bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Thermal Regime Influence on Water Use and Yield under Variable Irrigation
Authors: Wraith J.M. , Hanks R.J. 
Published: July 2010

AbstractSoil temperature has been shown to influence the early growth and development of many plants. It is not clear, however, how these findings are related to seasonal field soil water and crop growth dynamics. We conducted a study to investigate the seasonal influence of the field soil thermal regime on soil water depletion and growth of winter wheat and corn under variable irrigation levels, at Logan, UT, during 1987 and 1988. Soil surface mulches and buried heat cables were used to modify soil temperature, and a line‐source sprinkler system provided a range of water application levels. Soil water depletion increased with soil temperature, and depth of maximum soil water depletion was 0.2 to 0.4 m deeper for warm than cool soil treatments during most of the growing season for both crops. This was true even where early‐season temperature differences were minor or nonexistent. Earlier maturation of plants grown in the warmer soil caused reduced water uptake later in the season, resulting in similar cumulative soil water depletion for all temperature treatments. The depth of plant roots under low irrigation during 1988 increased with soil temperature, but this relationship was not consistent under the higher irrigation level. In 1987, soil temperature did not significantly affect final crop yields. Larger, and earlier, treatment differences in the soil thermal regime in 1988 caused significant plant growth responses to persist throughout the growing season. There were no interactive responses of plant growth and yield parameters to soil temperature and irrigation levels. Seasonal influences of the soil thermal regime on crop water use should be considered in applications where the seasonal status of soil water in the root zone is of fundamental importance.
Feruloyl‐ and Para‐Coumaroyl‐Carbohydrate Esters from Grass and Cellulose Degradation by Ruminal Microorganisms
Authors: Akin D.E. , Hartley R.D. , Borneman W.S. 
Published: July 2010

AbstractPhenolic compounds are a primary limitation to forage digestibility, but the specific mechanism that limits microbial activity requires elucidation. The objective of this research was to determine the influence of phenolic acid‐carbohydrate esters isolated from ‘Coastal’ bermudagrass (Cynodon dactylon L. Pers.) on cellulolysis by rumen microorganisms. One or 5mM concentrations of 0‐[5‐0‐(trans‐feruloyl)‐α‐L‐arabinofuranosyl]‐ (1→3)]‐0‐β‐D‐xylopyranosyl‐ (1→4)‐D‐xylopyranose (FAXX), 1 mM 0‐[5‐0‐(trans‐p‐coumaroyl)‐α‐L‐arabinofuranosyl]‐(1→3)‐0‐β‐D‐xylopyranosyl‐(1→4)‐D‐xylopyranoses(PAXX), equivalent concentrations of free phenolic acids and equivalent concentrations of L‐arabinose plus D‐xylose were added to anaerobic incubation vials containing MN 300 cellulose. Inhibition of cellulolysis by about 24% in the 5 mM study appeared to be due to the sugars and not the phenolic moiety. These studies suggest that these free phenolic‐carbohydrate esters have minimal effect on fiber‐digesting microorganisms in the rumen.
Soil Nitrogen Status as Affected by Tillage, Crops, and Crop Sequences
Authors: Eck H. V. , Jones O. R. 
Published: July 2010

AbstractConservation tillage practices, including no‐till (NT), reduce soil erosion and increase precipitation storage efficiency, but may decrease available soil N. We conducted studies at two sites to determine the comparative effects of NT and stubble mulch (SM) on the N supplying capacity of Pullman clay loam (fine, mixed, thermic Torrertic Paleustolls) cropped to continuous wheat (Triticum aestivum L.) (CW), continuous grain sorghum [Sorghum bicolor (L.) Moench] (CS), wheatsorghum‐fallow (WSF), and wheat‐fallow (WF) sequences. AT one site, accumulation of NO3‐N in the surface 1.2 m (in kg ha−1) was CW NT ‐ 20, CW SM ‐ 37, CS NT ‐ 28; CS SM ‐ 24, WSF NT ‐ 34, WSF SM ‐ 52, WF NT ‐ 57, and WF SM ‐ 60. Tillage significantly affected N accumulation only on the WSF sequence. Nitrate ‐N moved deeper into the profile under NT than under SM, indicating that differences in the root zone may have resulted from differential leaching rather than from differential nitrification. Yields under no‐till and stubble mulch were similar except on continuous grain sorghum where nitrogen deficiency was encountered and stubble mulch outyielded no‐till.
Fertilizer‐Nitrogen Use Efficiency of Irrigated Wheat: I. Uptake Efficiency of Preplant versus Late‐Season Application
Authors: Wuest S. B. , Cassman K. G. 
Published: July 2010

AbstractThe addition of N fertilizer late in the growing season to improve grain quality is a potential management option for production of irrigated hard red spring wheat (Triticum aestivum L.). This study compared the recovery of fertilizer N applied at planting with that of fertilizer N applied at anthesis, and evaluated the effects on soil N uptake. In a 2‐yr field study, N fertilizer rates of 120, 180, or 240 kg N ha−1 at planting and 0, 30, or 60 kg N ha−1 at anthesis were applied to ‘Yecora Rojo’ wheat. The experiment utilized a duplicate plot design such that for every N‐rate treatment there were two plots, one plot received 15N labeled fertilizer at planting, and the other received I5N labeled fertilizer at anthesis. The recovery of N applied at planting ranged from 30 to 55%, while that of N applied at anthesis ranged from 55 to 80%. The contribution of soil N (non‐fertilizer N) to total plant N was not affected by the N rate or timing of application. In another field study 120, 180, or 240 kg N ha−1 was applied at planting and 0 or 45 kg N ha−1 at anthesis the first year, and 85, 140, 195, and 250 kg N ha−1 applied at planting and 0, 25, 45, and 65 kg N ha−1 at anthesis the second year. A small dose (< 1 kg ha−1) of NH4‐15N was iqjected 5 cm below the soil surface to follow the effect of N application at anthesis on uptake of existing inorganic soil N. Fertilizer N at anthesis increased the amount of iqjected 15N taken up by the plants from 38 to 48% the first year, and from 49 to 61% the second year. In both studies, the amount of fertilizer N applied at anthesis had the greatest influence on postanthesis N uptake, which ranged from 17 to 77 kg N ha−1. Without supplemental N applied at anthesis, postanthesis N uptake only provided from 12 to 18% of the total grain N demand, and postanthesis N uptake was not increased by greater preplant N input levels. Likewise, extractable and mineralizable soil N at anthesis were not affected by preplant N treatments. These results indicate that a late N application can be efficiently taken up by plants, and does not decrease soil N uptake. To achieve acceptable grain protein levels for bread wheat in this. imgated cropping system, N should be supplied late in the season to improve N uptake during grain fill.
Closed‐Chamber Effects on Leaf Temperature, Canopy Photosynthesis, and Evapotranspiration
Authors: Wagner S.W. , Reicosky D.C. 
Published: July 2010

AbstractThe portable, closed‐chamber technique permits simultaneous measurement of crop canopy photosynthesis (carbon dioxide exchange rate, CER) and evapotranspiration rate (ET) under field conditions and is a valuable tool for evaluating new management practices to increase water‐use efficiency. Because plants react quickly to environmental changes, and the technique may affect the plant environment during the brief (1 min) measurement period, further exploration of the technique was required. The objective was to measure the effect of a portable closed chamber (8.15‐m3 volume, covering 2.67 m2 of soil surface area) on leaf and air temperatures and to determine any subsequent effects on calculated CO2 and water vapor exchange rates. Measurements of CER and ET were made on field plots of irrigated and non‐irrigated maize (Zea mays L.) shortly after anthesis. Leaf and air temperatures were measured at 2‐s intervals inside and outside the chamber for 1 min prior, 1 min during, and 1 min after chamber closure. Leaf and air temperatures in the closed chamber increased 2 to 4 °C in 1 minute. Changes in canopy CER and ET were not strongly correlated with mean leaf temperatures. The calculated CER and ET rates underestimated the rates extrapolated to time 0 by approximately 10%, partially attributed to the increase in leaf temperature. Therefore, chamber measurements should be made rapidly to minimize possible effects of temperature increases and other plant environment changes. While there are limitations, the chamber technique provides a practical method for measurements of field canopies.
Freezing and Ice Tolerance Tests for Winter Brassica
Authors: Andrews C.J. , Morrison M.J. 
Published: July 2010

AbstractCold stress tolerances of winter brassicas (Brassica napus L., B. compestris L.) have frequently been reported from tests on leaves, without regard for the requirement of an intact crown meristem for overwinter survival. A method is described to determine the LD50 of washed, trimmed plants for freezing and ice encasement. Plants were cold hardened in controlled environment or in the field and tested at the five‐leaf stage. To determine freezing tolerance, units of five plants were sealed in polyethylene bags and survival determined of samples withdrawn during a 1 °C h−l programmed temperature decline. For ice encasement tolerance, units of five plants were sealed in ice in polyethylene beakers and survival determined after thawing at intervals during exposure to ‐1 °C. The LD50 was determined by interpolation or the Probit procedure. Significant separation of the cold stress tolerance of a number of cultivars of B. napus and B. campestris is presented.
Sufficiency Level and Diagnosis and Recommendation Integrated System Approaches for Evaluating the Nitrogen Status of Corn
Authors: Dara Syed T. , Fixen P. E. , Gelderman R. H. 
Published: July 2010

AbstractAn irrigated corn (Zea mays L., cv. Pioneer 3732) N fertilizer field experiment was conducted for 3 yr to compare plant analysis interpretation of N status by the diagnosis and recommendation integrated system (DRIS) and sufficiency level (SL) methods. Preplant soil NO3‐N was supplemented with ammonium nitrate to provide seven available N levels. Leaf samples were taken at the silking stage and analyzed for N, P, K, Ca, Mg, S, Mn, Zn, and Cu. Nutrient indices were calculated using published standard and locally‐developed (South Dakota) DRIS norms derived from 600 observations. At bighest grain yield, 11.86 Mg ha−1, the average soil NO3‐N level was 247 kg ha−1 over the 3‐yr test period, while check yields averaged 6.54 Mg ha−1 and required 68 kg N03‐N ha−1. The SL approach (using a critical ear leaf N concentration of 27.6 g kg−1) diagnosed N as inadequate even when excess N was applied, indicating that the N sufficiency level for irrigated corn is inflated and needs to be readjusted to 25.2 g N kg−1. Nitrogen indices calculated from the standard and local DRIS norms at 90% of maximum yield were −2 and 2, respectively. Regression of Nutrient Balance Indices against relative yield indicated greater variability in the standard norms than in the local norms. Our data suggest that the SL approach overestimated ear leaf N requirement, and that DRIS indices calculated using published standard norms were less useful than those from locally‐developed norms.
Quantification of Symbiotically Fixed Nitrogen in Soil Surrounding Alfalfa Roots and Nodules
Authors: Lory J. A. , Russelle M. P. , Heichel G. H. 
Published: July 2010

AbstractSymbiotically fixed nitrogen (SFN) can be transferred from alfalfa (Medicago sativa L.) to intercropped nonlegumes and succeeding crops. Our objective was to quantify deposition of SFN from alfalfa roots and nodules to surrounding soil and to assess its significance in comparison to reported estimates of legume‐nonlegume N transfer. We quantified net loss of SFN to rhizosphere soil (i.e. rhizodeposition) at the end of one growing season under field and greenhouse conditions, using the 15N isotope dilution technique in soil that had been labeled with 15N 8 yr before initiation of the experiments. ‘Saranac’ and ‘Ineffective Saranac’ alfalfa were transplanted in the field into paired 0.75‐ by 1.0‐m microplots. In the greenhouse study these two alfalfas were grown separately in 15‐cm diam. by 90‐cm long polyvinylchloride tubes, four plants per tube. Plant organs were meticulously separated from soil at the end of one growing season. Soil adhering to roots and nodules was defined as rhizosphere and nodusphere soil, respectively, and was separated from the organs by 60 s sonication in 0.08 mol L−1 phosphate buffer. Symbiotically fixed N was quantified by comparing the atom % 15N of Saranac vs. Ineffective Saranac for each soil and plant N compartment. Harvested herbage contained 270 kg SFN ha−1 in the 135‐d field experiment and 55 mg SFN plant−1 in the 112‐d greenhouse experiment. Symbiotically fixed N was not uniformly distributed in the Saranac root system. Sampled rhizosphere soil contained no SFN in the field experiment and the equivalent of about 1 kg SFN ha−1 in the greenhouse experiment. Over one quarter of nodusphere soil N was apparently derived from SFN in both experiments, but amounted to less than 0.5 kg SFN ha−1 at the time of harvest. Nitrogen transfer to nonlegumes is often an order of magnitude larger than net deposition measured here. Thus it appears that rhizodeposition is a relatively small component of SFN loss from nodules and roots of alfalfa grown in monoculture.
Growth Chamber Modification to Emulate a Seed Germination Chamber
Authors: Springer T. L. , Tharel L. M. 
Published: July 2010

AbstractIn the absence of specialized research equipment, existing equipment often must be modified to meet research needs and objectives. Specialized germination chambers which control temperature, light, and humidity may not always be available to conduct detailed germination experiments. The objectives of this research were to modify a growth chamber to emulate a seed germination chamber and validate the system by reporting the variation in percentage seed germination and seedling root and shoot lengths. Modifications to the growth chamber consisted of mounting trays in space and adding cool humidified air. Within the modified growth chamber variation in seed germination was small for row or column placement on a tray and large between trays. Among the 11 trays, the optimum tray placement for seed germination was on Trays 4,5,6,7, and 8 for all species studied. Variation in seedling root and shoot lengths was attributed to row and column placement on a tray and tray levels, and was associated in part with light and temperature gradients in the modified growth chamber.
Dynamics of Soybean Growth in Variable Planting Patterns
Authors: Wells Randy 
Published: July 2010

AbstractReported soybean [Glycine max (L.) Merr.] yield responses to variable plant populations have been inconsistent. The varied responses are tied to the capacity of the plant stand to attain a minimal level of dry matter prior to reproductive growth. This study examined soybean growth expressed as functions of both plant and ground area to identify associations with yielding ability. Treatments consisted of high, medium, and low populations (approximately 21, 13, and 3 plants per square meter) at 0.96‐m row widths and a medium population (approximately 13 plants m−2) at 0.43‐m row widths for 2 yr. The values of total dry matter (TDM), stem DM, leaf DM, leaf area, height, and main stem node number were determined on both a whole plant and ground area basis. In addition, relative growth rate (RGR), relative leaf area growth rate (RLAGR) and net assimilation rate (NAR) were examined. Treatments with the greatest interplant space had the largest RGR, RLAGR, and NAR early in growth, thus resulting in compensation for reduced plant population. Decreases in plant DM at 91 DAP in response to increasing plant population were greater in 1988 than in 1989, and were related to poorer growing conditions in the latter year. The related TDM values were larger in 1988, with all treatments exhibiting a TDM above 500 g m−2 by early podfill (R5). In contrast, the TDM at 91 DAP of the wide row, low and medium population treatments was 300 and 426 g m−2, respectively in 1989. Seed yield differences were found in 1989 but not 1988. Differences among years and treatments concerning growth rates, plant DM, TDM, and seed yield emphasize the impact of limiting environmental factors on plant compensation in response to increased space.
Seed Production after Floret Removal from Sunflower Heads
Authors: Charlet L. D. , Miller J. F. 
Published: July 2010

AbstractThe banded sunflower moth (Cochylis hospes Walsingham; Lepidoptera: Cochylidae) is a pest of sunflower (Helianthus annuus L.) in the northern Great Plains. Larvae feed initially on sunflower florets and subsequently on immature and matue seeds (achenes). Our objective was to measure the compensatory ability of sunflower for increasing seed yield in response to the loss of florets caused by floret and seed feeding of the banded sunflower moth for the accurate computation of economic injury levels. Treatments were removal of floret at 10% increment intervals from 0 to 50% of the florets of sunflower heads (capitula) at flowering. Floret removal had a direct effect on the number of resulting fertile seeds. Reducing the number of florets by 10% resulted in a 20% decrease in the number of fertile seed, an 18% decrease in total seed weight of the head, and a 22% decrease in seed volume. Comparable decreases were found in the number of fertile seeds for other increments of floret removal. The sunflower plant can compensate for floret removal by increasing the weight of individual seeds. As percent of floret loss increased, seed weight increased, but even when only 10% of the florets were destroyed, the weight gain did not overcome the subsequent loss of seeds. Oil content of seeds significantly decreased as floret loss increased. In addition to consumption of mature seeds, simulation of damage showed that early feeding by banded sunflower moth larvae on florets can also directly and indirectly affect the final yield of infested plants.
Relationships between Soil Sulfate‐Sulfur and Seed Yields of Winter Rapeseed
Authors: Mahler R. L. , Murray G. A. , Swensen J. B. 
Published: July 2010

AbstractWinter rapeseed (Brassica napus L.) has a higher S requirement than most currently grown cereals and legumes. The objectives of this study were to (i) determine the effect of S fertilization rates on winter rapeseed yields and oil composition, (ii) establish relationships between winter rapeseed yields and soil SO4‐S levels for three cultivars, and (iii) determine the optimum time and depth of soil sampling for S diagnosis. Field experiments were conducted on a S deficient Latahco silt loam (fine‐silty, mixed, frigid, argiaquic Xeric Argiaboll) and two S deficient Palouse silt loam (fine‐silty, mixed, mesic pachic Ultic Haploxeroll) soils for three growing seasons. Each factorial trial had three cultivars, three S rates, and four replications. Soil samples were collected from all plots to a depth of 120 cm and sectioned into six 15‐cm and one 30‐cm sample in October, April, and June for SO4‐S analysis. Winter rapeseed yield was correlated to soil SO4‐S at different sampling depths. Both ‘Bridger’ and ‘Cascade’ cultivars responded to S; however, no response was observed for ‘Dwarf Essex’. The most significant coefficient of determination values between soil SO4‐S and rapeseed yield (Bridger r = 0.82, P = 0.01; Cascade r = 0.79, P = 0.01) were obtained with a 75‐cm soil sample from the April sampling. By linear plateau regression, critical soil test SO4‐S levels for Bridger and Cascade were 45 and 51 kg SO4‐S ha−1, respectively. This research demonstrates the need to modify current soil sampling for S management in winter rapeseed production to reflect the need for an April sampling to a 75‐cm depth.
Root Development and Nitrogen Influx of Corn Genotypes Grown under Combined Drought and Nitrogen Stresses
Authors: Eghball Bahman , Maranville Jerry W. 
Published: July 2010

AbstractKnowledge about the interactive effects of N and drought stresses on corn (Zea mays L.) root morphology and rate of N uptake is important for selecting drought tolerant and/or N efficient genotypes and for determining mechanisms that control root growth under stress. The objective was to study these interactions by growing three and four genotypes of known N utilization efficiency (NUE, kg grain/kg N uptake) responses in greenhouse and field experiments, respectively. Nitrogen application rates were 0, 30, 60, and 90 mg N kg−1 soil in the greenhouse and 0, 60, 120, and 180 kg N ha−1 in the field experiment. Water regimes included nonstress vs. an 8‐d water stress in the greenhouse experiment and dryland vs. irrigation in the field. Water‐regime‐by‐N‐rate interactions were not significant for root dry weight, length, average radius, root/shoot ratio, and N influx in either environment. Root weight and length were different among genotypes. The genotype with the greatest amount of roots deep in the soil had the highest grain yield increase with irrigation. Root mass and root length were greater, but mean N influx was two to three times smaller in the zero N treatment than in the applied N treatments (average of all genotypes). Severe water stress reduced corn root mass and length in the greenhouse. Moderate water stress in the field, however, significantly increased root length. Water use efficiency was positively correlated with root mass and length in the greenhouse. Water regime did not affect N influx in either experiment. These results showed that corn response to irrigation will be altered depending on root morphology, and that insofar as possible, the root system should be considered when selecting for N efficient and/or drought tolerant corn genotypes
Impact of Environmental and Harvest Management Variables on Alfalfa Forage Drying and Quality
Authors: Iwan J. M. , Shanahan J. F. , Smith D. H. 
Published: July 2010

AbstractThe objective of this study was to determine the impact of environment and harvest management variables on drying duration and quality of alfalfa (Medicago sativa L.) forage grown under semiarid conditions of the western USA. Untreated and conditioning agent (CA)‐treated forage was harvested with a commercial mower‐conditioner on four dates in 1989 to provide variation in drying duration. Drying duration was determined by periodically monitoring moisture concentration of the forage after harvest until the forage was baled at 180 g water kg−1 herbage. Samples from the bales of each harvest were taken to determine forage quality. Solar radiation, air temperature, air vapor pressure deficit (VPD), soil moisture, and windrow density were monitored during drying. To determine the effect of enviornmental and harvest management variables on drying, temperature‐ and VPD‐based models were used to predict forage moisture concentration at the end of several drying intervals. The VPD model included the variables of VPD, solar radiation, soil moisture, windrow density, and application of CA. The temperature model included of all the previous variables, except air temperature was substituted for VPD. The CA reduced drying duration by a maximum of 50% across the four harvests, with the greatest effect occuring under high solar radiation, temperature, and VPD. Crude protein was improved only slightly by the CA, with a maximum increase of 5.9% for the third harvest. Observed and predicted moisture concentration for several drying intervals closely agreed for both models (r2 = 0.80 for VPD, and 0.78 for temperature). These results suggest that manipulation of all variables included in the models should hasten alfalfa forage drying.