bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cover Crop Management and Nitrogen Rate in Relation to Growth and Yield of No‐Till Corn
Authors: Wagger M. G. 
Published: July 2010

AbstractCover crop management in no‐tillage systems prior to planting the principal crop can be an important tool in maximizing the beneficial effects of the cover crop on the principal crop. A field experiment was conducted in 1984 and 1985 to examine timing effects of cover crop desiccation relative to corn planting [early desiccation/early plant (EE), early desiccation/late plant (EL), and late desiccation/ late plant (LL)] and fertilizer N (0, 100, and 200 kg ha−1) on corn growth and yield. These management schemes were evaluated for fallow, rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), and hairy vetch (Vicia villosa Roth.) cover crop systems. Corn dry matter production and N uptake, monitored in all 0 kg N ha−1 treatments, were significantly affected by cover crop management and varied according to stage of development and climatic conditions. Cover crop type had a pronounced effect on corn growth, with corn dry matter production in a rye cover crop lower than in legume cover crops. Grain yield response to applied N was greatest in a rye cover crop system. In contrast, a grain yield response up to the first increment of fertilizer N (100 kg ha−1) in legume cover crop systems was observed only in 1984. Corn recovery of legume N was estimated at 40 to 45 kg N ha−1 (2‐yr avg.), representing approximately 36 and 30% of the total N content of crimson clover and hairy vetch, respectively. These data indicate that winter annual legume cover crops are capable of providing a substantial portion of the N required by corn. Additionally, cover crop management should insure that corn planting is not delayed to allow for additional legume growth and N production.
Rapid Dinitrogen Fixation During Soybean Pod Fill Enhances Net Photosynthetic Output and Seed Yield: A New Perspective
Authors: Imsande John 
Published: July 2010

AbstractNitrogen is frequently the limiting nutrient in plant growth and reproduction. Nevertheless, it is widely reported that the seed yield of the nodulated soybean [Glycine max (L.) Merr.] grown on fertile soil is not N‐limited. This paper, based on new experimental evidence obtained under carefully controlled laboratory conditions, seeks to review and reevaluate this conclusion. To test this claim, inoculated soybean plants were grown hydroponically in the presence of suboptimal urea or with an excess of either nitrate or nitrate plus urea. Acetylene reduction activities (i.e., N2 fixation rates) of plants grown on suboptimal urea were approximately tenfold greater than those of plants grown on excess nitrate. At maturity, plants that had fixed N2 at a rapid rate during pod fill had a greater biomass (i.e., a greater net photosynthetic output), a higher N content, and produced larger seeds than uninoculated or poorly nodulated plants grown on excess nitrate. Likewise, published reports show that plant biomass, seed N, and mean seed weight (i.e., g/100 seeds) of nodulated plants grown in the field without added fertilizer N were significantly greater than those of nonnodulated plants grown on adjacent field plots and given a modest level of fertilizer N. Calculations show that mean seed weight of both hydroponically grown and fieldgrown plants correlated significantly (r ≥ 0.93) with seed yield. Because of this strong positive correlation and because rapid N2 fixation during pod fill significantly increases mean seed weight without lowering the number of seeds, it is concluded that elevated N2 fixation by field grown plants would increase soybean yield significantly. An increase in both total plant N and net photosynthetic output is thought to promote this increase in seed yield.
Soil Temperature and Water Content, Seeding Depth, and Simulated Rainfall Effects on Winter Wheat Emergence
Authors: Lafond G.P. , Fowler B. D. 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L.) can be produced on the northern edge of the North American Great Plains provided it is protected from winterkill by an insulating blanket of snow. No‐till seeding into standing stubble (stubbling‐in) has provided the most efficient means of maintaining this protective snow cover. Soil water at seeding is usually below optimum level for growth and development with this management system, and producers are often left with the dilemma of either seeding at the optimum date into a dry seedbed or delaying seeding until after a rain. The objectives of this study were to determine the effects of soil temperature, soil water, and seeding date and depth on median emergence time, development, and cold tolerance of winter wheat plants grown under controlled laboratory conditions. Median emergence time decreased by 1.3 d and emergence was more uniform for every degree increase in soil temperature in the 5 to 20°C range. Median emergence time increased as soil water potential decreased from −0.20 to −1.5 MPa. However, simulation studies demonstrated that 9.3 mm of precipitation on a dry soil was adequate to establish winter wheat seeded less than 25 mm deep. Increasing the depth of seeding from 19 to 76 mm increased median emergence time by 4.4 d for the optimum seeding date and 9.6 d if seeding was delayed 3 wk. Consequently, delayed deep seeding resulted in poorly developed plants with a reduced ability to withstand low temperatures. From a practical standpoint, this study demonstrates that in western Canada stubbled‐in winter wheat should be seeded shallow (10 to 25 mm) at the optimum date even if it means seeding into a dry seedbed.
Dicamba Injury to Soybean
Authors: Weidenhamer J. D. , Triplett G. B. , Sobotka F. E. 
Published: July 2010

AbstractDicamba (3,6‐dichloro‐2‐methoxybenzoic acid) effectively controls many dicotyledonous weeds, but nontarget species such as soybean [Glycine max (L.) Merrill) are susceptible to spray or vapor drift. Field studies were conducted on a Canfield silt loam (fineloamy, mixed, mesic Aquic Fragiudalf) soil to determine the response of ‘Elf’ and ‘Williams’ soybean to dicamba over a wide range of applied rates, and to evaluate the use of dicamba injury symptoms to predict yield reductions. Soybean yield in response to increasing rates of dicamba was described by equations of the form y = Aexp( −bx), where y = yield, A = maximum yield (rate = 0 g ha−1), b is a constant, and x = rate of dicamba applied. Height reduction, seed number ha−1, and morphological symptoms of dicamba injury were useful in assessing yield reduction. Except for Elf soybean treated at the midbloom stage, there was no yield reduction without height reduction, regardless of foliar symptoms. Seed number ha−1 decreased with increasing rates of dicamba and was closely correlated with yield. Yield reductions greater than 10% were indicated by severe morphological symptoms of injury, such as terminal bud kill, splitting of the stem, swollen petioles, and curled, malformed pods. Other foliar symptoms, such as distinctive crinkling and cupping of the terminal leaves, occurred at rates much lower than those required to cause yield reductions.
Genotype × Environment Interaction in Maize
Authors: Kang M. S. , Gorman D. P. 
Published: July 2010

AbstractGenotype × environment (GE) interactions are a challenge to plant breeders because they cause difficulties in selecting genotypes evaluated in diverse environments. When GE interaction is significant, its cause, nature, and implications must be carefully considered. No information is available on the contribution of weather variables and environmental index (Ȳ.j or mean yield of all cultivars in jth location minus Ȳ.. or overall mean yield for all cultivars and all locations) to GE interaction for yield in maize (Zea mays L.). The objective of this study was to determine the effect of an environmental index, maximum and minimum temperatures, rainfall for the growing season, preseason rainfall, and relative humidity (covariates) on GE interaction for yield. Seventeen hybrids grown in 12 environments (4 locations × 3 yr) were studied. The GE interaction was significiant and was partitioned into σ2i (stability variance) components assignable to each genotype (hybrid). Heterogeneity (non‐additivity) due to each covariate was removed from the GE interaction, and the remainder of the GE interaction variance was partitioned into s2i components assignable to each genotype. Environmental index accounted for 9.61% of the GE interaction sum of squares (P = 0.10). This was the largest amount of heterogeneity removed from the GE interaction by any single covariate. Rainfall during the growing season removed 1.4% of the GE interaction sum of squares and preseason rainfall removed 1.1% of the GE interaction sum of squares as heterogeneity. Minimum temperature, maximum temperature, and relative humidity removed a negligible amount of heterogeneity from the GE interaction. The 17 hybrids evaluated in this study were differentially affected more by differential fertility and/or cultural practices (environmental index) than by weather factors. Seven of the 17 hybrids had unstable performance across the 12 environments.
Vegetative Establishment of Three Warm‐Season Perennial Grasses in Late Fall and Late Winter
Authors: Chamblee D. S. , Mueller J. P. , Timothy D. H. 
Published: July 2010

AbstractToo much moisture for field entry in late winter or early spring, or drought in late spring and summer create problems for vegetative establishment of warm‐season perennial grasses. Late fall planting, in drier months when the plants are dormant, offers an alternative and a possible advantage. The primary objective of this study was to determine the feasibility of late‐fall planting of ‘Coastal’ and ‘Tifton 44’ bermudagrasses [Cynodon dactylon (L.) Pers.] and ‘Carostan’ flaccidgrass (Pennisetum flaccidum Griseb.) compared with the late‐winter date commonly used for central North Carolina. Three field trials in different years were conducted on a Dothan loamy sand (fine‐loamy, siliceous, thermic Plinthic Paleudult) using the above cultivars planted in November, December, and March at two planting depths (3.8 and 7.6 cm) and two orientations (horizontal and vertical). In addition, at each planting date in the third trial, sprigs of the grasses were subjected to temperatures of 0, −3, −6, −9, −12, and −15°C in a low temperature stress simulator. Relative order of cold survival was Carostan flaccidgrass >Tifton 44 >Coastal bermudagrass. Nothing survived the −9°C or lower temperatures. Horizontal plantings of Tifton 44 bermudagrass in December to a depth of 7.6 cm produced stands in May of 79, 54, and 78% in Exp. 1, 2, and 3, respectively. For the same treatments Coastal bermudagrass produced stands of only 2, 2, and 21%, and Carostan flaccidgrass 77, 76, and 95%. Winter survival of Tifton 44 bermudagrass and Carostan flaccidgrass was markedly improved (71 vs. 32% stand in May for December planting) when placed horizontally at the 7.6‐cm depth, compared with 3.8 cm in the two more severe winters. The 7.6‐cm horizontal placement of Coastal bermudagrass in March plantings resulted in stands in May of only 36%, compared with 81% from 3.8 cm and 70% from the vertical orientation. Tifton 44 bermudagrass was less sensitive to deeper planting in March. We conclude that Carostan flaccidgrass and Tifton 44 bermudagrass may be successfully planted in the fall, particularly in areas with slightly more moderate winters than the central North Carolina area.
Corn Yield and Residual Soil Nitrate as Affected by Time and Rate of Nitrogen Application
Authors: Jokela W. E. , Randall G. W. 
Published: July 2010

AbstractEfficient use of N fertilizer for corn (Zea mays L.) production is important for increasing economic return to the grower and for minimizing the potential impact on water quality. Time and rate of application are important management tools for improving N efficiency. This experiment was conducted for 3 yr on two nonirrigated southern Minnesota soils—a Mt. Carroll silt loam (fine‐silty, mixed, mesic Mollic Hapludalf) and a Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquoll)—to evaluate the effect of time and rate of N application on corn yield, N uptake, and residual soil NO−3‐N. Nitrogen as (NH4)2SO4 was applied in a factorial arrangement of N rate (low and high) and time of application (at planting (PL), eight‐leaf stage (8L), or split evenly between the two times (SP)). A zero N control and a very high N rate at PL were also included. Nitrogen rates were 75, 150, and 225 kg ha−1 on the Mt. Carroll, and 100, 200, and 300 kg ha−1 on the Webster. Grain and total dry matter (DM) yield, and plant uptake of N were increased by N application in five of six site years, in most cases up to the high N rate. Delayed N application (8L or SP vs. PL) resulted in either no effect or a slight decrease in DM and in variable effects on N uptake, depending on the year and location. Residual NO−3‐N in the 1.5 m profile ranged from 150 to 400 kg ha−1 for most treatments in the fall but was 50 to 70% lower the following spring. Residual NO−3 in the fall was consistently increased by delayed application of the high N rate from the PL to 8L stage, with most of the increase occurring in the upper 0.6 m of the profile. The decrease in residual NO−3 from fall to spring, attributed in part to leaching beyond the sampled zone, minimized the potential carryover effect for the next year's production and indicated a potential for greater environmental impact where N application was delayed. Dry matter production, N uptake, and residual NO−3‐N were affected by unusually dry periods in midsummer of all 3 yr, especially at the Webster site.
Crop Yield as Affected by Rotation and Nitrogen Rate. I. Soybean
Authors: Peterson Todd Andrews , Varvel G. E. 
Published: July 2010

AbstractCrop rotation is reported to increase seed yield of soybean [Glycine max (L.) Merr.], but rotation effects are less pronounced than for cereal crops. This study compares yield of soybean grown in continuous monoculture with that of soybean grown (i) in a 2‐yr rotation with corn [Zea mays L.]; (ii) in a 2‐yr rotation with grain sorghum [Sorghum bicolor (L.) Moench]; (iii) in a 4‐yr grain sorghum‐oat+clover [Avena sativa (L.) + 80% Melilotus officinalis (L.) Lam., 20% Trifolium pratense]‐corn‐soybean rotation; and (iv) in a 4‐yr corn‐oat+clover‐grain sorghum‐soybean rotation. Interactions between crop rotation and fertilizer N rate were also determined. The study was conducted for 4 yr on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudoll) near Mead, NE. Continuous soybean produced less seed (2.4 Mg ha−1) than soybean in rotation (2.7 Mg ha−1 average). Rotations in which soybean followed sorghum in rotation produced higher seed yield (2.8 Mg ha−1) than soybean following corn (2.6 Mg ha−1), mainly because soybean following sorghum responded positively to N applications, while soybean following corn did not.
Genotype ✕ Environment Interactions on Soft White Winter Wheat Quality
Authors: Bassett L. M. , Allan R. E. , Rubenthaler G. L. 
Published: July 2010

AbstractEnhanced quality is essential to improve marketability of northwestern USA soft white winter (SWW) wheat (Triticum aestivum L.). The objectives were to compare four major SWW cultivars for six quality criteria and their relative environmental stabilities. Cultivars Daws, Lewjain, Nugaines, and Stephens were grown in 63 site years and evaluated for flour yield, cookie diameter, percent flour protein, alkaline water retention capacity (AWRC), hardness, and sedimentation. Cultivar and environmental effects were significant (P<0.01) for all traits. Genotype ✕ environment interactions were small, but significant. Among the variance components, years contributed most to total variance for percent protein, sedimentation, and AWRC. The year ✕ site component was greatest for flour yield, cookie diameter, and hardness. Relatively large cultivar ✕ environment components for cookie diameter, hardness, and AWRC required their evaluation across multiple site years. All cultivars had satisfactory overall SWW wheat quality, yet Lewjain and Stephens had the best cookie diameter and flour yield, respectively. Daws was marginal for cookie diameter and hardness, and Nugaines was usually low for flour yield. Stephens and Lewjain were generally the least and most sensitive to environmental variation for quality parameters. Most quality traits were correlated (P < 0.05) with each other within cultivars. The AWRC gave low and usually nonsignificant correlations with all quality parameters except cookie diameter. Intragenotypic differences in grain yield and grain volume weight were correlated (P < 0.05) with all quality traits except AWRC. Grain volume weight differences accounted for 26 to 40% and 36 to 67% of the variation in cookie diameter and flour yield, respectively.
Cotton Management Strategies for a Short Growing Season Environment: Water‐Nitrogen Considerations
Authors: Morrow M. R. , Krieg D. R. 
Published: July 2010

AbstractThe Southern High Plains of Texas represents the largest contiguous cotton (Gossypium hirsutum L.) production area in the USA. Water supply represents the greatest limitation to production under rainfed conditions. Where supplemental irrigation is used, growing season length represents a major limitation to attainment of high yields of desirable quality fiber and seed. The primary objective of this research project was to determine the inter‐relationships between H2O, N, and heat unit supplies as they affect lint yield of cotton. Field experiments were conducted during a 4‐yr period at a sandy soil (fine, loamy, mixed, thermic family of Aridic Paleustalf) site. Water supply was varied through irrigation with treatments ranging from dryland to fully irrigated. Superimposed on the water supplies were N rate treatments applied preplant and sidedress in a factorial design. Lint yield (LY) was defined as a function of components including plant density, bolls per plant and average boll size. Regression analysis was used to determine LY response to treatments. Lint yield was most highly correlated with boll number per unit ground area with equal contribution from plant density and bolls per plant. Water supply was most responsible for boll number; however, increasing N supply within each H2O regime resulted in a positive response in boll number per plant. Multiple regression analysis revealed that LY responded to H2O and N supplies during the fruiting period to a greater extent than to preflower supplies. Within any heat unit regime, LY was maximized as water supply increased by maintaining a constant ratio of 0.2 kg N ha−1 mm−1 H2O.
Seed Weight Response to Decreased Seed Number in Maize
Authors: Kiniry J. R. , Wood C. A. , Spanel D. A. , Bockholt A. J. 
Published: July 2010

AbstractWeight per seed (SDWT) of maize (Zea mays L.) has been rcported to show no response when seed number was manually decreased. This field experiment was designed to test the generality of this lack of response across techniques of reducing seeds per ear and across genotypes. Bagging ears of a dent hybrid 2 to 4 d after silking reduced seed number by 15 to 45% and increased SDWT by 19 to 25%. The same treatment applied to a popcorn hybrid reducvd seed number by 12 to 36% with no significant increase in SDWC. Open pollinated varieties representing different seed sizes showed similar variability in SDWT response to reduced seed number. When SDWT of the dent hybrid and one of the varieties increased in response to reduced reed number, seed volume increased by a similar fraction. Removal of the apical half of the ear of the dent hybrid caused a different SDWT response than ear bagging. Such removal 5 to 15 d after silking decreased SDWT while removal 20 to 25 d after silking produced no significant change. Thus, it appeared that the response of SDWT to reduced seed number depended on genotype, how seed number was reduced, and when the reduction occurred. The reduction in SDWT due to early ear cutting was not due to a reduction in number of endosperm cells or volume of the developing seeds. The possibility of a physical restraint on SDWT by the developing pericarp of some cultivars was discussed.
Quantifying the Nitrogen Contribution from Alfalfa to Soil and Two Succeeding Crops Using Nitrogen‐15
Authors: Harris G. H. , Hesterman O. B. 
Published: July 2010

AbstractWith the current interest in sustainable agricultural systems, the use of legumes in crop rotations to provide N to subsequent crops is increasing. The objective of this study was to quantify the N contribution from different alfalfa (Medicago sativa L.) plant parts to a subsequent corn (Zea mays L.) crop, various soil fractions, and a 2nd yr spring barley (Hordeum vulgare L.) crop. The study was conducted at two field locations in Michigan, on a Capac loam (fineloamy, mixed, mesic, Aerie Ochraqualf) in East Lansing (EL) and on an Oshtemo sandy loam (coarse‐loamy, mixed, mesic, Typic Hapludalf) at the Kellogg Biological Station (KBS) in Hickory Corners. Alfalfa shoots and roots/crowns labeled with 15N were applied separately to microplots in Fall 1985 and Spring 1986 at a rate equivalent to 112 kg N ha−1. Corn was harvested and soil was sampled from all microplots in Fall 1986 and analyzed for 15N. Corn recovered 17 and 25% of the alfalfa‐15N applied to the loam and sandy loam soils at ELand KBS, respectively. Alfalfa‐15N remaining in soil averaged 46% of the initial input for both locations. Most (96%) of the alfalfa‐15N remaining in soil was recovered in the organic fraction, with microbial biomass accounting for 18% of this recovery. More 15N was recovered by corn and in soil from alfalfa shoots than roots/crowns at both locations, and from spring‐incorporated than fall‐incorporated plant material on the loam soil. Only 1% of the alfalfa‐15N from the original application was recovered by a 2nd yr spring barley crop at both locations
Comparison of Models for Describing; Corn Yield Response to Nitrogen Fertilizer
Authors: Cerrato M. E. , Blackmer A. M. 
Published: July 2010

AbstractDecisions concerning optimum rates of fertilization directly or indirectly involve fitting some type of model to yield data collected when several rates of fertilizer are applied. Although several different models are commonly used to describe crop yield response to fertilizers, it is seldom explained why one model is selected over others. The objective of the work reported here was to compare and evaluate several models (linear‐plus‐plateau, quadratic‐plus‐plateau, quadratic, exponential, and square root) commonly used for describing the response of corn (Zea mays L.) to N fertilizer. The evaluation involved 12 site‐years of data, each having 10 rates of N appied preplanting. All models fit the data equally well when evaluated by using the R2 statistic. All models indicated similar maximum yields, but there were marked discrepancies among models when predicting economic optimum rates of fertilization. Mean (across all site‐years) economic optimum rates of fertilization as indicated by the various models ranged from 128 to 379 kg N ha−1 at a common fertilizer‐to‐corn price ratio. Statistical analyses indicated that the most commonly used model, the quadratic model, did not give a valid description of the yield responses and tended to indicate optimal rates of fertilization that were too high. The quadratic‐plus‐plateau model best described the yield responses observed in this study. The results clearly show that, especially amid increasing concerns about the economic and environmental effects of overfertilization, the renson for selecting one model over others deserves more attention than it has received in the past.