago sativa] when seeded into sods of orchardgrass [Dactylis glomerata L.] timothy [Phleum pratense L.], and Kentucky bluegrass [Poa pratensis L.], and to examine a possible phytoxic effect of glyphosate [N(phosphonomethyl) glycine] on germination and sod seedling growth of alfalfa. Identical field tests were conducted in the spring of 1981 and 1982 on an Enfield silt loam (coarse‐silty over sandy or sandy skeletal, mixed, mesic Typic Dystrochrept). With few exceptions, the number of alfalfa seedlings, seedling development and alfalfa yields increased as the interval increased between spraying of the sod and seeding. Rate of alfalfa seedling development was reduced in all sods, with timothy being the most inhibitory. Two harvests of alfalfa following seeding confirmed that yields were reduced by killed sod, particularly in orchardgrass and timothy, at early intervals after spraying. There were significant positive correlations between seedling numbers and first harvest yields and between seedling development and first harvest yields of alfalfa. Alfalfa germination was inhibited, seedling development was delayed and total dry weight was reduced when glyphosate‐sprayed grass shoot tissue was soil incorporated in growth chamber seeding tests. However, unsprayed fresh grass tissue was more inhibitory than sprayed grass tissue. Alfalfa germination and hypocotyl and radicle length were reduced by aqueous extracts from glyphosate‐sprayed grass shoot tissue but less so than with extracts from unsprayed herbage. No evidence for a phytotoxic effect of glyphosate could be detected, and it appeared that the inhibition of alfalfa germination and seedling growth was due to allelochemics released from fresh herbage and during the early stages of decomposition.
Fungicide and Temperature Affect Leachate‐Predicted Germination of Cotton1
Authors: Smith C. Wayne , Varvil J. J.
Published: July 2010

The ASA‐610 Automatic Seed Analyzer is used to predict the germination of acid delinted cotton (Gossypium hirsutum L.) seeds, reportedly in 24 h as compared to 7 days by standard methods. The prediction is based on the electrical conductivity of seed leachate, with higher leachate resulting in higher conductivity values and indicating lower germination potential. Because cotton planting seeds usually are treated with fungicides and instruments such as the ASA‐610 may be used to assess planting seed quality without using controlled environmental chambers, this research was initiated. We studied the effects of fungicide treatments and temperature during soaking on ASA‐610‐predicted germination of cotton seeds. Correlations among ASA‐610‐predicted germination and standard (30°C) and cool (18°C) germination tests were determined. Fungicide effects were evaluated by use of aliquots from a single seed lot of ‘Stoneville 213’ treated with 17 different fungicides and/or formulations plus an untreated control and a nine‐entry fungicide test, again applied to aliquots of a single seed lot of Stoneville 213. Samples from 17 commercial planting seed lots were used to study the effects of soaking temperatures and to investigate the correlation between the ASA‐610‐predicted germination and standard germination at 30°C. Of 25 fungicide treatments studied, 20 did not significantly affect ASA‐610‐predicted germination when seeds were soaked for 19 h and partitioned at 55μA/seed. Soaking cotton seeds for 19 h at 18°C resulted in Significantly higher ASA‐610‐predicted germination than soaking at 24 or 30°C. Correlation analysis indicated that the ASA‐610 will not predict accurately the germination of acid‐delinted, commercial planting seeds as defined by standard germination procedures.
An Economic Analysis of N Fertilization of Intermountain Hay Meadows1
Authors: Taylor D. T. , Seamands W. J. , Menkhaus D. J. , Jacobs J. J. , Delaney R. H.
Published: July 2010

Nitrogen fertilization is an essential management component of intermountain hay meadows. Insufficient studies have been conducted to determine the economic feasibility of the 67 to 90 kg N ha−1 typically applied by the producer. The objectives of this study were to estimate forage yield response functions and to determine the economic optimum levels of N application. Forage response to N fertilization data were collected in intermountain meadows in Wyoming during the period of 1965 to 1980. The three meadow types investigated were native, improved grass and grass‐alfalfa (Medicago sativa L.) mixtures with 29, 10, and 16 field trials, respectively. Application rates for the N fertilizers ranged from 0 to 180 kg ha−1. The yield response equations were used to determine the economic optimum level of N application for three alternative prices for hay and N fertilizer. The mean economic optimum level of N application for the three price levels was 149,161, and 101 kg N ha−1 on native, improved grass, and grass‐alfalfa meadows, respectively. The improved grass species demonstrated a greater response to the higher levels of N than the other two meadow types. This study indicates that average producers are applying N to intermountain hay meadows at average rates considerably below the economic optimum. Assuming a net hay price of $55 Mg−1 and an N price of $61.60 100−1 kg, the returns ha−1 over fertilizer and harvest costs could be increased $15, $19, and $1 ha−1 for native, improved grass, and grass‐alfalfa meadows, respectively, if the economic optimum N rates were applied as compared to the typical level of 90 kg ha−1.
Environmental Interactions among Reed Canarygrass Genotypes for Nutritive Value, Height, and Disease Severity1
Authors: Zeiders K. E. , Sherwood R. T.
Published: July 2010

The objective of this study was to determine whether genotypes of reed canarygrass (Phalaris arundinacea L.) that were superior for in vitro digestible dry matter (IVDDM), crude protein content (CP), plant height, and resistance to tawny blotch [Stagonospora foliicola (Bres.) Bubak] without irrigation were also superior under irrigation with municipal wastewater effluent involving two and three cuttings per year. Twenty‐five genotypes were established as spaced plantings in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf). Main blocks were not irrigated or were sprinkler‐irrigated with municipal wastewater effluent one or two times weekly from kite May through mid‐September. Subblocks in four replications were harvested two or three times per year. Plant height was measured at all harvests, and IVDDM and CP were determined for the first and third harvests. Tawny blotch severity was rated at the second and third harvests. Significant differences as determined by orthogonal contrasts were observed among the 25 genotypes for each trait. The number of genotypes involved in interactions with each environmental variable were: irrigation 16, cutting frequency 13, harvest 24, and year 18. The number of genotypes that contributed to interactions for each trait were: IVDDM 18, CP 16, height 24, and tawny blotch 12. These results indicated wide differences in environmental stability of genotypes. No genotype was superior for all traits over all environments. There were significant phenotypic correlations between irrigated and nonirrigated clonal means for IVDDM and CP in spring but not in fall harvests. In vitro digestible dry matter in fall never correlated with spring IVDDM, but fall CP often correlated with spring CP. In vitro digestible dry matter was correlated with CP in spring but not in fall. Plant height in any environment correlated with height in any other environment. Tawny blotch rating appeared to be independent of IVDDM, CP, and height. Some genotypes that performed well without irrigation also performed well under irrigation.
Comparison of Crop Phenology Models1
Authors: French Vikki , Hodges Tom
Published: July 2010

Three winter wheat (Triticum aestivum L.) phenology models (CERES‐wheat, TAMW, Robertson) were compared for accuracy in estimating jointing, heading, dough, and ripe stage dates for winter wheat at the Crop Reporting District (CRD) level in Kansas. The models' estimates of stage dates were compared to weekly USDA Statistical Reporting Service stage observations for even years during 1952 to 1980. Odd years were reserved for calibration of models. The CERES‐wheat model estimates were consistently more accurate for all stages.
Application Consistency of Operator‐Propelled Field Plot Spray Methods1
Authors: Krall J. M. , Packer D. S. , Davison J. C. , Book D. N.
Published: July 2010

Operator‐propelled spray methods were compared for consistency of application under field‐plot conditions. A bicycle sprayer, backpack sprayer, backpack sprayer with a metronome set for normal pace, and the backpack sprayer with a metronome set for a modified pace were tested over two terrains by three operators. Coefficient of variation of application output revealed that an operator can apply pesticides using a backpack sprayer and a metronome with the same application consistency as a speedometer‐aided bicycle sprayer. When the metronome is used to modify pace, ground speed may have greater variance, but should be more consistent than backpack application without a metronome.
Enhancing Germination of Indian Ricegrass Seeds with Sulfuric Acid1
Authors: Young James A. , Evans Raymond A. , Easi Debra A.
Published: July 2010

Indian ricegrass [Oryzopsis hymenoides (R. & S.) Ricker] is the dominant forage species on millions of hectares of rangeland in the western United States. Revegetation of degraded rangeland by seeding Indian ricegrass has been generally unsuccessful because of low seed germination. Our purpose was to evaluate the influence of acid seed scarification on germination of Indian ricegrass seeds. Seeds of ‘Paloma’ and ‘NezPar’ Indian ricegrass were scarified in sulfuric acid (H2SO4) from 0 through 45 min at 5‐min intervals. Without scarification, germination of the seeds of these two cultivars was less than 10%. Seedlots from 1 to 11 years old were treated. Germination data were used to develop regression equations for the relationship between duration of acid seed scarification and germination for each cultivar. Seeds of Paloma Indian ricegrass required 25 to 35 min of scarification, whereas seeds of NezPar required 15 to 25 min scarification. The relative composition and morphological forms of the seed may explain the difference in duration of required scarification. The scarified seeds were incubated at 55 constant and alternating temperatures to obtain data with which to construct quadratic response surfaces for temperature‐germination profiles. Even with scarification, the seeds of the two cultivars produced mean germination for the profiles of only 9 to 31%. The dormancy of Indian ricegrass seeds is controlled by complex interacting factors. Acid scarification is a very imprecise tool for enhancing the germination of dormant seeds of Indian ricegrass.
Endomycorrhizal Fungi in Breeder Wheats and Triticale Cultivars Field‐Grown on Fertile Soil1
Authors: Young J. L. , Davis E. A. , Rose S. L.
Published: July 2010

A survey of four cereal research fields growing various commercial and breeder wheat (Triticum aestivum L.), and triticale (X Triticosecale), cultivars revealed the presence of several endomycorrhizal fungi in soils with elevated levels of available P. Extractable (Bray) P levels of sampled fields ranged from 73 to 119 mg kg−1–this in an area where unirrigated wheat yields may exceed 5500 kg ha−1 (> 100 bu acre−1) and the Extension Service “Fertilizer Guide” calls for no P fertilizer additions on grains when soil test values for P are >30 mg kg−l. Cortex colonizations among the >60 breeder and commercial wheat cultivars (sampled just preharvest) were variable and relatively low (range <2 to >18%) partly due to declining root tissues at this stage. Atrophied fine feeder roots and degraded cortical areas were common, yet, in many cases, moderately abundant external hyphae remained adherent to weakened root segments, despite rigors of washing, clearing, and staining. Triticale roots, among the 12 cultivars sampled, were also colonized but at lower percentages (range, 1 to 13%). Vesicular‐arbuscular mycorrhizal (VAM) fungi isolated from the well‐fertilized fields included several Glomus spp., Acaulospora laevis, and an occasional Sclerocystis sporocarp. The A. laevis and a Glomus mosseae type were by far the most common endophytes in terms of spores recovered. Of these isolates tolerating the plentiful soil P status, the Gl. mosseae‐type spores predominated at pH's 5.7 and 6.3. Acaulospora laevis spores greatly dominated in the strongly acid field (pH 4.3 to 4.8) although the Gl. mosseae began to reestablish/recompete where liming nudged the soil back to ~pH 5.7. The abundance of A. laevis spores found with the monocotyledonous wheats contrasts with a published suggestion that Acaulospora species develop in association with dicot hosts. One hopes that bioassay of such higher‐fertility tolerant species will lead eventially to discovery of effective VAM fungal isolates that can still benefit crops despite high‐input fertilizer, pesticide, or water management practices.
Effect of N, P, and S Fertilizers on Alfalfa Grown on Three Soil Types in Northeastern Saskatchewan. II. Nitrogen, P, and S Uptake and Concentration in Herbage1
Authors: Nuttall W. F.
Published: July 2010

Because N, P, and S fertilizers may be important in the production of high quality alfalfa (Medicago media Pers.) herbage in northern Saskatchewan, concentration of these elements in herbage was measured from experiments with N, P, and S fertilizers applied to alfalfa plots over an extended time period. Nitrogen rates at 10, 45, and 67 kg N ha−1 were applied in combination with 0, 22, and 45 kg S ha−1. Twenty kilograms P ha−1 was applied with these treatments. Other treatments were 10, 0, 0; 10, 10, 0; 22, 0, 26; and 0, 0, 0 (Control); N, P, S ha−1 rates, respectively. In general, first cut alfalfa herbage was lower in protein‐N than the second cut with the exception of 1 year. The lowest N concentration per cut was 33.4 g kg−1 averaged over the life of the stand at the Whitefox site (Wf fsl, Whitefox fine sandy loam, Typic Cryoboralf). The highest N concentration in herbage per cut was 39.7 g kg−1 at the Waitville site (Wv 1, Waitville loam, Typic Cryoboralf). Only at the Wv 1 site, and only with S fertilizer, was N concentration consistently increased every year (after establishment year). The percentage of applied N recovered in the alfalfa ranged from 48 to 95%. Approximately 14 kg S ha−1 per year (two cuts) was removed by herbage when fertilized at 22 kg S ha−1 at the Wv 1 site. At a fertilizer rate of 45 kg S ha−1, uptake of P per year (two cuts) was approximately 19.0 kg P ha−1. The lowest yield of N was 78 kg N ha−1 per cut at the Wv 1 site averaged over the life of the stand. The highest uptake was 128 kg N ha−1 per cut at the Melfort soil site (M sic, Melfort silty clay, Typic Cryoboroll). A range of 14:1 to 21:1 of the N to S ratio in herbage was the limit indicated for a S deficiency in the alfalfa crop. Plant testing could be used in conjunction with the soil test for S in making fertilizer recommendations.
Corn Growth and Yield Response to Ethylene Dibromide and Nitrogen1
Authors: Touchton J. T. , Rodriguez‐Kabana R.
Published: July 2010

Even in fields where parasitic nematode populations are low, ethylene dibromide (EDB) will often result in improved plant growth and yields. Visual growth responses to EDB are similar to responses obtained from N fertilizer. The purpose of this field study, which was conducted for 2 years on two Coastal Plain soils (Plinthic Paleudults), was to determine if corn [Zea mays (L.)] growth, nutrient uptake, and yield are influenced by EDB and N interactions. Treatments consisted of a factorial arrangement of N (0 to 269 kg/ha) and EDB (0 to 36 kg/ha) rates replicated eight times in a randomized complete block design. Parasitic nematodes were either nonexistent or exceptionally low. Judging from the persistence of ammonium‐N in the soil, EDB was an effective nitrification inhibitor for several weeks after application. The effects of EDB and N on plant populations were not consistent among years and soils; the effects, however, were small and probably not of practical significance. Six weeks after emergence, plant weights and heights generally followed typical N response curves. In three of the four tests, EDB resulted in greater plant heights, and in two of the four tests, EDB resulted in higher plant weights (up to 113%). Applied N had typical effects on earleaf‐nutrient concentrations, but EDB did not affect leaf‐nutrient concentrations. Grain yields also followed typical N response curves. In all tests, EDB resulted in grain yield increases that ranged from 9 to 26%. Although EDB and N had similar effects on plant growth and yield, there were no interactions between EDB and applied N.
Nitrification Inhibitor Evaluation on Cotton. II. Inhibitor Incorporation Depth and N Placement1
Authors: York A. C. , Tucker M. R.
Published: July 2010

The use of nitrification inhibitors (NIs) in the Southeast has given inconsistent results. Because application techniques may affect the efficacy of NIs, a 3‐year experiment with cotton (Gossypium hirsutum L.) was conducted on a sandy, low organic matter soil (Arenic Paleudults) to evaluate the efficacy of etridiazol [5‐ethoxy‐3‐(trichloromethyl)‐1,2,4‐thiadiazole] and nitrapyrin [2‐chloro‐6‐(trichlorometlyl) pyridine] when N was broadcast and deeply incorporated or applied as a 36‐cm band over the row surface. The NIs, tankmixed with trifluralin (α,α,α‐trifluor0‐2,6‐dinitro‐N,N‐dipropyl‐p‐to‐luidine) herbicide, were deeply incorporated with a disk prior to bed formation or shallowly incorporated with a rolling cultivar after bed formation. Regardless of N placement method or NI incorporation depth, neither inhibitor affected cotton yield, percent lint, fiber quality, or leaf N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, or B contents. Split N applications, with one‐third at planting and the remainder sidedressed at the early square stage, increased N‐use efficiency in 2 of 3 years. Nitrogen placement did not affect cotton yield, fiber quality, or leaf nutrient content. Surface‐banding the N reduced stands by 9 to 20%. As compared to shallow incorporation, deep incorporation of trifluralin reduced cotton yield 6 to 17% and leaf K content at the peak flowering stage 7 to 24%, but did not affect fiber quality. Deep incorporation of trifluralin, combined with either surface‐banded N or application of all N at planting, reduced cotton stands in 2 of 3 years.
Predicting Corn Planting Dates for Moldboard and No‐till Tillage Systems in the Corn Belt1
Authors: Gupta S. C.
Published: July 2010

Surface crop residues under conservation tillage systems slow warming of the seed zone and thus delay corn (Zea mays L.) planting. The purpose of this study was to develop a model that predicts corn planting dates for the Corn Belt states under two extreme tillage surface residue conditions. The simulation procedure involves integration of soil temperature predictions with the seed zone growing degree day concept for corn emergence. Predicted time to corn emergence was tested against the measured values from nine locations in Ohio, Iowa, and Minnesota. These data sets covered several planting dates, a total of eight corn hybrids and two tillage systems (in Ohio only). Except for a few cases, predicted time to corn emergence was within 4 days of the measured values. This model was further extended to develop probabilities of time required to achieve 75% corn emergence for various planting dates using the historical climatic record (12 to 17 years) of daily maximum and minimum air temperatures. Assuming that 75% corn emergence should be achieved in 14 days or less, earliest corn planting dates were selected from the probability graphs corresponding to three spring weather conditions. Using the predicted earliest corn planting dates for 44 locations in the Corn Belt states, two sets of maps delineating areas with similar corn planting dates were developed. These maps cover two soil moisture conditions under moldboard and no‐till tillage systems. Based on planting date maps procedures are also suggested to (i) forecast earliest corn planting date from a 30‐ or a 90‐day outlook of precipitation and air temperature by the National Weather Service and (ii) match corn hybrid maturity with tillage system and spring climate.
Influence of Some Management Parameters on Glucosinolate Levels in Brassica Forage1
Authors: Gustine D. L. , Jung G. A.
Published: July 2010

Brassicaforage species may be used as alternative crops to provide supplemental herbage during the fall in the Northeast. However, these crops contain naturally occurring and potentially toxic constituents (glucosinolates and S‐methyl cysteine sulfoxide). Research was conducted to determine glucosinolate concentrations in 21 cultivars of five Brassicaspecies: turnip (Brassica rapaL.), rape (B. napusL.), kale (B. oleraceaL.), swede (B. napusL.), and Chinese cabbage type (B. cumpestris sensulatoL. ✕ B. rapaL.). Top (leaves plus stem), leaf (blade plus petiole), and root samples of each species were collected 60 or 90 days postseeding at Rock Springs, PA on a Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf). Glucosinolates extracted from freeze‐dried, ground samples were bound to an anion exchange resin and hydrolyzed. The released glucose was quantified on an autoanalyzer. Of the five Brassicatypes, tops or leaves of kales had the lowest glucosinolate Concentration, 1.2 to 6.3 g kg−1; tops or leaves of rapes had the highest concentration, 2.9 to 11.9 g kg−1. Of the 21 cultivars, ‘Gruner’ and ‘Marrowstem’ kale, ‘Doon Major’ and ‘Calder’ swede, ‘Rangi’ rape, and ‘Sirius’ turnip had the lowest glucosinolate levels in tops and leaves; ‘Sipal,’ ‘Silona,’ and ‘Solo’ rape and ‘Green Globe’ and ‘York Globe’ turnip had the highest glucosinolate concentration. Roots of turnip and swede had glucosinolate concentrations as high or higher than those found in tops or leaves. All cultivars combined had significantly higher glucosinolate concentrations in 1980 than in 1979, and glucosinolate levels were significantly higher at 90 days than at 60 days postseeding each year. In a second field study, P and K fertilization at different rates only slightly increased glucosinolate concentration of ‘Fora’ rape, ‘Perko’ Chinese cabbage type, and Sirius turnip, whereas dry matter yields were dramatically increased (fourfold) by high N (132 kg N ha−1) and P (60 kg P ha−1). These data established that glucosinolate levels were sufficiently high (> 3 g kg −1) to produce inorganic isothiocyanate‐induced goiter (thyroid enlargement) in young growing sheep (Ovis aries) and cattle (Bos taurus). To minimize the potential for animal health problems, we conclude that Brassicaspp. should be fed in combination with other forages and that new varieties with reduced glucosinolate concentration should be developed.
Poorly Drained Conditions and Root Development of Eight Indeterminate Soybean Cultivars1
Authors: Stone J. A.
Published: July 2010

The productivity of soybeans [Glycine max(L.) Merr.] grown on the poorly drained, finely textured soils of southwestern Ontario is often limited by excess spring rainfall. Identifying cultivars able to withstand these conditions may improve productivity. The objective of this experiment was to determine if the effect of poorly drained, non‐flooded conditions on the early root growth of soybeans varies between cultivars. ‘Amcor’, ‘Beeson 80’, ‘Corsoy’, ‘Hawkeye 63’, ‘Harosoy 63’, ‘Kentland’, ‘Premier’, and ‘Wayne’ soybean cultivars were evaluated. Drainage treatments were imposed by maintaining 0.0 to 0.002 m or 0.002 m to 0.0028 m aggregate fractions of Brookston clay loam (clayey, mixed, mesic Typic Haplaquolls) at < 0.02 MPa suction. Plants were grown until 21 days after emergence in 0.0762 m i.d. by 0.92 m long acrylic tubes immersed in 23 °C constant temperature baths located in a controlled environment room. Daytime (16 h) ambient temperatures were maintained at 27 °C and night temperatures at 20.0 °C. Response variables analyzed were the rate of taproot and lateral root extension with time, the number of upper lateral roots with depth, and top and root dry weight. The poorly drained treatment significantly reduced the rate of taproot and lateral root extension; however, the magnitude of the response varied between cultivars. Premier and Harosoy 63 exhibited the largest and Corsoy the smallest reduction in root extension. The number of upper lateral roots was not significantly affected by the drainage treatments. The top/root ratio was significantly higher for the poorly drained treatment due to a greater reduction in root than in shoot dry weight. The results indicate that soybean cultivars differ in their ability to withstand poorly drained conditions during vegetative growth.
Effects of Phosphorus, Calcium, and Hup− and Hup+ Rhizobia on Pigeon Pea Yields in an Infertile Tropical Soil1
Authors: Hernandez B. S. , Focht D. D.
Published: July 2010

Pigeon peas [Cajanus cajan(L.) Millsp. var. 64‐28] were grown in the Republic of Panama in an infertile acid Oxisol (Bayano) in both greenhouse and field studies to determine if yield parameters could be increased by addition of P, Ca, and Rhizobium. In the greenhouse, P additions to the Bayano soil increased shoot and nocule weights, acetylene reduction activity, and hydrogen evolution, but neither inoculation with Rhizobiumnor Ca additions had any effect on yields or N2fixing characteristics. Similar results were observed from field trials in the Bayano soil, where grain yields and plant N content were not increased after inoculation with Rhizobiumstrains P170 or P168, which were hydrogenase positive and negative, respectively. Strain P170 was a poor competitor with indigenous rhizobia as noted by the low recovery of antibiotic resistant rhizobia from nodules, while P168 was a superior competitor as noted by its recovery from nodules and by the higher production of H2from nodules than from the uninoculated control. Grain yields in the Bayano soil were considerably lower (245 kg ha−1) in the absence of Ca and P and were increased progressively with P additions of 45, 90, 182, and 363 kg ha−1. Addition of CaCO3(909 kg ha−1) and P (90 kg ha−1) gave grain yields (1407 kg ha−1) comparable to the highest P level (1320 kg ha−1) without additional Ca. With modest addition of Ca and P, pigeon peas in a less fertile acid soil could produce yields comparable to those in a more fertile and less acid soil.
Agronomic Characterization of ‘Yogo’ Hard Red Winter Wheat Plant Height Isolines1
Authors: Allen S. G. , Taylor G. A. , Martin J. M.
Published: July 2010

In spite of the success of semidwarf wheats (Triticum aestivumL.) throughout the world, there are currently no adapted semidwarf hard red winter wheat cultivars with sufficient winterhardiness being grown in Montana and the Northern Great Plains. Studies were initiated to determine the suitability of short stature winter wheats for Montana. Selected agronomic traits were evaluated in 20 ‘Yogo’ winter wheat isogenic height lines and the recurrent parent, Yogo, representing three plant height phenotypes: dwarf, semidwarf, and tall. Yogo is a hard red winter wheat cultivar adapted to harsh winters and low rainfall. Significant differences (P< 0.01) among plant height phenotypes were observed for percent emergence, emergence rate, coleoptile length, test weight, and grain yield. Percent emergence, emergence rate, and coleoptile length were all positively associated with plant height, with linear coefficients of determination of 0.79,0.76, and 0.65, respectively. Grain yield was negatively correlated with plant height (r2= 0.77). Average grain yields over four Montana locations were 1486,1287, and 996 kg ha−1for the dwarf, semidwarf, and tall plant height phenotypes, respectively. There were no significant differences among phenotypes for crown depth. No winter‐kill was observed among isolines at any location, including one at which other winter wheats had differential winter injury ranging from 30 to 100% winter survival. Backcrossing of the rht1and rht2semidwarfing genes into the Yogo genetic background resulted in no apparent effect on winterhardiness. In spite of short coleoptiles and poor field emergence, short stature winter wheat appears well suited to Montana and the Northern Great Plains dryland wheat growing areas, particularly in areas with a high production potential.
Use of Portable Rainout Shelters to Induce Water Stress1
Authors: Clawson K. L. , Blad B. L. , Specht J. E.
Published: July 2010

Rainout shelters provide a method for developing drought stress under field conditions in years when rainfall is adequate. The primary objective of this study was to determine the feasibility of using portable rainout shelters in water stress studies. The study was conducted at Mead, NE in 1981 with three near‐isogenic lines of soybeans [Glycine max(L.) Merr. cv. Harosoy] differing in pubescence density. The soil at this site is a Typic Argiudoll (Sharpsburg silty clay loam). Soybean isolines were planted in small plots, 46 m2in size and were either rainfed or rainout sheltered. The shelters covered an area of 18 m2. The plots were instrumented with leaf thermocouples, strip net radiometers, and neutron access tubes. Phytomass and leaf area index (LAI) measurements were made in the 12 small plots and from four adjacent large plots maintained under rainfed conditions. Leaf temperature was 8 °C warmer and net radiation was 40% lower at midday in the sheltered plots compared to the unsheltered plots. The shelters induced water stress as indicated by a rise in leaf temperature of about 2 °C. However, significant lateral and/or upward movement of soil water into the sheltered plots greatly reduced the effectiveness of the shelters. Phytomass accumulation and LAI from the small and large plots did not agree. The errors of the estimates in the small plots were much greater than those from the large plots. Because of our results, we do not recommend the use of small, portable rainout shelters.
Emergence of Several Grasses from Pregerminated Seed and Some Soil Water Effects1
Authors: Hauser Victor L.
Published: July 2010

Grasses are difficult to establish on range or pasture land in the Southern Plains. Previous research showed that germinating the seeds of two grass species before planting (pregermination) substantially improved plant establishment. Twelve grass species adapted to the Southern Plains were evaluated to learn their response to pregermination treatment. The seeds were germinated in aerated water held at constant temperature, then suspended in gel. They were planted in soil bins in the greenhouse and covered by 1.3 cm of soil (fine, mixed, thermic, Udertic Paleustalfs). Kleingrass (Panicum coloratumL.) was included in each of the eight experiments, and it produced best plant stands when soil water at the seed depth was near or above field capacity. Pregermination doubled the number of plants established by kleingrass and buffelgrass (Cenchrus ciliarisL.). Weeping lovegrass [Eragrostis curvula(Schrad.) Nees], and buffalograss [Buchloe dactyloides(Nutt.) Engelm.] produced 40% more plants from pregerminated seeds than from untreated seeds. Switchgrass (Panicum virgatumL.) and blue panicum (Panicum antidotaleRetz.) responded favorably to pregermination treatment in one test but not in the other. Six other grass species produced the same number of plants from either pregerminated seeds or untreated seeds. Grass species should be individually tested to determine their response to pregermination.
Technique to Measure Rooting of Sods Grown in Small Containers1
Authors: Schmidt R. E. , White R. H. , Bingham S. W.
Published: July 2010

A technique for anchoring small containers so that a vertical force may be used for efficiently measuring rooting is described in this paper. The technique consists of placing sod plugs in wire mesh bottom ringed plugs and transplanting to metal growing containers. After approximately 4 weeks, containers are anchored to a heavy base and the sod‐holding rings are attached to a block and tackle. Vertical force is applied to separate the sod from the underlying soil by slowly adding sand to a container attached to the opposite end of the tackle. Weight of the sand is a measure of root development. Results of five experiments show this technique may be used to efficiently detect rooting differences. Rooting variances of grasses grown in different textured soils under varying herbicide treatments and different soil moisture content were shown. Energy required to vertically separate roots from soil significantly correlated with fresh and dry root weights.
Kleingrass Yield and Quality under Three Irrigation Regimes when Harvested at Anthesis1
Authors: Clark R. P. , Lugg D. G.
Published: July 2010

Kleingrass (Panicum coloratumL.) is a promising forage species for irrigated areas in the southwestern USA. However, the effect of different irrigation regimes on dry forage yield and forage quality has not yet been extensively investigated under field conditions. Accordingly, ‘Kleingrass‐75’ kleingrass was irrigated at intervals of 2, 3, and 5 weeks during the 1981 and 1982 growing seasons near Las Cruces, NM on a fine‐loamy, mixed, calcareous, thermic Typic Torrifluvent soil. Dry forage yields, in vitro dry matter disappearance (IVDMD), and Ca, Mg, N, and P concentrations were measured for forage harvested at anthesis. Significant (P≤0.01) negative relationships were found between amount of irrigation water applied and Ca concentration, Mg concentration, and IVDMD, respectively. In addition, there were significant (P≤0.01) negative relationships between dry forage yield and Ca concentration, Mg concentration, and IVDMD, respectively. No relationships between amount of irrigation water applied or dry forage yield and N or P concentration were found. It was concluded that Ca and Mg concentrations and IVDMD were higher with lower soil moisture contents, possibly due to higher leaf weight to stem weight ratios in the lower‐yielding, water‐stressed kleingrass.