bluuebunny/crossref_metadata_2025_split huggingface dataset:
Germinability of Tobacco Seed as Affected by Culture of the Mother Plant1
Authors: Thomas Judith F. , Raper C. David 
Published: July 2010

AbstractUniformity of plant growth, which is important for efficient mechanization, is influenced by uniformity of seed germination. Since germinability characteristics of tobacco (Nicoticznu tabacum L.) seed produced in a phytotron are affected by the environment during develop ment of the mother plant, a field experiment was conducted to determine if measurable changes in germinability of seed result from alterations in cultural practices during mother‐plant growth. Cultural variables were N‐applied at 50, 72, and 94 kg ha−1 and normal or no leaf harvest. The increases in N applied to the mother plant reduced the time and enhanced the uniformity of seed germination. Leaf harvest had no effect on germinability characteristics. These effects were not significantly correlated with seed size.
Manure and Iron Effects on Sorghum Growth on Iron‐Deficient Soil1
Authors: Thomas J. D. , Mathers A. C. 
Published: July 2010

AbstractIron deficiency in sorghum [Sorghum bicolor (L.) Moench] occurs in spots throughout the High Plains on calcareous soils. This greenhouse experiment was conducted to determine the effect of N, P, and K with and without Fe and the effect of manure with and without additional Fe on Fe‐deficiency and dry matter yield of sorghum. Residual effects on a second and third crop also were measured. Pelleted manure and NPK (300‐100‐100 ppm) with Fe treatments were mixed with 3 kg of Arch fine sandy loam (Ustochreptic Calciorthid of the fine‐loamy, mixed thermic family). The treatments were Check, NPK, 0.5, 1.2, and 4% manure with Fe added to supply 0, 5, 10, 20, and 40 ppm Fe to the soil. Soil moisture was increased to 20% by weight periodically to maintain adequate soil moisture. Dry matter yield and observations indicated that manure effectively reduced Fe chlorosis and increased sorghum growth on Fe‐deficient calcareous soil. Either ferrous sulfate alone at rates up to 40 ppm Fe or fertilizer without Fe did not increase yields. Although yields were increased by adding Fe with fertilizer increases from Fe were not as great as those from manure. Manure had a residual effect on yield in the second and third crops. This indicates that manure can be used to correct Fe deficiency of grain sorghum on calcareous soils.
Soybean Top and Root Response to Temporary Water Tables Imposed at Three Different Stages of Growth1
Authors: Stanley C. D. , Kaspar T. C. , Taylor H. M. 
Published: July 2010

AbstractKnowledge of the response that a crop's root system exhibits with respect to changing soil environments can be useful if that change can be altered by man. Such is the case with crops grown on soil where temporary high fluctuation of the water table can occur. Knowing at what growth stages a crop may be more tolerant or susceptible to injury could be valuable in determining to what depth and at what rates drainage should occur.A field‐situated rhizotron study was conducted using two water table heights (45 and 90 cm) to determine the effects of temporary high water tables imposed at different growth periods on the development of the tops and roots of soybean [Glycine max (L.) Merr.] plants. Water‐table heights were established for 7 days during preflowering, postflowering (before podset), and post‐podset growth periods. Top and root growth parameters were monitored continuously throughout the growing season.Results indicated that root tolerance to water‐table level changed as the plant progressed through its growth cycle. Root tolerance is described as the ability of the root system to withstand or adjust to the conditions caused by imposed water tables. During preflowering individual root tolerance was exhibited. Little damage occurred to the roots during imposition or removal of the water table treatments. During postflowering less individual root tolerance, but strong total root system adjustment was evident. Extensive damage to the roots occurred once the water tables were imposed, but the plant's ability to adjust to the situation by initiating new roots in soil areas above the water table levels was quite strong at this particular growth period. No root tolerance of the water‐table conditions was observed for post‐podset growth.
Drought Adaptation of Cowpea. IV. Influence of Drought on Water Use, and Relations with Growth and Seed Yield1
Authors: Turk Kenneth J. , Hall Anthony E. 
Published: July 2010

AbstractIn concurrent studies it was demonstrated that the drought resistance of cowpeas [Vigna unguiculata (L.) Walp.] is associated with extreme drought avoidance resulting from drought‐induced regulation of water loss. The present studies were conducted to quantify drought effects on crop water use, and relations with growth and seed yield.Two cowpea cultivars were subjected to different drought intensities at the vegetative, flowering, and pod filling stages in the field during 2 years having contrasting weather patterns. Soil moisture was measured weekly throughout the season using the neutron scattering method. Water use (ET) and its ratio with pan evaporation (ET/Epan) were calculated both weekly and for the entire season.The seasonal patterns of ET/Epan were similar for the 2 years which had contrasting patterns of potential evaporation. Under well‐watered conditions, ET/Epan increased linearly with ground cover and had an average value of 0.94 with complete ground cover. ET was restricted well below the potential level by different levels of drought, and at different growth stages, but showed rapid recovery following a vegetative‐stage drought.When plant cover was not limiting, ET/Epan was extremely sensitive to percent available water in the rooting zone with a high threshold of 90% in contrast to results from earlier work with other crops. A more general description of the factors influencing ET of cowpeas under varying types and levels of drought was provided by a linear relationship between ET/Epan and fractional, ground cover × available water.Root growth increased linearly throughout the season to a depth of 135 cm under well‐watered conditions, but was restricted greatly under dry conditions.A linear relationship was observed between relative seed yield and relative water use from early flowering to harvest. Water‐use efficiency (WUE) generally increased with vegetative‐stage drought and was reduced by flowering‐stage and late‐season droughts. WUE increased slightly with moderate reductions in the level of weekly irrigation and decreased with further reductions in irrigation level.
Seasonal Nitrogen Accumulation and Fixation by Soybeans Grown at Different Densities1
Authors: Nelson A. N. , Weaver R. W. 
Published: July 2010

abstractIntra‐row spacing is expected to affect N accumulation and fixation because of the gross morphological changes that occur for plants grown at different densities. Enhancement of N fixation may lead to increases in soil N for nonleguminous crops and increase efficiency of soybean [Glydne max (L.) Merr.] production. Nodulating and non‐nodulating isolines of Lee cultivar soybeans were grown in a field experiment on Ships clay (very fine, mixed thermic, Udertic Haplustolls) at densities of 48,500, 97,000 and 194,000 plants ha−1 to determine the effect of plant density on seasonal patterns of N fixation and N distribution within plant tops. The distance between rows was 70 cm. The tops of the nodulating isoline plants were separated into leaflets, stems plus petioles, and pods. The rate of acetylene reduction and nodule mass was determined on the roots. Root density determinations were made using mini‐rhizotrons. The rate of dry matter accumulation per hectare and distribution of N within the plants was not greatly affected by planting density. No significant differences in root densities were found between isolines or among plant densities. The highest planting density of the nodulating isoline accumulated more than 300 kgNha−1 but total plant N in the non‐nodulating isoline was approximately 75 kgNha−1. During the first 17 days of the pod filling period, N accumulation in the pod sink was greatest and averaged approximately 7.5 kgNha−1 day−1 without a net loss of N from the leaflets. This indicates that N fixation can meet the N needs of soybeans without mobilization of leaf N.
Chemical Composition of Winter Wheat Forage Grown Where Grass Tetany and Bloat Occur1
Authors: Stewart B. A. , Grunes D. L. , Mathers A. C. , Horn F. P. 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L.) is widely used in the southern High Plains as a forage for beef cattle. Although grazing wheat is generally financially profitable, death losses often occur. Frothy bloat and grass tetany are often mentioned as causes, but the conditions under which these metabolic disorders occur are not completely understood. The objectives of the present study were: (1) to determine the changes in chemical composition of wheat forage during the normal wheat grazing season; (2) to determine the effect of N fertilizer on the chemical composition of the forage; and (3) to gain insight into the factors predisposing cattle grazed on wheat pasture to tetanic or bloat‐related death. Wheat pastures at Bushland, Texas, and El Reno, Oklahoma, were studied for 3 years by taking forage samples almost weekly during the growing seasons. Samples were analyzed for N, K, Ca, Mg, P, ash alkalinity, aconitate, and total nonstructural carbohydrates. Significant changes in forage composition occurred within very short periods. For example, in 1978 at El Reno, the K concentration increased from 2 to 4.5% in 2 weeks. During the same period, large changes occurred in the N, aconitate, ash alkalinity, and total nonstructural carbohydrate concentrations; but Mg concentrations did not change significantly. Nitrogen fertilization clearly affected chemical composition of the forage and generally increased the indices that are commonly associated with high incidence of frothy bloat and grass tetany. Elimination of fertilizer N is not practical because of the resulting pronounced decrease in forage and grain production. Therefore, other management practices are required to minimize or prevent frothy bloat and grass tetany problems on winter wheat forage.
Remote Sensing of Canopy Temperature at Incomplete Cover1
Authors: Heilman J. L. , Heilman W. E. , Moore D. G. 
Published: July 2010

AbstractA field study was conducted in a barley (Hordeum vulgare L.) canopy to assess the potential for extracting canopy temperature information from nadir radiometric measurements at incomplete cover. Composite temperatures consisting of emitted and reflected longwave radiation from the barley and the soil background were measured by a nadir‐viewing infrared radiometer. Canopy temperatures were measured by an infrared radiometer at a 30° angle from the horizontal. Soil temperatures were measured with thermocouples.Composite temperatures were 0.5 to 11.5 C higher than canopy temperatures with the largest difference occurring at low canopy cover. The correlation between composite and canopy temperature for data acquired throughout the growing season was not significant. A model which considered emitted radiation from both the canopy and the soil background, and which included reflected longwave sky irradiance was used to predict crop temperatures from nadir measurements. Predicted temperatures agreed with observed values (r2 = 0.88), and the prediction accuracy was independent of canopy cover. When emissivity corrections were not applied, prediction accuracy varied with percent cover with largest errors occurring at low cover. Prediction accuracy also varied with canopy cover when appropriate emissivities were used but sky irradiance was ignored. Results indicate that canopy temperatures can be estimated from nadir measurements at incomplete cover if percent cover, soil temperature, soil and canopy emissivities, and sky irradiance are known.
Cabbage Plant Responses to Nitrogen Fertilization1
Authors: Peck N. H. 
Published: July 2010

AbstractNitrogen fertilization may affect the yield components and quality attributes of vegetables grown for processing. The objective of this study was to determine the effects of N fertilization systems on cabbage (Brassica oleracea L. Capitata group) grown for kraut. The concentrations and contents of nitrate‐N and total N in the plants were used to determine the availability of N and uptake of N from the soil and/or fertilizer N during the growing season.Urea broadcast at 15 g N/m2 and worked into the soil preplant was compared to ammonium nitrate applied at a rate of 15 g N/m2 split into three 5 g N/m2 applications (banded at planting time plus sidedressed early plus sidedressed midseason) as fertilization systems for cabbage grown under field conditions in 1978 and 1979. The soil was a Lima silt loam (Glossoboric Hapludalf, fine loamy, mixed mesic), a productive soil derived from calcareous glacial till. Plants were spaced 4/m2.Tops of four plants grown without fertilizer N contained 12 g N/m2 at harvest. Fertilizer N applied at 15 g N/m2 increased the total N in the plant tops to 22 g N/m2. This was an increase in plant N equivalent to two‐thirds of the rate of fertilizer N applied.Cabbage plants grown without fertilizer N yielded 4 kg fresh weight/m2. Fertilizer N at 15 g N/m2, either as urea or ammonium nitrate, yielded 8 kg of heads/m2. Fertilizer N at 30 g/m2 from urea plus ammonium nitrate yielded 10 kg heads/m2. Plants grown with fertilizer N had a lower percentage of dry weight in the heads, and had higher percentages of burst heads and heads with tipburn than heads of plants grown without fertilizer N. Thus, fertilizer N increased the yield but decreased the quality of cabbage heads grown for kraut.
Effect of Selenium and Cadmium Additions to Soil on Their Concentrations in Lettuce and Wheat1
Authors: Cary Earle E. 
Published: July 2010

AbstractIt has been reported that increasing selenium (Se) Concentration in nutrient solution decreased cadmium (Cd) concentration in plants grown in these solutions. In a greenhouse study, Se and Cd were added to Lima (Glossoboric Hapludalf, pH 7.3) and Mardin (Fragiochrept, pH 4.7) silt loam soils to investigate if a Se × Cd interaction could be used to lower Cd concentrations in plants grown on these soils. In a 3 × 3 factorial design, three replications of the following treatment were prepared 0, 2, and 4 µg Se/g soil added as Na2SeO3 and 0, 2, and 8 µg Cd/g soil added as CdCl2. The treatments were pipetted onto 100 g of soil. The soil was dried to a slightly moist state, aggregates were crushed, and the 100 g portion was blended into 2.9 kg of untreated soil for 15 min using a twinshell blender. All treatments received a blanket application of 58 µg/g soil each of N, P, and K. Additional N, P, and K was added before each new crop was planted. Lettuce (Lactuca sativa); ‘Black Seeded Simpson’, was grown on the lima soil before and after wheat (Triticum sp.), ‘Sheridad’. Only wheat was grown on the Mardin soil. After germination each crop was thinned to 3 plants/pot. In all crops, the concentration of an element added to the soil was correlated (P<l%) with that same element's concentration in the plant. In the first crop of lettuce, increased additions of Cd to soil reduced Se concentration in the plant from 1.3 to 0.8 µg Se/g and from 2.7 to 1.6 µg Se/g for the 2 and 4 µg Se/g soil treatments, respectively. Increasing soil Cd levels did not affect the Se concentration in the second lettuce crop. Selenium treatment did not affect Cd concentrations of lettuce in the first crop, but did reduce Cd concentrations in leaves of the second crop from 24 to 13 µg Cd/g and from 66 to 48 µg Cd/g for the 2 and 8 µg Cd/g soil treatments, respectively. The Se × Cd interaction was significant in both crops. In wheat, Cd reduced the concentration of Se in grain produced on the Lima soil 27% for the low‐Se and 227, for the high‐Se treatments, and in grain produced on the Mardin soil 33% for the low‐Se and 27% for the high‐Se treatments. Cadmium had little effect on the concentration of Se in the leaf and stem of the wheat, and Se had little effect on the Cd concentration in the aerial portion of wheat.
Effects of Seeding Date and Population on Water‐Use Efficiency and Safflower Yield1
Authors: Alessi J. , Power J. F. , Zimmerman D. C. 
Published: July 2010

AbstractOilseed crop production has increased greatly in the Northern Plains in recent years. Cultural practices to optimize oilseed production were studied for 4 years (1974–1977) to obtain information on safflower (Curthamus tinctoris L.) seed yield, oil concentration, and wateruse efficiency as affected by seeding date and plant population. Safflower was seeded on previously cropped or fallow land on three dates: early (16 May), midseason (6 June), or late (25 June) on Temvik silt loam (Typic Huploborolls). Soil water depletion by safflower was generally confined to the upper 150‐cm soil depth. Average water use by safflower seeded in mid‐May was greater by 4 and 8 cm than that used by the midseason and late seeding, respectively, and was unaffected by population. Significant positive correlations (r = 0.78) were obtained between oil concentration and degree days for the period after flowering. Correlation coefficients showed that 79% of the total variation in oil concentration was accounted for by variation in water use and temperature. Average water‐use efficiency for mid‐May, early June, and late June seeding was 34, 33, and 15 kg seed/cm water used, respectively. Seed and oil yields were highest for early and lowest for late seeding. In all years, seeding date affected seed yield and oil concentration. Population affected seed and oil yield in 1976. The results showed that safflower grown under dryland conditions in the Northern Plains should be seeded not later than mid‐May. Previous research in North Dakota showed that for best results safflower should be planted between 20 April and 10 May.
Harvested Dry Matter from Single and Double‐Cropping Systems1
Authors: Helsel Zane R. , Wedin W. F. 
Published: July 2010

AbstractDouble‐cropping (DC) has been advocated in the United States for increasing feed and food production and production efficiency. We studied single‐cropping (SC) and DC systems to determine the most productive crops or crop combinations for harvestable dry matter. Ten crops grown from 1974 to 1976 at Ames in central Iowa were: corn for silage, corn for grain, tropical corn (all Zea mays L.), grain sorghum, forage sorghum, sorghum × Sudangrass (all Sorghum bicolor Moench), pearl millet (Pennisetum americanum (L.) K. Schum), sugarbeets (Beta vulgaris L.), soybeans [Glycine max (L.) Men.], and sunflowers (Helianthus annas L.). These crops were planted alone at recommended times in a SC system and as main (second) crops in DC systems following first crops of winter rye (Secale cereale L.) and spring oats (Avena saliva L.) harvested for forage.Dry matter (DM) yields of oats were greater than for rye. Rye, however, had the advantage of providing soil cover during the winter and being harvested earlier in the spring, thus permitting earlier planting of the main crop.Average DM yields of main crops were greater in the SC system than in the DC system, where the main crop DM yields declined with the later dates of planting. Seme crops (sorghum Average DM yields of main crops were greater in the SC system than in the DC system, where the main crop DM yields declined with the later dates of planting. Some crops (sorghum × sudangrass hybrid, forage sorghum, pearl millet, sunflowers, soybeans) produced comparable yields in the rye‐DC and SC systems. Grain yields of grain crops and root yields of sugarbeets declined at a greater rate with later plantings than did whole‐crop yields. Corn for grain and corn for silage in the SC system and forage sorghum and sorghum × sudangrass hybrid in both the SC and rye‐DC systems produced the highest whole‐crop yields. Total DM yields were greater for the early‐harvested oat‐DC system in 1974 and the rye‐DC system in 1975 and 1976 than for other systems. We concluded that there is potential for increased harvestable dry matter by DC in the north central United States, particularly if a small grain harvested early for forage is the first crop of the DC system.
Response of Upland Rice to Phosphorus Fertilization on an Oxisol of Central Brazil1
Authors: Fageria N. K. , Filho M. P. Barbosa , Carvalho J. R. P. 
Published: July 2010

AbstractSoils of the Cerrado region of Brazil are deficient in available P in their native state and require fertilizer P for optimum crop yield. But information on optimum rates of P application is lacking for upland rice production. Therefore, a 2‐year study was conducted to evaluate the response of rice (Oryza sativa L. cv. IAC 47) to different levels of P in a dark red latosol. The P treatments were 0,22,44, and 66 kg P/ha (0, 50, 100, and 150 kg P2O5/ha). Grain yield, dry matter production, tillers, leaf area index (LAI), and nutrient (N, P, K) accumulation in aerial plant parts were determined at different stages of growth.In the 1st year (1977–1978), grain yield increased significantly up to 66 kg P/ha application; in the 2nd year (1978–1979), significant differences in yield were only obtained by application of 44 kg P/ha. Under the existing soil fertility levels upland rice needed 44 to 66 kg P/ha for its optimum P nutrition. With application of these levels of P, yield between 4,451 and 4,811 kg/ha was obtained. Dry matter production, LAI, and number of tillers per unit area were increased with the use of higher levels of P. The maximum number of tillers/m2 was reached between 60 to 70 days of growth and then started to decline. The uptake of N, P, and K increased with higher levels of P and age of the plant.
Cultivar Differences in N Redistribution in Soybeans1
Authors: Zeiher Carolyn , Egli D. B. , Leggett J. E. , Reicosky D. A. 
Published: July 2010

AbstractThe redistribution of N from vegetative plant parts to the developing seed in soybeans [Glycine max (L.) Merrill] may influence the duration of seed filling and yield. The objective of this study was to investigate the N redistribution characteristics of soybean cultivars of varying maturities and growth habit. Eight cultivars ranging from Maturity Group II to V and including indeterminate, determinate, and semi‐dwarf growth habits were grown in the field in 1977 and 1978 at Lexington, Ky. using conventional cultural practices. The soil type was a Lanton silt loam (Cumulic Haplaquolls) in 1977 and an Eagam silt loam (Cumulic Hapludolls) in 1978. Nitrogen redistribution was estimated by harvesting plants at beginning seed growth (R5) and at maturity. The abscised leaf blades and petioles were also collected and the dry weight and total N was measured in all plant parts. The vegetative dry weight at RS increased in cultivars of later maturity. There were no consistent culvar differences in N concentration at R5. The proportion of seed N that came from redistribution varied from 30 to essentially 100% and there were significant cultivar differences. The cultivar differences were positively correlated with the amount of N in the plant at R5 which was determined primarily by the vegetative dry weight at R5. Late maturing cultivars got more of their seed N from redistribution than early maturing cultivars. Although there were significant cultivar differences in yield and the duration of seed fill, they were not related to the amount of seed N that came from redistribution. Nitrogen redistribution does not appear to be an important factor determining the duration of seed filling or yield in soybeans.