bluuebunny/crossref_metadata_2025 huggingface dataset:
Wetting and Maturity Effects on Mineral Concentrations in Legume Hay1
Authors: Collins Michael
Published: July 2010

Wetting by rainfall during field drying of legume hay reduces forage yield and in vitro dry matter disappearance. Field experiments were conducted to evaluate wetting effects on mineral composition of alfalfa (Medicago sativaL.) and red clover (Trifolium pratenseL.) hay. Three and one‐half kg samples of each species, grown on Plano silt loam soil (fine silty, mixed, mesic Typic Argiudolls) and harvested at early and late maturity stages, were placed on wire screens and allowed to dry without wetting or were exposed to natural or artificial wetting in 1980 and 1981. A completely random design was used with three replicates in 1980 and two in 1981. In 1980, 25 mm of water was applied using sprinklers to hay wetted during drying. In 1981, hays wetted during and after drying were exposed to 41 and 62 mm of natural precipitation, respectively. Late maturity (fullto late‐bloom) forage was lower in P, K, Ca, Mg, and S than early maturity forage (early bud to first flower) of the same species. Artificially wetted and well cured hay did not differ significantly in concentrations of P, K, Ca, Mg, or S in 1980. Precipitation totaling 62 mm on dry early to late‐bud alfalfa hay reduced the K concentration from 28.1 to 15.5 g kg−1, indicating substantial leaching. The same treatment increased P concentration from 4.1 to 5.5 g kg−1, increased Ca from 13.0 to 19.7 g kg−1, and increased Mg from 4.2 to 5.0 g kg−1. Late‐bud and first‐flower red clover responded similarly when subjected to the same treatment. Late‐bloom alfalfa, exposed to 41 mm of precipitation during drying had 2.4 g kg−1of P, 15.9 g kg−1of K, 8.2 g kg−1of Ca, 1.9 g kg−1of Mg, and 1.6 g kg−1of S compared with 2.5,20.8, 11.5,2.5, and 2.2 g kg−1, respectively, for the same minerals in hay cured without wetting. Based on these data, the impact of wetting during hay curing on concentrations of P, Ca, Mg, and S was smaller than wetting effects on forage yield and in vitro dry matter disappearance. Wetting reduced K concentration to a greater extent than it reduced the other minerals studied. Alfalfa forage was consistently higher in S and lower in Mg than red clover forage of similar maturity.
Water Injection at Seeding of Winter Wheat1
Authors: Noori Fariborz , Bolton Floyd E. , Moss Dale N.
Published: July 2010

Often wheat (Triticum aestivumL. em Thell) is grown in areas of limited rainfall, and stand establishment can be a serious production problem when seeding is done in dry soil. These experiments were designed to measure the effect of injecting small amounts of water into the soil seed zone at seeding on the germination, stand establishment, and yield of winter wheat. The experiments were done in the 1979–1980, 1980–1981, and the 1981–1982 growing seasons on a mixed mesic Typic Haploxeroll soil. The soil water potential at seeding was −1.1 MPa in 1979–1980, −0.9 MPa in 1980–1981 and −0.6 MPa in 1981–1982. Water injection rates were either 0, 20,. 40, 50, or 60 mL water/m row. Compared with the 0 rate, injection of any amount of water resulted in faster germination, most treatments gave denser stands, and all but one treatment in one year resulted in greater grain yields. Injection of 50 mL water/m row in 1979–1980 resulted in a 16% yield increase. In 1980–1981 injection of 20 mL water/m row gave a 4% greater yield than the check and injection of 40 mL water/m row gave a 33% yield increase. The soils were wetter in the 1981–1982 growing season and there was no difference between 20, 40, and 60 mL water/m row injection rates; all gave yield increases of 21 to 29%.
Whole‐Plant Dry‐Down Patterns of Short‐Season Maize Hybrids1
Authors: Major D. J. , Schaalje G. B.
Published: July 2010

In semiarid regions, rapid decreases in whole‐plant moisture content of maize (Zea maysL.) make it difficult to harvest large land areas for silage at the correct moisture content. The objective of this study was to determine the pattern of moisture loss from maize hybrids grown at Lethbridge, Alberta. Wet and dry weights of 20 commercial hybrids grown under irrigation in 1979, 1980, and 1981 on a Typic Haploboroll silty clay loam were determined at weekly intervals between early September and late October. A segmented regression analysis provided the most suitable model relating moisture content to thermal time. There was a decrease in moisture content of about 0.3% per day until a changeover point about 50 days after silking, and then moisture content decreased at the rate of about 2% per day. The changeover point may have coincided with physiological maturity. There were insufficient data after the first killing frost to detect any effect of frost on dry‐down rate, nor were any hybrid differences detected although there were differences among years.
Dry Matter and Nitrogen Partitioning in Mechanically Dewatered Alfalfa, Red Clover, and Birdsfoot Trefoil1
Authors: Collins Michael
Published: July 2010

Improved forage harvesting techniques are needed to reduce the losses incurred during field drying silage or hay, especially in areas where rainfall is high. A 2‐yr field study was conducted to evaluate mechanical dewatering of first cutting forage of alfalfa (Medicago sativaL.), red clover (Trifolium pratenseL.) and birdsfoot trefoil (Lotus corniculatusL.) harvested at four maturity stages. Separate plots of each species grown on Plano silt loam soil (Typic Argiudolls) were harvested at weekly intervals beginning on 27 May 1980 and 26 May 1981 and the forage was macerated and pressed at 6.9 ✕ l05Pa for 2 min. A protein concentrate was obtained by heating the whole juice to 80°C using steam. Pressed forage dry matter (DM) concentration increased as whole crop DM increased. Alfalfa was the highest of the whole crops in DM concentration and thus produced the highest DM pressed forage, suggesting that modification in processing conditions might be necessary to produce pressed forages consistently > 300 g DM/kg of total mass. Stepwise multiple regression indicated that a model including whole‐crop DM and neutral detergent fiber (NDF) accounted for significant portions of variation in pressed forage DM concentration in every case. Pressing removed an average of 45% of the initial fresh weight and 20% of the DM from alfalfa, about the same amounts from red clover, and somewhat less from birdsfoot trefoil. Higher whole crop DM concentrations reduced extraction of both total fresh weight and solids. The protein concentrate contained 8.5, 7.0, and 4.9% of whole crop DM for alfalfa, red clover, and birdsfoot trefoil, respectively. The alfalfa protein concentrate and deproteinized juice fractions contained a greater percentage of the whole crop N than the same fractions from red clover and birdsfoot trefoil. Red clover was generally intermediate in N percentage contained in the protein concentrate and deproteinized juice. Results of this 2‐yr experiment indicate that significant species and maturity differences exist in crop response to mechanical dewatering, which are related to differences in the concentrations of DM and NDF in the whole crop.
Foliar Application of Phosphorus to Spanish Peanuts1
Authors: Suwanvesh Thienchai , Morrill L. G.
Published: July 2010

The effect of soil P (root P) availability on response of Spanish peanuts (Arachis hypogaeaL.) to foliar P applications has not been documented. Greenhouse studies were initiated to investigate the effect of root P on foliar P utilization by Spanish peanuts and determine the effect of an experimental stick‐spreader on peanut response to foliar P. Three levels of root P were supplied in a nutrient solution‐sand rooting system. Two lines (late and early medium maturing) were used in separate experiments. Growth responses and increases in plant P were obtained when foliar P from KH2PO4was applied with limiting P in the rooting medium. Stick‐spreader increased plant P (g kg−1) at 0.5 and 1.0 g L−1levels but reduced P use at 2.0 g L−1rate. Dilution effects for N and K were equivalent, concentrations being higher when P was limiting but lower when P was supplied to foliage or roots. Increased total uptake of N and K was observed when foliar or root P was supplied, however. It was concluded that (i) Spanish peanut utilization of foliar P was dependent upon root availability, a significant response being obtained when root P was limiting and (ii) the use of a stick‐spreader was beneficial at low application rates but detrimental at high rates.
Digestion of Several Temperate Forage Species by a Prepared Cellulase Solution1
Authors: Bughrara S. S. , Sleper D. A.
Published: July 2010

Rapid, inexpensive, and accurate procedures are required for predicting in vivo dry matter digestibility (DMD) of forages, particularly in a forage breeding program when many samples may be analyzed simultaneously. The primary objective of this study was to investigate the relationships of several cellulase digestion procedures to in vivo DMD, in vitro DMD using rumen liquor, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and hemicellulose for several temperate forage species. A cellulase solution was produced by culturing the conidia from Trichoderma reeseiSimmons in a mineral medium containing 10 g L−1cellulose. Apparent activity of the cellulase solution was determined by digesting cool season forages of known DMD and solka floe substrate. Forty‐two dried cool season forages which previously had been evaluated for per cent NDF, ADF, ADL, in vitro DMD using rumen liquor, and in vivo DMD using sheep were subjected to different cellulase digestion procedures. Correlations between the various cellulase DMD techniques and in vivo DMD were highly significant (p< 0.01) and ranged from 0.89 to 0.97. Correlations of the cellulase in vitro DMD techniques and NDF, ADF, ADL, and hemicellulose were negative and similar in magnitude to the same parameters when correlated to in vitro DMD using rumen liquor. The data suggested that the in vitro DMD obtained by using a prepared cellulase solution was an excellent predictor of in vivo DMD and the digestion was similar to that when digesting forages with rumen liquor.
Effect of Standing Small Grain Stubble on Snow Cover Characteristics in Alternate Fallow Strip Cropping1
Authors: Caprio Joseph M. , Grunwald Gary K. , Snyder Robert D. , Cleary Edward C.
Published: July 2010

This study was directed to the evaluation of snow cover characteristics in standing small grain stubble and fallow fields in climatic areas of Montana distinguished by differences in long‐term average annual number of chinook events. Field work was conducted over three winters (1976–1977, 1977–1978, and 1978–1979). The first winter was warmer and drier than normal, whereas the last two winters were wetter and colder than normal. Each winter, two transects consisting of four to six experimental sites each were established. The climate of one transect was distinguished from the other transect by the greater long‐term average annual number of chinook occurrences. Treatments at each site included a fallow area and adjacent stubble area situated in alternating north‐south strips approximately 50 m wide. Six to 10 observations of snow depth and water in snow were made each winter at all sites. Snow depth was greater in standing stubble fields than in fallow fields. Snow depth in standing stubble exceeded snow depth in fallow fields by 80% during the driest winter and 30% during the other two winters. The density of the snow was slightly greater in fallow fields than in standing stubble fields. The average density of snow cover was about 0.250 Mg m−3varying usually from 0.100 to 0.350 Mg m−3. The average density of snow cover early in the season (early November) was about 0.140 Mg m−3, and increased about 0.008 Mg m−3each week thereafter when the snow cover persisted. The snow cover across the standing stubble area was nearly uniform in depth. Significant differences between climatic areas in snow depth, water in snow, and snow density were found only during the comparatively dry first season.
Accumulation and Distribution of Dry Mass and Nutrients in Birdsfoot Trefoil1
Authors: McGraw R. L. , Russelle M. P. , Grava J.
Published: July 2010

Development of efficient fertilizer management and forage utilization strategies is facilitated by knowledge of nutrient accumulation and distribution patterns within plants. The objectives of this experiment were to determine patterns of nutrient accumulation and distribution in birdsfoot trefoil (Lotus corniculatusL.) from late vegetative growth through reproductive development and to compare these patterns with dry mass (DM) accumulation and distribution. Birdsfoot trefoil was established on an Aeric Calciaquoll soil in Roseau County, Minnesota, in 1980, and on a Typic Hapludoll near Rosemount, Minnesota, in 1981. Shoot samples procured at approximately biweekly intervals in the year following establishment were separated into stems, leaves, umbels, and seed, and DM and elemental accumulation for each were determined. Herbage DM accumulation rate and final production were greater at the southern location than at the northern location, but the converse was true for seed production. Fractional accumulation of DM, N, K, Ca, Mg, S, B, Zn, and Mn remained relatively stable in stems during seed filling, but decreased in leaves during the same period. The rate of leaf DM loss during seed filling was greater at the Roseau location where seed yield was greatest. These results suggest that leaves may be an important source of nutrients for developing reproductive tissue. Stems tended to accumulate smaller and leaves greater proportions of nutrients than DM, relative to the total amounts present at each stage. Seeds contained consistently higher proportions of N, P, and S than DM at both locations, and greater Zn and Cu than DM at Rosemount. Relative accumulation of N, P, S, Zn, and Cu was generally two to four times greater than the fractional accumulation of DM in seeds.
Corn Response to Starter Fertilizer Acidity and Manganese Materials Varying in Water Solubility1
Authors: Miner G. S. , Traore S. , Tucker M. R.
Published: July 2010

Manganese deficiencies occur on sandy Atlantic Coastal Plain soils that have been limed excessively. Granular Mn materials can be blended with starter fertilizer to overcome these deficiencies but variation in their water solubility and in starter fertilizer acidity affects the availability of Mn from these materials. Seven Mn materials varying in water solubility and three starter fertilizers were band‐applied to supply 11 kg ha−1of Mn to corn (Zea maysL.) on a sandy soil (fine‐loamy, siliceous, thermic Aquic Paleudult) at pH 6.9. Starter fertilizers, in order of increasing acid‐forming potential [NaNO3+ triple superphosphate (SNT); diammonium phosphate (DAP); and (NH4),SO4+ triple superphosphate (AST)] were applied at rates that supplied 28 and 31 kg ha−1of N and P, respectively, at planting. Soils were sampled through the fertilizer band at 30 days, whole plants were sampled at 30, 60, and 90 days, and leaves opposite and below the ear were collected at silking (75 days). Soil Mn, whole plant Mn concentration and uptake, and leaf Mn concentration increased with increasing solubility of the Mn materials. The MnO in the Mn materials did not contribute to these relationships. Increased acidity of the starter fertilizer also increased plant Mn concentration and uptake. Manganese deficiency symptoms occurred with the least acid‐forming starter fertilizer (SNT) and decreased with increasing water solubility of the accompanying Mn materials. Equations were developed to predict recommended rates of Mn material, depending on water solubility, to apply with each starter fertilizer
Estimation of Spring Wheat Spike Water Concentration and Grain Maturity from Air Temperature1
Authors: Bauer Armand , Frank A. B. , Black A. L.
Published: July 2010

The domestic agricultural industry and crop yield forecasters/modelers would benefit from an index that estimates spike and grain water concentration of spring wheat (Triticum aestivumL.) as a measure of maturity stage. A three‐part, 5‐yr field study was conducted on Williams loam (fine‐loamy Typic Argiborolls). First, the spike water concentration and content were measured in five trials with variables including cultivars, water, and fertility, and regressed on the growing degreedays (GDD) from anthesis to grain maturity. Second, the interrelationships of spike, grain, and chaff water concentration were determined in ‘Sinton’ wheat from 2000 g kg−1spike water concentration to maturity in four trials. Third, the effect of spike water concentration at windrowing on grain yield and quality was measured in Sinton wheat in three trials. Cumulative GDD accounted for 90% of the variability in spike water concentration and 49% of the variability in spike water content among all treatments. Spike water concentration was inversely related to grain dry matter assimilation, ranging from 3140 g kg−1near anthesis to 270 g kg−1at maximum grain dry matter. Spike water content averaged about 590 mg spike−1at anthesis, reached a maximum of about 750 mg spike−1at 200 to 600 GDD after anthesis, and then declined sharply. Linearily related grain water concentration was about 1.3 and chaff about 0.5 times the spike water concentration at 2000 g kg−1and less. Spring wheat windrowed at spike water concentrations of 600 g kg−1or less did not adversely affect grain yield or grain N concentration. This water concentration exists at about 670 GDD after anthesis. Windrowing as early as possible enhances the water conservation potential, with the primary benefit accruing to an autumn‐planted crop.
Application of Bentazon and Sethoxydim in Soybean Oil with Rotary Atomizers1
Authors: Cantwell John R. , Kapusta George
Published: July 2010

Rotary atomizers have been reported to have the capability to apply herbicides effectively in substantially reduced carrier volumes when compared to conventional application methods using flat fan nozzles. Several field studies (Typic Ochraqualfs, Argiaquic‐Argialbolls, and Aerie Ochraqualfs soils) were conducted during 1983 and 1984 to evaluate weed control in soybean [Glycine max (L.) Merr.] with bentazon {3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐ one 2,2‐dioxide] and sethoxydim {2‐[1‐(ethoxyimino)butyl]‐5‐[2‐ (ethylthio)propyl]‐3‐hydroxy‐2‐cyclohexene‐1‐one} applied in 2.3 to 9.4 L ha−1soybean oil concentrate (SOC) with rotary atomizers operating at two different cup rotating speeds. These treatments were compared with water carrier treatments applied with rotary atomizers at 28 L ha−1and flat fan nozzles at 187 L ha−1. Weed control attained with bentazon and sethoxydim applied with rotary atomizers was equal to that obtained with flat fan nozzles. Herbicide rate and rotary atomizer cup speed affected the .weed control realized with rotary atomizer applications in 2.3 to 9.4 L ha−1SOC, but not with 28 L ha−1water carrier. No increase in weed control was observed when bentazon or sethoxydim were applied in SOC carrier with rotary atomizers, compared with applications in water with either rotary atomizers or flat fan nozzles. Rotary atomizers offer the ability to apply herbicides effectively in carrier volumes of 28 L ha−1or less, greatly increasing the efficiency of spray operation.
Analysis of Cultivar‐Use Options with Sugarcane as Influenced by Threats of New Pests1
Authors: Glaz B. , Alvarez J. , Miller J. D.
Published: July 2010

In many sugarcane (Saccharum spp.) production areas, there are one or at most a few outstanding cultivars. However, one cultivar is rarely grown on more than 70% of an area because of the perceived risk that a new pest or a new strain or race of an established pest could cause devastating losses if the most widely grown cultivar is susceptible. The objective of this study is to present a model that will allow sugarcane growers to use their commercial data and their predictions on the levels of yield losses due to a new pest, and what percentage of their cultivars will be susceptible to the new pest, to determine how to allocate their land among different cultivars. To establish a reference point, a 20‐yr period for a grower producing four cultivars was assumed. One cultivar had a yield level 5% higher than the other three cultivars, which were all equal in yield. It was assumed that during the 20‐yr period there would be one new pest that would cause a 20% yield reduction in the best and one other cultivar. Under these assumptions, it was found that the best option was to grow the highest‐yielding cultivar on 88% of the available land. It was concluded that sugarcane growers do not make optimum use of their best cultivar.
Subirrigated Meadow Response to Application of Nitrogen, Phosphorus, and Atrazine1
Authors: McConnell S. G. , Waller S. S.
Published: July 2010

Botanical composition of native hay meadows throughout the True Prairie has shifted from predominantly native, warm‐season grasses to introduced, cool‐season species following mismanagement. To determine if a shift in composition back to warm‐season grasses and subsequent increased seasonal production could be achieved, atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] herbicide in combination with N and P fertilizer was evaluated on an eastern Nebraska subirrigated meadow. The soil is classified as a Lawet Variant fine sandy loam (fine‐loamy, mixed [calcareous], mesic Fluvaquentic Haplaquoll). Five rates of N (0, 45, 90, 135, and 180 kg ha−1), two rates of P (0 and 34 kg ha−1), and two rates of atrazine (0 and 2.2 kg ha−1) in factorial combination were arranged in a randomized complete block design. Atrazine and P were applied in late April to late May, and N was applied in early June in 1982 through 1984. A combination of 180 kg N ha−1 and 34 kg P ha−1 produced dry matter yields 95,101, and 77% greater than untreated plots in 1982, 1983, and 1984, respectively. Atrazine altered botanical composition from predominantly cool‐season grasses to predominantly warm‐season grasses. Changes in species composition by weight indicated a twofold increase in warm‐season yield. This shift in seasonal distribution of yield was accomplished without a reduction in total dry matter yield compared with plots recieving 180 kg N ha−1 in combination with 34 kg P ha−1.
Nitrogen Cycling in Seven Cool‐Season Perennial Grass Species1
Authors: Power J. F.
Published: July 2010

Among cool‐season grasses few comparisons have been made of the effects of N fertilization over an extended time period. An experiment was established at Mandan, ND, to study the effects of low (45 kg N ha−1) and excessive (225 kg N ha−1) fertilizer N rates for 9 yr on growth, N uptake, and fertilizer N accounted for in forage, roots, and soil inorganic N by seven temperate cool‐season grass species: western wheatgrass [Pascopyrum smithii Rybd. (Lõve)], crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.], intermediate wheatgrass [Elytrigia intermedia (Host) Nevski], smooth bromegrass (Bromus inermis Leyss.), Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], green needlegrass (Stipa viridula Trin.), and Garrison creeping foxtail (Alopecurus arundinaceus Poir). Total N concentrations of forage were increased with 225 kg N ha−1 annually only, and were often lowest for higher‐yielding species (B. inermis, A. desertorum, and E. intermedia). Cumulative total N uptake was usually greatest for those species plus P. smithii. Total N concentration and uptake in roots were increased by 225 kg N ha−1 annually, with few differences among species. Total N in roots gradually increased with the season, and by fall was double the spring levels. Minimum root‐N concentrations were at the 20‐ to 50‐cm soil depth. Soil inorganic N concentrations for the check and 45 kg N ha−1 rate were < 60 kg N ha−1 compared with 300 to 500 kg N ha−1 for the 225 N rate. For higher‐yielding species, 70 to 90% of the fertilizer N was initially accounted for in forage, roots, and inorganic N compared with 40 to 50% by the ninth year after extreme drought. At the higher fertilizer rate, 820 kg ha−1 fertilizer N was found in soil organic N. For all species and fertilizer N rates, 200 to 250 kg fertilizer N was not accounted for.
Modeling Cotton Fruiting Form Abscission1
Authors: Lieth J. H. , Arkin G. F. , Hearn A. B. , Jackson B. S.
Published: July 2010

Abscission of cotton (Gossypium hirsutum L.) fruit and flower buds occurs even in well managed crops and influences subsequent fruit growth and development. Relationships that describe the abscission of flowering buds (squares), flowers, and fruit (bolls) were developed and incorporated into a process‐based cotton crop simulation model. These relationships are essential components of yield simulation models useful for management decision making. The abscission model developed is based on established hormonal and nutritional theories. Younger squares and bolls are predicted to abscise more readily than older ones. Abscission of bolls and squares depends on organ age, boll load, and environmental stresses. External stresses and internal competition for carbohydrates modify the probability of abscission multiplicatively. The effects of insects are approximated through a factor representing a uniform level of shedding throughout the growing season. Detailed fruiting site plant maps of greenhouse grown plants were used for model calibration. Simulations were carried out using input data collected at California, Texas, and Arizona. Simulated fruit development was in agreement with observed fruiting form counts and the frequency distribution for fruiting form age at abscission agreed with field observations.
The Influence of Chaff Extracts on the Germination of Spring Triticale1
Authors: Salmon D. F. , Helm J. H. , Duggan T. R. , Lakeman D. M.
Published: July 2010

Germination inhibitors associated with the chaff of spring triticale (X Triticosecale Wittmack) could provide an important means of reducing sprouting caused by prolonged periods of rain during harvest. Eight spring triticales and two spring wheats (Triticum aestivum L. em. Thell) were grown on Navarre loam soil (fine clayey, montmorillonitic, frigid Aquic Cryoboroll) at Lacombe, Alberta and evaluated for germination inhibitors in their aqueous chaff extracts from 1982 to 1984. Each year, 200 spikes from each line were collected at harvest and air‐dried prior to storage at −20 or 20°C for 3 months. Only the chaff stored at −20°C was used for extract production. During 1982 and 1983, extracts from each line or cultivar were evaluated on their own seed stored at 20°C, whereas, in 1984, seed stored at both −20 and 20°C was used. Extracts were also compared with distilled water on the seed stored at 20°C from the sprouting susceptible wheat, ‘Fielder’ during 1983, as well as Fielder seed stored at −20°C, and seed from the sprouting resistant wheat line, ‘RL4137’, stored at 20°C during 1984. Extracts evaluated on seed that had been stored at 20°C for 3 months only briefly reduced germination in all lines except RL4137. Extracts evaluated on Fielder seed stored at −20°C or RL4137 seed stored at 20°C reduced germination up to 120 h. Regardless of the year, extract concentration, or storage temperature of the seed, the chaff extracts provided the greatest protection against germination when combined with high levels of seed dormancy. Selection for high levels of germination inhibitors in the chaff will be a valuable means of prolonging sprouting resistance in spring triticale.
Phenology of Dent Corn and Popcorn. II. Influence of Planting Date on Crop Emergence and Early Growth Stages1
Authors: Stevens E. J. , Stevens S. J. , Flowerday A. D. , Gardner C. O. , Eskridge K. M.
Published: July 2010

Date of planting and date of crop emergence have been used as reference points for calculating heat sums used in modeling corn (Zea mays L.) phenology. An interactive agroclimatology program and service (AGNET) offered by the University of Nebraska, Lincoln (UNL), accumulates daily heat sums from the time of planting using data generated by an expanding automated network of meteorological stations. The objectives of this research were to evaluate current UNL‐AGNET procedures for modeling corn phenology with special reference to early development and, where necessary, develop and evaluate modified procedures. Time of planting and crop emergence were used separately as reference points for accumulating heat sums calculated using different procedures thereby addressing the impact of slow crop emergence and poor early seedling vigor associated with early planting. Daylength at emergence was included in regression models to investigate the likelihood of bias resulting from a delay in the date of planting. A 2‐yr phenology study incorporating three planting dates and daily and hourly heat sums was conducted in eastern Nebraska during 1982 and 1983. Data generated using staging criteria and regression models currently used in the UNL‐AGNET service were unsuitable for modeling early crop development; alternative procedures were developed using a modified staging criteria and hourly temperature data accumulated from the time of crop emergence. The phenologies of one dent corn cultivar (B73 X Mol7) and three popcorn cultivars (P410, P609, and Iopop 12) were studied using growth curve analysis. Response profiles (growth curves) differed significantly (P = 0.01) among cultivars and among planting dates. Growth curves derived using heat sums calculated using a base temperature of 5°C varied less between years when compared with other procedures for calculating hourly heat sums. A need was demonstrated to (i) account for the effect of planting date in corn phenology models, (ii) accumulate heat sums from either the time of crop emergence or preferably after stem elongation rather than from the time of planting, (iii) develop separate regression coefficients for different cultivars of corn, and (iv) develop hourly rather than daily heat sums when data are available from automated agro‐meteorological networks. Plant development response to day length variation across planting dates and the post‐emergence accumulation of thermal units did not fully account for differences in response profiles developed for early phenological development of four corn cultivars. Photoperiod effects appeared to be confounded with the impact of soil temperature on seedling emergence and growth prior to elongation of stem internodes.
Interactions of Maize Hybrids with Tillage Systems1
Authors: Newhouse K. E. , Crosbie T. M.
Published: July 2010

The use of conservation tillage for commercial production of maize (Zea mays L.) has expanded substantially in the past 10 yr. Few previous studies have compared the relative performance of a large number of hybrids in no‐tillage and conventional tillage cropping systems. In this study, 60 commercial hybrids were grown at two locations in Iowa in 1981 and 1982 to examine the interaction of commercial maize hybrids with no‐tillage and conventional tillage systems. Hybrid ✕ tillage interactions were not significant for any of the seven traits examined in a combined analysis of variance over tillage systems. Hybrid ✕ tillage ✕ environment interactions were significant for percentage emergence and mature plant height. Rank correlations of hybrid means from one tillage system to the other were significant and large, ranging from 0.66 to 0.94 for the agronomic traits measured, which was consistent with the lack of significant hybrid ✕ tillage interactions. No specific traits were of more importance for performance in no‐till than in conventional tillage. Also, no differential hybrid response to tillage systems, which was repeatable across environments, was observed. The study suggested that evaluation of performance in conventional tillage environments provided sufficient information to select among contemporary hybrids for use in conservation tillage environments.
Mono‐ and Double‐Cropped Wheat and Grain Sorghum under Rainfed and Irrigated Conditions1
Authors: Crabtree R. J. , Greenland R. G. , Mehdawi S. O. , Claypool P. L.
Published: July 2010

Sufficient amounts and distribution of rainfall are often the major limiting crop production factors in the southern Great Plains. This is especially true for summer crops whether grown in mono‐ or double‐cropping situations since these factors have significant impact on yields and profitability. This study was conducted at the Oklahoma Vegetable Research Station, Bixby, OK, from 1980 to 1984, on a Wynona silt loam soil (Cumulic Haplaquolls) with 0 to 1% slope. The objectives were to compare yields and net economic returns of mono‐ and double‐cropped wheat [Triticum aestivum (L.) em. Thell] and grain sorghum [Sorghum bicolor (L.) Moench] where all wheat was produced under rainfed conditions and where mono‐ and double‐cropped grain sorghum were produced under both rainfed and irrigated conditions. Over the 5‐yr period, rainfed, monocropped wheat yielded an average of 3498 compared to 2848 kg ha−1 for rainfed, double‐cropped wheat. Irrigated, conventionally tilled, monocropped grain sorghum yielded an average of 5650 compared to 4866 kg ha−1 for rainfed, conventionally tilled, monocropped grain sorghum. Irrigated, no‐till, double‐cropped grain sorghum yielded an average of 4976 compared to 3856 kg ha−1 for rainfed, no‐till, double‐cropped grain sorghum. Rainfed, monocropped wheat produced the highest net economic return per hectare of any of the five cropping systems. Net return from rainfed, conventionally tilled, monocropped grain sorghum was nearly equal to that of wheat. Irrigation increased the yields of mono‐ and double‐cropped grain sorghum 784 and 1120 kg ha−1, respectively. However, given these yields, the price of grain sorghum would have to increase from 0.10 to 0.25 and 0.19 dollars kg−1 for mono‐ and double‐cropped grain sorghum, respectively, before irrigation would become economically feasible.
Nitrogen Fertilizer Effects on Growth, Flowering, Oil Yield, and Yield Components in Meadowfoam1
Authors: Pearson C. H. , Jolliff G. D.
Published: July 2010

Meadowfoam (Limnanthes alba Benth.) seed is a source of oil for use in industrial products and processes. Nitrogen fertilization typically has not increased seed yields of meadowfoam. Data are lacking for characterizing plant growth responses, flowering, honey bee (Apis mellifera L.) foraging, oil yield, and yield components of meadowfoam when fertilized with N. Thus, this field study was conducted in 1981 and 1982 on a Woodburn silt loam soil (fine‐silty, mixed, mesic Aquultic Argixeroll) to determine the effects of ammonium sulfate applied at 0 (control), 50 (50N), and 100 (100N) kg N ha−1. Increased vegetative growth of meadowfoam in response to spring application of N appears to be consistent. Nitrogen fertilization lowered canopy light transmittance and caused a differential flowering response from nonfertilized plants. Seeds per flower in the N‐fertilized treatments were not increased. Flower densities in N‐fertilizedtreatments in 1982 averaged 135% higher than in the control. Seed yields were not increased by N in 1981, but in 1982, seed and oil yields were increased by 113 and 99%, respectively, when N was applied. Oil content was consistently lower when N was applied, but this effect was more than offset by the higher seed yield in 1982. Because of the similar response of agronomic characters in 50N and 100N treatments, applications of 100 kg N ha−1 do not appear to be advantageous. Spring N fertilization of meadowfoam increased seed yield primarily through increased flower number.
Growth Analysis of Cottons with Differing Maturities1
Authors: Kohel R. J. , Benedict C. R.
Published: July 2010

Field and greenhouse experiments were conducted on cotton (Gossypium hirsutum L.) lines with differing maturities to determine what factors of plant growth contributed to early crop maturity and how these factors were related. Earliness was measured in terms of flowering, boll setting, length of boll maturation, and crop maturity. Additional measurements included plant growth and dry weight partitioning, productivity, and agronomic performance. Plant maturity was determined by time of flowering and length of boll maturation. Lines with the earliest crop maturities produced the lowest yields per plant. Performance of individual early maturing lines, such as 6 M, with improved agronomic properties, demonstrated the ability to increase early crop maturity with improved yield.
Growth Retardation of Bermudagrass with Metsulfuron Methyl and Sulfometuron Methyl1
Authors: Rogers J. N. , Miller E. M. , King J. W.
Published: July 2010

Our primary objective was to determine optimum times and rates for applications of metsulfuron methyl (MSM) (methyl 2‐[(([(4‐methoxyd‐methyl‐l,3,5‐triazin‐2‐y1) amino] carbonyl) amino) sulfonyl] benzoate) and sulfometuron methyl (SMM) (methyl 2 [(([(4,6‐dimethyl‐2‐primidinyl) amino] carbonyl) amino) sulfonyl] benzoate) to reduce mowing requirement without adversely affecting the aesthetic value of the bermudagrass [Cynodon dactylon (L.) Pers.] turfgrass. Field studies were conducted on mature bermudagrass lawn turf grown on a Captina silt loam soil (fine‐silty, mixed, mesic Typic Fragiudalt). Results of 1982 and 1983 experiments showed that MSM alone produced much less growth reduction than a combination of MSM and SMM. The combination at rates of 35 + 35 and 70 + 70 g ha−1 and higher produced good growth suppression for 6 to 8 weeks followed by a flush of growth, but excessive discoloration injury especially when repeated at 5‐week intervals. In 1984 the combination applied at 8.8 + 8.8 on 24 May, 17.5 + 17.5 on 28 June, and 35 + 35 on 2 August provided excellent growth retardation (70% mowing reduction) all season with only very slight injury. The influence of irrigation and N fertilization was minimal.
Variation between Soybean Cultivars in Vesicular‐Arbuscular Mycorrhiza Fungi Colonization1
Authors: Heckman J. R. , Angle J. S.
Published: July 2010

The potential exists for soybean [Glycine max (L.) Merr.] cultivars to be differentially colonized by indigenous soil populations of vesicular‐arbuscular mycorrhiza (VAM) fungi. A pot experiment (Typic Palendults) was conducted in a greenhouse to assay the colonization of various soybean cultivars by VAM fungi. Relative colonization of 15 soybean cultivars at two P levels was determined. Individual root systems were compared for the percentage of roots colonized by VAM fungi using an acid fuchsin‐lactic acid staining procedure. Colonization was shown to vary significantly with cultivar. The cultivar colonized by the highest percentage was the nonnodulating isoline of Clark rj1 rj1 with 80% of root segments examined being colonized. ‘Williams 82’ exhibited the lowest percentage (57%) of colonization by VAM fungi. The addition of P to the soil reduced the percentage of colonized roots from 68 to 64%, and there was no cultivar ✕ P interaction.
A Hot‐Wire Technique for Girdling Stems and Petioles of Herbaceous Plants1
Authors: Dewey Steven A. , Chilcote David O. , Appleby Arnold P.
Published: July 2010

Girdling is often useful in studying translocation of herbicides, plant‐growth regulators, and natural plant components. A hot‐wiretechnique for girdling petioles and stems of herbaceous broadleaf plants using two girdling instruments was studied. One apparatus used AC current to heat a loop in a copper wire. Current was regulated with a rheostat. The other device was a battery‐powered medical cautery instrument with a modified nichrome wire loop. With either device, the hot wire was passed back and forth along a 20‐ to 30‐mm section of petiole or stem until cellular collapse was evident, usually 30 to 60 s. Girdling essentially eliminated basipetal movement of 14C‐assimilate but did not reduce acropetal translocation of simazine (6‐chloro‐N,N′‐diethyl‐1,3,5‐triazine‐2,4‐diamine), an apoplastically mobile herbicide, in tall morningglory [Ipomoea purpurea (L.) Roth]. The method is quick and allows precise placement of girdles
Mefluidide Effects on Forage Quality of Crested Wheatgrass1
Authors: Haferkamp M. R. , Miller R. F. , Sneva F. A.
Published: July 2010

Crested wheatgrass, (Agropyron desertorum [Fisch.] Schult), a valuable spring forage in semiarid environments, produces stiff reproductive shoots that become unpalatable and are of poor nutritive quality. Mefluidide (N‐[2,4‐dimethyl‐ 5{[(trifluoromethyl)sulfonyl] amino} phenyl]acetamide), a plant growth regulator, has the potential to reduce reproductive shoots and improve nutritive quality. Mefluidide was applied to crested wheatgrass, which was grown on coarse‐loamy, mixed, frigid Orthid Durixerolls in May 1982 and 1983, at 0.14, 0.28, and 0.42 kg a.i. ha−1. Herbage yield, density of reproductive shoots, and concentrations of ash, acid insoluble residues, total N (crude protein), in vitro digestible organic matter (IVDOM), and neutral detergent fiber (NDF) in accumulated forage during July through October were determined each year. Reproductive shoot density was reduced by mefluidide up to 91% in both years. The reduction in reproductive shoot density was accompanied by a 20 to 60% decrease in dry matter yields. Ash contents increased 50 to 70 g kg−1 with mefluidide application. A relatively large portion of the ash was acid insoluble residue (silica) and may have been the result of soil contamination on leaves of treated plants. Mefluidide also increased crude protein 18 to 19 g kg−1 and IVDOM 30 to 40 g kg−1, and decreased NDF 50 to 80 g kg−1. The greatest changes occurred with the 0.28 and 0.42 kg ha−1 rates. Major benefits of mefluidide applications include increased forage quality and decreased stemminess.
Evapotranspiration and Yield Comparisons among Soil‐Water‐Balance and Climate‐Based Equations for Irrigation Scheduling of Sweet Corn1
Authors: Braunworth William S. , Mack Harry J.
Published: July 2010

As water for crop production becomes limited and costs of water increase there is a need for more accurate irrigation scheduling. Irrigation scheduling can be improved with reliable and rapid estimates of crop evapotranspiration (ET). The use of three climatebased equations and the soil‐water‐balance equation for estimating sweet corn (Zea mays L. ‘Jubilee’) ET for irrigation scheduling were compared in a 2‐yr field study on a mixed, mesic Cumulic Ultic Hapoxeroll soil. The three climate‐data‐based equations used were the Food and Agriculture Organization of the United Nations (FAO) modified Penman and the FAO and Soil Conservation Service (SCS) Blaney‐Criddle equations. Five irrigation levels ranging from 0 to 100%, with the 100% level intended to refill the root zone to field capacity, were all proportionately irrigated when approximately 50% of the available water was depleted in the 100% level as measured with a neutron meter. A sixth treatment in this randomized complete block experiment was irrigated with the amount of water equivalent to the crop ET estimated by the FAO modified Penman (M PEN) equation, when the crop ET had accumulated to 50% of the available soil water. The crop ET estimated by the soil‐water‐balance equation in 1984 was 481 and 447 mm for the 100% level and for plots irrigated according to the M PEN equation, respectively. In 1985 these ET estimates were 506 and 488 mm, respectively. The crop ET in 1984 was 404, 372, and 374 mm as estimated by the M PEN, FAO, and SCS Blaney‐Criddle equations, while in 1985 these equations estimated 450,448, and 379 mm, respectively. Yield differences were not significant between plots irrigated according to the M PEN equation and the irrigation levels of 50% or more in both years. Calculations indicated that the lower estimates of ET by the FAO and SCS Blaney‐Criddle equations, if used to schedule irrigations, would not be expected to cause yield decreases.
Phosphorus Fertilization Reduces Vesicular‐Arbuscular Mycorrhizal Infection and Changes Nodule Occupancy of Field‐Grown Soybean1
Authors: Hicks P. M. , Loynachan T. E.
Published: July 2010

Mycorrhizal infection of the roots of soybean [Glycine max (L.) Merr.] has been reported to stimulate both nodulation and N2 fixation, especially in soils low in available P. Less is known about yield responses of field‐grown soybean due to mycorrhizal infection, and little is known about the effects of mycorrhizal development on nodule occupancy by Bradyrhizobium japonicum strains. These field studies used two soils each of 2 yr to evaluate the changes in mycorrhizal infection, nodule occupancy, total nodulation, and seed yield when the level of mycorrhizal infection was reduced by adding 112 kg P ha −1 as triple superphosphate. Soils were chosen to represent a range of Bray PI extractable P (12–91 kg P ha −1), and belonged to Aquic Hapludolls, Typic Argiudolls, and Typic Haplaquolls. Mycorrhizal infection and nodulation were assessed, and the occupying bradyrhizobial strains identified at growth stages R1.0 in 1984 and R4.5 in 1985. Even though P fertilization significantly reduced mycorrhizal infection from 25.4 to 5.2 vesicles per 4‐cm root length, there was no effect on the number of nodules per plant or on the resulting seed yields. There was a significant change, however, in nodule occupancy; serogroup 123 averaged 72% in the nonfertilized plots and 37% in the plots fertilized with P. Because mycorrhizal reduction and P fertilization were confounded in the field studies, a greenhouse study was conducted where vesicular‐arbuscular mycorrhizal infection could be controlled by soil sterilization. Inoculation of soybean by Glomus mosseae in sterile soil did not increase the competitiveness of USDA 123 when challenged by USDA 110.
Relationships between Canopy Botanical Composition and Diet Selection in Aeschynomene‐Limpograss Pastures1
Authors: Sollenberger L. E. , Moore J. E. , Quesenberry K. H. , Beede P. T.
Published: July 2010

The proportion of aeschynomene (Aeschynomene americana L.) in diets of cattle (Bos spp.) grazing aeschynomene‐limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] pastures is critical because protein concentration of the grass is often below levels thought needed to prevent intake depression (70 g kg−1 dry matter). A study was conducted on a Pomona sand (sandy, siliceous, hyperthermic Ultic Haplaquod) to determine the effect of botanical composition of aeschynomene‐limpograss canopies on the composition of diets selected by cattle. Esophageally fistulated steers were used to determine selection at first exposure to a pasture, and a sward difference technique was used to quantify the botanical composition of the herbage consumed during 48‐h mob grazing periods. Fistulated steers selected a diet higher in percentage aeschynomene than that in the upper layer of the canopy, but over a 48‐h grazing period, percentage legume in herbage consumed was not different than percentage legume in the grazed horizon. As the canopy was grazed down, total herbage bulk density of the surface layer increased and the legume leaf/stem ratio decreased. These factors ended selection for aeschynomene, and late in a grazing period animals were likely to choose the most accessible grass and weed forage and to avoid legume stems. These data are evidence of a dynamic plant‐animal interface in that (i) canopy characteristics influenced diet botanical composition, (ii) the act of consumption changed the canopy, and (iii) animals responded by altering their degree of selection. The results show that aeschynomene leaf and fine stem are highly palatable to cattle. This finding, along with previous reports of excellent forage quality, suggests that aeschynomene is capable of providing satisfactory levels of protein in steer diets if legume stands are adequate and if grazing ends before all aeschynomene leaf and fine stem are removed from the grazed horizon.