bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synchrony between Legume Nitrogen Release and Corn Demand in the Upper Midwest
Authors: Stute James K. , Posner Joshua L. 
Published: July 2010

AbstractIf legume cover crops are to be an effective, environmentally sound N source for corn (Zea mays L.), there must be a synchrony between legume N release and corn demand. A field study was conducted in Wisconsin during 1991 and 1992 that measured the release of legume N throughout the growing season using mesh bags, and compared resultant levels of soil mineral N following legume incorporation to those following fertilizer N applied at the recommended rate (179 kg N ha−1) and a control (no cover crop, no fertilizer) in a conventional tillage (CT) system. Corn N uptake during the growing season was also measured to determine if legume N could meet uptake demands. Hairy vetch (Vicia villosa Roth) and red clover (Trifolium pratense L.) residues decomposed rapidly, releasing half of their N within 4 wk after burial, while very little N was released after 10 wk (corresponding to corn silking). Soil tests indicated an increase in mineral N levels corresponding to legume N release, similar to those following an application of 179 kg ha−1 fertilizer N, occurring before the period of rapid N uptake by corn. Mean corn grain yields of 11.25 Mg ha−1 in 1991 and 10.89 Mg ha−1 in 1992 following the legumes were similar to those produced with 179 kg ha−1 fertilizer N, indicating that, in addition to releasing N in synchrony with the uptake pattern of corn, legumes released N in adequate amounts for corn production. Finally, postharvest levels of potentially leachable soil NO3‐N following the legumes were similar to or less than when following fertilizer. Therefore, legume cover crops can be an effective N source for corn in the Upper Midwest.
Observed and Calculated Potassium Uptake by Maize as Affected by Soil Water Content and Bulk Density
Authors: Seiffert Stefan , Kaselowsky Joachim , Jungk Albrecht , Claassen Norbert 
Published: July 2010

AbstractPotassium uptake of field crops may be restricted when the upper soil layer, which is usually high in available K, dries out or is compacted. To evaluate the factors involved, the effect of soil water content and bulk density on maize (Zea mays L.) root growth, soil solution K concentration, and K mobility in soil was studied. Plants were grown in soil‐filled pots where roots could penetrate the bottom into a K‐free nutrient solution underneath. The soil was adjusted to bulk densities of 1.2, 1.4, and 1.6 g cm‐3 and gravimetric water contents (ω) of 10.7 to 19.0% w/w (corresponding to pF of 4.2 to 3.0), with a low (0.2 mol m−3) and a high (1.5 mol m−3) soil solution K concentration (CLi). Plants were harvested 11 and 19 d after sowing and root length, shoot dry weight, and K content were determined. High bulk density reduced root growth up to the first harvest. Thereafter, relative root growth rate varied from 1.0 × 10−6 s−1 at low to 2.3 × 10−6 s−1 at high water content independent of soil strength. Potassium uptake decreased with decreasing soil water content, because both root length and K influx were reduced at low water content by about 50%. Increasing soil bulk density tended to increase K influx because the volumetric water content (θ) increased when the gravimetric water content (ω) was kept constant. Drying the soil increased CLi, but its influence on K uptake was counteracted by the decrease of both θ and the impedance factor for diffusion (f). Model calculations simulating K transport in soil and K uptake by roots agreed fairly well with observed data, except at high soil water content, low K application, and high bulk density. Under these conditions, measured influx was lower than the calculated influx. It is concluded that this was due to uneven root distribution in compacted soil, which led to interroot competition. At high CLi, K influx was almost unimpaired by low water content because, as model calculations showed, the reduced K mobility was compensated by an increase of the K concentration gradient towards the root.
Nitrogen Cycling in an Alfalfa and Bromegrass Sward via Litterfall and Harvest Losses
Authors: Tomm Gilberto O. , Walley Frances L. , van Kessel Chris , Slinkard Alfred E. 
Published: July 2010

AbstractBelowground transfer of N from legumes to associated grasses has been extensively documented; however, transfer of N via decomposition of plant material and reabsorption of released N remains poorly understood. This study was conducted to (i) assess the intensity of litterfall and harvest losses of alfalfa (Medicago sativa L.) and meadow bromegrass (Bromus riparius Rhem.) under field conditions and (ii) determine the quantity of N transferred from aboveground plant components. Litterfall and harvest losses were quantified over 3 yr. Nitrogen transfer was estimated using the 15N isotope dilution technique. The return of N to the soil via litterfall losses of alfalfa and bromegrass was 13 and 4 kg N ha−1 yr−1, respectively. Alfalfa returned an additional 15 kg N ha−1 yr−1 to the soil via harvest losses; bromegrass contributed an additional 7 kg N ha−1 yr−1. Bromegrass remained a source of N to the N2‐fixing alfalfa, even though it was N‐limited, and alfalfa successfully competed with the N‐stressed bromegrass for available N derived from litterfall and harvest losses. Alfalfa accumulated twice the amount of N from litterfall and harvest losses compared with bromegrass (2 vs. 1 kg N ha−1 yr−1). Clearly, alfalfa was a strong competitor for available N and acted as both a source and a strong sink for recycled N. The total amount of N transferred from alfalfa to bromegrass and vice versa via decomposition of aboveground plant components was found to be remarkably similar (≈ 1 kg N ha−1 yr−1). Therefore, the net flow of N between alfalfa and bromegrass was negligible, and no net N contribution of alfalfa to associated bromegrass from the decomposition of litterfall and harvest losses was detected. We concluded that, although alfalfa released more N through the decomposition of litterfall and harvest losses than bromegrass, alfalfa also reabsorbed more recycled N. Published estimates of net N transfer between alfalfa and bromegrass, therefore, could not be explained by the input of N from litterfall and harvest losses.
A Peanut Simulation Model: I. Model Development and Testing
Authors: Hammer Graeme L. , Sinclair Thomas R. , Boote Kenneth J. , Wright Graeme C. , Meinke Holger , Bell Mike J. 
Published: July 2010

AbstractA biophysically robust crop simulation model can assist industry planning and farmer decision‐making via simulation analyses to quantify production potential and production risks. Accordingly, we developed a simple, yet mechanistic peanut simulation model for use in assessing climatic risks to production potential for both irrigated and dryland conditions. The model simulates pod yield, biomass accumulation, crop leaf area, phenology, and soil water balance and is suitable for application over a diverse range of production environments. The model uses a daily time step, utilizes readily available weather and soil information, and assumes no nutrient limitations. The model was tested on numerous data from experiments spanning a broad range of environments in the tropics and subtropics. The model performed satisfactorily, accounting for 89% of the variation in pod yield on data sets derived from independent experiments, which included crops yielding from 1 to 71 t ha−1. Limitations of the model and aspects requiring better understanding to improve quantification are discussed. Despite some limitations, the model attains a useful degree of predictive skill for a broad range of situations and environments. This outcome is testimony to the utility of the simple, generic framework used as the basis for this model. The model is suitable for simulation studies aimed at assisting industry planning and farmer decision‐making.
Fine Root Dynamics of Alfalfa after Multiple Cuttings and During a Late Invasion by Weeds
Authors: Pietola Liisa M. , Smucker Alvin J. M. 
Published: July 2010

AbstractThe dynamics of fine root systems for alfalfa (Medicago sativa L.) during seasonal harvests are important for plant regrowth, yet they are not well understood. The primary objective of this study was to determine fine root responses to multiple cuttings of an alfalfa crop for a 5‐yr period and during an invasion of companion weed plants during the last 2 yr of the study. Root development, distribution, and turnover rates were evaluated by minirhizotron (MR) and microvideo camera methods on a Kalamazoo loam (fine‐loamy, mixed, mesic Typic Hapludalfs). The development and distribution of alfalfa fine roots were modified more by season and age of the plants than by defoliation. New root development occurred primarily in the spring and immediately following rainfall interruptions of extended dry periods. Spatial accumulations of roots were observed at the interface of the Bt and 2Bt soil horizons, which also accumulated water and nutrients. More roots died with the progression of each season, especially when plants were 3 to 5 yr of age. New root growth decreased and root death rates increased at soil depths from 0 to 1.1 m, during the period between cuttings from July and August 1993 in the aging alfalfa stand, whose active region of root growth exceeded the depths of the MR observation tubes. New alfalfa root growth appeared at progressively greater depths, especially after 3 yr of cropping. Therefore, mature alfalfa root systems should be sampled to soil depths greater than 1 m. Root systems of encroaching weeds appeared to accumulate in the 0‐ to 0.6‐m region of the soil profile.
Interactions Involving Allelopathy in Cropping Systems
Authors: Einhellig Frank A. 
Published: July 2010

AbstractAllelopathic inhibition typically results from the combined action of a group of allelochemicals which, collectively, interfere with several physiological processes. The objectives of this paper are to summarize research that illustrates the joint action of allelochemicals, and to provide evidence that both the amount and detrimental action of these compounds depends on the extent of associated abiotic and biotic stresses. Allelopathy is strongly coupled with other stresses of the crop environment, including insects and disease, temperature extremes, nutrient and moisture variables, radiation, and herbicides. These stress conditions often enhance allelochemical production, thus increasing the potential for allelopathic interference. In the paradigm of interactions, the data indicate that crops are more sensitive to allelopathy when moisture, temperature, or nutrient conditions are less than optimal. For example, the inhibition threshold concentration for ferulic acid to affect seedling growth was reduced with even minor moisture stress (Ψ = − 0.15 MPa) or a growth temperature at the higher end of the normal range for a species. Under greenhouse conditions, additive inhibition resulted from the joint action of ferulic acid with low levels of alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide], atrazine [6‐chloro‐N‐ethyl‐N’‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], or trifluralin [2,6‐dinitro‐N,N‐dipropyl‐4‐(trifluoromethyl)benzenamine]. Interactions of multiple stresses in crop environments will determine the relative impact of allelopathy. Allelopathystress interactions also have implications for herbicide and residue management strategies, crop rotations, biological control measures, and tillage practices that can contribute to a more sustainable agriculture.
Restoration of Productivity to a Desurfaced Soil with Livestock Manure, Crop Residue, and Fertilizer Amendments
Authors: Larney Francis J. , Janzen H. Henry 
Published: July 2010

AbstractMany agricultural fields on the semiarid Canadian prairies have areas of inherently low productivity associated with loss of soil quality due to erosion. This study compared the efficacy of various amendments in restoring productivity to a desurfaced fine‐loamy, mixed Typic Haploboroll (Lethbridge series) in southern Alberta. In spring 1992, 14 amendment treatments (including livestock manures, crop residues, combinations of straw and chemical fertilizer, and fertilizer alone) were applied to a site where the Ap horizon (≈ 15‐cm depth) had been mechanically removed to simulate erosion. The manures and crop materials were incorporated into the degraded surface on an equivalent dry‐weight basis at 20 Mg ha−1. The plots were seeded to spring wheat (Triticum aestivum L.) in 1992, 1993, and 1994. The overall best amendments were hog manure, poultry manure, and alfalfa hay. In all years, yields from desurfaced plots amended with hog or poultry manure were not significantly different from plots with no topsoil removal. Nitrate‐N concentration in the 0‐ to 60‐cm soil depth explained 71% of the variation in restorative ability of the amendments, while extractable P concentrations in the 0‐ to 15‐cm depth explained 16% of this variation. Results demonstrate that livestock manures and crop residues can restore productivity to eroded soils by substituting for lost topsoil. Application of high rates of manure to severely eroded soils offers a means of utilizing the large amounts of manure generated by southern Alberta feedlot operations.
Double‐Emitter Source (DES) for Irrigation Experiments in Salinity and Fertilization
Authors: De Malach Y. , Ben‐Asher Jiftah , Sagih M. , Alert A. 
Published: July 2010

AbstractA double‐emitter source (DES) irrigation system was designed, using trickle instead of sprinkler irrigation. Two trickle laterals and their emitters connected to two tanks of stock solutions are coupled together to form a double‐joint lateral. The emitters of the two lines have different and varying discharges to obtain various mixings between the two stock solutions while maintaining constant application rates. The layout produces a sequence of intermediates between maximal and minimal concentrations. The method was tested for a salinity experiment on globe artichoke (Cynara scolymus L.) and a fertilization experiment for amaryllis (Hippeastrum hybrid). Average electrical conductivity (EC) of the fresh and saline laterals was 1.5 and 6.2 dS m−1, respectively. The N and K concentrations in the stock solution were 13.12 g L−1 and 9.38 g L−1, respectively, for a mixed and diluted maximum of 777 and 556 mg L−1 N and K at the irrigation solution. Artichoke yield declined by 60% due to salinity when EC increased from 1.5 to 6.2 dS m−1. Hippeastrum bulb diameter and weight increased 35% with high N and low K application. We condude that the double‐emitter source can be used for precise application of varying salts or nutrients in multivariable experiments. Advantages include prevention of canopy wetting by saline water, precise distribution of the factor to be evaluated, and small experimental plots (reducing time, area, and labor requirements).
Leaf Azimuth in Strip‐Intercropped Corn
Authors: Fortin M.‐C. , Pierce F. J. 
Published: July 2010

AbstractIn strip‐intercropping conditions where rows of corn (Zea mays L.) are subjected to widely different levels of radiation interception and of water and nutrient competition, leaf azimuthal direction may be an important determinant of yield. Observations of ear leaf direction were made on two outside rows and one middle row of a corn strip grown with small‐grain cereal and soybean [Glycine max (L.) Merr.] stripintercrops in four trials with north‐south rows in Ontario and Michigan. The objectives were to assess if row position within the strip and seed orientation at planting affect leaf azimuth and to find out if ear leaf azimuth and yield are related. In only one of the four trials was there a correlation between yield and the frequency of ears from ear leaves pointing in a specific direction (west). In both locations, row position affected the proportion of ear leaves in a direction perpendicular to the row and toward the inside of the strip rather than toward the outside in the case of border rows. When seed orientation at planting was controlled, 60 to 74% of ear leaves (leaves 11 or 12) developed in the same direction as the embryo orientation or opposite this orientation. Random orientation of the seed resulted in random ear leaf azimuths, except in a very dry growing season, when leaf azimuthal directions were mostly parallel to row direction, minimizing interception of radiation. This suggests that leaf azimuth could be an indicator of water deficit.
Packing Summer Fallow in the Pacific Northwest: Agronomic Benefits and Environmental Concerns
Authors: Schillinger William F. 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L.) is sown as deep as 20 cm below the summer fallow soil surface in dry years in the semiarid Pacific Northwest (PNW). Many growers pack the summer fallow mulch in late August before seeding winter wheat to improve stand establishment. But packing may increase blowing dust, which is a major soil loss and air quality concern. A 2‐yr study was conducted on two silt loam soil types in 280 mm and 230 mm average annual precipitation zones in eastern Washington to determine the agronomic benefits and potential wind erosion hazards associated with packing. Packing a loose, thick surface mulch increased soil bulk density (BD) between the 5‐ to 12‐cm depth. This significantly benefited wheat seedling emergence and stand establishment, which subsequently increased grain yield 9% over nonpacked plots. But packing a soil with a thin mulch layer overlying a high BD tillage pan had no effect on soil BD, wheat seedling emergence, or grain yield. Packing rendered the soil more vulnerable to wind erosion at both locations by reducing soil clod mass 55% and surface residue 38% compared with not packing. There are agronomic benefits from packing summer fallow mulch before seeding, but packing should be practiced judiciously, and not considered when surface residue or soil clods are lacking. This is especially true for poorly aggregated coarse‐textured soils where soil structure is difficult to maintain.
Shoot‐to‐Root Relations in Field‐Grown Maize Seedlings
Authors: Richner W. , Soldati A. , Stamp P. 
Published: July 2010

AbstractIn northern latitudes, maize (Zea mays L.) seedling growth is generally limited by low temperatures. A better knowledge of mechanisms limiting maize seedling growth at suboptimal temperatures is needed for improving growth models and, ultimately, for breeding of genotypes with improved vegetative growth at low temperatures. Shoot‐to‐root ratios are known to be sensitive to suboptimal temperatures, but information for field conditions is scarce. In three environments with mean soil temperatures of 14.6, 16.9, and 18.0°C at the 5‐cm depth, we investigated shoot‐to‐root relations at the 2−, 3−, and 4‐leaf stages in two maize inbred lines differing in chilling tolerance. Environment characteristically influenced temporal patterns of the shoot‐to‐root dry matter ratio (SDM/RDM), leaf area to root length ratio (LA/RL), and leaf area to root surface area ratio (LA/RSA). The chilling‐sensitive Penjalinan showed close LA/RL and LA/RSA ratios only in the warmest environment, whereas the same traits in chilling‐tolerant Z 7 were almost unaffected by environment, mainly due to Z 7’s temperature‐stable root development. Since root dry matter of Penjalinan was not affected by environments, the inefficient conversion of dry matter into root length and root surface area was responsible for the unbalanced relationship between shoot and root of this genotype at suboptimal temperatures. Our results indicate that already relatively small reductions of 2 to 3°C in soil temperatures near 15°C may distinctly reduce root development in chillingsensitive maize seedlings under field conditions.
Frost‐Seeding Legumesin to Established Switchgrass: Establishment, Density, Persistence, and Sward Composition
Authors: Gettle Randall M. , George J. Ronald , Blanchet Kevin M. , Moore Kenneth J. , Buxton Dwayne R. 
Published: July 2010

AbstractLegumes incorporated into established switchgrass (Panicum virgatum L.) could provide symbiotic N, improve herbage quality, and extend the grazing season. Almost no information exists for legume renovation of switchgrass by frost‐seeding. The objective of this study was to identify cool‐season legumes that can be established into switchgrass by frostseeding, yet not provide excessive competition to the associated grass. Six legumes [biennial ‘Polara’ white‐flowered sweetclover (Melilotus alba Medik.), biennial ‘Madrid’ yellow‐flowered sweetclover (Melilotus officinalis Lam.), ‘Norcen’ birdsfoot trefoil (Lotus corniculatus L.), ‘Redland II’ medium red clover (Trifolium pratense L.), ‘Apollo Supreme’ alfalfa (Medicago sativa L.), and a 50:50 mixture of Redland II red clover and Norcen birdsfoot trefoil] were inoculated with rhizobia and frost‐seeded into established ‘Cave‐in‐Rock’ switchgrass in mid‐March of 1991 and 1992. These mixtures were compared with switchgrass fertilized at four N levels (0, 60, 120, and 240 kg ha−1). Successful legume establishment was observed, with an average of 24 and 25% of viable seed producing seedlings by June for 1991 and 1992 seedings, respectively. Mean legume density was 160 and 170 plants m−2 by June of the seeding year (YR 1) and 95 and 55 plants m−2 by June of the second year (YR 2) for 1991 and 1992 seedings, respectively. Legume renovation of switchgrass stands did not affect grass stem density by July YR 1. Mean forage stand composition (based on stem counts) was 87, 67, and 45% legume in June, July, and August YR 2, respectively, for 1991 seedings, and 54, 29, and 23% legume during the same time periods for 1992 seedings. Legumes did not seriously reduce switchgrass stem density, although red clover, birdsfoot trefoil, and their mixture were more competitive than others. Legumes can be successfully introduced into established Cave‐in‐Rock switchgrass by frost‐seeding and they will persist for at least 2 yr with favorable weather.
Performance of ‘Grasslands Puna’ Chicory at Different Management Levels
Authors: Jung Gerald A. , Shaffer John A. , Everhart John R. , Varga Gabriella A. 
Published: July 2010

Abstract‘Grasslands Puna’ chicory (Cichorium intybus L.) is a perennial taprooted herb that shows potential to produce high yields of palatable forage for ruminants. Our objective was to determine management effects on herbage production and quality, and stand persistence. Chicory and ‘Pennlate’ orchardgrass (Dactylis glomerata L.) were established on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf) soil at Rock Springs, PA. Treatments were intensive, moderate, and lenient management, corresponding to 25‐, 37‐, and 50‐cm chicory canopy height at harvest, with N fertilizer applied after each harvest except the last. The experimental design was a 2 × 3 (species × managements) factorial with five replications. Total yields of forage averaged 9A Mg ha−1 for chicory and 7.9 Mg ha−1 for orchardgrass in 1992 and 1993. Management did not affect total yield of chicory the first harvest year, nor that of orchardgrass in either year. Chicory yield was greatest from plants under lenient management the second year. Mean crude protein concentration in chicory and orchardgrass was 200 g kg−1 and 185 g kg −1 respectively, but both species showed a potential to accumulate concentrations greater than 250 g kg−1. Low concentrations (110 g kg−1) were associated with floral stem production. Chicory herbage had higher concentrations of Ca, Mg, Na, Fe, Cu, and Zn, than did orchardgrass. Our results show that Grasslands Puna can withstand a range of defoliation intensities while maintaining excellent productivity.