bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Five Methods for Characterizing Soybean Rooting Density and Development1
Authors: Böhm W. , Maduakor H. , Taylor H. M. 
Published: July 2010

AbstractMany methods are used to study plant root system development and function. Most methods are tedious and time‐consuming. Some require expensive, sophisticated equipment and frequently require highly trained operators. Few studies are published where several methods are compared for their time requirements, equipment needs, soil applicability, and validity of the results. This study determined usefulness of five methods for characterizing soybean (Glycine max (L.) Merr.) rooting depth and density in a loess [fine, silty, mixed (calcareous) mesic family of Typic Udorthents] soil. The methods were: (a) soil water‐depletion, (b) framed‐monolith and pinboard, (c) core‐sampling, (d) mini‐rhizotron, and (e) trench‐profile. Each method was used or attempted on several dates during the 1975 growing season. The soil water‐depletion method was fast, required only simple equipment, and provided satisfactory estimates of rooting depth but did not provide reliable estimates of rooting density. The framed‐monolith method was very time‐consuming, but provided quantitative estimates of rooting density with depth and could have provided rooting density estimates with distance from the row. The core‐sampling method was faster than the framed‐monolith method. Cores could be obtained either with a hand‐turned bucket auger or with a coring machine, but several profiles were required to obtain rooting density distributions with depth and distance from the row. The mini‐rhizotron method was fast, but did not provide accurate results, presumably because the mini‐rhizotrons were installed too late. The trench‐profile method provided semiquantitative estimates of rooting density with depth and distance from the row. The trench‐profile method was rapid and required no time‐consuming separation of live roots from debris of previous years. The hand‐augered core, soil water‐depletion, and the trench‐profile methods could be used through the entire growing season, but the framed‐monolith and the mechanized‐core methods were not satisfactory during a drought period because the soil column collapsed during sampling.
Sterility in Rice Cultivars as Influenced by MSMA Rate and Water Management1
Authors: Wells B. R. , Gilmour J. T. 
Published: July 2010

AbstractIn recent years an expansion of rice (Oryza sativa L.) acreage in Arkansas has resulted in rice being produced on soils with a history of cotton production. Most of these cotton soils have had repeated applications of monosodium methanearsonate (MSMA) as a herbicide. There is some evidence that arsenical residues in the soil can lead to sterility in rice. In an effort to answer this question, we conducted a field experiment on a Crowley silt loam soil (Typic Albaqualf) in 1975 to evaluate the influence of MSMA on plant growth and yield of rice. Treatments included two water management regimes (continuous flood vs. one drain and dry), three levels of MSMA [0, 1.1, and 11.2 kg/ha of arsenic (As)] and 15 rice cultivars and experimental strains differing in susceptibility to straighthead disease (abnormally developed or sterile flowers resulting in reduced grain yields).Soil samples taken 65 days after arsenic application showed that As remained in the rice root zone. Vegetative growth prior to panicle initiation was not affected by any of the treatments; however, visual observations made near maturity showed that where MSMA had induced sterility, the plants were dark green suggestive of straighthead. Reproductive growth as shown by panicle weights and sterility ratings was affected most by high MSMA rates and continuous flooding. Under continuous flood, panicle weights were reduced and sterility ratings increased as MSMA rate increased. This effect was more pronounced in cultivars most susceptible to straighthead and was minimized by draining the flood and drying the soil. This data suggests that the MSMA residues induced straighthead. A significant and similar relationship was found between panicle weights and sterility ratings at maturity for both water management regimes.
Effect of K on N Utilization by Spring Wheat During Grain Protein Formation1
Authors: Koch K. , Mengel K. 
Published: July 2010

AbstractSeveral researchers reported that high nitrogen rates for cereals require also an ample potassium supply in order to produce maximum grain yields. The physiological relationships between N and K in grain production are not yet completely understood. For this reason experiments have been carried out to study the effect of K on the translocation of N in wheat plants and its incorporation into the grains during the grain filling period. Spring wheat (Triticum aestivum L. cv. ‘Kolibri’) was gown in solution culture at two K levels throughout the growing period and at three N levels during the reproductive stage. Nitrogen was labeled 15N with the beginning of anthesis.Plants at the higher K rate produced more vegetative dry matter, higher grain yields, fewer unproductive tillers and improved translocation of N from the vegetative plant parts into the grain. Between 87.4 and 89.0% of the N absorbed during the reproductive stage was present in the grain of plants which had received the higher K supply. In plants grown with the lower K level the percentage ranged from 78.9 to 81.0%. This improved translocation of nitrogenous compounds from the various plant parts to the grain caused by K resulted mainly in higher contents of prolamin, glutelin, and soluble amino acids in the grain. For the content of albumin and globulin the reverse was true. All four grain protein fractions showed the same degree of N labeling indicating that none of the four protein fractions was preferably supplied by the N absorbed during the reproductive stage. The label of the soluble amino acids in the grain was lower than that of the grain proteins. It is assumed that at the last stage of grain filling a relatively high amount of N from senescing plant parts is exploited for grain filling, thus diluting the N taken up from the nutrient solution.The higher N levels applied during the reproductive stage had a negative rather than a positive effect on grain yield. The additional N increased mainly the content of soluble amino acids, prolamin, and glutelin in the grain.
Response of Soybeans to Overseeding Followed by Plant Thinning at Various Growth Stages1
Authors: Boerma H. R. 
Published: July 2010

AbstractAccurate field plot technique is an important factor in soybean [Glycine max (L.) Merr.] experimentation. The practice of overseeding followed by plant thinning has become a common practice for many experiments involving the estimation of physiological parameters, and for some experiments designed to measure seed yield. In most cases the results of these experiments are extended to the general field situation. The purpose of the present study was to determine the growth stage at which thinning of overseeded plots must be accomplished to provide similar results to direct seeding at the desired population rate.Three soybean cultivars, in maturity groups VI, VII, and VIII, were overseeded at 53 viable seeds/m in rows spaced 0.96 m apart and different plots were thinned to 23 plants/m for 8 consecutive weeks following emergence. The experiment also included a control which was seeded at 26 viable seeds/m and obtained a plant population of 23 plants/m. The results indicated that the week of thinning had a significant effect on seed yield, nodes/ plant, and branches/plant. Seed yield and nodes/plant decreased at thinnings after the V4 growth stage (2 weeks after emergence) and branches/plant at thinnings at the V5 growth stage (3 weeks after emergence). The cultivar × thinning week interaction across years was nonsignificant for all characteristics. There was a significant year × week of thinning interaction for plant height at maturity and lodging. To obtain the same seed yield and general plant characteristics expected from seeding at the desired population rate, overseeded plots should be thinned prior to the V5 growth stage.
Relationship between Fibrous Components and In vitro Dry Matter Digestibility of Autumn‐saved Grasses1
Authors: Archer K. A. , Decker A. M. 
Published: July 2010

AbstractChemical techniques for the determination of cell wall constituents and cell contents have been developed which provide relatively quick, convenient methods for predicting the digestibility of forage samples. These purely chemical laboratory methods may not be as reliable as in vivo or in vitro techniques for forage quality evaluations but they do not require the maintenance of digestion stalls or fistulated animals. There is a need for a better understanding of the relationships between chemical determinations and the actual feed value of forage samples. The specific objective of this paper was to investigate the relationship between in vitro dry matter digestibility and chemical analyses of cell walls and cell contents for evaluating the digestibility of autumn‐saved forage grass samples.Forage samples of ‘KY‐31’ tall fescue (Festuca arundinacea Schreb.) and ‘Potomac’ orchardgrass (Dactylis glomerata L.), collected from two field experiments were used for these quality evaluations. These field experiments were designed to measure the influence of nitrogen fertilization and soil temperature on cell wall constituents and in vitro dry matter digestibility of previously unharvested fall accumulated growth sampled at early, medium and late fall dates. Samples were analyzed for neutral detergent fiber, acid detergent fiber, cellulose, hemicelouse, lignin and silica. In vitro digestable dry (IVDMD) matter was also determined for each forage sample.Fiber, lignin, and silica contents of autumn‐saved forage samples were all highly correlated with IVDMD, and equations were developed to predict IVDMD from these chemical constituents. The following summative equation is proposed for the calculation of IVDMD: IVDMD = 0.98 (100 − NDF) + NDF (91.1 − 1.43 (LIG + SIL) / ADF)
Response of Two Cotton Genotypes to Five Equidistant Spacing Patterns1
Authors: Fowler J. L. , Ray L. L. 
Published: July 2010

AbstractHigh population densities have been proposed as one way of achieving earlier maturity in cotton (Gossypium hirsutum L.) by increasing the potential number of early fruiting points. But competition among closely spaced plants may adversely affect initiation and set of fruit. Theoretically, competition can be reduced by improving the uniformity of plant distribution. A year field study was conducted to determine the morphological and agronomic reactions of cotton to intraspecific competition over a wide range of plant populations within equidistant spacing configurations. Response to equidistant plant spacing was studied using two genotypes of upland cotton (Gossypium hirsutum L.) with contrasting plant types and five population densities ranging from 38,750 to 620,000 plants/ha in patterns where distance between plants within the row equaled the distance between rows. Vegetative and fruiting components were measured and dry weight determinations were made after destructive fractionation at three harvest dates. Yield, earliness, and fiber quality data were accumulated from weekly harvests of mature bolls. As plant population increased, dry weight per unit land area of all plant components increased except vegetative branches, which decreased. Leaf area index and the number of nodes to the first fruiting branch also increased with higher populations. A smaller, more compact plant developed as plant density increased, which was indicated by reductions in plant height, stem diameter, and number of branches. Boll size, number of seed/boll, seed index, and lint index were all reduced as plant spacing decreased. Retention rate of fruiting forms was apparently much lower in the very high plant densities. Population levels of 79,000 and 155,000 plants/ha were earlier maturing and produced higher lint yield than population levels on either side of this range. These results generally agree with those of investigations of cotton spaced in 1‐m rows. There was no evidence that high population densities in equidistant spacing patterns improve earliness or yield.
Sugar Cane Growth in Response to Mulch and Fertilizer on Saline‐Alkali Subsoils1
Authors: Eavis B. W. , St. J. Cumberbatch E. R. 
Published: July 2010

AbstractIn many parts of the world where salinity or alkalinity limit crop yields, leaching is impracticable. In Barbados saline‐alkali subsoils remained unproductive 6 years after they were exposed during earth‐moving operations. The objective of this study was to devise agronomic techniques to restore these lands to sugar cane (Saccharum officinarum L.) production. The effects of mulching and N‐K fertilization were studied. Factorial field experiments in which bare plots and plots mulched with cut grass were treated with fertilizer at three rates (70:82, 208:247, 416: 495 kg NK/ha) were carried out at two locations (sandy clay and clay soil respectively). Sugar cane tillers and soil moisture contents were measured weekly, and root development fortnightly. After 9 months of growth bare plots failed to produce any marketable yield in contrast to mulched plots which gave up to 53 metric tons/ha (sandy clay) and 118 tons/ha (clay). There were no responses to fertilizer rate on bare land, but on mulched land 1.2 times (sandy clay) and 2.2 times (clay) more yield resulted from the high compared with the low fertilizer rate. Regression analysis indicated the importance of root development and nutrient uptake to tiller elongation rates in rainy periods. In drier intervening periods of slower shoot growth, soil moisture status was most important, mulched land having a volumetric moisture content 4% higher than bare land. Mulching reduced run‐off and increased rainfall preservation. The experiments show that growth and response to fertilizer on saline‐alkali soils depends on the soil physical environment. Mulching combined with adequate fertilizer application is a satisfactory reclamation procedure for saline‐alkali soils in the semi‐arid tropics.
Ammonium Effects on Nutrient Cation Absorption by Wheat1
Authors: Cox W. J. , Reisenauer H. M. 
Published: July 2010

AbstractAdditions of small amounts of NH1 to adequate‐NO3 culture have been shown to increase crop yield and total N content, and to decrease the plant's content of metal cations. The magnitudes of these effects can be appreciable. Accordingly, experiments were done to elucidate their mechanisms, and to evaluate their roles in crop production. Wheat (Triticum aestivum L. ‘INIA’) was grown in the greenhouse in dilute constant‐composition cultures that supplied, in factorial combination, three levels of NH4 with four levels of either K, Ca, Mg, Mn, or Zn. Intake of mineral cations increased with the concentration of the ion in solution and was decreased by added NH4. Ammonium had a greater effect on the intake of the divalent than of the monovalent cations. Among the divalent cations the magnitude of the NH4 effect varied in the order: Zn > Mn ≥ Mg > Ca. The reduced influx of multivalent cations from added NH4 is postulated to result from the NH4 induced reduction of the level of slowly diffusible organic anions within the root. This results in a smaller chelate sink, increased internal cation activity, and reduced net influx.
Hard Red and Durum Spring Wheat Responses to Seeding Date and NP‐Fertilization on Fallow1,2
Authors: Black A. L. , Siddoway F. H. 
Published: July 2010

AbstractWith recent development of high‐yielding semidwarf hard red (Triticum aestivum L.) and medium‐height durum (T. turgidum L.) spring wheats, information voids have been created in the management guidelines needed to obtain optimum production. Our objective was to determine if the two wheat types, planted at the same rate and seeding depth, would respond similarly to NP‐fertilization and to early, medium, and late seeding dates. The soil at both field sites was a Williams sandy loam (fine‐loamy, mixed, Typic Argiborolls). Although grain yields were nearly two times greater with 25.1‐cm rainfall at Culbertson than with 17.2 cm of rainfall at Outlook, the two speciesof wheat responded similarly to seeding dates and fertilization. Applying N and P, each at 45 kg/ha, significantly increased grain yields 30 to 60% at both sites. With adequate P‐fertilizer, ammonium nitrate and urea increased grain yields of both varieties similarly on all three seeding dates.Based on the results of this study, both types of wheat responded positively to early seeding and NP‐fertilization, so there would be no need to prepare separate production and fertilizer management guidelines for each wheat species. Grain yield increases from NP‐fertilization were greater for both types of wheat for the early and medium seeding than for the late seeding date.
Influence of Soybean Seed Size and Position on the Rate and Duration of Filling1
Authors: Egli D. B. , Leggett J. E. , Wood J. M. 
Published: July 2010

AbstractInformation on factors influencing the rate and duration of seed growth is needed to understand completely yield production. This study was undertaken to determine the relationship of seed size and the timing of pod development to the rate and duration of seed growth in soybeans (Glycine max (L.) Merrill). Field studies were conducted for 2 years (1974‐75) on a Maury silt loam soil (Typic Paleudults) utilizing five cultivars of varying seed size: ‘Kanrich’, 234 mg/seed; ‘Williams’, 171 mg/seed; ‘Cutler 71’, 165 mg/seed; ‘Custer’, 129 mg/seed; and ‘Essex’, 114 mg/seed. Each year the rate of dry matter accumulation in the seed was measured on the first and the last pods to develop on each cultivar. Kanrich had the highest seed growth rate (7.96 mg seed−1 day−1); Essex the lowest rate (3.64 mg seed”1 day1), and the other cultivars had rates intermediate between Kanrich and Essex. Seed growth rates were relatively constant across the early and late pods. The duration of the effective filling period (EFP) was less for the late pods on the indeterminate cultivars (Kanrich, Williams, Cutler 71, and Custer), and this resulted in slightly smaller seed. There was no difference in the length of the EFP among the five cultivars used. Air temperatures during the filling period were lower in 1974 than in 1975, and the low temperatures were associated with low seed growth rates, a long EFP and large seed. These data suggest that the rate of seed growth is partially determined by the genetic makeup of the seed. The direct relationship between seed growth rates and seed size provides an explanation of the negative correlations frequently observed between seed size and the number of seed produced by the plant.
Relationship of Soybean Germination and Vigor Tests to Field Performance1
Authors: Johnson Richard R. , Wax Loyd M. 
Published: July 2010

AbstractA number of soybean (Glycine max (L.) Merr.) seed vigor tests are available through seed testing laboratories for use by seed producers and farmers. In order to determine if these tests provide more information on field performance than the standard warm germination test, seed lots differing in quality were planted in different field environments at a constant seeding rate (350,000 seeds/ha) and evaluated for percent emergence, final stand at maturity, and grain yield. Several germination tests, including the warm germination test (also evaluated for percent strong seedlings and percent diseased seeds), cold test, accelerated aging test, and tetrazolium test were conducted by seed analysts and statistically correlated with field performance.Experiments were conducted on Cisne silt loam (Mollic Albaqualf) at Brownstown, Ill. and Proctor silty clay loam (Typic Argiudoll) at Urbana, Ill. When the same seed lots were planted at different planting dates and locations, field performance differed markedly depending on seedbed conditions. Stress seedbed conditions were difficult to predict in advance. For example, at one location poorer emergence was observed with a warm, dry seedbed than with a cold, moist seedbed. A greater number of laboratory tests correlated with field emergence in favorable seedbed environments than in unfavorable environments. The cold test showed a consistent high correlation with field emergence and final stand. In general, reduction in yield was associated with a loss in stand. The cold test was the most effective germination test for identifying seed lots that would perform well in the field and should provide more assistance than the standard warm germination test in identifying problem seed lots.
Chemical Soil Conditioner Effects on Sand Soils and Turfgrass Growth1
Authors: McGuire E. , Carrow R. N. , Troll J. 
Published: July 2010

AbstractIn recent years new chemical soil conditioners have been utilized for agricultural purposes. However, limited information is available on their potential for improving the moisture and/or nutrient retentions of sand soils subjected to compaction under turfgrass conditions. Two bitumenous emulsions, five polyacrylamides (PAM), and one polyvinyl alcohol (PVA) were evaluated in a greenhouse experiment and/or two field studies. The greenhouse soils were a washed concrete sand and a mesic Entic Fragiorthod, while the field studies were on a constructed golf green utilizing an urban laid, flood plain sand. Recommended rates were applied by injection (greenhouse study) or mixing prior to turf establishment (field studies). The influence of these chemical soil conditioner treatments on soil physical properties, cation‐exchange capacity (CEC), and growth of ‘Manhattan’ perennial ryegrass (Lolium perenne L.) or ‘Penncross’ creeping bent, grass (Agrostis palustris Huds.) was determined. In the field studies compaction was applied periodically with a power roller. Hydrophilic bitumenous emulsion did not retain a hydrophilic nature but became hydrophobic, which decreased moisture retention by 12.5 to 30.0% by volume at 0.10 bar tension. Turf quality was decreased. Hydrophobic bitumen emulsion treatment resulted in similar responses. With minor exceptions PAM materials did not significantly affect the soil physical, CEC, or turf growth parameters in these studies, irrespective of molecular weight or presence of a cross‐linker. The PVA material also did not influence these parameters. Under conditions of these studies, where sand soils were subjected to compaction, chemical soil conditioners used did not benefically affect soil physical properties, CEC, or turfgrass growth. In some instances the influence was detrimental to turfgrass quality and growth.