bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regrowth, Nodulation, and Nitrogenase Activity of Strophostyles helvola with Rigorous Defoliation1
Authors: Lynd J. Q. , Odell V. 
Published: July 2010

AbstractIndigenous legumes contribute toward increased N nutrition and enhanced grazing productivity of both native and improved pasture swards. However, quantitative assay of symbiotic dinitrogen fixation by pastured legumes is difficult. The objective of these studies was to determine defoliation effects on regrowth, nodulation, nitrogenase activity (C2H2 red.) and associated nodule enzymology of trailing field bean [Strophostyles helvola (L.) Ell.]. Plants were grown in a Psammentic Paleustalf (Eufaula) and inoculated with Rhizobium leguminosarum Frank, ATCC 10314. Characteristics of nondefoliated plants during 3 years of field experiments included near exponential growth with 10‐fold increase in dry weight from 1.49 to 17.45 g at 30 to 120 days after emergence (DAE). Number of stems tripled and stem length increased six‐fold. Average nodules per plant increased from 80.2 to 239.6. Nodule mass as fresh weight increased from 0.94 to 6.17 g, and mature nodules increased from 13% to 89%. Differences in regrowth after defoliation at 30‐day intervals was not significant averaging 4.21 g, CV 11 %. Nodules per plant after regrowth averaged 113 with fresh nodule wt. 2.06 g and 27 % were mature nodules. Nitrogenase (C2H2 red.) activity levels were highest at 90 DAE, 168.2 μmols. C2H4g−1h−1. Regrowing plants after defoliation averaged 156.3 μmol C2H4g−1h−1. Highest cytosol enzyme activity levels were for aspartic transaminase (AST) with 25.0 IU (nondefoliated) and 25.9 IU (defoliated) g−1 fresh nodule. Glutamine synthetase (GS) was 1.7 IU (nondefoliated) and 12.0 IU (defoliated). Multiple regression indicated significance for glutamate dehydrogenase (GDH) but not glutamine 2‐oxoglutarate aminotransferase (GOGAT) with interactions for the equation of best fit with P < 0.05 level as nitrogenase (C2H2 red.) = 13.3 nodule wt. + 0.5 nodule no. + 4.5 nodule maturity % + 58.6 GDH, R2 = 80.9 and CV 11%. More knowledge of indigenous pastured legumes, as S. helvola, could have practical significance for improvement of symbiotic N fixation and grazing production for the extensive pastured regions with severe soil and climate limitations.
Dry Matter and Leaf Area Relationships in Winter Barley1
Authors: Ramos J.M. , Garcia Del Moral L.F. , Recalde L. 
Published: July 2010

AbstractAn estimate of leaf area, which is required for most models of plant growth, is a time‐consuming and costly process, especially in large‐scale field experiments. The objective of this study was to obtain equations which could be used to determine quickly the leaf area of barley (Hordeum spp.) plants with the least margin of error. Six cultivars of winter barley were used, four, six‐rowed (Hordeum vulgare L.) and two, two‐rowed (Hordeum distichon L.) grown in Granada, Spain, (thermic, Calcixerollic Xerochrept soil) during 1979, 1980, and 1981. Leaf area was found to be strongly correlated with the leaf dry matter (r=0.957) during all of Feekes stages of growth. The aboveground dry matter was also found to be highly correlated with leaf area (r=0.969), but only until Feekes seventh stage (second node of stem formed, next‐to‐last leaf just visible). From this it is apparent that leaf dry matter in winter barley gives a good estimate of leaf area during all of its development, while the total dry matter can also be used until the seventh growth stage.
Forage Yield and Quality of Brassicasp. Established Using Preemergence Herbicides1
Authors: Griffin J. L. , Jung G. A. , Hartwig N. L. 
Published: July 2010

abstractBrassica sp. may serve as high energy forage crops at times when forage availability may be limited. Field studies were conducted in the Northeast to assess forage yield and quality of 'Sirius' turnips (Brassica rapa L.) and 'Perko' rape (B. napus L.) planted on a Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf) soil in late May (1978) and late April (1979). Preemergence herbicides including metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐ l‐methylethyl) acetamide], pendimethalin [Nl‐ethylpropyl)‐3,4 dimethyl‐2,6‐dinitrobenzeneamine], and nitrofen [2,4‐dichlorophenyl p‐nitrophenyl ether] were applied alone and in various combinations to determine effectiveness in reducing weed competition. Forage yields of turnips and rape 100 days after seeding were generally not affected by the herbicide treatments. However, associated weed yields in both turnips and rape were significantly reduced with all herbicide treatments applied. Pendimethalin applied at 2.2 kg ha−1was phytotoxic to both turnips and rape reducing yields 67 and 17%, respectively, as compared to the untreated control. Forage dry matter yields of turnips and rape with adequate weed control were as high as 5068 and 6711 kg ha−1, respectively. In 1978, turnip whole plant crude protein (CP) concentration was highest (227 g kg−1) where pendimethalin was applied at 2.2 kg ha−1. The 2nd year CP levels for turnip leaves were similar for all herbicide treatments, but root levels were highest where pendimethalin at 2.2 kg ha−1was used. The high rate of pendimethalin severely inhibited root development resulting in smaller roots with higher CP. Rape CP levels in 1978 were generally highest where herbicides were used, but in 1979, rape CP was not affected by herbicide application. Averaged across herbicide treatments, turnip (whole plant) and rape CP levels averaged 121 and 106 g kg−1, respectively. In vitro dry matter disappearance for turnips and rape were similar averaging 898 g kg−1and were not affected by herbicide application. Results indicate that appropriate preemergence herbicides will reduce early season weed competition and will enhance early production of turnips and rape. The high production potential and the high dry matter digestibility 100 days after seeding warrant consideration of turnips and rape for use as supplemental summer forage crops.
Dryland Rice Response to an Irrigation Gradient at Flowering Stage1
Authors: Cruz R. T. , O'Toole J. C. 
Published: July 2010

AbstractSensitivity of rice (Oryza sativaL.) to flowering stage water stress is well recognized. However, as with other cereals, there is lack of field research which quantifies plant and soil water status at the flowering stage in relation to water stress‐mediated reductions in crop yield. A rice cultivar was subjected to six levels of irrigation using a line‐source sprinkler system in the field on a silty clay loam, Typic Hapludoll soil during the dry season in which a stable rainless period is the climatic norm. Irrigation level 6 (wettest) was irrigated at the rate of 1.10 of pan evaporation while level 1 (driest) relied solely on pre‐line source water storage. Evapotranspiration during the 15‐day treatment period at flowering was linearly related to grain yield. The dominant yield component influencing grain yield was spikelet sterility.At irrigation level 6 in which soil moisture was reduced to 95% of the total crop extractable water, midday leaf water potential was −0.9 MPa, and spikelet sterility was 20%. At level 1, soil moisture was 28.6% of the total crop extractable water, midday leaf water potential −2.5 MPa, and spikelet sterility 73%. The exsertion of the rice panicle was found to be sensitive to changes in leaf water potential. Up to 30% of water stress‐mediated spikelet sterility was associated with poor panicle exsertion. The degree of panicle exsertion during flowering stage water stress may be a useful visual criterion in the selection of breeding lines with high degree of reproductive stage drought resistance.
Salt Effects on Emergence and Seedling Mortality of Guayule1
Authors: Miyamoto S. , Piela K. , Davis J. , Fenn L. B. 
Published: July 2010

AbstractEstablishment of guayule (Parthenium argentatumGray) by direct seeding has been unreliable due to poor seedling emergence and subsequent mortality. Laboratory germination, greenhouse and small field plot tests were performed for evaluating possible salinity interactions. Guayule seeds (593, 11591, and bulk collection) germinated 60 to 85% in petri dishes containing high saline solutions (EC = 22 dSm−1). Yet, emergence from well‐watered sandy soils was reduced sharply with increasing salinity, e.g., less than 10% emergence at irrigation water salinity of 4.5 dSm−1in field plots irrigated twice a day. Seedling mortality was negligible when irrigated with distilled or low salt water, but increased with increasing salinity. Both emergence and seedling survival rates were highly correlated (r = −0.94) with the salinity of surface (0 to 1 cm depth) soil samples. Salts introduced through irrigation water accumulated mostly in the surface 0.5 cm of soils with concentrations ranging from 4 to 22 dSm−1in soil saturation extract. Salt concentrations at seeding depths (0.5 to 0.8 cm) were, however, low enough to allow seed germination. Low emergence and high seedling mortality observed here appeared to be related to hypocotyl and seedling damage by salts accumulated on soil surfaces. Such damage can occur in soils classified as nonsaline when irrigated with water having salinity as low as 1 dSm−1.
Nitrogen, Climate, and Previous Crop Effect on Corn Yield and Grain N1
Authors: Asghari M. , Hanson R. G. 
Published: July 2010

AbstractTwo N response experiments, previously cropped with alfalfa and small grain, were conducted for 4 years (1977 to 1980) on Mexico silt loam soil, (fine, montmorillonitic, mesic Udollic Ochraqualf). The study included the evaluation of temperature and precipitation effects upon corn (Zea mays L.) yield, predicting the N requirement for maximum yield, based on N content of corn grain. A fertilizer N gradient of 0, 45, 90, 135, 180, and 225 kg N ha−1 with four replications was established. By dividing the growing season into 3 monthly periods (June, July, and August) the monthly heat units and precipitation were included as independent variables. Regression analysis related relative yield to monthly precipitation, monthly heat units and their products of grain N and the square of grain N. There was a significant yield response to N fertilizer 3 of 4 years where corn followed a small grain, but corn yield was not increased by N fertilization following alfalfa. Corn grain N content was significantly increased by N fertilization with the N content always higher where corn followed alfalfa (Glycine max L.). Relative yield of 100% was obtained with grain N content of 1.09 mol kg−1. June precipitation did not significantly effect corn yield, while above average heat units in June showed a positive effect on corn yield. The models showed that above average precipitation in July will increase corn yield and above average heat units would decrease yield. The effect of above average July heat units could be offset with a higher quantity of precipitation. To reach 100% relative yield, 114.3 mm of precipitation would be required in July (36.9 mm above mean) with mean of 450 heat units. On this soil, this 114.3 mm precipitation predicted corn yield of 9.36 Mg ha−1 requiring 136 kg N ha−1 of fertilizer N.
Fertilizer Effects on Crop Removal of P and K in ‘Coastal’ Bermudagrass Forage1
Authors: Day J. L. , Parker M. B. 
Published: July 2010

AbstractIn 1959, an N‐P‐K ratio of 9.1‐1‐3.8 (4‐1‐2 N‐P2O5‐K2O ratio) was proposed as the proper nutrient balance for fertilizing ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] for forage, but nutrient removal in forage was not taken into consideration with this ratio. The purpose of the study was to determine fertilizer effects on removal of P and K in ‘Coastal’ bermudagrass forage using increments of a fixed N‐P‐K ratio and high rates of P and K over a range of N rates. An established sod which had not received fertilizer for at least 5 years was selected for the 3‐year study. The soil was a Fuquay loamy sand (loamy, siliceous, thermic arenic Plinthic Paleudult) which was medium in P and low in K. Annual treatments for the first 2 years were 84,168,336, and 672 kg N ha−1 applied with P and K in a 9.1‐1‐5.7 N‐P‐K ratio (4‐1‐3 N‐P2O5‐K2O ratio). In the 3rd year 73.6 kg P ha−1 and 420 kg K ha−1 were applied uniformly at all N rates. The 9.1‐1‐5.7 N‐P‐K ratio supplied inadequate amounts of P and K to compensate for crop removal at the lower fertilizer rates but were excessive at the higher fertilizer rates. The N‐P‐K ratio required the 3rd year to supply P and K equivalent to that removed in the forage ranged from 6.4‐1‐6.5 for the 84 kg N ha−1 treatment to 14.4‐1‐7.9 for the 672 kg N ha−1 treatment. This study indicates that the use of regression equations for determining P and K needs for Coastal bermudagrass is a more suitable method than the N‐P‐K ratio method.
Soybean Irrigation Serially Timed During Stages R1 to R6. II. Yield Component Responses1
Authors: Kadhem F. A. , Specht J. E. , Williams J. H. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] seed yield components are established and fixed in a temporally ordered sequence during stages R1 to R6. To determine the effect of irrigation timing during R1 to R6 on these traits, we examined the seed yield component responses of 16 soybean cultivars to nine irrigation treatments in a 3‐year experiment. Treatments T1 thru T7 consisted of only a single irrigation coinciding with the average R stages 1.1, 2.5, 3.7, 4.7, 5.6, 5.9, and 6.4, respectively. ‘Check’ treatments included T0, which was not irrigated, and T8 which received seven total irrigations coincident with those for T0 and T7. Averaged over cultivars and years, the mean number of seeds/plant were: T0: 87f, T1: 121a, T2: 111bc, T3: 115ab, T4: 105cd, T5: 99def, T6: 102de, T7: 95ef, and T8: 122a. T0 and T8 thus established the minimum and maximum ‘limits’ in the seeds/plant response, respectively, with declining responses as irrigation was delayed from T1 to T7. The 100‐seed weight (g) means were: T0: 19.1b, T1: 17.8c, T2: 17.8c, T3: 18.3c, T4: 20.3a, T5: 20.4a, T6: 19.8ab, T7: 20.3a, and T8: 18.3c. Seed size for T8 was thus smaller than T0. The T4 thru T7 responses were significantly greater than T0, while the T1 thru T3 responses were significantly less than T0. Average seed yields were greatest for the T3 and T4 treatments, although for determinate cultivars, T8 also resulted in high yields. Only minimal changes in seed number and size were affected by irrigation in the determinate cultivars (in contrast to indeterminates), which may have accounted for the greater yield responsiveness of determinate cultivars to irrigation. Based on both the seed yield and yield component data, it would appear that stage R3.5 to R4.5 represents the reproductive period in soybeans most responsive to irrigation.
Excess Soil Water and Phytophthora Root Rot Stresses of Phytophthora Root Rot Sensitive and Resistant Alfalfa Cultivars1
Authors: Alva A. K. , Lanyon L. E. , Leath K. T. 
Published: July 2010

AbstractThe adaptation of alfalfa (Medicago sativa L.) to well‐drained soil has limited its range of culture. The poor performance of this crop in wet soils has often been attributed to the effects of Phytophthora root rot (PRR). However, excess soil water itself may reduce alfalfa growth. The impact of continuous excess soil water stress (ESWS) and PRR stress (PRRS) and the growth potential after elimination of the excess soil water was studied on PRR‐resistant (Oneida) and PRR‐susceptible (Iroquois) alfalfa cultivars. The impact of ESWS on the two cultivars was similar. No visible root injury symptoms were apparent despite significantly reduced root growth when compared to stress‐free (SF) plants. Shoot growth was less consistently affected than root growth. For the plants subjected to continuous PRRS the severity of PRR was 4.7 for Iroquois and 3.5 for Oneida on a scale of 1 to 5 representing increasing damage. The PRR symptoms were 42 and 15% less for the Oneida and Iroquois cultivars, respectively, after a recovery period following the elimination of excess soil water. Shoot and root growth after the recovery period were significantly greater than that of continuously stressed plants of Oneida, but the growth of Iroquois was not significantly different. Manganeses concentration in the plants under continuous stress was twice that of SF plants or of stressed plants after the recovery period. The concentrations did not reach toxic levels for the plants. Alfalfa response to wet soil is not a simple phenomenon that may be attributed to the same single factor in each situation. It may best be described as a “wet‐soil syndrome” the cause and intensity of which will depend on the magnitude and balance of all the individual stresses that are involved.
Yields of Forages Irrigated with Wastewater and the Fate of Added Nitrogen‐15‐Labeled Fertilizer Nitrogen1
Authors: Bole J. B. , Gould W. D. , Carson J. A. 
Published: July 2010

AbstractIrrigation of legume and nonlegume forage species with municipal waste water at rates designed to approximate and double the net evapotranspiration minus precipitation deficit was studied for 11 yr at Taber, Alberta, Canada. The soil was a Brown Chernozemic Cavendish loamy sand (Aridic Haploboroll). Reed canarygrass required additional N to give yields similar to those of the alfalfa (Medicago sativaL.). Alfalfa yields were not greatly affected by increasing levels of N and P fertilizer or by the application of excess wastewater. The N uptake by reed canarygrass (Phalaris arundinaceaL.) was considerably less than that of alfalfa when the N supply was limited, but about the same when the N supply was adequate. Reed canarygrass recovered nearly 50% of applied fertilizer 15N over 2 yr with about 80% of total uptake in the first cutting after N application. Alfalfa only recovered 24% of applied N at low irrigation rates and 14% at the higher rate. Estimates of fertilizer N uptake based on the increase in N yield of reed canarygrass due to fertilization would have been much higher. About 25% of the fertilizer N remained in the soil after two irrigation seasons, independent of forage species or irrigation rate. Sixty percent of that N remained in the surface 15 cm. Losses of N from alfalfa were nearly double those from reed canarygrass plots. Wastewater irrigation did not lead to levels of any element phytotoxic to plants or harmful to animals consuming the forage and probably increased the nutritional quality of the forage.
Supplemental Boron Effects on Yield and Quality of Seven Bermudagrasses1
Authors: Monson Warren G. , Gaines T. Powell 
Published: July 2010

AbstractBoron (B) has been recognized for many years as an essential element for plant growth, but there is limited information available on its effects on forage grasses. This 4‐yr study was initiated to examine the effects of B rates of 0, 1.1, 2.2, or 4.4 kg ha−1on yield and quality of established stands of seven bermudagrasses [Cynodon dactylon (L.) Pers.] growing on a Tifton sandy loam soil (Plinthic Paleudult). The effect of the B treatments across all grasses was an increase in dry matter (DM) yield when 2.2 kg ha−1B was applied annually. However, the effect was significant (P = 0.05) only for ‘Tifton 44’ and ‘Midland’ bermudagrasses. ‘Coastal’ and ‘Coastcross‐1’ bermudagrasses showed no response to treatments while ‘Callie’ and ‘Tifton 67’ tended to yield more with added B and ‘Tifton 84’ tended to yield less. There was no effect of B treatments on digestibility or crude protein concentration of the grasses. The data would not support a general recommendation of supplemental B on bermudagrasses
Samples Needed for Estimation of Plant Height of Pima Cotton1
Authors: Kittock D. L. , Cain C. J. , Selley R. A. , Taylor B. B. 
Published: July 2010

AbstractPlant populations giving the highest lint yield of American pima cotton (Gossypium burbdense L.) grown in 1‐m spaced rows change as plant heights change. Therefore, plant height should be considered in future plant population studies with pima cotton. This study was conducted to determine the number and type of plant height measurements needed to give a satisfactory estimate of mean plant height for a plot. Plant height uniformity data were obtained from 12 plots (four locations with three plots per location) in Arizona. Soils were Torrifluvents Haplostolls, Anthropic Torrifluvents, and Thermic Torrifluvents. Measurement of four to eight plants per plot, half of the number on each end, appeared to be adequate to characterize the plant height of a plot. Plant heights were normally distributd. A systematic selection produced lower variation (about onehalf as many plants needed to be measured) but over‐estimated mean plant height by an average of 12.5%.
Evaluating Ten Cropping Alternatives for the Midsouth1
Authors: Sanford J. O. , Eddleman B. R. , Spurlock S. R. , Hairston J. E. 
Published: July 2010

AbstractMany crop production systems and cropping sequences are available in the Midsouth and each differs in its management and potential contribution to net farm income. This paper considers several of these variables using yields and costs of production data from a 3‐yr crop production study in Mississippi. A nonirrigated experiment was conducted on Leeper silty clay (fine montmorillonitic, nonacid, thermic Vertic Haplaquepts) from 1976 through 1980. The experiment contained 10 treatments of five monocrop and five doublecrop enterprises in randomized block design. Monocrops were commercial hybrid corn (Zea mays L.), soybean [Glycine max (L.) Merr.], grain sorghum [Sorghum bicolor (L.) Moench], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.). Doublecrops were wheat followed by the first four monocrops plus an experimental, insect and disease resistant corn hybrid. Yield and production records were maintained and used to calculate net returns for the cropping alternatives. The five enterprises with highest net returns per hectare (in descending order) were monocrop corn ($495), doublecropped wheat‐soybean ($407), monocrop soybean ($326), doublecropped wheat‐resistant corn ($306), and doublecropped wheat‐sunflower ($285). The farming system that most fully utilized a complement of sixrow equipment and associated power units, and maximized net farm income above variable costs, machinery ownership costs, and land costs was calculated to be 279 ha of cropland as determined by linear programming techniques. This 279 ha would be partitioned as follows: monocrop corn (120 ha), monocrop wheat (13 ha), doublecropped wheat‐resistant corn (62 ha), and doublecropped wheat‐soybean (84 ha). Net return above specified expenses was computed to be $45 897 annually.
Titanium Determination for Correction of Plant Sample Contamination by Soil1
Authors: Cary E. E. , Grunes D. L. , Bohman V. R. , Sanchirico C. A. 
Published: July 2010

AbstractAn accurate method for determining Ti in plant material and soil was developed. Titanium concentrations in plant and soil were used to correct analytical data of plant materials for contamination by soil. Different digestion schemes were used in the analysis of National Bureau of Standards (NBS) reference materials for Ti. A satisfactory result was obtained when the sample was digested in a Teflon beaker containing HNO3 and HClO4, taken to dryness, baked at 185°C, and then dissolved overnight at room temperature in HF. The solution was made to volume with 3M HCl, in polyethylene, after addition of H3BO3 to complex excess F . Titanium was determined by inductively coupled argon plasma (ICP) spectrometry. Certified Ti values for NBS mineral samples 120b and 692 are 899 and 270 mg kg 1, respectively. This method gave values of 898 ± 14 and 264 ± 6 mg kg 1, respectively. Correction of elemental analysis for soil contamination of plant, rumen fistula, and feces samples using this method agreed well with corrections using Fe or Al as a reference element as well as with determination for Ti by x‐ray fluorescence. Using residual ash content (Si) as a reference element appeared to be less reliable. The assumptions needed to make this correction using Ti are less prone to error than the assumptions needed when Fe, Al, or residual ash are used. It was imperative to use HF in the digestion procedure for quantitative determination of Ti in some samples.