bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Status of the Developing Grain of Maize1
Authors: Westgate mark E. , Boyer John S. 
Published: July 2010

AbstractDeveloping grain undergoes large changes in water content. Since there are no direct vascular connections between the grain and the maternal plant, grain growth may depend on large osmotic forces. To determine the nature and magnitude of these forces, we investigated the water potential (Ψw), osmotic potential (Ψs) and turgor in the developing grain of maize (Zea mays L.) from anthesis to harvest maturity in three commercial hybrids grown in the field. Grain Ψw, Ψs and turgor were determined using isopiestic thermocouple phychrometry. Seasonal trends in grain Ψw were similar in all three hybrids despite differences in maturity rating (85 to 110 days), maximum grain water content, and environmental conditions after anthesis. Prior to maximum dry matter accumulation (physiological maturity), grain Ψw was 0.4 to 0.9 MPa lower than leaf Ψw reasonably stable, and largely independent of atmospheric conditions. Variations in grain Ψw were similar to the changes in grain Ψs which was between −0.7 and −1.6 MPa and not affected by matric forces. Turgor was usually 0.2 to 0.3 MPa. After maximum dry matter accumulation, grain Ψw responded to atmospheric conditions and decreased rapidly to potentials as low as −8.5 MPa as grain water content decreased and large matric forces developed. The relationship between grain Ψw and percent grain moisture (PM) was similar for all three hybrids and given by PM = 23.7 Ψw−1.16 + 20 (r2 = 0.83). These results indicate either that a large hydraulic resistance exists or that high solute concentrations are present between the developing grain and the vascular supply of the maternal plant. Thus, large osmotic forces are associated with water uptake by the grain. Also, prior to physiological maturity, grain Ψw is controlled mostly by the internal metabolic events associated with development. After physiological maturity, however, it is controlled mostly by grain moisture content.
Herbicide Applications on Wheat and Stubble for No‐Tillage Corn1
Authors: Wicks G. A. 
Published: July 2010

AbstractNo‐tillage corn (Zea mays L.) production following winter wheat (Triticum aestivum L.) is increasing in the central Great Plains. Timely weed control is essential to reduce weed seed production and loss of soil water. This research dealt with the effects of applying herbicides to wheat grown on a fine‐silty, mixed, mesic Typic Argiustolls soil, in North Platte, NE, and herbicide applications 5,20, 35, 50, and 260 days after wheat harvest. Applying metribuzin [4‐amino‐6‐(1,1)‐dimethylethyl)‐3‐(methylthio)‐1,2,4‐triazin‐5(4H)‐one] to wheat reduced post‐harvest weed biomass 24 to 81%. When herbicide application was delayed until 50 days after wheat harvest, as compared to 5,20, or 35 days, barnyardgrass [Echinochloa crus‐galli (L.) Beauv.] populations before and after corn planting were the highest. The addition of glyphosate [N‐(phosphonomethyl)glycine], paraquat (1,1'‐dimethyl‐4,4'‐bipyridinium ion), or terbutryn [N‐(1,ldimethylethyl)‐ N'‐6‐(methylthio)‐1,3,5‐triazine‐2,4‐diamine] + 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] to atrazine [6‐chloro‐N'‐ethyl‐N'‐(l‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] sometimes improved corn yields, when applied after wheat harvest, compared with plots treated with atrazine alone. Optimum corn grain yields were obtained when plots treated with atrazine + paraquat at 5, 20, and 35 days after wheat harvest were sprayed with cyanazine {2‐[[4‐chloro‐6‐ (ethylamino)‐1,3,5‐triazin‐2‐yl]amino]‐2‐methylpropanenitrile} preemergence or handweeded once after the corn was planted. Delaying post‐wheat harvest herbicide application for 260 days reduced corn yields 20%.
Effect of Salinity on Grain Yield and Quality, Vegetative Growth, and Germination of Semi‐Dwarf and Durum Wheat1
Authors: Francois L. E. , Maas E. V. , Donovan T. J. , Youngs V. L. 
Published: July 2010

AbstractSemi‐dwarf bread wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum L., Durum Group) are often grown on saline soils in the western United States. Because of the lack of information on salinity effects on vegetative growth and seed yield of these two species, a 2‐yr field plot study was conducted. Six salinity treatments were imposed on a Holtville silty clay [clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent] by irrigating with waters salinized with NaCl and CaCl2 (1:l by wt). Electrical conductivities of the irrigation waters were 1.5, 2.5, 5.0, 7.4, 9.9, and 12.4 dS/m the first year, and 1.5, 4.0, 8.0, 12.0, 16.1, and 20.5 dS/m the second year. Grain yield, vegetative growth, and germination were measured. Relative grain yields of one semi‐dwarf wheat cultivar and two durum cultivars were unaffected by soil salinity up to 8.6 and 5.9 dS/m (electrical conductivity of the saturated‐soil extract), respectively. Each unit increase in salinity above the thresholds reduced yield of the semi‐dwarf cultivar by 3.0% and the two durum cultivars by 3.8%. These results place both species in the salt‐tolerant category. Salinity increased the protein content of both grains but only the quality of the durum grain was improved. Vegetative growth of both species was decreased more by soil salinity than was grain yield. Both species were less salt tolerant at germination than they were after the three‐leaf stage of growth.
Osmotic Adjustment of Cotton to Moderate Potassium‐Chloride Stress and Subsequent Water Stress During Early Stages of Development1
Authors: Bar‐Tsur A. , Rudich J. 
Published: July 2010

AbstractHigh KCl fertilization of drip irrigated cotton (Gossypium hirsutum L.) under intensive growth conditions, mainly in wheat‐ (Triticum aestivum L.) cotton double cropping when the soil profile is dried out and the cotton has a restricted root volume, may cause moderate osmotic stress. Therefore, the response of cotton to KCl stress and successive water stress was evaluated by measurements of leaf water potential (ψL), osmotic potential (ψs) turgor pressure (P), and mineral composition of leaves and flower buds. Young cotton plants (var. Acala SJ2) grown in 10‐L plastic pots filled with a peat/ tuff mixture (1:1) in a field environment were exposed to prolonged osmotic stress for 35 days by application of KCI. Electrical conductivity of the nutrient solutions was 1.5,3.6,6.7,9.8, and 13 dS m−1, and the final ψs of the growth medium at the time of measurement 65 days after planting was 0.05, 0.16, 0.27, 0.38, and 0.47 MPa, respectively. The prolonged 35‐day‐long KCl stress caused stunting of vegetative growth and reduced ψL, which was accompanied by reduction in ψs and maintenance of positive P. Osmotic adjustment was also observed in developing flower buds, but their ψs, was higher than leaf ψs. The main contribution to osmotic adjustment was from the accumulation of inorganic minerals such as K+ and Cl− in leaves and flower buds. Exposure of the control and KCl‐treated plants to successive water stress by withholding irrigation reduced ψL in both treatments. Plants from the KCl treatment responded by a concomitant decrease in ψs, which enabled maintenance of positive P, whereas the control plants that were exposed to water stress did not show osmotic adjustment. The results indicate that prolonged KCl stress enabled the cotton plant to exist and withstand successive water stress, but the cotton plant could not overcome growth inhibition.
Animals for Biological Brush Control1
Authors: Wood G. M. 
Published: July 2010

AbstractBiological control of undesirable brush species in rundown or abandoned pastures using animals, particularly goats (Capra hircus), is a viable alternative to chemical and mechanical methods. Vermont experiments on a brushy hill pasture (mesic Aeric Hapalaquepts soil) with cattle (Bos taurus typicus), sheep (Ovis aires), and goats showed that the goat was the best animal for the task. Goats reduced the brush in 1 yr and virtually eliminated it from a badly infested pasture in 2 yr. In contrast, 2 yr of grazing were required before cattle and sheep could decrease brush below the ungrazed control. Unlike cattle and sheep, the goats destroyed small trees and saplings by debarking, were not deterred by thorny vegetation, and browsed much higher by standing on their hind legs. As brush was destroyed, grass increased.
Water‐Use Efficiency of Grasses Grown under Controlled and Field Conditions1
Authors: Frank A. B. , Barker R. E. , Berdahl J. D. 
Published: July 2010

AbstractForage production from grasses grown in the semiarid northern Great Plains is primarily a function of available water during the growing season. There is a need to develop procedures using controlled environments to shorten the time for identifying germplasm that differs in water‐use efficiency (WUE). Field determination of WUE requires several years to evaluate genetic and environmental effects. This study compares WUE of field grown cultivars of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Shult.], intermediate wheatgrass [Thinopyrum interdium (Host) Barkworth and Dewey], and western wheatgrass [Pascopyrum smithii Rybd. (Löve)] to identical plants grown in a controlled environment. Net CO2 assimilation (A), transpiration rate (E), A/E ratio, and conductances on a leaf basis for plants grown in a controlled environment were compared to WUE calculated from dry matter accumulation and total evapotranspiration for field grown plants. Generally, cultivars within a species that exhibited higher E and A and a lower A/E ratio in controlled environments also had higher field WUE. In contrast, comparisons among species indicated that crested wheatgrass had the lowest E, A, and A/E ratio, but had the highest field WUE. The intercellular C02 concentration (C1) differed among cultivars within species, with the stomates of the higher WUE cultivars functioning to maintain higher c1. Correlations of field WUE with controlled environment measurements suggest that the A/E ratio is not a good predictor of field WUE for the species examined in this study.
Shoot Growth Rate of Soybean as Affected by Drought Stress1
Authors: Hoogenboom Gerrit , Peterson Curt M. , Huck M. G. 
Published: July 2010

AbstractShoot size at time of flowering has a strong effect on final yield and can be significantly reduced by drought stress. Studies were performed at the Auburn rhizotron from 1981 through 1983 to investigate the effects of drought stress on daily shoot growth rates of soybean [Glycine max (L.) Merr. ‘Braxton’]. Plants were grown in a Marvyn loamy sand (fine‐loamy, siliceous, thermic Plinthic Paleudult) and received only rainfall (NI) or rainfall and supplemental irrigation (IR) during each growing season. Irrigation was controlled by tensiometers installed 0.4 m deep, and water was added when soil water potential (Ψ soil) fell below −15 kPa. Shoot growth patterns, e.g., stem elongation, leaf formation, and leaf area increase, followed characteristic exponential growth curves during early vegetative development when no moisture stress was evident. Sensitivity to water stress (Ψ soil < −15 kPa) increased as total leaf area and resulting transpiration demand increased. Stem elongation and leaf area expansion rates decreased significantly for the NI treatment during periods of water stress. During periods of moisture stress, leaves formed on NI plants were smaller than leaves at comparable nodes on IR plants (0.0075 vs. 0.010 m2). After periods of rainfall, shoots of NI plants grew more rapidly than those of IR plants (0.025 vs. 0.020 m/day), and most of the growth reduction during the previous stress period was regained. Accumulated growth over time, i.e., total leaf area (0.22 m2), number of nodes (17), final internode lengths (e.g., 0.08 m), and mainstem height (1.15 m), was comparable between NI and IR treatments. Thus, no long‐term differences were observed between IR and NI treatments because significant short‐term reductions in shoot growth rate due to drought stress were followed by compensatory growth during periods of rainfall.
Seeding Rate and Row Spacing Effects on Yield and Yield Components of Ratoon Rice1
Authors: Jones D. B. , Snyder G. H. 
Published: July 2010

AbstractRatoon cropping of rice (Oryza sativa L.) has recently received renewed attention as a means to lower unit production costs. However, little information is available on the effect of main crop cultural practices on ratoon yields of drill‐seeded rice. The objective of this study was to determine the effect of main crop seeding rate and row spacing of drill‐seeded rice on yield and yield components of the ratoon crop. Two contrasting plant types, tall (cv. Lebonnet) and semi‐dwarf (cv. Bellemont and Lemont), were drill‐seeded at rates of 50, 100, and 150 kg seed ha−1 in 0.15‐, 0.20‐, and 0.25‐m row spacings in three tests conducted on an organic soil. Ratoon grain yields differed significantly (P<60.01) among tests for both plant types, and were not significantly (P<60.05) correlated to main crop grain yields (r= −0.62). Ratoon grain yields of both cultivars were not significantly (P<0.05) affected by main crop seeding rate, row spacing, or seeding rate X row spacing interaction. Increased seeding rates significantly increased ratoon panicles per square meter (P< 0.01) and decreased ratoon filled grain number per panicle (P<0.01) in all tests for both plant types. Panicles per square meter and filled grain number per panicle accounted for over 85% of the variation in ratoon grain yield. Compensation between these two yield components stabilized ratoon grain yield at relatively low levels.
Atmospheric Carbon Dioxide Enrichment Effects on Cotton Midday Foliage Temperature: Implications for Plant Water Use and Crop Yield1
Authors: Idso S. B. , Kimball B. A. , Mauney J. R. 
Published: July 2010

AbstractIn an experiment designed to determine the likely consequences of the steadily rising carbon dioxide (CO2) concentration of Earth's atmosphere for the foliage temperature, water use, and yield of cotton (Gossypium hirsutum L. var. Deltapine‐61) plants, cotton was grown out‐of‐doors at Phoenix, AZ, in open‐top, clear‐polyethylene‐wall, CO2‐enrichment chambers for three summers under mean daylight CO2 concentrations of 340, 500 and 640 μmol CO2 mol−1 air on an Avondale clay loam soil [fine‐loamy, mixed (calcareous), hyperthermic Anthropic Torrifluvent]. Infrared thermometer measurements of the cotton foliage temperature (TF) indicated that a 330 to 660 μmol CO2 mol−1 air doubling of the atmospheric CO2 content results in a midday TF, increase of 1.1 °C for well‐watered cotton at Phoenix in the summer. This temperature increase was predicted to produce a 9% reduction in per‐unit‐leaf‐area plant transpiration rate and an 84% increase in crop biomass production, which compared favorably with the measured crop biomass increase of 82% for such a doubling of the air's CO2 content. These findings, together with similar findings for a second plant species—water hyacinth [Eichhornia crassipes (Mart.) Solms]—allowed us to develop a technique for assessing the effects of a 330 μmol CO2 mol−1 air CO2 concentration increase on the percentage yield increase (Y) of a crop via infrared thermometry by means of the equation Y = 7.6% × (IJ)−1, where IJ represents the Idso‐Jackson plant water stress index. If this equation holds up under further scrutiny, it could provide a rapid and efficient means for assessing the yield response of crops to atmospheric CO2 enrichment.
Salt Effects on Alfalfa Seedling Emergence1
Authors: Assadian N. Waissman , Miyamoto S. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) is regarded as susceptible to salts at establishment. This study was conducted to evaluate: (i) emergence reduction by irrigation with saline waters; and (ii) the relationship among seed germination, hypocotyl salt injuries, and seedling emergence. Greenhouse experiments were conducted using ‘Moapa’ and ‘Mesilla’ grown in Bluepoint fine loamy sand (calcareous, thermic Typic Torripsamment). In Exp. 1, seedling emergence and salt accumulation near the soil surface were monitored after seeding at three depths (3, 10, and 15 mm) and irrigated with water of 0.8 to 7.6 dS m−1. In Exp. 2, seed germination was measured in sponges moistened with saline solutions (0.8‐32 dS m−1). In Exp. 3, seedling emergence was monitored after placing a 5‐mm layer of salted‐sand having the saturation extract salinity of 0.8 to 45 dS m−1 onto emerging seedlings to evaluate hypocotyl salt injuries. Results indicated that the rate and final emergence of both cultivars declined when salinity of irrigation waters exceeded 4.3 dS m−1, even though the seed germinated well in saline solutions of 28 dS m−1. Soluble salts had accumulated mostly in the top 5‐mm depth where salinity increased to 20 dS m−1 in 4 days when irrigated at 4.3 dS m−1. A significant reduction in emergence occurred in Exp. 3 when the salinity of the surface‐placed sand exceeded 17 dS m−1. Emergence reduction observed from a seeding depth of 3 mm was probably due to the reduction in seed germination, whereas from seeding depths of 10 mm or more, emergence appeared to be limited by hypocotyl salt injuries after germination. Alfalfa could be established with minimal salt damage from water, up to approximately 4 dS m−1, when seeded approximately 10 mm deep.
Nitrogen Utilization from Fertilizer and Legume Residues in Legume‐Corn Rotations1
Authors: Hesterman O. B. , Russelle M. P. , Sheaffer C. C. , Heichel G. H. 
Published: July 2010

AbstractLegume‐corn (Zea mays L.) rotations are common throughout the U.S. Corn Belt, but little information is available about the efficiency of legume residue N utilization, or about fertilizer‐N use efficiency in different cropping sequences. Our objective was to determine the contribution of N from soil, fertilizer, and legume residues for six legume‐corn sequences. The effect of applied fertilizer N rate was also examined. Field studies were conducted on a Udorthentic Haploboroll and a Typic Hapludoll. First‐phase (Year 1) rotation components included alfalfa (Medicago sativa L.), corn, soybean [Glycine max L. (Merr.)], or fallow. Nitrogen–15‐depleted (NH4)2SO4 was applied to second‐phase (Year 2) corn. Fertilizer‐N use efficiency for second‐phase corn was 51% for the whole plant and 36% for grain, with no effect of first‐phase treatment. Average use efficiency of legume‐N (uptake of legume‐N/legume‐N incorporated) was 43% for the whole corn plant and 30% for grain. Second‐phase corn derived a greater proportion of its N from residue of alfalfa (36%) than soybean (12%). When the rate of N applied to corn was increased from 56 to 168 kg N ha−1, the proportion of N derived from legume residue decreased from 44 to 19% in whole corn plants and from 57 to 23% in grain. Results suggest that the N credit commonly attributed to legumes in crop rotation may be inflated by as much as 132%.
Grazing Effects on the Total Nonstructural Carbohydrate Pools in Caucasian Bluestem1
Authors: Christiansen Scott , Svejcar Tony 
Published: July 2010

AbstractTotal nonstructural carbohydrates (TNC) may be overemphasized relative to other factors governing plant survival in pastures. A grazing study was conducted on established 1‐ha pastures of Caucasian bluestem [Bothriochloa caucasica (Trin.) C.E. Hubb.] during 1983–1984 at the Forage and Livestock Research Laboratory, 2 km west of El Reno, OK. The objective was to compare allocation of TNC to leaf, stem (plus sheath), stem base, and dead components of heavily or lightly grazed Caucasian bluestem. Soils were fine‐silty Pachic Haplustolls of the Dale Series. Put‐and‐take stocking was used to maintain high and low grazing pressures from mid‐May to late September both years. Pastures were sampled four times in 1983 and three times in 1984 by excavating representative plants, separating them into plant parts, and analyzing for TNC. Heavy grazing pressure initially decreased (P<0.1) concentrations of TNC in all living tissues. However, no differences in TNC concentration due to grazing pressure were found the second year. On six of seven sampling dates over 2 yr, grazing pressure did not affect (P>0.1) the amount of TNC located in stem bases. Stem bases contained more than half the total shoot TNC in heavily grazed plants; however, lightly grazed plants contained much more total shoot TNC (as much as seven times greater) compared to heavily grazed plants, due to light utilization by animals. A densely appressed physical arrangement of stem bases provided sites for tiller initiation and protection from grazing. Crown architecture in Caucasian bluestem, together with physiological and morphological adjustments, ensured a nongrazeable mass of stem bases containing sufficient quantities of TNC to sustain plants under heavy grazing.
Corn‐Hybrid Performance under Conventional and No‐Tillage Systems after Thinning1
Authors: Carter P. R. , Barnett K. H. 
Published: July 2010

AbstractCorn (Zea mays L.) producers question the relative performance: of hybrids under different previous‐crop residue management systems. The objective of this study was to assess tillage system ✕ corn hybrid interactions for hybrids commonly grown in the northern United States. Field experiments were conducted at four locations in Wisconsin during 1984 and 1985, including sites with Plano and Nickin silt loam (Typic Argiudoll) and Meridian loam (Mollic Hapludalf) soils. Fifteen hybrids with a range of maturities (90–115 days based on the Minnesota Relative Maturity System) were compared under conventional (moldboard plowing and disking)(CT) and no‐till (NT) systems, in a corn‐following‐corn sequence. Stands were thinned after emergence. No‐till resulted in cooler soil temperatures (0.8–3.8°C cooler), lower emergence percentage (7–12% lower), delayed vegetative growth [4.4 (NT) vs. 7.9 (CT) g plant−1], later silking (2–5 days later), and increased grain moisture (10–20 g kg−1) compared to CT. For grain yield, differences occurred for all main effects (locations, years, tillage systems, and hybrids), and most interactions were significant. Yields under NT were 92% (cool spring, 1984) and 96% (warm spring, 1985) of CT yields. On silt‐loam soils, NT yields were 92 to 95% of CT yields, but tillage systems had similar yields on the loam soil. Superior‐yielding hybrids under CT were also good choices with NT, although delayed growth under NT limited the yield potential of later‐maturing (100–115 days) hybrids.