bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Water Balance of Intercropped Maize and Cowpea Grown in a Tropical Hydromorphic Soil in Western Nigeria1
Authors: Hulugalle N. R. , Lal R. 
Published: July 2010

AbstractWater‐use efficiency (WUE) and soil water extraction by four maize (Zea maysL.)/cowpea (Vigna unguiculataWalp.) cropping patterns were studied in a tropical hydromorphic soil over two consecutive growing seasons in 1983 and 1984. The cropping patterns used were: monocropped cowpea (T1), monocropped maize (T2), intercropped maize and cowpea planted in the same row as alternate plants (T3), and intercropped maize and cowpea planted in alternate rows (T4). Evapotranspiration (Et) was calculated from the soil water balance. Soil water extraction was limited to the surface 0.35 m of the profile due to the restriction of roots by a gravel layer at this depth. Upward water flux into the root zone was negligible due to low hydraulic conductivity. All cropping patterns were subjected to drought stress in 1983. Mean runoff and net water flux in the root zone in 1983 and 1984 were 2.4 and 0.04%, respectively, and 1.4 and 0.4%, respectively, of the seasonal rainfall. Intercropping increased seasonal WUE. The WUE (kg grain per mm water per ha) of T1, T2, T3, and T4were 0.5, 2.2, 1.6, and 1.6, respectively, for the droughty conditions in 1983 and were 2.1, 2.1, 4.2, and 3.6, respectively, for the favorable moisture regime in 1984. One of the benefits of intercropping maize and cowpea is, therefore, a higher WUE in relation to monocropping provided soil water is not limiting
Comparison of Water Potential Components Measured with a Thermocouple Psychrometer and a Pressure Chamber and the Effects of Starch Hydrolysis1
Authors: Bennett J. M. , Cortes P. M. , Lorens G. F. 
Published: July 2010

AbstractRecent reports have shown that discrepancies exist between water potential components measured with a pressure chamber and those determined with a thermocouple psychrometer. It has been hypothesized that the differences might be attributable to a number of reasons including starch hydrolysis within the tissue during the time required for equilibration when using thermocouple psychrometers. We conducted a series of experiments to (i) compare xylem water potential measured with a pressure chamber (Ψx) with leaf water potential (ΨL) and leaf osmotic potential (Ψs) measured with a thermocouple psychrometer, and (ii) examine changes in starch concentration during the time period required to measure ΨLand Ψswith thermocouple psychrometers for field‐grown alfalfa (Medicago salivaL.), soybean [Glycine max(L.) Merr.], and corn (Zea maysL.) leaves. Good agreement was found between Ψxand ΨLexcept for severely stressed corn leaves where Ψxwas lower than ΨLWhen measuring Ψsand ΨLwith thermocouple psychrometers on flaccid leaves assumed to be at zero turgor potential, Ψsdetermined after freezing and thawing of the tissue agreed well with ΨLmeasured before freezing, suggesting that dilution of cell sap by apoplastic water may be either very small or fully compensated for by production of solutes during equilibration of the tissue. There was a tendency for some starch hydrolysis to occur during the 4‐h period between harvest of leaf material and determination of ΨLwith a thermocouple psychrometer, especially with tissue sampled at midday and late afternoon when leaf starch concentrations were high. However, significant starch hydrolysis between freezing and thawing of the leaf tissue and measurement of Ψswas not detected. Starch hydrolysis was dependent on time of day and species; however, except for soybean leaves having high concentrations of starch, starch hydrolysis during equilibration could potentially account for only small changes (generally <0.1 MPa) in measured ΨLand Ψs
Rice Responses to a Short‐Duration Green Manure. II. N Recovery and Utilization1
Authors: Morris R. A. , Furoc R. E. , Dizon M. A. 
Published: July 2010

AbstractRecent research demonstrated that fast‐growing tropical legumes [mungbean, Vigna radiata(L.) Wilczek and cowpea, V. unguiculata(L.) Walp.], when used as a green manure for lowland rice (Oryza sativaL.), can increase grain yield by 2 Mg ha−1, and that supplemental inorganic applications increase yield further. To guide research on the combined use of inorganic and green manure N, apparent N recovery (kg N uptake kg−1N applied) and N utilization (kg grain kg 1N uptake) were determined in three experiments. The experiments were conducted on a fine mixed isohyperthermic Aeric Tropaqualf in the Philippines during the 1983 and 1984 wet seasons. In two experiments, factorial combinations of inorganic N (0 and 80 kg N ha 1) and green manure growth duration (20, 30, and 40 days in the first year; 25,35, and 45 days in the second year), were tested. Apparent N recoveries from inorganic fertilizer and green manure were 49% in 1983 and 41% in 1984. At N levels < 51 kg N ha−1, inorganic N utilization was inferior to green manure N utilization in 1983 but similar in 1984. In the third experiment, mungbean was planted at 300 000 and 600 000 plants ha−1and grown for 20, 30, and 40 days before incorporation. Inorganic N (80 kg N ha−1) was applied to plots that were fallow during the green manure growth period. Apparent N recovery from both sources was 33%. Utilization of N from 80 kg inorganic N ha−1was slightly more efficient than from an equivalent quantity of green manure N. Although differences were noted, the experiments suggest that apparent recovery and utilization of N from short‐duration green manures are similar to those from inorganic N fertilizers. Research is required to determine how efficiency from the combined use of both N sources can be maximized.
Effects of Seeding Method and Time of Fertilization on Urea‐Nitrogen‐15 Recovery in Rice1
Authors: Westcott M. P. , Brandon D. M. , Lindau C. W. , Patrick W. H. 
Published: July 2010

AbstractBoth water seeding and dry seeding are utilized in U.S. rice (Oryza sativaL.) cultural systems. Early season N applications are soil incorporated or deep placed prior to planting with water seeding, but are broadcast on the soil surface just prior to permanent flooding with dry seeding. Field studies were conducted on a Crowley silt loam (Typic Albaqualf) and a Sharkey clay (Vertic Haplaquept) to determine the effects of seeding method and time of application on the recovery of urea−15N by rice (var. Lemont). A total rate of 100 kg N/ha was added as (i) a single preplant (water seeded) or preflood (dry seeded) application, or (ii) a split with an initial application (preplant or preflood) of 67 kg N/ha and a topdressing of 33 kg N/ ha broadcast into the floodwater at midseason. Nitrogen‐15‐labeled materials were utilized in microplots (0.255 m2). The plant recovery of preplant N with water seeding (41.7% of the applied N) was significantly greater than the uptake of preflood N with drill seeding (30.2%). Water seeding also increased total N uptake and dry matter production, but grain yields were unaffected by seeding method due to a higher harvest index (HI) for drill‐seeded rice. Topdressed N was taken up with equal efficiency (45.8% recovery) in either seeding method. Soil recovery of labeled N was unaffected by seedling method; differences in total recovery of labeled N in the soil‐plant system at harvest (ranging from 40.0 to 57.7% of the application rate), therefore, primarily reflected differences in plant uptake. Overall, differences between seeding methods reflected a stimulation of early season growth and N uptake characteristics on the part of water seeding.
Crabgrass and Goosegrass Control in a Bentgrass Green in the Transition Zone1
Authors: Callahan Lloyd M. 
Published: July 2010

AbstractA creeping bentgrass (Agrostis palustris Huds. cv. Penncross) high porosity green was treated with ethofumesate (2‐ethoxy‐2,3‐dihydro‐3,3‐dimethyl‐5‐benzofuranyl methanesulfonate), metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐1,2,4,‐triazin‐5(4H)‐one], NC‐20484 (structure undisclosed, belongs to benzofuran group), napropamide [N,N‐diethyl‐2‐(l‐naphthalenyloxy)propanamide], oxadiazon {3‐[2,4‐dichloro‐5‐(1‐methylethoxy)phenyl]‐5‐(1,1‐dimethylethyl)‐1,3,4‐oxadiazol‐2‐(3H)‐one}, and prosulfalin (N‐[4‐(dipropylamino)‐3,5‐dinitrophenyl]sulfonyl}‐S,S‐dimethylsulfilimine) to determine phytotoxicity and effectiveness in controlling large crabgrass (Digitaria sanguinalis L. Scop.) and goosegrass [Eleusine indica (L.) Gaertn.]. No sod loss occurred with a 1‐yr treatment of prosulfalin at 3.4 and 6.7 kg ha−1 or ethofumesate at 1.1 kg ha−1. Repeat treatments for 3 more years at reduced rates resulted in no sod loss with ethofumesate or NC‐20484 at 0.6 and 1.1 kg ha−1, oxadiazon at 2.2 and 4.5 kg ha−1, and prosulfalin at 1.7 and 3.4 kg ha−1. Single and sequential treatments of oxadiazon and prosulfalin, at both rates for each, gave 96 to 100% control of crabgrass. Only oxadiazon at 4.5 kg ha−1 and prosulfalin at 3.4 kg ha−1 gave 91 to 100% control of goosegrass. There was no evidence of herbicide residue buildup from treatments to the same plots during four successive years in the high porosity green (95.3% sand, 3% silt, 1% clay, 0.7% OM by weight).
Forage Growth, Consumption, and Performance of Steers Grazing Bermudagrass and Fescue Mixtures1
Authors: Mitchell Ronald L. , McLaren J. B. , Fribourg Henry A. 
Published: July 2010

AbstractDetailed information regarding forage quality and pasture productivity of various species and combinations that support rapid animal gains in the southeastern USA is needed for successful stocker cattle performance prior to feedlot placement. To evaluate productivity and quality of pastures for grazing beef (Bos taurus L.) steers, an experiment was conducted in 1979–1981 on a Typic Hapludalf. The 1.2 ha pastures were (i) Midland bermudagrass [Cynodon dactylon (L.) Pers.] + tall fescue (Festuca arundinacea Schreb.) seeded in 25‐cm rows + N, (ii) Midland + fescue in 25‐cm rows + legumes, (iii) Midland + fescue in 50‐cm rows + legumes, (iv) fescue + legumes, (v) common bermudagrass + fescue in 25‐cm rows + legumes, and (vi) orchardgrass (Dactylis glomerata L.) + ladino clover (Trifolium repens L.). Legumes refer to overseedings of ladino clover, red clover (T. pratense L.) and ‘Kobe’ lespedeza (Lespedeza striata (Thunb.) H & A). Midland + fescue at 25 cm + N pastures were topdressed with 290 kg N ha−1 each year. Pastures were grazed using a continuous put‐and‐take grazing management with stocking rate adjustments made to maintain orchardgrass at 8 to 14 cm and other pasture combinations at 5 to 8 cm. Forage growth and consumption were estimated by the cage‐and‐strip method. Yearling beef steers averaging 230 kg in the spring grazed 131 to 168 days and were weighed at 21‐day intervals. Forage dry matter (DM) yield was 14.2 Mg ha−1 for Midland + fescue at 25 cm and ranged between 6.8 and 9.1 Mg ha−1 for the other treatments. Forage consumption was 70% or more of growth in all treatments. Crude protein ranged from 134 to 158 g kg−1. Neutral detergent fiber ranged from 600 to 670 g kg−1, and acid detergent fiber was 390 g kg−1. Stocking rates were between 3.2 and 7.7 steers ha−1. Average daily gains were greatest on orchardgrass + clover (869 g day−1) and ranged from 478 to 821 g day−1 for the other pastures. Productivity was 591 animal grazing days ha−1 for common + fescue at 25 cm + legumes, 1537 for Midland + fescue at 25 cm, and ranged from 605 to 833 for the other pastures. Daily forage DM intake was 6.3 to 9.9 kg steer−1. Beef production was 392, 474, 510, 545, 597, and 630 kg ha−1 for common + fescue at 25 cm + legumes, Midland + fescue at 50 cm + legumes, Midland + fescue at 25 cm + legumes, orchardgrass + clover, fescue + legumes, and Midland + fescue at 25 cm + N, respectively.
Development and Testing of an Improved Soil‐Root Sampling Technique for Rice in Flooded Puddled Soil1
Authors: Thangaraj M. , O'Toole J. C. 
Published: July 2010

AbstractUndisturbed, intact root and soil samples have rarely been acquired from rice (Oryza sativa L.) grown in flooded, puddled lowland soils. Common sampling techniques used in aerobic dry soil conditions are useless under the flooded conditions of a rice field. This note presents an improved volumetric soil‐root sampling method and associated root isolation techniques for accurately measuring root length and root weight of rice in flooded soils. The metal field sampler was used to extract a soil monolith 0.2 by 0.2 by 0.5 m deep. The sampler and soil monolith were then frozen for 12 to 14 h. In a frozen state, the previously unmanageable flooded soil sample could be moved to a sample holder that facilitated cutting the monolith into sections 0.2 m by 0.2 m by 50 mm. The individual sections were treated to remove soil and organic matter from the roots. Root samples were then available for root length measurement or any other analytical procedure. Analysis of root lengths at 50‐mm vertical increments at three different growth stages of the rice crop illustrated the reliability of the sampler and analysis techniques. Coefficients of variation (CV) were less than 10% for samples between 0 and 0.25‐m depths. Below this level to 0.4 m, CV's were about 15%. We conclude that the soil‐root sampler and associated analytical techniques provide a means of overcoming the inherent problems of soil and root sampling in flooded rice fields.
Preliminary DRIS Norms for Alfalfa in the Southeastern United States and a Comparison with Midwestern Norms1
Authors: Walworth J. L. , Sumner M. E. , Isaac R. A. , Plank C. O. 
Published: July 2010

AbstractFoliar tissue norms were developed for ‘Apollo’ alfalfa (Medicago sativa L.) grown on two highly weathered soils in the Georgia Piedmont for use in the diagnosis and recommendation integrated systems (DRIS). These norms were generated from a data bank comprised of tissue nutrient composition and plant yield and consisting of 3915 field observations. A yield of 3.5 Mg ha−1 per cut was used to divide high yielding from low yielding members. Norms were generated by averaging values from the high yielding segment for all possible ratios of N, P, K, Ca, Mg, Zn, Cu, B, and dry matter (DM) and compared to those previously calculated from midwestern data. Values from Georgia were generally similar to those from the Midwest, except for Mg, which was lower, and B, which was higher. Differences in Mg norms were attributed to soil conditions. Norms generated in Georgia correctly diagnosed nutrient requirements of plants grown in Georgia, but differences between the two sets of norms indicate some regionality in DRIS norms for alfalfa. The DM index was demonstrated to adequately separate nutrients present in sufficient and insufficient quantities for recommendation purposes.
Amaranth Seedling Emergence as Affected by Seeding Depth and Temperature on a Thermogradient Plate1
Authors: Webb D. M. , Smith C. W. , Schulz‐Schaeffer J. 
Published: July 2010

AbstractSeedling emergence studies are normally conducted in growth chambers, greenhouses, or field plots and require much space, equipment, and time when several factors are considered. Amaranth (Amaranthus spp.) is a new crop in the United States that often exhibits inadequate field emergence because of environmental constraints. Two seedlots, one white seeded and one black seeded, from the same population of Amaranthus hypochondriacus L. were assessed for emergence index and percentage emergence in a peat‐sand medium over a range of temperatures and seeding depths using a modified thermogradient plate. Seed color produced no difference in emergence, but significant differences in emergence were caused by temperature, seeding depth, and temperature × depth interaction. A predictive response surface shows expected amaranth seedling emergence index at temperatures between 15 and 42°C and seeding depths between 13 and 51 mm. Highest amaranth emergence index and percentage emergence on the thermogradient plate occurred from the 13‐mm seeding depth and at temperatures between 24 and 34°C; these data suggest field emergence may be satisfactory with soil temperatures between 18.5 and 24°C.
Estimating Corn Growth, Yield, and Grain Moisture from Air Growing Degree Days and Residue Cover1
Authors: Swan J. B. , Schneider E. C. , Moncrief J. F. , Paulson W. H. , Peterson A. E. 
Published: July 2010

AbstractLow spring soil temperatures commonly restrict the early growth of corn (Zea mays L.) in the northern Corn Belt. A quantitative assessment of the effects of tillage and residue management practices on soil temperature would improve tillage recommendations in this region. The effect of tillage and surface residue cover on seedbed soil temperatures and subsequent corn growth were studied at four sites in the northern Corn Belt that differed widely in soil characteristics including drainage, texture, slope, and organic matter content. Tillage systems included no‐tillage, chisel plow, moldboard plow, paraplow, ridge plant, and wheeltrack plant. A wide range of surface residue cover was imposed on each system at three sites. Corn emergence and leaf number to the six‐leaf stage were closely related to percent in‐row cover and air temperature growing degree days (air GDD) through their mutual relationship to soil temperature growing degree days (soil GDD) at all sites. For a given site and year, percent in‐row cover following planting was the major factor affecting corn growth rate until the six‐leaf stage. Corn planted under high percent residue cover required more time and consequently more air GDD to reach the six‐leaf stage. This added time represents a growth delay that can be expressed as the additional air GDD required to reach the six‐leaf stage. Such delays were related to increased grain moisture and decreased corn grain yield when net cumulative air GDD were less than the threshold value of 1319 and water stress was minimal. In‐row residue cover due to tillage and previous crop can have a major impact on the growth and development of corn in the northern Corn Belt. These factors should be considered in selecting tillage systems in this region.
Effects of Grazing Management on Establishment and Productivity of Aeschynomene Overseeded in Limpograss Pastures1
Authors: Sollenberger L. E. , Quesenberry K. H. , Moore J. E. 
Published: July 2010

AbstractLow protein concentration in limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] herbage is thought to limit the performance of grazing animals. In 1983 and 1984 an experiment was conducted on a sandy, siliceous, hyperthermic Ultic Haplaquod soil to evaluate effects of grazing management on establishment and productivity of the legume aeschynomene (Aeschynomene americana L.) seeded in limpograss. Existing limpograss pastures were grazed in the spring to 75‐ or 150‐mm stubble heights. After broadcast seeding aeschynomene, stubble heights were maintained by grazing until (i) legume cotyledons were exserted, (ii) two true leaves were present, or (iii) 2 weeks after the two‐leaf stage. Summer grazing was initiated when aeschynomene plants were 0.20, 0.40, or 0.80 m tall in 1983 and 0.20, 0.40, or 0.60 m tall in 1984. After initiation of grazing, pastures were grazed every 5 weeks. Limpograss stubble height during legume establishment did not affect legume productivity, but there was a trend favoring the 75‐mm level. Extending the period of early season grazing of limpograss until aeschynomene seedlings reached at least the two‐leaf stage controlled grass competition and maximized legume performance. Legume dry matter (DM) accumulation was greatest if initiation of summer grazing was delayed until aeschynomene was 0.80 (1983) or 0.60 (1984) m tall. Initiation of grazing when aeschynomene was 0.20 to 0.40 m tall resulted in more uniform distribution of total and legume DM, higher efficiency of grazing, more vigorous legume regrowth, and a trend toward greater total herbage consumption. These data indicate that aeschynomene can be established into limpograss sods under grazing, and that this association has potential on the large expanses of poorly drained soils in Florida.
Influence of Growth Retardants (Anti‐Gibberellins) on Corn Vegetative Growth, Water Use, and Grain Yield under Different Levels of Water Stress1
Authors: Shanahan J. F. , Nielsen D. C. 
Published: July 2010

AbstractCorn (Zea mays L.) grown under the semiarid conditions of the Central Great Plains requires supplemental irrigation to obtain maximum yields. This practice has become increasingly less profitable as the cost of application of irrigation water has risen. It may prove to be more cost effective to reduce the water requirement of corn by limiting the vegetative development of the plant. Two anti‐gibberellin, seed‐applied, experimental plant growth regulators (PGRs), BAS 106. .W and BAS 110. .W, were used on corn grown under low and high levels of irrigation in a 2‐yr (1984 and 1985) field study on a Rago silt loam soil (fine, montmorillonitic, mesic Pachic Argiustolls) to determine the effect of these PGRs on vegetative growth, water use, water stress, grain yield, and yield components. The PGRs were applied at three rates in both years (0, 100, and 200 mg a.i. kg−1 of BAS 106. .W in 1984 and 0, 125, and 250 mg a.i. kg−1 of BAS 110. .W in 1985). Increasing application rates of the PGRs caused a significant reduction in early season plant height, leaf area index (monitored in 1985 only), and dry matter accumulation (monitored in 1985 only), resulting in reduced early season evapotranspiration in both years. The PGR treatments reduced plant water stress during silking and early grain fill, particularly under the low irrigation treatment. The changes in plant growth and development associated with the PGRs resulted in a 9 and 16% increase in grain yield in 1984 and 1985, respectively, under the low irrigation treatment and a 7 and 9% reduction in grain yield in 1984 and 1985, respectively, under the high irrigation treatment. Therefore, reducing early season vegetative growth with the PGRs proved to be advantageous to productivity under water stress and counterproductive under nonlimiting water conditions.
Effect of Water Depth on Nitrogen Use Efficiency and Nitrogen‐15 Balance in Lowland Rice1
Authors: De Datta S. K. , Obcemea W. N. , Chen R. Y. , Calabio J. C. , Evangelista R. C. 
Published: July 2010

AbstractBasic studies to understand and delineate N loss mechanisms and to develop management practices to minimize N losses are vital to increasing rice (Oryza sativa L.) productivity and N use efficiency in lowland rice. In 1984, two field studies in lowland rice evaluated the effect of water depth on potential N loss and N use efficiency on Maahas clay (Andaqueptic Haplaquoll) and 15N balance on Maligaya clay (Vertic Tropaquept). In the first experiment on Maahas clay, the partial pressure of NH3 (ρNH3) in the floodwater was lower when fertilizer was incorporated without standing water than when incorporated with 50 mm water. However, when fertilizer was topdressed 10 days after transplanting (DT), ρNH3 was lower with 100 and 150 cm standing water than with 50 mm water due to dilution and lower floodwater pH and temperature. In the second experiment conducted on Maligaya clay, grain yield from urea applied basally and incorporated without and with 25 mm standing water was similar to that from point‐placed urea supergranules. Yields from fertilizer topdressed 10 DT with 0, 50, and 100 mm standing water were similar but significantly lower than when fertilizer was applied basally and incorporated at all water depths. Nitrogen‐15 balance data show that fertilizer applied basally and incorporated without standing water gave a total 15N recovery of 66% and crop (grain + straw) recovery of 39%. Standing water at depths of 25 and 50 mm during incorporation decreased total 15N recovery by 5 to 7%. Topdressing fertilizer 10 DT without standing water resulted in 59% total N recovery and 38% plant recovery.