bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bean Leaf Beetle Injury to Seedling Soybean: Consumption, Effects of Leaf Expansion, and Economic Injury Levels
Authors: Hunt Thomas E. , Higley Leon G. , Witkowski John F. 
Published: July 2010

AbstractThe bean leaf beetle (BLB) [Cerotoma trifurcata (Forster)] is a major pest of seedling soybean [Glycine max (L.) Merr.], but little is known of the effects of seedling leaf expansion on final leaf tissue loss resulting from BLB injury. This field study was conducted to (i) determine a precise daily consumption rate of BLB on seedling soybean; (ii) determine the direct and indirect reduction of leaf area resulting from BLB injury and soybean leaf expansion; and (iii) develop economic injury levels for BLB on seedling soybean. The study was conducted on a Sharpsburg silty clay loam in an ‘Elgin 87’ soybean field near Mead, NE. Experimental designs were completely random. Consumption rate treatments consisted of 2 beetles leaflet−1, in the field and laboratory. Leaf expansion treatments consisted of an uninjured check and three levels of injury. Injury (gross removal of leaf tissue) was imposed at Vegetative Stage V3 on a lateral leaflet of the fourth trifoliate leaf. Mean BLB consumption of soybean was 0.31 cm2 d−1. An injury expansion coefficient matrix was developed to estimate final leaf tissue loss at late V3. Final estimated tissue loss resulting from one BLB feeding for 1 d on an unexpanded leaf was 2.74 cm2. Final estimated tissue loss caused by one BLB feeding from Stage V1 through V3 (14 d) was 13.93 cm2. Seedling soybean yield‐loss relationships were used to calculate economic injury levels (EILs) for VC, V1, and V2 soybean. These EILs were more than twice the value of the current EIL of 1.33 beetles plant−1.
Root and Shoot Growth Responses to Salinity in Maize and Soybean
Authors: Shalhevet Joseph , Huck Morris G. , Schroeder Bryan P. 
Published: July 2010

AbstractSalinity generally reduces shoot growth of crops more than root growth, based on dry weight rather than length measurements. The objective of this study was to compare changes in root length to changes in shoot height under conditions of salinity, using the minirhizotron technique. The experiment was conducted in soil containers (55 cm long, 15 cm diam.), using greenhouse‐grown soybean [Glycine max (L.) Merr.] and field‐grown maize (Zea mays L.) as test crops. Segmented, nonlinear regression analysis showed changes in root length as viewed through minirhizotron tubes to be more sensitive to salinity than changes in shoot height, while there was no response to salinity treatment for final root dry weight. The regression coefficients of changes in relative shoot and root length vs. the electrical conductivity of the soil saturation extract (ECe) were 5.3 ± 4.0% per dS m−1 for soybean shoots and 6.6 ± 4.3% per dS m−1 for soybean roots. For maize, the values were 6.9 ± 1.6% per dS m−1 for shoots and 9.0 ± 4.9% per dS m−1 for roots. The regression coefficients of relative shoot height vs. relative root length of soybean and maize were 0.61 ± 0.27 and 0.66 ± 0.20, both significantly smaller than one. The discrepancy between the response in root length as measured by the minirhizotron technique and the response as measured in final root dry weights was attributed to the fact that changes in root length, as viewed in the minirhizotron video frames, depend more on new lateral root initiation than on extension of individual existing roots. Root extension is a turgor‐dependent process, as is shoot elongation, while lateral root initiation is not turgor dependent, and thus may be more sensitive to salinity. One might also speculate that the young, thin lateral roots are more sensitive to salt stress than the older, thicker main root system. Additionally, final root weight is insensitive to the addition of lateral roots if salinity treatments are initiated after the main root system is established, as was the case in this experiment.
Selection for Reproductive Stage Drought Avoidance in Rice, Using Infrared Thermometry
Authors: Garrity Dennis P. , O'Toole John C. 
Published: July 2010

AbstractWater deficits cause major yield reductions on the world's rainfed riceland. The most severe water deficits occur during the reproductive phase. Differences in canopy temperature among crop cultivars are known to be related to drought avoidance characters. In developing a practical field screening system for reproductive phase drought resistance in rice (Oryza sativa L.), we assessed the canopy temperature response of a range of germplasm, and related the results to other plant characters related to drought resistance. Field experiments were conducted on a silty clay loam Typic Hapludoll at the International Rice Research Institute. Planting of the test cultivars was staggered, to synchronize flowering during the water‐deficit period. Canopy temperature measurements were made on 12 dates in Trial 1 and 8 dates in Trial 2. Mean canopy temperatures (Tc) increased from 28 to 37°C during the stress period. Grain yield (r2 = −0.63**) and spikelet fertility (r2 = 0.51**) were related to midday Tc on the day of flowering. Highly significant differences were observed in canopy temperature among entries, with low coefficients of variation (2.0–2.7%). Entries with a history of outstanding vegetative stage drought screening scores consistently remained coolest under stress. Visual drought tolerance scores (r = 0.72**) and leaf rolling scores (r = 0.68**) were correlated with mean canopy temperatures under moderate water stress, but not under severe stress (r = 0.31NS; r = 0.21NS). Infrared thermometry was judged well‐suited to monitor the progression of crop water stress development, and to aid in classifying cultivars for relative drought avoidance. However, caution is necessary to assure proper application of the technique and in data interpretation.
Implications of Nitrogen Management Strategies for Nitrate Leaching Potential: Roles of Nitrogen Source and Fertilizer Recommendation System
Authors: Durieux Robert P. , Stewart E. J. , Zhao J. Q. , Magdoff Frederick R. , Jokela William E. , Brown Hugh J. 
Published: July 2010

AbstractUsing the soil‐based pre‐sidedress nitrate test (PSNT) rather than the yield‐goal‐based cropping and manure history (CMH) to recommend N for corn (Zea mays L.) frequently results in less N applied. Our objectives were (i) to determine if this reduction in N application substantially reduces the potential for N leaching and (ii) to compare dairy manure and commercial fertilizer as N sources, both within PSNT‐based systems. The 4‐yr field study included (i) a control (no manure or N fertilizer), and three N fertilizer rates based on (ii) PSNT, no manure added (PSNT−M); (iii) cropping and manure history (CMH), no manure added; and (iv) dairy manure application with additional sidedress N if recommended by the PSNT (PSNT + M). The PSNT − M treatment received 112 kg N ha−1 in 1990 and 123 kg N ha−1 in subsequent years, while the CMH treatment received 168 kg N ha−1 in all 4 yr. Corn yield, N uptake (defined as net aboveground N accumulation), spring and fall soil NO‐3 levels, and overwinter NO3‐N losses were measured. Silage yields of PSNT + M generally were greatest (average of 16.5 Mg ha−1), followed by PSNT−M and CMH treatments, which were similar (14.8 Mg ha−1). The CMH system resulted in the highest soil NO3‐N levels (to 120 cm) at harvest and greatest overwinter net profile NO3‐N loss (average 66 kg ha−1). The results indicate (i) a reduced residual N after harvest and therefore reduced potential for N leaching when using the PSNT for N recommendations and (ii) similar or higher yields using manure compared with commercial fertilizer.
Planting and Harvest Date Effects on Productivity and Root/Shoot Quotient of Four Brassica Cultivars
Authors: Jung Gerald A. , Shaffer John A. 
Published: July 2010

AbstractSummer‐planted turnip (Brassica rapa L.) is a highly productive crop, and may allow farmers to extend the grazing season and lower animal production costs. A field study was conducted to determine the influence of planting date and harvest date on morphological development and productivity of leafy plants like turnip in late fall. Turnip and a spinach ✕ mustard hybrid were seeded in rows on Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalfs), using a factorial treatment structure (6 planting dates ✕ 4 cultivars) in a split‐plot design, with planting date as whole plot, cultivar as subplot, and four replicates. Three to six harvest dates were used, depending on planting date, resulting in an overall incomplete factorial treatment structure. Mean yield of all cultivars with optimal planting date‐harvest date combinations was 11.5 Mg ha−1 without severe foliar disease and 9.7 Mg ha−1 with alternaria leaf spot (caused by Alternaria spp.). The interaction of planting date and harvest date on morphological development depended on resource allocation characteristics of the cultivar for top and root production. Delay of planting from late July to late August decreased top and root production more in 1990 than 1989. An optimum harvest date for maximizing fall top yield occurred each year regardless of planting date. Root yields increased in November and early December, whereas top yields did not. In general, total yields were high for crops planted in late July and harvested in late October or early November. Top/root quotient (top yield divided by root yield) was increased by delaying summer planting, and decreased by delaying fall harvest. Savanna had the highest, and Purple Top had the lowest top/root quotient. Turnip offers very high production potential for late‐fall grazing, with a wide range of top/root yields.
Growth and Nutrient Uptake of Wheat in Clinoptilolite‐Phosphate Rock Substrates
Authors: Allen Earl R. , Ming Douglas W. , Hossner Lloyd R. , Henninger Donald L. , Galindo Charlie 
Published: July 2010

AbstractMixtures of zeolite and phosphate rock react to release cations and anions into soil solution through dissolution and ion exchange. These mixtures have the potential to serve as slow‐release sources of nutrients in synthetic soils. The term zeoponics has been used to describe such systems. Research was conducted to monitor dry matter production and nutrient uptake of wheat (Triticum aestivum L.) in a zeoponic system containing phosphate rock and NH4‐ and K‐saturated zeolite. The objective was to evaluate the ability of zeolite and phosphate rock to provide a balanced supply of N, P, K, and Ca for plant growth. Two zeolite samples (San Miguel and Wyoming clinoptilolite) and two phosphate rock samples (North Carolina and Tennessee phosphate rock) were combined factorially to form four zeoponic mixtures. A series of synthetic soils was formed by combining selected rates of each zeoponic mixture with acid‐washed quartz sand. Zeoponic rates (ZR) were 1, 5, 10, 25, 50, 75, and 100% (v/v) of the synthetic soil. Pots were placed in a growth chamber after planting, and plants were harvested every 45 d for a 225‐d period. Foliar spray supplied essential nutrients other than N, P, K, and Ca. High yields of wheat dry matter were produced through several cuttings when at least 25% of the synthetic soil was comprised of the zeoponic mixture and when the zeoponic mixture contained a highreactivity phosphate rock (North Carolina). Tissue analyses suggested that K, and to a lesser extent N, limited wheat growth when ZR ≤ 10%. Calcium limited wheat growth at ZR > 10% when a low‐reactivity phosphate rock (Tennessee) was used, but not when a high‐reactivity phosphate rock (North Carolina) was used. Properly formulated zeoponic mixtures of San Miguel or Wyoming clinoptilolite and North Carolina phosphate rock are capable of supplying sufficient levels of N, P, K, and Ca for intensive growth of wheat.
Influence of Alfalfa Escapes on Estimating Spring Barley Yield
Authors: Krall James M. , Miller Stephen D. , Legg David E. 
Published: July 2010

AbstractIn Wyoming, spring barley (Hordeum vulgare L.) can follow alfalfa (Medicago sativa L.) in irrigated rotations. To avoid serious wind erosion, this conversion should be done using conservation tillage. However, this can be complicated by alfalfa escapes. The relationship between the level of established alfalfa interference and barley is unknown. Establishment of the season‐long impact of alfalfa escapes on barley yield would be important for crop‐loss assessment. Forecasting the impact on production would be valuable as a decision making tool. The objective of this study was to estimate yield losses from season‐long interference of alfalfa escapes and to forecast impact of alfalfa escapes on spring barley yield. Replicated field studies were conducted under sprinkler irrigation at a site near Torrington, WY. Herbicide treatments were used to provide for barley production across a range of levels of alfalfa interference. Barley yield response was regressed on various measures of alfalfa infestation. Consistency of regression over years for barley yield on end‐of‐season alfalfa stand or alfalfa yield allowed for simple interpretation of the expected barley yield reduction, as well as calculation of the expected barley yield given a specific level of alfalfa infestation. Use of a growing season visual assessment of alfalfa control did not result in consistency of regression slopes over years. Calculation of an expected barley yield based on models developed using alfalfa stand and alfalfa yield was accomplished. The predictors are −84.747 and −0.5577 for alfalfa plants 0.5 m−2 and kg ha−1 alfalfa yield, respectively.
Methods for Soil Infestation with Striga hermonthica Seeds
Authors: Berner Dana K. , Ikie Felix O. , Aigbokhan Emmanuel I. 
Published: July 2010

AbstractField screening of maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench] can be an efficient means of selecting for resistance to the parasitic plant Striga hermonthica (Del.) Benth. Spatial variability in natural S. hermonthica seed infestations necessitates supplemental infestation for effective field screening. For uniformly heavy levels of infestation, sieved sand has been used as a carrier material for the extremely small S. hermonthica seeds, and a 7‐ to 14‐d waiting period between infestation and planting is often provided to environmentally condition the S. hermonthica seeds for germination and uniform infection. These steps are labor‐intensive, requiring sieving of large amounts of sand and separate infestation and planting times. The objective of this study was to develop alternative soil infestation methods for S. hermonthica seeds that require less labor and produce levels of infection comparable to standard procedures. Nine different methods of soil infestation with S. hermonthica seeds were tested in a screenhouse and in two field locations on maize and sorghum cultivars. To assess effectiveness of the methods, S. hermonthica emergence and host yield were measured. Infestation using sand as a carrier material followed by a 14‐d in situ conditioning period resulted in the greatest amount of infection in the screenhouse. In the field, methods that employed no conditioning period, and thus allowed infestation and planting on the same day, produced levels of infection comparable to methods with 7‐ and 14‐d preplant conditioning periods. The most easily accomplished of these methods used water as the carrier material, producing levels of infection equivalent to methods using sand.
Chain Diking Effects on Runoff and Winter Wheat Production
Authors: Wiedemann Harold T. , Clark Lewis E. 
Published: July 2010

AbstractThe major factor limiting crop production in the Texas Rolling Plains is water, and better methods of conserving soil water in dryland wheat production are needed. Chain diking is a novel method of forming basins on flat‐tilled land to impound and conserve water received from precipitation. The objective of this research was to determine the influence of chain diking on dryland winter wheat (Triticum aestivum L.) yield and on runoff during the growing season. The study site, in northwest Texas, has an annual mean rainfall of 632 mm and a cropping season average of 444 mm. Following September drill‐seeding of wheat, plots were chain diked or not diked. All other cultural practices were the same for all plots. Exit flumes and automatic recording devices were installed to measure runoff from each plot during the growing season. Grain was harvested in June. Diking reduced runoff an average of 40% (P = 0.02), which amounted to 1.0 ha‐cm over three crop years, compared with tillage without diking. The increase in wheat grain yield from diking was not significant over four crop years (P = 0.75). When analyzed by year, diking increased yields 11% (277 kg ha−1; P = 0.02) in 1989, when cropping‐season rainfall was 22% below average. The probability of receiving rainfall below average by more than 20% during the cropping year is 30%, based on 88‐yr records at this test site. Diking following planting apparently will be valuable less than 30% of the time, although other applications for chain diking are possible.
Experimental Design Factors Affecting Error Variation in Orchardgrass
Authors: Casler M. D. , Tageldin M. H. 
Published: July 2010

AbstractSeveral experimental design factors over which the researcher has control may affect the precision of field experiments. The objective of this experiment was to identify the effects of changing plot size, incomplete block size, and incomplete block shape on precision of forage yield and quality estimates in orchardgrass (Dactylis glomerata L.). Orchardgrass seed was planted uniformly into 288 plots of various sizes. Forage yield, in vitro dry matter digestibility (IVDMD), and neutral‐detergent fiber (NDF) were determined over a 2‐yr period. Error variances (Vw) were computed for variously sized incomplete blocks (in one or three strips and from 1 to 12 plots strip−1) within each plot size and expressed as log(Vw). Values of log(Vw) for IVDMD and NDF concentration were unaffected by experimental design factors. Values of log(Vw) for forage yield increased with increasing number of plots per strip, but these effects varied among plot sizes and for one‐ vs. three‐strip blocks. Three‐strip blocks had a mean log(Vw) 71% greater than one‐strip blocks, an effect that could be offset only by doubling the number of replicates in a field test. To obtain maximum precision in cases where a large number of replicates impossible or impractical, orchardgrass field experiments should employ incomplete block designs, particularly when limited seed stocks or land requires a plot size near 1.4 m2. Incomplete block designs with this plot size should not contain multiple strips within incomplete blocks.
Environment Affects the Corn and Soybean Rotation Effect
Authors: Porter Paul M. , Lauer Joseph G. , Lueschen William E. , Ford J. Harlan , Hoverstad Tom R. , Oplinger Edward S. , Crookston R. Kent 
Published: July 2010

AbstractCorn (Zea mays L.) and soybean [Glycine max (L.) Merr.], the backbone of Midwestern crop production, respond to rotation, but how growing conditions affect this is not well documented. Our objectives were to determine the effect of various corn and soybean cropping patterns on yields and to evaluate environmental effects on the rotation effect. The study began in 1981 at Lamberton, MN, on a Webster clay loam (fine‐loamy, mixed, mesic Typic Endoaquoll), in 1982 at Waseca, MN, on a Nicollet clay loam (fine‐loamy, mixed, mesic Aquic Hapludoll), and in 1983 at Arlington, WI, on a Plano silt loam (fine‐silty, mixed, mesic Typic Argiudoll). Cropping sequences were (i) continuous monoculture of each crop; (ii) annual rotation of the two crops; and (iii) 1, 2, 3, 4, and 5 yr of each crop following 5 yr of the other crop. Results are based on 11 yr of data at Lamberton, 8 yr (soybean) or 9 yr (corn) at Waseca, and 9 yr at Arlington. Corn rotated annually with soybean yielded 13% more, and 1st‐yr corn following multiple years of soybean yielded 15% more than continuous corn. Soybean annually rotated with corn yielded 10% more, and 1st‐yr soybean following multiple years of corn yielded 18% more than continuous soybean. The crops differed in response to increasing years of consecutive planting: 2nd‐yr to 5th‐yr corn yields were no different from continuous corn yields; 2nd‐yr soybean yielded 8% more than continuous soybean, 3rd‐yr soybean yielded 3% more, and 4th‐ and 5th‐yr soybean yielded the same as continuous soybean. Relative increase in yields of both crops in annual rotation compared with monoculture was approximately twofold greater in low‐yielding than in high‐yielding environments. In low‐yielding environments, the yield advantage of an annual rotation of corn and soybean compared with monoculture was frequently greater than 25%. The commonly practiced annual rotation of corn and soybean maximized corn yields, but not soybean yields, relative to the other sequences studied.
Modefying a Carter Flail Forage Harvester to Stabilize the Weighing System
Authors: Hall Marvin H. , Todd Richard F. , Hoffman Lynn D. , Everhart James R. 
Published: July 2010

AbstractThe single bending‐beam load‐cell weigh system that is standard equipment on a Carter flail forage harvester allows the forage collection weigh basket to pitch and sway. This movement can allow some forage to be lost when it is blown past the basket. In addition, this movement requires additional time for the basket to stabilize at the end of each plot before a weight can be recorded. A specialized frame with three bending‐beam load cells was designed and constructed to restrict movement of and to support the forage collection weigh basket. Total cost of materials for this modification was about $750. The modifications can be completed with normal shop tools and are readily interfaced with standard equipment on the Carter harvester. The modified support bracket and weigh system performed well, harvesting nearly 10 000 forage plots annually. Compared with the single bending‐beam load cell weigh system, the modified support bracket and weigh system reduced pitch and sway of the forage collection weigh basket, was equally precise, and required an average of 7 s less for the basket to stabilize at the end of each plot.
Estimation of Direct, Residual, and Total Effects of Canopy Treatments Affecting Intake by Grazing Cattle
Authors: Dougherty Charles T. , Cornelius Paul L. 
Published: July 2010

AbstractEffects of transient treatments imposed on grazing cattle diminish over time but many experimental designs and statistical analyses only estimate integrated responses. We describe a change‐over design that estimates direct, first residual, second residual, and overall effects of three treatments (water, saline solution, or syrup solution) applied to alfalfa (Medicago sativa L.) canopies on the ingestive behavior of Angus cows (Bos taurus L.). Syrup‐treated canopies evoked a direct effect. Animals grazed water‐treated canopies at 32 bites min−1 and ingested herbage dry matter (DM) at 0.55 kg 100 kg−1 body mass h−1, while others grazed syrup‐treated canopies at 48 bites min−1 (P < 0.01) and ingested herbage DM at 0.64 kg 100 kg−1 h−1 (P < 0.01). As residual effects were not significant (P > 0.05), the animal responses to syrup‐treated canopies were considered preingestive responses and were attributed to enhanced sweetness. Salt‐treated alfalfa canopies, conversely, had no direct (immediate) effect (P > 0.05) on herbage intake, but summed first and second residual effects, expressed the day after application of NaCl, revealed that animals grazing untreated and syrup‐treated alfalfa ingested DM at 0.47 kg 100 kg−1 h−1, while those grazing salt‐treated alfalfa ingested herbage DM at 0.55 kg 100 kg−1 h−1 (P < 0.05). The residual effects of salt were considered postingestive responses and were attributed to Na deficiency. Change‐over designs that estimate direct and residual effects of treatments may be used to determine preingestive and postingestive components of intake.