bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Subsurface Layered Herbicides on Horsenettle and Various Crops
Authors: Banks P. A. , Santelmann P. W. 
Published: July 2010

AbstractHorsenettle (Solanum carolinense L.) is a perennial weed species of increasing importance in much of the southern and eastern U. S. Experiments were conducted to determine the usefulness of subsurface layering (SSL) of herbicides for the control of horsenettle in several crops. Herbicides were applied to horsenettle infested fields with spray nozzles mounted beneath a 2.4 m wide sweep type plow operated about 20 cm below the soil surface. Crops were then planted. Picloram (4‐amino‐3,5,6‐trichloropicolinic acid) and dicamba (3,6‐dichloro‐o‐anisic acid) were successful for horsenettle control but severely injured broadleaved crops planted over the SSL. Dinitroaniline herbicides generally suppressed emergence of horsenettle plants up to 82 days. Postemergence treatments of 2,4‐DB [4‐(2,4‐dichlorophenoxy)butyric acid] plus SSL dinitroaniline treatments did not enhance horsenettle control above that achieved with 2,4‐DB alone. Trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) and fluchloralin [N‐(2‐chloroethyl)‐2,6‐dinitro‐N‐propyl‐(decrease in yields of cotton (Gossypium hirsutum L.), soybeans (Glycine max L. Merr.), and peanuts (Arachis hypogaea L.) when used SSL. Butralin [4‐(l,l‐dimethylethyl)‐N‐(1‐methylpropyl)‐2,6‐dinitrobenzemamine] caused the least yield reductions. Trifluralin was more soil persistent as a SSL than dinitramine (N4N4‐diethyl‐α,αα‐trifluoro‐3,5‐dinitrotoluene‐2,4‐diamine). These two herbicides were also more persistent when applied deeper in the soil.
Analysis of Potato Growth Under Differing P Regimes. II. Time by P‐status Interactions for Growth and Leaf Efficiency1
Authors: McCollum R. E. 
Published: July 2010

AbstractFew full‐season studies of potato (Solanum tuberosum L.) growth under mid‐latitude environments have been conducted. Furthermore, published reports about effects of nutrient status on leaf efficiency in any species are inconclusive. Hence, the effects of factorially combined levels of initial soil P (SP = 35, 66, and 110 kg/ha) and row‐applied fertilizer P (FP = 0, 28, and 56 kg/ha) on dry matter accumulation, leaf‐area generation, leaf efficiency, and partitioning of assimilates by potatoes were studied via growth‐analysis concepts. Tops and tubers of field‐grown ‘Pungo’ potatoes (40,000 plants/ha on Portsmouth fsl—Typic Umbraquult, fine‐loamy, mixed, thermic) were harvested weekly, and all parameters essential to a detailed growth analysis were derived.Growth curves for P‐adequate plants (Sp ⋝ 66, FP > 0) were typically sigmoidal with three post‐emergent ontogenetic phases: 1) pre‐tuber vegetative (emergence − 28 days); 2) tuber initiation and early bulking concurrent with rapid leaf growth (28 to 50 days); and 3) continued tuber growth during rapid leaf loss followed by death of haulms. Plants on the low‐P extreme (SP = 35, FP = 0) never entered the third phase; they produced in 80 days only 50% of the “normal” leaf canopy (LAI = 1.6 vs. 3.2 at optimal P) and lost none of it. Curves for plants with moderate P supplies lay between these extremes. Row‐applied P enhanced early growth; but it also hastened leaf senescence and, if initial soil P was low, shortened the duration of tuber bulking.Leaf growth rate was maximal with 0.35% P in foliar tissue. Tuber growth rate was a quadratic function of leaf area during most of the tuber bulking period, but the estimate of 3.4 as optimal LAI was tenuous because no treatment generated a LAI greater than 3.2. Tuber yield was linearly related to leaf‐area duration (LAD); doubling the LAD resulted in a 45% increase in yield.Phosphorus deficiency reduced mean net assimilation rate (NAR) during early growth, had no statistically measurable effect during mid‐season [NAR (35 to 63 days) = 7.76 gm−2 day−1], but markedly increased NAR during late growth stages. Instantaneous estimates of NAR derived from growth equations suggested that effects of low P on leaf efficiency were even more severe and longer‐lasting than indicated by NAR's. Initiation of tubers as an additional metabolic sink halted a downward trend in NAR, and partitioning of assimilates between tops and tubers during bulking depended on P supply and the manner of supplying it.
Arsenic Pollution from Underdrainage and Runoff from Golf Greens1
Authors: Duble R. L. , Thomas J. C. , Brown K. W. 
Published: July 2010

AbstractModern golf greens are subject to intense management which includes frequent pesticide applications. Tricalcium arsenate, Ca3(AsO4)2, is commonly used on a regular basis for control of grubs and Poa annua even though the As losses associated with leachate and runoff have not been established. This study was thus undertaken to develop data on As losses from golf greens.A field study was conducted using four lysimeters each 3 m by 3 m) containing a Tabor sandy loam soil (Udertic Paleustales) and 16 lysimeters containing different sand‐soil‐peat mixtures, each equipped with a gravel underdrainage system. The lysimeters having a sandy loam soil simulate older greens built of sandy soil placed over a gravel drainage system while those lysimeters having mixtures of sand, soil and peat typify modern greens. Bermudagrass (Cynodon dactylan L.) turf was maintained at a height of approximately 1 cm throughout the investigation. Sprinkler irrigation was used to apply approximately 1 cm of water daily. Tricalcium arsenate was applied on two dates at a rate of 88 kg ha−1. Leachate and runoff water from individual plots was collected in 208 liter barrels. This was measured and sampled on a regular basis and more frequently when required by rainfall.Arsenic was found in significant concentrations in both drainage and runoff from lysimeters. Particularly high concentrations were found in the drainage from plots previously cored for soil samples. Concentrations of 8 ppm As were found in the drainage water from these plots. Concentrations of As in the runoff were as great as 14 ppm when a heavy rain occurred shortly after application of Ca3(AsO4)2. Drainage from the plots typically contained 1 to 3 ppm and decreased slowly with time. Arsenic concentrations of 0.8 ppm were still found in the drainage 115 days after application. Concentrations of As in the runoff and drainage from all the plots exceeded acceptable limits for irrigation water established by the U. S. Public Health Service.
Influence of N Nutrition on Flower and Pod Abortion and Yield of Soybeans1
Authors: Brevedan R. E. , Egli D. B. , Leggett J. E. 
Published: July 2010

AbstractThe number of seed produced by a soybean (Glycine max (L.) Merrill) community is one of the important determinants of yield. Since soybeans usually abort a high percentage of their flowers and pods, this study was undertaken to investigate the influence of N nutrition on flower and pod abortion. Experiments in which the N supply to the soybean plant was varied during flowering and pod filling were conducted in the greenhouse and field. The greenhouse experiment was conducted in a hydroponics system with 5 meq NO3‐/liter in the nutrient solution. Some plants were shifted to 12.5 or 18.0 meq NO3‐/liter at initial bloom and maintained at these levels until maturity, while others were exposed to the high NO3‐/levels only until the end of bloom. Treatments in the field consisted of (1) 168 kg N/ha as NH4NO3 applied at initial bloom, (2) 168 kg N/ha at the end of bloom, and (3) 168 kg N/ha at both growth stages (total of 336 kg N/ha). The field experiments were conducted on a maury silt loam soil (Typic Paleudalts). Increasing the N supply to the plant during the period from initial bloom to the end of bloom increased yield 33% in the greenhouse and 28 to 32% in the field. Yields were not affected by high levels of N during the filling period. In the greenhouse experiment and one field experiment all of the yield increase resulted from an increase in seed per plant, which was due to an increase in the number of nodes and a reduction in flower and pod abortion. Flower abortion ranged from approximately 55% on the controls to approximately 45% on the treatments giving the maximum yield increase. In a second field experiment, the yield increase came partially from an increase in seed size and partially from an increase in seed number. The data demonstrate the importance of an adequate supply of N to the plant during the period of flowering and pod set for maximum yield.
Weed Control in Reduced Tillage Corn Production Systems1
Authors: Moomaw R. S. , Martin A. R. 
Published: July 2010

AbstractTill‐planting and slot‐planting are two reduced tillage corn (Zea mays L.) production systems used in Nebraska and other states. Farm operators frequently encounter existing weed populations at planting time with these systems when tillage does not precede the planting operation. Our research investigated weed control in tillplanted and slot‐planted corn with preplant translocated and contact herbicides, broadcast or band applications of preemergence herbicides, and a cultivation variable. Field experiments utilized previously undisturbed ridges of old corn rows for till‐planting or slot‐planting corn. Applications of 2,4‐D[(2,4‐dichlorophenoxy)acetic acid] ester and paraquat (l,l'‐dimethy 1‐4,4'‐bipyridinium ion) were used in combination with preemergence herbicide treatments that were either row banded or broadcast. One or two cultivations were imposed on the two tillage systems. Till‐planting resulted in more soil surface tillage and less dependence on herbicides than did slot‐planting. Maximum corn yield was achieved in the till‐plant system by row banding several preemergence herbicide treatments, coupled with one cultivation. Slot‐planting resulted in less soil disturbance with the planter than did till‐planting and required more herbicide usage. With slot‐planting, a preplant application of 2,4‐D was essential to remove the predominantly broadleaf weed population and maximize corn yields. When preplant 2,4‐D was used with slot‐planting, corn yields were not significantly different between band and broadcast applications of the preemergence herbicides used. Two cultivations rather than one tended to increase yields of slot‐planted corn.
Alfalfa Water Use and Production on Dryland and Irrigated Sandy Loam1
Authors: Bauder J. W. , Bauer A. , Ramirez J. M. , Cassel D. K. 
Published: July 2010

AbstractField studies were conducted during a 4‐year period to determine “Vernal“ alfalfa (Medicago satva L.) dry matter yield in response to irrigation and fertilization variables. In the Northern Great Plants alfalfa forage production contributes significantly to overall agricultural land use; consequently optimization of resources use is desirable. Limited available information has created a need for such research.This study was carried out on a Maddock sandy loam soil, a member of the sandy, mixed frigid Udorthentic Haploboralls. Four irrigation levels, ranging from dryland to excessive irrigation, were established as whole plots in a randomized block, split plot design. Eight different fertilizer treatments of P, K, and S were applied to split plots during the 1st year of the study. Under a three harvest per season management system dry matter yield was significantly affected by harvest number and irrigation treatment each year. Within the dryland and deficient irrigation treatment by year, yields decreased with each cutting; with optimum and excessive irrigation, yields varied inconstantly with cutting; yields increased 14 to 330% over dryland by increasing irrigation applications. Total seasonal crop water use, or evapotranspiration (ET), was determined using a water balance approach. Drainage (DRAIN) was calculated, using flux gradients calculated from tensiometer data, and appropriate soil properties. Other inputs, including irrigation (IRR), growing season precipitation (PPT), and soil water depletion (DEPL), were measured. In addition, water use efficiency (WUE) was calculated by treatment by year. Multiple linear regression analyses were used to relate actual dry matter yield (YIELD) and relative yield (RELY) to several independent variables. When plant water stress existed throughout the growing season, RELY correlated with relative evapotranspiration (RELET) in a near perfect, linear manner. Under nonstress conditions IRR, PPT, and DEPL required consideration to attain nearly perfect correlation of RELY with RELET. The results of this study indicate that under plant water stress conditions, alfalfa dry matter yield is a linear function of plant water use.
Relative Yield Totals and Yield Components of Intercropped Sorghum and Soybeans1
Authors: Wahua T. A. T. , Miller D. A. 
Published: July 2010

AbstractA 2‐year field study was conducted to determine how total grain yield per unit of land area could be maximized by intercropping sorghum (Sorghum bicolor (L.) Moench) and soybeans (Glyycine max (L.) Merrill). These two species are being intercropped more frequently through‐out the world to increase protein yield per unit of area and utilize available moisture. Grain yields, yield components, and relative yields were analyzed. Two sorghum cultivars, grain type ‘DeKalb BR‐44’ (semi‐dwarf) and dual purpose ‘DeKalb FS‐16’ (tall), were intercropped with soybean cultivars ‘Calland’ (Group III) (constant plant density) at 16 sorghum population densities, ranging from 1.38 to 33 plants/m2. The soil was a Flanagan series, a fine, montmorillonitic, mesic Aquic Argiudoll.Intercropping changed the response patterns of sorghum yield components as plant population changed and reduced yields of FS‐16 and BR‐44 by 14 and 74%, respectively. Sorghum yield components were reduced more in mixtures of BR‐44 than in mixtures of FS‐16; with number of heads per plant being the most affected. Intercropping also reduced the compensatory alterations in sorghum yield components as population changed. In mixtures, tillering ability and population density were the main determinants of grain yield.Highest yields in monoculture were obtained at densities higher than 25 plants/m2 for FS‐16. and between 12 and 15 plants/m2 for BR‐44. Grain yields of both sorghum cultivars increased linearly with increases in plant population in the mixture. lntercropping soybeans with FS‐16 and BR‐44 reduced soybean yields by 75 and 17%, respectively; primarily due to reduced pod number.Relative yield curves indicated that the highest relative yield totals might be obtained by planting soybeans 5 cm apart between rows of sorghum planted at a density of 5 plants/m2 at a spacing of 74 ✕ 74 cm.
Description of an Inexpensive Forage Sample Dryer1
Authors: Swain R. H. , Jones E. R. , Walpole E. W. 
Published: July 2010

AbstractForage sample dryers are often needed but may not be available in many outlying stations. The purpose of this paper is to describe a dryer design suitable for modest sized research programs or for use in remote locations. The dryer cabinet is 1.22 m2 × 2.44 m high with controls, blower, and air ducts mounted on the exterior of the cabinet. Design features include limited power surge, adaptability to various drying regimes, and use of readily available materials and limited construction skills. Approximately 175, 0.45 kg forage samples can be dried to constant weight in 72 hours.
Measuring Symbiotic Nitrogen Fixation in Rangeland Plots of Trifolium subterraneum L. and Bromus mollis L.1
Authors: Phillips Donald A. , Bennett James P. 
Published: July 2010

AbstractAccurate assessment of seasonal nitrogen fixation in improved rangeland is an important objective for researchers investigating N budgets and management impact. The 15N A‐value technique and the acetylene reduction method were compared for their accuracy in determining seasonal symbiotic N2 fixation on a ground area basis in rangeland plots of Trifolium subterraneum L. and Bromus mollis L. To simulate range management practices, seeds were planted at 10, 141, or 1970 seeds/m2 in pure stands or 50:50 mixtures in Laughlin loam, a member of the fine‐loamy, mixed, mesic family of Ultic Haploxerolls. Amounts of N2 fixed, calculated by the 15N A‐value technique, varied significantly with planting density and proportion of clover at different densities. Seasonal, symbiotic N2 fixation, calculated from the acetylene reduction method, did not vary significantly with either planting density or proportion of clover. It is concluded that with appropriate studies on possible differences in isotope accumulation by a grass and a legume, including morphological, physiological, and biochemical differences, the 15N A‐value technique should be more quantitative and discriminatory than the acetylene reduction technique. The single seasonal sampling requirement of the 15N A‐value technique also is more amenable to the overall goal of determining the effect of range management systems on symbiotic N2 fixation.
Effect of Soil Matric Potential and Seeding Depth on Emergence of Barley1
Authors: Sepaskhah A. R. , Ardekani E. Raessi 
Published: July 2010

AbstractAdequate crop stands resulting from vigorous seedling emergence is important for optimum crop production. Seedling emergence is usually influenced by soil water potential and seedling depth as well as other environmental factors. The effects of soil matric potential and seeding depth on emergence percent and rate of emergence of barley (Hordeum vulgare L.) were investigated. Seedling emergence of ‘Zarjo’ cultivar of barley was measured in a Calcixerollic Xerochrept soil at −0.6 to −30.0 bars soil matric potentials and at 2 to 12 cm seedling depths in the greenhouse. Cultivar response to seeding depth was determined by seedling emergence measurements of ‘Torsh’, Zarjo, and ‘Shaneii’ cultivars at seeding depths of 2 to 12 cm under the same experimental conditions. Soil matric potential of ‘30.0 bars reduced the seedling emergence of Zarjo and resulted in the lowest emergence rate. However, soil matric potentials of −0.6 and −1.5 bars also reduced Zarjo emergence at the 12‐cm seeding depth. Seedling emergence and emergence rate of Zarjo were lower at the 12 cm seeding depth at all levels of soil matric potentials. The emergence rate was also reduced at the 8‐cm seeding depth, but only at −30.0 bars. Seedling emergence of Shaneii was found to be lower than that of the Torsh and Zarjo cultivars. The rates of emergence of the cultivars were not greatly different at the various seeding depths.
Differential Tolerances of Turfgrass Cultivars to an Acid Soil High in Exchangeable Aluminum1
Authors: Murray J. J , Foy C. D 
Published: July 2010

AbstractSoil acidity is a major problem in establishing and maintaining turfgrass in many areas. Aluminum toxicity is probably the most important factor limiting growth of turfgrass in many, if not most, acid soils, particularly below pH 5.0. Liming turfgrass soils to pH 6.0, or higher, to detoxify Al, is not always economically feasible. A promising alternative or supplementary approach is to select or develop cultivars tolerant to Al. To explore the possibilities of this approach, 35 Kentucky bluegrass (Poa pratensis L.), 15 fineleaf fescue (Festuca rubra L.), and 6 tall fescue (Fescue arundinacea Schreb.) cultivars were grown in greenhouse pots containing 1.0 kg of Altoxic Tatum soil (clayey, mixed, thermic, typic, Hapludult) at two pH levels (pH 4.6 and 5.7 for bluegrasses and pH 4.3 and 5.7 for fescues). Relative top yields (pH 4.6/pH 5.7)% of Kentucky bluegrass cultivars ranged from 8.0% for ‘Windsor’ to 91.0% for ‘Fylking’; relative root yields ranged from 5.3% for ‘Kenblue’ to 101.8% for ‘Victa’. Relative top yields (pH 4.3/pH 5.7)% of fineleaf fescues ranged from 17.1% for common creeping to 91.1% for ‘Wintergreen’; however, 11 of the 15 cultivars studied made satisfactory growth at pH 4.3. Relative top yields (pH 4.3/pH 5.7)% of the tall fescues ranged from 1.8% for ‘Fawn’ to 35.4% for ‘Kentucky 31’. Within several tall fescue cultivars, individual plants (in the same pot of unlimed soil at pH 4.3) showed wide growth differences which were largely equalized by liming the soil to pH 5.7. Results of our studies suggest appreciable potential for selecting or developing turfgrass cultivars for greater tolerance to acid soil stress factors (particularly Al toxicity) that may not be economically correctable. Such cultivars would be deeper rooted and better adapted to low maintenance conditions.
Evaporative Flux from Irrigated Cotton as Related to Leaf Area Index, Soil Water, and Evaporative Demand1
Authors: Al‐Khafaf S. , Wierenga P. J. , Williams B. C. 
Published: July 2010

AbstractA simple, reliable method for predicting evapotranspiration (ET) for crops is needed. The purpose of this study was to formulate and test empirical relationships far estimating soil evaporation and transpiration based on evaporative demand and crop development with limiting and non‐limiting soil water regimes. The relationships were compared with evaporation and transpiration data for irrigated cotton (Gossypium hirsutum L.).Evaporation from the soil surface was determined by measuring diurnal changes in the surface soil‐water content and weight changes in embedded containers. Evapotranspiration was calculated from the quantity of irrigation water applied, rainfall, drainage, and changes in soil‐water content measured by the neutron scattering technique. Evaporation from the soil surface on the 1st day after irrigation (ESo) was related to potential evaporation (Eo) and leaf area index (LAI) as: ESo = Eo exp(−0.623 LAI). On successive days after irrigation, surface evaporation (ES) was computed as: ES = 5,8t0.6 − 5.8(t − l)0.6, where t is time in days. For transpiration on the day after irrigation (EPo), the following relationship was found: EPo = Eo(l − exp(−0.623 LAI)). l'or limiting soil‐water conditions, transpiration (EP) Mas computed with: EP = EPo/ (1 + 6.2 exp − 15.2 FAW), where FA W is the fraction of available water in soil. The results obtained with these equations agreed well with values for ES and EP measured in this study and with data presented by Ritchie (1972).
Value of Drip Irrigation Compared with Conventional Irrigation for Vegetable Production in a Hot Arid Climate1
Authors: Singh S. D. , Singh Panjab 
Published: July 2010

AbstractThe application of water by drip irrigation is a relatively new technique. Much remains to be learned about its effects on crops under soil and climatic conditions of hot desert areas. Studies were undertaken to evaluate the relative merits of water application by drip irrigation, overhead sprinkling, and furrow irrigation with respect to the yield potential and water‐use efficiency (WUE) of long gourd (Lagenaria siceraria (Molina) Standl.), ridge gourd (Luffa acutangula Roxb.), watermelon (Citrullus lanatus Thunb. Mansf.), and round gourd (Citrullus vulgaris var. Fistulossus (Stocks) Duthie and Fuller). The effects of daily water application by sprinkling (SP‐1) on the latter two crops were also evaluated. With drip irrigation and SP‐1, water was applied daily in amounts equal to 68% of the evaporation from a Class A pan. With furrow and overhead irrigation, water application commenced when the cumulative total of evapotranspiration reached 3.2 em.Drip irrigation increased the yield of long gourd by 45 to 47%, of round gourd by 21 to 38%, and of watermelon by 10 to 22% compared with sprinkler and furrow irrigation. All irrigation methods gave similar yields of ridge gourd. Thus, drip irrigation showed the potential to increase the yield of most, if not of all, vegetable crops. The water use efficiency with drip irrigation was nearly twice as high as with other methods of water application. Daily irrigation by sprinkling (SP‐1) on watermelon and round gourd decreased yields from 20 to 32% when compared with drip irrigation. Hence, on loamy sand soils in hot arid regions, daily irrigation is advantageous when the water is applied by drip irrigation but probably not when the water is applied by sprinkler irrigation.