bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stubble Burning Effects on Winter Wheat Yield and Nitrogen Utilization under Semiarid Conditions
Authors: Rasmussen P. E. , Rohde C. R. 
Published: July 2010

AbstractAlthough cereal residues are reportedly burned to accelerate vegetative growth, reduce disease or weed competition, or prevent microbial immobilization of N, there may be no yield enhancement in semiarid regions where drought stress limits yield. Experiments were initiated in 1979 and 1980 in a winter wheat (Triticum aestivum L.)—fallow rotation to determine burning effects on wheat yield and N utilization on a Walla Walla silt loam soil (coarse‐silty, mixed, mesic Typic Haploxeroll). Burning versus not burning wheat stubble was examined at three N levels (0, 45, and 90 kg ha−1) over 6 yr (three crops in each wheat‐fallow secquence). Wheat stubble was burned on designated plots in the spring of the fallow year, then all plots were plowed 0.22 m deep. Nitrogen as NH4NO3 was applied in October prior to wheat seeding. Stubble burning had no effect on grain yield or grain N uptake in any of the 6 yr. Burning tended to increase straw yield when wheat was fertilized with N but had no effect on straw N uptake. Overall, burning did not increase total N uptake. Nitrogen fertilization increased yield and N uptake in all years. Six‐year grain yield averages for 0, 45, and 90 kg N ha−1 were 3.1, 4.7, and 5.3 Mg ha−1. Stubble burning did not decrease foot rot (Pseudocercosporella herpotrichoides) incidence or severity in either of the 2 yr that it was present. Burning did reduce downybrome (Bromus tectorum) density in the 1 yr that it was not effectively controlled by mechanical tillage.
Effects of Moisture Stress on Nitrogen Fertilizer Response in Dryland Wheat
Authors: Korentajer L. , Berliner P. R. 
Published: July 2010

AbstractLong‐term N fertilizer trials with dryland wheat (Triticum aestivum L.) are frequently confounded by large year‐to‐year variability in yields resulting from moisture stress fluctuations. To account for this variability, an N fertilizer study was conducted in which the magnitude of moisture stress was monitored. The experiment was carried out during 1983 and 1984 (389 and 136 mm of seasonal rainfall, respectively) on a Plinthustalf loamy fine sand soil, with wheat (cv. Betta), using a completely randomized block design with four replicates and five levels (N) of N fertilizer: 0, 30, 60, 90, and 120 kg N ha−1. The seasonal moisture stress index, S, was estimated from a weighted product of ET/ETp ratios (actual to potential evapotranspiration) obtained for the different phenological wheat growing periods. The ET was estimated from soil moisture (monitored by means of a neutron moisture meter), whereas ETp was calculated from meteorological measurements using Penman's equation. The response to N in both years was significant; the mean yields were 3.18 and 1.7 Mg ha−1, for the 1983 and 1984 seasons, respectively. The data were statistically analyzed by means of a postulated multiple regression model, with N and S levels as the explanatory variables. The model was validated using yield and meteorological data from several other 2‐yr N response studies. A good correlation (R2 = 0.63, standard error of the estimate = 0.27 Mg ha−1) was obtained between the predicted and the observed yields. The results of the study highlight the need for moisture stress measurements to be included in fertilizer trials conducted in areas of large seasonal rainfall variability.
Root Growth Dynamics of a Rice Cultivar Grown at Two Locations
Authors: Beyrouty C. A. , Wells B. R. , Norman R. J. , Marvel J. N. , Pillow J. A. 
Published: July 2010

AbstractRoot growth dynamics of rice (Oryza saliva L.) under submerged soil conditions are poorly understood. Two field experiments were conducted in 1986 to compare root growth of rice at two locations on different soils. The rice cultivar Bond was seeded in leveed plots on a Captina silt loam (fine‐silty, siliceous, mesic Typic Fragiudults) at Fayetteville, AR, and on a Crowley silt loam (fine, montmorillonitic, thermic Typic Albaqualfs) at Stuttgart, AR. Plots contained rectangular Plexiglass root observation tubes oriented at a 45° angle from the soil surface and extending 0.57 m (Captina) and 0.44 m (Crowley) below the soil surface. Root recordings were taken during vegetative and reproductive growth. Root growth was most rapid during vegetative growth at both locations, with maximum root length occurring at panicle initiation. Root lengths either plateaued or declined during reproductive growth. Root lengths were greater on the Captina soil than on the Crowley soil. The pattern of root length densities (RLD) was similar between soils; however, RLDs were generally lower on the Crowley soil. During early stages of rice growth, a greater percentage of rice roots was measured in the upper 20 cm of the Crowley soil. By harvest, about 50% of the rice roots occurred in the top 20 cm in both soils. Harvesting appeared to reduce the percentage of roots found below 20 cm on the Crowley soil, and to have little effect on the Captina soil. Results suggest that rice root growth can vary dramatically between soils, and is influenced by soil profile characteristics, soil moisture, air temperatures, and growth stage.
Carbohydrate Reserves and Tillering of Switchgrass Following Clipping
Authors: Anderson Bruce , Matches A. G. , Nelson C. J. 
Published: July 2010

AbstractStands of switchgrass (Panicum virgatum L.) often decline following defoliation, a response often attributed to a high fertile/vegetative stem ratio and a paucity of basal shoots and foliage. Information is lacking on interactions among meristem removal, tiller development, and energy reserves. Field studies on a Mexico silt loam soil (Udollic Ochraqualf) were conducted for 2 yr to examine tillering and total nonstructural carbohydrate (TNC) trends of ‘Pathfinder’ switchgrass following clipping. Harvests were taken on six dates between the vegetative and heading stage during two consecutive years. In Year 2, tiller density was determined periodically during the season. First‐harvest yield increased 699 kg ha−1, and regrowth yield decreased 281 kg ha−1 with each week delay of first harvest. When apical meristems were removed, TNC in aboveground tissue declined more (28 vs. 5 g kg−1) during regrowth and to a lower concentration (51 vs. 43 g kg−1) than when apical meristems remained intact. By the end of the growing season, all clipped plants had similar TNC concentrations, but uncut plants contained 22 and 40% more TNC in above‐ and belowground tissue, respectively, than clipped plants. Tiller development appeared to be unrelated to TNC or to date of first harvest when harvested between vegetative and heading stages. However, clipping during the first year reduced yield during the second year by 34 to 60%. Lengthy regrowth periods following severe defoliation, defoliation that allows apical meristems or leaf area, or both, to remain, and control of weeds are likely to enhance stand maintenance and plant vigor of switchgrass.
Bahiagrass Response to Sulfur on an Aeric Haplaquod
Authors: Mitchell C. C. , Blue W. G. 
Published: July 2010

AbstractSulfur fertilization of bahiagrass (Paspalum notatum Flugge ‘Pensacola’) has not been a common practice on northern Florida Spodosols. A 6‐yr study was begun in 1978 on an established sward of bahiagrass on Myakka fine sand (sandy, siliceous, hyperthermic Aeric Haplaquod) to determine if an S response could be obtained by intensive management of bahiagass and to evaluate N and S rates for this forage crop. Herbage yield, N and S uptake, the stolon‐root mass, and soil S were measured and evaluated at two rates of N fertilization (200 and 400 kg ha−1) and four rates of S fertilization (0, 10, 20, and 40 kg ha−1) as gypsum (CaSO4·2H2O). Splitting S into four applications had no effect on yield, S uptake, or N uptake over a single annual application. At the low N rate, a dry matter yield response did not occur until the fourth year of the study, with maximum yields thereafter predicted at an average annual S application between 27 and 33 kg ha−1. At the high N rate, a dry matter yield response occurred the second year with 10 kg S ha−1 applied, and by the fifth and sixth years, maximum dry matter herbage yield was predicted at an annual S application between 40 and 51 kg ha−1. The stolon‐root system accumulated N and S, but S treatments had no effect on extractable or total soil S. Sulfur removed in the herbage exceeded that applied at all but the highest S rate. Sulfur fertilization also enhanced N recovery. A critical S concentration of 1.61 g kg−1 was identified for bahiagrass herbage.
Water Deficit Timing Effects on Yield Components in Maize
Authors: Grant R. F. , Jackson B. S. , Kiniry J. R. , Arkin G. F. 
Published: July 2010

AbstractThis study was designed to determine the interval of sensitivity of maize (Zea mays L.) yield components to moisture stress, and to evaluate that interval using estimates of plant available water (PAW). Individual maize plants were grown in containers in a glasshouse. For each treatment, water was withheld until the accumulated water use in well‐watered control containers was 20 L, approximately twice the PAW in each container. Containers were well watered at all other times. Containers were weighed to determine water use rates and to estimate PAW. Moisture stress was assumed initiated when water use rates declined below the average for well‐watered containers. The interval when kernel number was sensitive to moisture stress began 2 to 7 d after silking and ended 16 to 22 d after silking. Stress initiated prior to silking but relieved within 2 d after silking did not reduce kernel number, kernel weight, or plant yield. The fewest number of kernels, 45% of the control, occurred for stress during the 7‐d period after silking. Kernel weight was reduced by stress during the grain filling period, and the lowest weight, 51% of the control, occurred for stress 12 to 16 d after silking. Water use rates in treatment plant containers were compared to estimates of the soil moisture stress index (SMI) determined as the percentage of PAW in the containers. Water use rates declined when SMI declined below thresholds of between 0.20 and 0.30. These thresholds were similar to those reported for other crops. Thus, this analysis demonstrated that parameters based on PAW can be useful for evaluating the timing of moisture stress on maize yield components.
Seeding Depth in Relation to Plant Development, Winter Survival, and Yield of No‐Till Winter Wheat
Authors: Loeppky Heather , Lafond G. P. , Fowler D. B. 
Published: July 2010

AbstractSuccessful production of winter wheat (Triticum aestivum L.) on the Canadian prairies requires no‐till seeding into standing stubble (stubbling‐in) in order to trap snow and thereby prevent low temperature freezing injury of the young seedlings. In the present study, a total of 14 no‐till winter wheat field trials were seeded into standing stubble on several Saskatchewan soil types (Aridic, Typic, Vertic, and Udic Haploborolls, and Udic Agriborolls) to investigate the effect of seeding depth on plant growth and development. The influence of seeding depth and date on winter wheat growth and development were also investigated in a hand‐planted trial on conventional summerfallow. Increases in seeding depth as small as 17 mm resulted in significantly deeper crown placement and delayed plant emergence. Delayed seeding into cooler soils was associated with slower plant emergence and shorter sub‐crown internodes than earlier seeding at warmer soil temperatures. Consequently, delayed deep seeding resulted in very slow plant emergence, a reduction in the number of tillers plant−1 and fewer heads m−2 the following year. Winter survival was significantly higher for shallow seeded treatments in four of seven trials that experienced differential winterkill. A significant yield advantage (11%) was observed with shallow seeding in four of six trials that escaped serious winter damage. In contrast, improved winter survival and/or yield advantages were never obtained with increased seeding depths. These observations demonstrate that seeding shallow (10–25 mm) at the recommended date is necessary to optimize plant establishment in the fall, minimize the risk of winter damage, and maximize yield potential of no‐till winter wheat produced on the Canadian prairies.
Esophageal Plug and Fasting Effects on Particle Size Distribution and Quality of Extrusa from Grass Pastures
Authors: Fisher D. S. , Burns J. C. , Pond K. R. 
Published: July 2010

AbstractDiet selection and mastication by cattle (Bos taurus L.) can be examined using extrusa from esophageal fistulas. Experiments were conducted to investigate the use of an esophageal plug and the influence of a 16‐h fast, prior to collection, on the particle size distribution and quality of masticated forage. Extrusa was freeze‐dried and sieved into seven size‐classes, and the weight of masticate in each class was determined. The proportions of large (>1.7 mm), medium (0.5–1.7 mm), and small (<0.5 mm) particles and the mean and median particle sizes were analyzed. Neutral detergent fiber (NDF) and in vitro dry matter disappearance (IVDMD) were also determined. In both experiments, significant differences between single pastures of Coastal bermudagrass [Cynodon dactylon L. (Pers.)] with 3500 kg ha−1 and flaccidgrass (Pennisetum flaccidum Griseb.) with 2900 kg ha−1 available forage were found in particle size, NDF, and IVDMD. Averaged over experiments, the proportions of large, medium, and small particles found in bermudagrass were 20, 54, and 26%, respectively, and 35, 47, and 18%, respectively, for flaccidgrass. The NDF of bermudagrass and flaccidgrass averaged 550 and 505 g kg−1, respectively, and the IVDMD averaged 640 and 700 g kg−1, respectively. Neither the esophageal plug nor the fasting had an influence on the particle size distribution, NDF, or IVDMD.
Soybean Field Losses as Influenced by Harvest Delays
Authors: Philbrook B.D. , Oplinger E.S. 
Published: July 2010

AbstractConflicts for time and machinery can postpone harvests beyond the initial time when optimum conditions exist. This study was conducted to determine the effects of delaying soybean [Glycine max (L.) Merr.) harvests on grain losses in the field. Field studies were conducted each year from 1983 to 1986 at Arlington, WI. Two cultivars from each of maturity groups (MG) 0, I, and II, one more susceptible to lodging than the other, were used. Initial harvest for each maturity group began 3 to 7 d beyond stage R8. Three additional harvests were made for each maturity group at 14, 28 and 42 d beyond their initial harvest. Average soybean field losses were 10% of the potential yield, but ranged from 5.5% in 1983 to 12.7% in 1984. Loss of potential yield increased linearly at a rate of 0.2% d−1 from an average of 6.1% at the initial harvest to 13.9% 42 d later. In 1984 and 1986 net yields were reduced 14 and 18 kg ha−1d−1, respectively. Harvest delays of 42 d resulted in plant deterioration and, in turn, lodging increased 20%, and preharvest, shatter, and stem losses increased 62, 95, and 70 kg ha−1, respectively. Shatter losses were influenced by moisture conditions at harvest, but plant deterioration also increased shattering beyond that accounted for by moisture. On the average the MG I cultivars Hardin and Northrup King S1346 lost only 7.3 and 8.3% of their potential yield versus 10.4 and 11.4% for the MG 0 cultivars Ozzie and Evans, and 10.8 and 9.2% for MG II cultivars Wells II and Corsoy 79. Both of the MG I cultivars exhibited slower rates of harvest loss increases. The proportion of potential yield lost was inversely related to potential yield, indicating that harvest efficiency was improved with higher yields. Harvest delays can ultimately result in plant deterioration, increased grain losses, increased harvesting difficulties, and reductions in net yield of 11 kg ha−1d−1.
No‐till Winter Wheat Production on the Canadian Prairies: Placement of Urea and Ammonium Nitrate Fertilizers
Authors: Fowler D. B. , Brydon J. 
Published: July 2010

AbstractA practical snow management system, which utilizes no‐till seeding into standing stubble immediately after harvest of the previous crop has permitted the expansion of winter wheat (Triticum aestivum L.) production in western Canada. In the present study nine field trials were conducted on several Saskatchewan soil types (Aridic, Typic, Vertic, and Udic Haploborolls) from 1982 to 1986. The objectives were to compare stubbled‐in winter wheat grain yield (GY), grain protein yield (GPY), and protein concentration (PC) responses to urea and ammonium nitrate (AN) fertilizer banded and broadcast at seeding, or broadcast in the late fall or early spring. A prolonged dry period following spring broadcast of urea and AN delayed the availability of added N in one trial, which resulted in negligible GY response, limited GPY response, and large PC response to spring N applications. Reduced yield responses, which were probably due to N losses through denitrification, were also observed for both urea and AN broadcast in the late fall in one trial. Reduced CY and GPY responses for urea compared with AN in three trials indicated that, under some conditions, volatilization losses of greater than 50% can be experienced with broadcast urea. Fall banding prior to seeding was effective in reducing losses with urea, but this method of application presents other problems in the stubbling‐in production system and, in these trials, fall banding did not outperform AN broadcast at the same time.
Photosynthetic Rates of Six Maize Cultivars During Development
Authors: Dwyer L. M. , Stewart D. W. , Balchin D. , Houwing L. , Marur C. J. , Hamilton R. I. 
Published: July 2010

AbstractProduction estimates based on photosynthate accumulation are affected by changes in photosynthesis rates related to aging in different cultivars. The influence of leaf and plant age on photosynthetic rates was investigated in six maize (Zea mays L.) cultivars with maturity ratings ranging from <2300 to >3500 CHU (corn heat units). Photosynthesis and irradiance measurements were fitted to rectangular hyperbolas using a nonlinear fitting technique. These curves were analyzed as a function of cultivars, and leaf and plant age. For comparison among cultivars and age groups, photosynthesis was represented by P2000 (net photosynthetic rate at irradiance (I) = 2000 µmol m−2 s−1). In all cultivars, early leaves had lower P2000 values at a given leaf age than late maturing leaves. The P2000 values tended to increase to a maximum at the time of full individual leaf expansion and then decrease. The duration of maximum P2000 values for leaves nearest the ear were longer than for earlier or later developing leaves. Leaves nearest the ear for early maturing cultivars tended to have lower P2000 values than later maturing cultivars at comparable leaf ages. Plant photosynthesis patterns were the same for all cultivars in relation to plant age and phenological development. Photosynthesis (P2000) was low for the six‐leaf stage, reached a maximum just before tasselling, and then declined during brown silk, blister, and dent stages. A quadratic equation described the relationship between P2000 and plant age. The trend was for latermaturing cultivars to have significantly (P < 0.05) larger P2000 values than earlier‐maturing cultivars at comparable phenological stages. Significant cultivar differences were found in leaf development rate and length of vegetative period (P < 0.10).
A Conservation Tillage System for Profitable Cotton Production in the Central Texas High Plains
Authors: Harman W. L. , Michels G. J. , Wiese A. F. 
Published: July 2010

AbstractIrrigation water supplies are dwindling in the southern High Plains and effective methods of conserving precipitation during fallow periods are needed. This study was conducted to compare soil water storage, yield of cotton, and profitability of conventional and notillage in a 2‐yr, double crop, irrigated barley (Hordeum vulgare L.)‐ dryland cotton (Gossypium hirsutum L.) cropping sequence with a 48 wk fallow from barley harvest and cotton planting. The soil was a Sherm (fine, mixed, mesic Torrertic Paleustolls) clay loam with 2.2% organic matter, a soil pH of 6.9, and 28, 31, and 41% sand, silt, and clay, respectively. Kochia [Kochia scoparia (L.) Schrad.], Russian thistle [Salsola kali (L.) var. tenuifolia Tausch], pigweed (Amaranthus blitoides S. Wats.), and witchgrass (Panicum capillare L.) were controlled during fallow with disk and field cultivator in conventional tillage. Herbicides used for no‐tillage were dicamba [3,6‐dichloro‐2‐methoxybenzoic acid], atrazine [6‐chloro‐N‐ethyl‐N′‐(l‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], fluometuron [N,N‐dimethyl‐N′‐[3‐(trifluoro‐methyl)phenyl] urea], and glyphosate [N‐(phosphonomethyl)glycine]. A 45 mm increase in soil water storage with no‐tillage increased dryland cotton yields 110 kg ha−1. Although herbicide costs were $155.00 ha−1 greater with no‐tillage, long‐term annual profit with no‐tillage increased $82.00 ha−1 over conventional tillage because of increased yield and lower machinery depreciation Costs.
Flood Duration Effects on Soybean Growth and Yield
Authors: Scott H. D. , DeAngulo J. , Daniels M. B. , Wood L. S. 
Published: July 2010

AbstractFlooding is often a problem in areas of the southern USA with high rainfall and impermeable soils. A field study was conducted on two poorly drained, slowly permeable soils, a Sharkey clay (veryfine, montmorillonitic, nonacid, thermic Vertic Haplaquept) and a Crowley silt loam (fine, montmorillonitic, thermic Typic Albaqualf), to determine the influence of prolonged flooding on the growth and seed yield of eight determinate soybean [Glycine max. (L.) Merr.] cultivars. Soybean was continuously flooded 3 cm above the soil surface at either the V4 or R2 growth stage for 2, 4, 7, or 14 d. Soil water pressures were monitored at four depths in the Sharkey profile. Flood duration effects on the soybean plant were manifested in yellowing and abscission of leaves at the lower nodes, stunting, and reduced dry weight and seed yield. Canopy height and dry weight decreased linearly with duration of the flood at both growth stages. The growth rates were 25 to 35% less when soybean was flooded at R2 than at V4. The additional 4 wk of vegetative growth after flooding allowed the soybean flooded at V4 to recover to a greater extent than the cultivars flooded at R2. A linear relation was found between seed yield and monthly average crop growth rates for the 4 wk following flooding. A linear decrease in seed yield with flood duration was also found. On the Sharkey clay, rates of yield reduction were 157 and 124 kg ha−1 d−1 of the flood for the soybean flooded at R2 and V4, respectively. On the Crowley silt loam, yield reduction rates were 101 and 53 kg ha−1 d−1 of the flood duration for the soybean flooded at R2 and V4, respectively. Crop susceptibility factors (CS) were determined by dividing the decline in yield by the unstressed control, where the 2‐d flooded soybean cultivars were considered the controls. Values of CS ranged from 0.0 to 0.6 and were linearly related to flood duration after 2 d. The slopes of the lines were 1.5 times greater for the flood applied at R2 than at V4, and 2.4 times greater with soybean grown on the Sharkey clay than on the Crowley silt loam. The determinate soybean cultivars were more susceptible to prolonged flooding during early reproductive growth than early vegetative growth and when grown on the clayey soil than on the silt loam.