bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Use by Wheat and Plant Indicators of Available Soil Water1
Authors: Meyer Wayne S. , Green George C. 
Published: July 2010

AbstractThis study was carried out during 1978 on the Highveld plateau of the Republic of South Africa to provide a more fundamental understanding of the water relations of wheat for irrigation management. The aim was to determine the amount of soil water extracted by wheat (Triticum aestivum L.) and to examine the response of leaf growth and predawn leaf water potential to a decline in soil water content. Evapotranspiration was measured with four weighing lysimeters which contained repacked profiles of the two soil types (Rhodic Paleustalf and Typic Ustropept) of the surrounding area. Three watering treatments were applied. One lysimeter was kept well‐watered by replenishing the deficit when 50% of the plant available water was depleted. The second treatment maintained the profile in a well‐watered state initially; thereafter no further water was applied while the plants dried the soil profile. The third treatment allowed the profile to be dried; a single irrigation was given and again the profile was dried.Plants with well‐developed root systems extracted 80% of the plant available water at or near potential evapotranspiration rates. Plants with less well‐developed root systems extracted only 70% before a decline in the rate of water use was apparent.Measurement of leaf and stem length during the drying cycle indicated that only 52 to 57%, of the plant available water was extracted before the plant growth rate in the drying treatment declined below that of plants which were well‐watered.A rapid decrease in predawn or covered plant leaf water potential was evident around the time that the rate of water use began to decline. This indicated that the decline was primarily the result of a large resistance to water movement through the soil rather than a plant induced control.
Double Cropping Corn on the Coastal Plain of the Southeastern United States1
Authors: Widstrom N. W. , Young J. R. 
Published: July 2010

AbstractThe adoption of double‐cropping systems involving corn, Zea mays L., following corn in the same year would greatly improve the efficiency of land utilization in areas where the practice is possible. A study was conducted to determine if such a system would be useful in the southeastern U. S. where many locations have more than 240 frost‐free days during the growing season. Growing two crops during the same season would also help alleviate the feed‐grain deficit of states in the southeastern area. Our objectives were to determine which maturity Combinations could be expected to perform best and produce the greatest return when grown for grain or forage. We also wanted to determine whether there was an advantage in using hybrids with tropical germplasm for the summer crop. Two locally recommended hybrids and two hybrids containing exotic germplasm, each pair having one early‐maturing and one late‐maturing hybrid, were evaluated on the coastal plain of Georgia at Tifton in 1976 and 1977. The spring planting, consisting of the two recommended hybrids only, was harvested as grain; the summer planting, having all four hybrids, was harvested for grain and forage. The spring planting was effectively a 24‐replicate test to provide space for the six‐replicate summer planting which included all hybrid combinations. The experiments were planted as a split‐plot design, with the two hybrid adaptation types (exotic and recommended) providing the split, and maturity (late and early) combinations being randomized within each adaptation split. Early frost in 1976, hot weather in 1977, and an unusually heavy insect population during both years resulted in low grain yields for the summer planting each year. Overall performance levels were slightly better in 1976 than in 1977, but relative performance of the various hybrid and maturity combinations of the double‐cropping system was similar for both years.Double cropping of corn might be a viable option on the coastal plain of the southeastern U. S. if the second crop were taken as forage rather than as grain. Grain yields of the summer crop were all less than 40 q/ha, and the early hybrids could not compete with late hybrids in forage production. Among maturity combinations, a recommended early hybrid, grown for grain as the spring crop, followed by late‐maturing hybrids, produced the highest ($957 to $1308/ha) average economic return. We suggest that some benefit may be obtained from using a hybrid with exotic (tropical or subtropical origin) germplasm for the summer crop and future testing of corn double‐cropping systems should include hybrids of this type.
Harvest Schedule, Persistence, Yield, and Quality Interactions Among Four Perennial Grasses1
Authors: Marten G. C. , Hovin A. W. 
Published: July 2010

AbstractComprehensive analysis of the interactions between harvest schedule and persistence, hay yield, and forage quality is lacking for cool‐season perennial grasses. Our objective was to determine whether harvest schedules typical of those producing a range from poor to excellent hay quality (two, three, or four times of cutting/year) under weed‐free conditions would differentially influence these properties for orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.), and smooth bromegrass (Bromus inermis Leyss.).Three harvest schedules were used during the first 3 production years of this field experiment on Typic Hapludoll soil. In the 4th and 5th years, all plots were harvested three times to determine whether any adverse responses by the grasses to either more or less frequent harvest could be overcome.Smooth bromegrass persisted poorest at the four‐cutting schedule, tall fescue and orchardgrass persisted poorest at the two‐cutting schedule, and reed canarygrass persisted best at all cutting schedules. Smooth bromegrass cut four times recovered substantially after the switch to three‐time harvest.In vitro digestibility and crude protein concentration of reed canarygrass declined most rapidly, while those of orchardgrass or tall fescue declined least rapidly, due to maturation. The grasses did not differ greatly in rate of cell wall concentration increase. We obtained new evidence that crude protein concentration cannot be relied upon for assessment of generalized forage quality.Reed canarygrass consistently yielded more dry matter than did smooth bromegrass, but otherwise frequent year‐to‐year yield variations existed among species and cutting schedules.Our results show the necessity for imposition of several controlled harvest schedules over prolonged periods for accurate measurement of the potential of grasses intended for flexible forage management systems.
Floret Sterility in Rice in a Cool Environment1
Authors: Board J. E. , Peterson M. L. , Ng E. 
Published: July 2010

AbstractFloret sterility induced by low temperatures of 15 C or below at meiosis (10 to 15 days before heading) is a major factor in reducing yields of Oryza sativa, var. japonica, L. in California. The objective of this study was to reduce Sterility by manipulating genotypic environmental interactions. Field experiments employing differences in plant height, maturity, and water level were conducted at the Davis Rice Research Facility. Microclimatic studies were also conducted to determine temperature profiles within the canopy. Sterility was compared among nine cultivars with similar genetic origin but differing in plant height and maturity. Those that were short‐statured and/ or early‐maturing exhibited significantly less sterility than tall and late cultivars. All cultivars in a water depth study showed less sterility in deep water (15 to 25 cm) than in shallow water (5 to 15 cm). Mean differences were significant at the 0.05 level. The beneficial effect of earliness in reducing sterility was caused by the weather patterns of the rice‐growing region in the Sacramento Valley. The probability of receiving temperatures below 15 C at meiosis was considerably reduced as maturity was shortened. Increased water depth and decreased plant height reduced sterility by placing the panicle in closer proximity to water. Field water temperature at the coldest part of the night was usually 5 to 6 C warmer than air temperature. The microclimatic study demonstrated that absence of substantial nocturnal wind caused a temperature inversion at night between the mid‐canopy level (50 cm above soil surface) and the top of the canopy. Temperature also increased from mid‐canopy to water level because of the warming effect of the water. Thus mid‐canopy is the coldest part of the vertical profile in a rice field.
Manure and Mineral Fertilizer Effects in Continuous and Rotational Crop Sequences in Central New York1
Authors: Baldock Jon O. , Musgrave Robert B. 
Published: July 2010

AbstractEstimates of the effects of mineral fertilizer, manure, and legumes on crop yields and soil fertility in various technologies and environments are important for maintaining efficient crop production and reducing energy use in agriculture. Estimates of these effects were made in a long‐term study (1955 to 1968) at Aurora, N.Y. on soils of the Honeoye‐Lima and Kendaia series (Glossoboric Hapludalf and Aeric Haplaquept; fine loamy, mixed mesics; respectively). The crop sequences included continuous corn (Zea mays L.), wheat (Triticum aestivum L.), and grass and legume forage species, as well as several five‐phase rotations. The management treatments were manure (13.5 metric tons wet weight/ha/year averaged over the crop sequence), no manure, and different rates of N‐P‐K. The phases of each crop sequence were assigned to whole plots (0.0254 ha) in a randomized, complete‐block design (with six blocks or replicates), and the management treatments were assigned to the four sub‐plots.Two years of alfalfa (Medicago sativa L.) apparently contributed 135 kg N/ha to subsequent crops. Manure apparently supplied 5‐1‐4 kg N‐P‐K per metric ton (wet weight). The amounts of N available from manure, alfalfa, and mineral fertilizer were additive, at least on corn. A common N response curve over all cropping systems fit the corn data well, which suggests that manure and crop rotation only affected corn yields through their plant nutrient contributions. Soil organic matter and pH were maintained and extractable soil P and K were increased over the 14 years of the study in both continuous and rotational cropping systems (with or without manure). The results suggest that on these soils, the plant nutrient requirements of field crops can be completely supplied by legumes and manure, by mineral fertilizer, or by some combination of them without leading to decreases in soil fertility.
Germination of Cool Season Annual Clovers1
Authors: Evers G. W. 
Published: July 2010

AbstractInformation on the effect of temperature on germination of the major cool season annual clover species adapted to the southeastern United States is limited. Such data would be useful in determining optimum planting dates and reveal differences between species. Seed of arrowleaf (Trifolium vesiculosum Savi.), crimson (Trifolium incarnatum L.), subterranean (Trifolium subterraneum L.), and Persian (Trifolium resupinatum L.) cultivars was placed on indented blotter pads in 90 ✕ 50 cm petri dishes. Petri dishes were placed in a low temperature incubator and subjected to day/night temperatures of 15/5, 20/10, 25/15, 30/20 and 35/25 C with 12‐hour light periods which simulate natural temperatures during clover establishment in the southern states bordering the Gulf of Mexico. Numbers of normal and abnormal seedlings were recorded every 2 days from the 3rd to the 13th day.Crimson and Persian clover had the fastest germination rate followed by subterranean and arrowleaf. Persian clover was the least responsive to temperature with only 11% difference in germination between treatments by day 13. Crimson clover reached maximum germination across all temperatures most rapidly with only 1 to 4% difference between day 9 and 13, but the number of abnormal seedlings was three to four times greater than the other clover species. Good germination of Persian and crimson clovers occurred at the highest temperature of 35/25 C. This could result in poor natural reseeding if hard seed content and dormancy decrease too quickly after seed maturation to prevent summer seed germination.Arrowleaf clover was affected most severely by the temperature treatments with maximum germination reaching only 17 and 9% under the 30/20 and 35/25 C treatments, respectively. Therefore, good arrowleaf seed germination occurs later in the fall than the other species which means less fall forage production and increases the risk of seedling damage by an early frost. Subterranean clover germination was depressed only at the 35/25 C treatment with the best germination rate at 30/20 C.
Temperature Response of Seed Growth Characteristics of Soybeans1
Authors: Egli D. B. , Wardlaw I. F. 
Published: July 2010

AbstractThe growth rate and duration of an individual seed are important parameters in the yield production process of a grain crop. Experiments were conducted in the CSIRO phytotron at Canberra, Australia to investigate the effect of temperature on the rate and duration of seed growth and associated plant characteristics in soybeans [Glycine max (L.) Merr.]. Soybeans (‘Fiskeby V’) were grown at 24/19 C until beginning seed growth and shifted to 18/13, 24/19, 27/22, 30/25, and 33/28 C (day/night temperature, 8‐hour day) until maturity. Seed growth rates (SGR) were estimated by harvesting seeds at 5‐day intervals, and from the growth rate of excised cotyledons cultured in nutrient media for 96 hours. The SGR of seed developing on the plant increased from 6.1 to 7.9 mg seed−1 day−1 as air temperatures increased from 18/13 to 27/22 C, but there was no further change as the temperature increased to 33/28 C. Excised cotyledons showed a similar growth rate response to temperature. Exposing the plants to high temperatures (33/28 C) during the period of flowering and pod set reduced SGR (36%) regardless of the temperature during the subsequent seed growth period, suggesting that seed growth is sensitive to temperature levels at these early stages. Seed respiration on a dry weight basis (mgCO2h−1 g−1) was not affected by temperature. The duration of seed growth was not affected by temperatures of 24/19 to 30/25 C but was reduced by 3 days at 33/28 C, and this was associated with accelerated leaf senescence as shown by leaf yellowing and reductions in CO2 exchange rate. Final seed size was reduced from 200 to 151 mg seed−1 at 18/13 and 33/28 C. The data suggest that SGR and duration are relatively insensitive to temperatures ranging from 24/19 to 30/25 when these are imposed after flowering and pod development. The reduction in the duration of seed growth at high temperatures may be one mechanism by which high temperatures reduce yield.
Influence of Potassium on Helminthosporium Cynodontis and Dry Matter Yields of ‘Coastal’ Bermudagrass1
Authors: Matocha J. E. , Smith Leon 
Published: July 2010

AbstractA study was conducted to investigate K nutrition in relation to occurrence of a leaf spot disease identified as Helminthosporium cynodontis Marig. on ‘Coastal ’ bermudagrass (Cynodon dactylon L. Pers.) grown on sandy soils of east Texas. Previously studied research plots of Coastal bermudagrass production via clipping removal were used. These were located on Darco (Grossaronic Paleudult; loamy, siliceous, thermic) and Cuthbert (Typic Hapludult; clayey, mixed, thermic) soils, typical of those used in forage production in east Texas. The influence of applied K at 112 and 224 kg K/ha with varying P on incidence of the disease, tissue K levels and exchangeable soil K was measured. Disease severity was curvilinearly related to tissue K levels. Midseason tissue K levels of 0.60% or less were associated with progressively increasing disease severity and decreasing dry matter yield. The first increment of 112 kg K/ha decreased disease severity and increased dry matter yield substantially. Phosphorus supply without K appeared to slightly aggravate the disease, possibly due to nutrient imbalance. Longevity of intensified forage production without K fertilization before development of the disease anomaly was soil dependent and varied from two production seasons for the Cuthbert soil to six seasons on the Darco soil. Differences in soil K reserves and soil depth were apparently responsible for the timing of the K related problem.
Post‐Harvest Sucrose Losses in Sugarbeet Roots Treated with Soil‐Injected Ethylene1
Authors: Akeson W. R. , Freytag A. H. , Stout E. L. 
Published: July 2010

AbstractSucrose worth millions of dollars is lost annually in the United States during storage of sugarbeet (Beta vulgaris L.) roots from harvest until they are processed. Our objective was to evaluate the effect of treatment of roots with ethylene during the growing season on sucrose loss and change in quality components during storage. Ethylene was injected 20 cm into the soil between rows at the 11‐leaf‐stage of development. Changes in weight, sucrose content, and purity of harvested roots during storage were measured for determination of gross sucrose and recoverable sucrose losses.Treatment at a rate of 0.25 liter ethylene/m of travel reduced losses of weight, gross sucrose, and recoverable sucrose 31.2, 22.4, and 20.7%, respectively, during storage in 12 tests conducted in 1973, 1974, and 1975. The 0.50 liter/m ethylene treatment gave reductions in losses of weight, gross sucrose, and recoverable sucrose intermediate between those of the 0.25 liter/m and control treatments.The 0.25 liter/m ethylene treatments reduced post‐harvest respiration and invert sugar accumulation which are primarily responsible for sucrose losses. The 0.50 liter/m ethylene treatment reduced respiration. Both treatments reduced the post‐harvest ethylene evolution of the roots.Use of ethylene to reduce storage losses is limited by the lack of economic increase in sucrose yield per hectare at harvest.
Root Temperature and Percentage NO3−/NH4+ Effect on Tomato Development II. Nutrients Composition of Tomato Plants1
Authors: Ganmore‐Neumann Ruth , Kafkafi U. 
Published: July 2010

AbstractThe possibility of supplying nutrients daily to tomato plants (Lycopersicum esculentum Mill.) grown in various seasons raised the question of the best percentage NO3‐/ NH4+ to be supplied to these plants. The effect of four (8, 16, 24, and 34 C) temperatures and four percentage NO3‐/NH4+ (100/0, 75/25, 50/50, and 0/100) on the nutrient composition of tomato plants were studied. To obtain constant pH, percentage NO3‐/NH4+ and temperature continuous flow technique was used. The solution was flushed through the pots at a rate of 1 liter/hour.Increasing root temperature increased total‐N, P, Mg, and K in the shoot irrespective of percentage NO3‐/ NH4+ in the solution. Calcium concentration increased in the shoot with increasing temperature only when the plants were fed with NO3‐ as the only source of N. The presence of NH4+> in the nutrient solution caused a decrease in Ca concentration in tomato plants grown in temperatures 16 C and above. Increase in the root temperature increased total‐N and Ca, slightly increased P, and decreased Mg and K. Increasing root temperature increased N‐N03‐ concentration in the shoot, while decreasing it in thc roots. Low root temperature caused accumulation of N‐NO3‐ and K in the roots. It is suggested that the hindering of translocation of these ions at low temperature is one of the factors that slows down growth of tomato plants fed with nutrient solution containing a high ratio of NO3‐.
Close‐Grown Tobacco: Agronomic Characteristics, Total Alkaloid, and Sugar Content1
Authors: Campbell C. R. , Chaplin J. F. , Johnson W. H. , Miner G. S. 
Published: July 2010

AbstractThe development of synthetic smoking materials has prompted researchers to consider non‐conventional production methods as a means of producing a low cost, flue‐cured tobacco (Nicotiana tabacum L.) material which might be used in the manufacture of cigarettes. In order to evaluate yield potential, chemical content, and physical characteristics of close‐grown tobacco, plants were grown in the field at populations of 45,448, 90,896, and 136,344/ha with different planting designs (twin or equidistant), nitrogen levels (84, 168, 252, and 336 kg/ha), and topping regimes (topping or no topping). The soil was a Durham loamy sand (fine loamy, siliceous, thermic, Typic Hapudult). The entire plant was flue‐cured and separated into lamina, midrib, and stalk for yield and chemical analysis. A wide range of yield, chemical content, and physical characteristics of the harvested material was produced by manipulating various cultural practices. Topped plants averaged 26% lamina, 12% midrib, and 62% stalk as compared to 19% lamina, 10% midrib, 54% stalk, and 17% top material for plants not topped. Yields increased progressively with N‐rate through 252 kg/ha and/or increased plant population. Twin or equidistant row spacing had no effect on yield. Topping decreased whole‐plant yield but increased the concentration of alkaloids and reducing sugars and the lamina: stalk ratio. Total alkaloids ranged from 0.18% for wholeplant nontopped tobacco receiving 84 kg N/ha to 0.84% for topped plants receiving 336 kg N/ha. Total reducing sugars averaged 8.0 for nontopped and 9.6% for topped plants.Results indicate that high yields can be obtained by utilizing the close‐grown production system and harvesting the entire plant. Desirable chemical content and physical characteristics of close‐grown tobacco might be obtained by manipulating cultural practices.
Growth of Trickle‐Irrigated Tomato as Related to Rooting Volume and Uptake of N and Water1
Authors: Bar‐Yosef B. , Stammers Claire , Sagiv B. 
Published: July 2010

AbstractInformation about responses of plants in general, and of tomato (Lycopersicum esculentum Mill.) in particular, to various trickle‐irrigated soil volumes is meager. This information is essential in planning water rates and geometries and in scheduling drip irrigation systems.Our objective was to study root development and distribution in a sandy soil in the field under three trickle irrigation regimes; yields, dry matter production, water and N content in the root zone and N uptake by the tomato were all evaluated in relation to root development.Irrigation frequency increases from one to three irrigations per day produced a significant increase in dry matter yield, but decreased fresh fruit yield. A seasonal application of 620 mm compared to 320 mm, both applied as one irrigation per day, did not increase dry fruit yield, but increased fresh fruit yield by a factor of 1.46.The main factor that contributed to the different response of the plants to the irrigation treatments, was the root weight and distribution in the soil during the growth period. In the once‐a‐day irrigation treatments, the root weight declined at the time of fruit filling, which caused a delay in production, while when irrigating three times a day, that decrease was not observed, and fruit dry matter production occurred at a higher rate. This response produced a greater final dry matter yield. In all the treatments the rapid fruit filling period was followed by a 55‐day period of slow dry matter production, which, in turn, was followed by an enhanced production rate.